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wii
A

MANUAL OF BOTANY

VOL. IT.

CLASSIFICATION AND PHYSIOLOGY
MANUAL OF BOTANY

so pv BY

J. REYNOLDS GREEN, 8c.D., F.R.S.,, F.L.S.

PROFESSOR OF BOTANY TO THE PHARMACEUTICAL SOCIETY OF GREAT BRITAIN
EXAMINER IN BOTANY TO THE UNIVERSITY OF LONDON AND THE VICTORIA
UNIVERSITY, THE PHARMACEUTICAL SOCIETY AND THE ROYAL COLLEGE
OF VETERINARY SURGEONS ; LATE EXAMINER IN BOTANY TO
THE UNIVERSITIES OF CAMBRIDGE AND GLASGOW

VOL. II.
CLASSIFICATION AND PuysioLocy

 

BASED UPON THE MANUAL OF THE LATE PROFESSOR BENTLEY

\

LONDON
I & A. CHURCHILL

7 GREAT MARLBOROUGH ST.
1896
CONTENTS

—eo+ —_

BOOK III.
SYSTEMATIC BOTANY,

OR THE CLASSIFICATION OF PLANTS.

CHAPTER I.

GENERAL PrIncIpLes or CLASSIFICATION

Species, genera, orders, and classes
Species .
Varieties
Races .
Genera if
Natural Orders
Classes é : ‘ : ;
Characters, nomenclature, abbreviations, and symbols
Characters .
Nomenclature
Abbreviations and symbols

CHAPTER II.

SysTEMs oF CLASSIFICATION

Artificial systems . A
System of Linneus
Natural systems .
System of Ray
Linneus
3 Jussieu .
De Candolle " :
, Endlicher . . c : - .

VAG

ro

woe

i

HH
enznuea

12

16
16
17
17
17
18
1s
21
vi MANUAL OF BOTANY

System of Lindley . .
ey Bentham and Hooker

3% Warming .
CHAPTER III.
THALLOPHYTA
Alge . é 7
Cyanophycee .
Diatomacere

Pheophycee or Melanophyeew
Rhodophycee or Floridee .
Chlorophycez E :
Fungi. . . .
Schizomycetes ki .
Myxomycetes .

Phycomycetes 5 . .
Ascomycetes. . ‘
Aicidiomycetes .
Basidiomycetes . 3 s
Classification of Brefeld .
Lichens . . . :

CHAPTER IV.

BRyorHYTA . .
Hepatice or Liverworts . : .
Musci or Mosses . 7 ‘
CHAPTER V.
PTERIDOPAYTA
Filicine =. . :

Isosporous leptosporengiats ferns
Isosporous eusporangiate ferns
Ophioglossacer i 7
Marattiacese . .
Heterosporous lepioenorangiats fare
Equisetine o .
Lycopodine . ‘
Isosporous Tiyeomodiens : ‘
Heterosporous Lycopodinse rs -

PAGE

24
a7

29

34
39
40
41
48
54
66
7A
76
V7
81
87
90
93
95

98

104
113

121

127
127
139
139
141
142
150
155
155
159
CONTENTS

CHAPTER VI.
SPERMAPHYTA or PHANEROGAMIA

Gymnosperme
Angiospermee
Monocotyledones
Series of
Natural Orders of ; ‘
Artificial analysis of Natural Cider :
Synopsis of British Natural Orders
Dicotyledones ;
Monochlamydex
Series of .
Polypetala
Thalamiflore
Cohorts of
Disciflore
Cohorts of
Calycifiore
Cohorts of ‘
Gamopetale or Corolliflors
Infere ‘
Cohorts of .
Supere or Heteromere
Cohorts of . ‘
Bicarpellate : ;
Cohorts of
Natural Orders of Monedidam yaar
Artificial analysis of Natural Orders
' Synopsis of British Natural Orders
Natural Orders of Thalamifiore
Artificial analysis of Natural Orders .
Synopsis of British Natural Orders
Natural Orders of Disciflore . 5
Artificial analysis of Natural Orders
Synopsis of British Natural Orders
Natural Orders of Calyciflore . :
Artificial analysis of Natural Orders .
Synopsis of British Natural Orders
Natural Orders of Corolliflore F
Artificial analysis of Natural Orders
Synopsis of British Natural Orders

vii

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174
181
188
188
190
219
222
224
224
224
226
226
226
228
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229
231
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258
262
263
300
304
305
328
331
331
361
365
366
402
405
viii MANUAL OF BOTANY

BOOK Iv.
PHYSIOLOGY OF PLANTS.

CHAPTER I.
Tue Rewation or WaTER To THE PROTOPLASM OF THE CELL

Arrangement of the protoplasm
Absorption of water
Osmosis . “
Influence of the proteplaem on osmosis
CHAPTER II.

Tue Transport oF THE WATER IN THE PLANT

Absorption of water from the soil .
Transport of water through the plant
Evaporation of water, or transpiration .

CHAPTER III.

Tur SKELETON oF THE PLANT

Arrangements to secure rigidity
Character of the cell-walls
Supporting tissues

CHAPTER IV.

Tue TRANSPIRATION CuRRENT—Root-PRESSURE— TRANSPIRATION

Path of the current
Root-pressure

Transpiration
CHAPTER VY.
Tue Foop or Puants. Intropuctory .
True nature of plant food . : : ‘
The materials from which it is eGtisinseted 5 ,

PAGE

409

410
411
411
412

416

416
418
419

423
420

421
423

431

431
432
CONTENTS ix

CHAPTER VI.

PAGE
Tur ABSORPTION oF Foop-maTERIALS BY A GREEN Puant 435

Substances absorbed . , , 7 5 3 ‘ . 485
Absorption from the soil . 3 F 2 - . 436
a a9 air. f i 5 é ‘ ‘ . 438

CHAPTER VII.

Tur CHLOROPLASTIDS AND THEIR Function . . 440

Properties of chlorophyll . : 3 oe - . 441
Formation of carbohydrates . A : . . . 442
3 proteids 5 . 444

CHAPTER VIII.

Reserve Mareriaus anp THEIR Deposirion . . 447
Removal of the surplus material constructed . . ‘ . 447
Path of the stream of elaborated products . : : . . 448
Formation of starch grains : 5 ‘ : : . 449
Other carbohydrate stores i ‘ . z 450
Aleurone grains. ‘ ; . ‘ : : . 451
Fats, oils, glucosides, &c. . $ ‘ ‘ : . . 452

CHAPTER IX.

Dicestion or Reserve MATERIALS . ‘ » 453

Nature of digestion : j : , 3 . 453

Enzymes or unorganised tena * : : 4 454

Digestive power of the protoplasm : : : . . 459
CHAPTER X.

Tur Catazotic Processes ‘ ‘ . 460

Nature of catabolism . : : ‘ . : ‘ . . 460

Secretion ‘ ‘ ‘ f 3 . ‘ 461
x MANUAL OF BOTANY

CHAPTER XI.

Tue REsPrrsrion oF Puants .

The absorption of oxygen by the plant
The nature of respiration :
Relation of respiration to caaioltam

CHAPTER XT.

GrowTH .

Nature of growth

Distribution of growth .

Growth of a cell a OR

Grand period of growth

Growth of a multicellular organ
Variations of turgidity during growth
Hyponasty and epinasty :
Nutation and cireumnutation
Tensions set up by growth

CHAPTER XIII.

INFLUENCE OF THE ENVIRONMENT ON PLANTS

Peculiarities of aquatic phanerogams
xerophilous plants
Alpine plants

ss epiphytes

parasites ‘
insectivorous plants

CHAPTER XIV.

Tue RevatTion oF THE Puanr ro irs ExvironmMEnt—
IeriraBiuity

Conditions under which oe is manifested .
Phototonus

Relation of plants to lich

Paraheliotropism

Epistrophe and apnetuaglis

Nyctitropic movements

Relation of plants to temperature.

PAGE
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465
466
469

470

471
472
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474
475
475
476
ATT

478

478
480
480
481
482
483

484

484
484
485
486
487
489
490
CONTENTS

CHAPTER XV.

SpeciaL SENSITIVENESS AND ITs RESULTS

Heliotropism
Geotropism
Contact .
Chemical stimuli

CHAPTER XVI.

Tur Nervous Mecuanism or Piants .

CHAPTER XVII.

AvuromaTismM—RayTHM

Automatic movements .

Ciliary motion

Creeping movements of My comveates .
Contractile vacuoles

Rotation of protoplasm .

Rhythmic movements

Periodicity i

Artificial rhythm

CHAPTER XVIII.

REPRODUCTION .

Vegetative reproduction “
Asexual reproduction by spores or sonia
Sexual reproduction by gametes
Alternation of generations .

Evolution of sexuality

Fertilisation

Pollination

Dichogamy

Diclinism

Dimorphism and Peiveotplitan ‘
Prepotency

Cleistogamy

Hybridisation

Germination of seeds : ‘
Apospory, apogamy, and parthenogenesis

xi

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513
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516
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519
520
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521
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521
522
523
MANUAL OF BOTANY.

2 2

BOOK III.

SYSTEMATIC BOTANY,
OR THE CLASSIFICATION OF PLANTS.

CHAPTER I.

GENERAL PRINCIPLES OF CLASSIFICATION.

Section 1.—Sprcins, GENERA, ORDERS, AND CLASSES.

Our attention has been hitherto directed to the examination of
the structure and shapes of the various organs and parts of
plants. In doing so, we cannot but have noticed the almost
infinite varieties of forms which have thus been presented to
us, and also at the same time observed that, notwithstanding
such variations, there are some striking resemblances in the
structure of the members of certain plants, by which a close
relationship is thus clearly indicated between them. It is the
object of Systematic Botany to take notice of such relation-
ships, and thus to bring plants together which are allied in
their forms and structure, and to separate those that are unlike ;
and in this way to take a comprehensive view of the whole
Vegetable Kingdom. In its extended sense, Systematic Botany
has for its object the naming, describing, and arranging of plants
in such a manner that we may readily ascertain their names,
and at the same time get an insight into their affinities and
general properties.

At the present time there are at least 120,000 species of

voL, Il. B
2 MANUAL OF BOTANY

plants known to exist on the earth. It is absolutely necessary

- therefore, for the purpose of study, or in order to obtain any
satisfactory knowledge of such a vast number of plants,
that we should arrange them according to some definite and
fixed rules; but before we proceed to describe the systems that
have been devised at various times for their arrangement, it
will be necessary to define the principal terms which are in
common use in such systems.

1. Specres.—By the term species we understand a collection
of individuals which resemble each other more nearly than they
resemble any other plants, so that we may infer that they have
all been derived originally from one common stock. Thus, if we
walk into a field of Beans, Peas. or Clover, we observe thousands
of individuals, which, although differing to a certain extent in
size, and in some other unimportant characters, we at once
associate together under a common name. In like manner we
commonly observe around us, in the gardens and fields, similar
collections of individuals. Such collections of plants, thus seen
to resemble one another in all their important parts, constitute
our first idea of a species; and that idea is at once confirmed if,
on propagating them, we obtain other plants exactly resembling
the parents. Species are, however, under special conditions,
liable to variations, and we have then formed what are termed
varieties and races.

a. Varieties or Sub-species.—It has just been observed that
if a species be propagated it will reproduce its parent, or,
in other words, produce a plant resembling its parent in all its
important parts. But this will only happen when the new in-
dividual has been exposed to the same influences of soil, heat,
light, moisture, and other conditions, as its parent; and hence
we find that variations in such particulars will lead to certain
peculiarities in form, colour, size, and other minor characters,
in the young plants. In this manner we have produced what
are termed varieties. In some cases such variations are
merely transient, and the individuals presenting such peculiari-
ties will in time return to their original specific type, or
perish altogether ; while in other instances they are permanent
and continue throughout the life of the individual, the whole
plant being, as it were, impregnated with the: particular
variations thus impressed upon it, and hence such variations
may be perpetuated by the gardener in the operations of
Budding, Grafting, &c., as is the ease with many of our fruit
trees and flowers. But even these varieties are not perma-
GENERAL PRINCIPLES OF CLASSIFICATION 38

nent; for the successive generations which will be produced
will have a tendency to revert to the original species from
which such varieties have been obtained, so that the nature
of the plant raised will depend upon the character of the soil
in which it is placed, and the other external conditions to
which it is exposed. Thus, if we sow the seeds of a num-
ber of different varieties of Apples, the fruit subsequently
produced by the new generation of Apple trees wil], instead of
resembling that of their parents, have a tendency to revert to
that of the common Crab, from which species all such varieties
have been originally derived. Hence a variety differs essen-
tially from a species in the fact that it cannot be propagated
without tending to revert to the type from which it sprang.

b. Races.—Besides the varieties just alluded to, there are
others, which are called permanent varieties or races, because
their peculiarities can be transmitted by seed. Familiar ex-
amples of such races are afforded by our Cereal grains, as Wheat,
Oats, and Barley ; and also by our culinary vegetables, as Peas,
Lettuces, Radishes, Cabbages, Cauliflowers, and Broccoli. How
such races of plants have originated, it is impossible to say with
any certainty. At the outset they probably arose in an ac-
cidental manner, for it is found that plants under cultivation
are liable to produce certain variations or abnormal deviations
from their specific type, or to sport, as it is termed. By further
cultivation under the care of the gardener, such variations are
after a time rendered permanent, and can be propagated by seed.
These so-called permanent varieties, however, if left to them-
selves, or if sown in poor soil, will soon lose their peculiarities,
and either perish, or return to their original specific type ; it will
be seen, therefore, that races present well-marked characters
by which they are distinguished from true species. Hence,
although our cereal grains and culinary vegetables have become
permanent varieties by ages of cultivation and by the skill of
the cultivator, they can only be made to continue in that state
by a resort to the same means, for if left to themselves they
would, as just observed, either perish or revert to their origi-
nal specific type; and hence we see also how important is the
assistance of the agriculturist and gardener in perpetuating and
improving such variations.

Another cause which leads to constant variations from the
specific type is hybridisation. The varieties thus formed, which
are called hybrids and cross-breeds, are, however, rarely constant
for long— although, in some instances, such is the case for a few

B2
4 MANUAL OF BOTANY

generations—but they gradually revert to one or the other
parent stock.

We have now seen that species, under certain circumstances,
are liable to variations, but that all such varieties have a ten-
dency to revert to their original specific type. Hence, from a
practical point of view, species must be considered as permanent
productions of Nature, which are capable of varying within
certain limits, but in no cases capable of being altered so as to
assume the characters of another species. There is not the
slightest foundation for the theory, which has been advocated
by some naturalists, of a transmutation of species. All such
statements, therefore, that have been made, of the conversion
of Oats into Rye, or of any species whatever into another, are
entirely without foundation, and have arisen from imperfect
observation.

In practice it is important that we should distinguish
varieties from true species, for nothing is so calculated to lead
to confusion in Descriptive Botany as the raising of mere
varieties to the condition of species. No individuals should be
considered as constituting a species unless they exhibit important
and permanent distinctive characters in a wild state. Great
uncertainty still prevails in our systematic works as to what is a
species and what is a variety; and hence we find different
authors, who have written on British and other plants, estimate
the number of species contained in such genera as Rosa, Rubus,
Saxifraga, Hieracium, Salix, Smilaz, and others, very
differently.

2. GENERA.—-The most superficial observer of plants will
have noticed that certain species are more nearly allied to each
other than to other species. Thus, the different kinds of Roses,
Brambles, Heaths, Willows, may be cited as familiar examples

such assemblages of species; for, although the plants com-
prehended under these names present certain well-marked dis-
tinctive characters, yet there are at the same time also striking
resemblances between them. Such assemblages of species are
called genera. A genus, therefore, is a collection of species
which resemble each other in general structure and appearance
more than they resemble any other species. Thus, the various
kinds of Brambles constitute one genus, the Roses another, the
Willows, Heaths, Clovers, and Oaks form also, in like manner,
as many different genera. The characters of a genus are taken
exclusively from the organs of reproduction, while those of a
species are derived generally from all parts of the plant; hence

a
GENERAL PRINCIPLES OF CLASSIFICATION 5

a genus is defined as a collection of species which resemble each
other in the structure and general characters of their organs of
reproduction. It is not necessary, however, that a genus should
contain a number of species, for, if a single species presents
peculiarities of a marked kind, it may of itself constitute a
genus,

It frequently happens that two or more species of a genus
have a more striking resemblance to each other in certain im-
portant characters than to other species of the same genus, in
which case they are grouped together into what is termed a sub-
genus, and further subdivisions of more nearly allied species,
such as sections, suwb-sections, &c., may be made.

3. ORDERS oR NaTuRAL ORDERS.—If we regard collections of
genera from the same point of view as we have just done
those of species,—that is, as to their close resemblances,—
we shall find that some of them also resemble each other
more than they do other genera. Thus, Mustards, Turnips,
Radishes, and Cabbages have a strong common resemblance,
while they are unlike Strawberries and Brambles, even less like
Hazels, Oaks, and Beeches, and still more unlike Larches,
Pines, Firs, and Cedars. Proceeding in this way throughout
the Vegetable Kingdom, we collect together allied genera, and
form them into groups of a higher order called Orders or Natural
Orders ; hence, while genera are collections of related species,
orders are collections of allied genera. Thus, Turnips, Radishes,
and Cabbages, all belong to different genera, but they agree in
their general structure, and are hence included in the order
Crucifere ; while Strawberries, Brambles, Roses, Apples, and
Plums, constitute different genera, but, from the general resem-
blance they bear to each other in their structure, they are placed
in one order, called Rosacea. Again: Oaks, Beeches, and Hazels
belong to different genera, but to one order; also the Pines
and Cedars are different genera, but as the fruit of them all is
a cone, they are grouped together in one order, which is termed
the Contfere.

We find also that certain genera of an order, like certain
species of a genus, have a more striking resemblance to each
other than to other genera of the same order; hence such are
grouped together into what are called Swb-orders. Thus the
Chicory, Dandelion, Sow-thistle, Lettuce, Thistle, Burdock, and
Chamomile, all belong to the same order, but there is a greater
resemblance in the Chicory, Dandelion, Sow-thistle, and Lettuce
to each other than to the Thistle and Burdock. Hence, while all
6 MANUAL OF BOTANY

the above genera belong to the order Composite, they are at the
same time placed in two different sub-orders. Thus, one sub-
order, called the Ligulzflore, includes the Chicory, Dandelion,
Sow-thistle, and Lettuce; and another sub-order, the Tubuli-
flore, that of the Thistle, Burdock, and Chamomile. In like
manner, while we find the Plum, Strawberry, Raspberry, Rose,
and Apple, all belonging to the same order Rosaceae, some of
them have more resemblance to each other than to others.
Thus, the Plum has a drupaceous fruit, and is therefore placed in
a distinet sub-order, which is called Drupacee ; the Strawberry,
Raspberry, and Rose are much more like each other than they
are like the Plum or Apple, and they are put in a sub-order
called Rose; while the Apple, from the character of its fruit,
is placed in a sub-order termed Pomee.

It is also found convenient to subdivide sub-orders into
Tribes, Sub-tribes, ke., by collecting together into groups
certain very nearly allied genera, but it is not necessary for
us to illustrate such divisions further, as the principles upon
which they depend have been now sufficiently treated of.

4, Cuasses.—By a class we understand a group of orders
possessing some very important structural characters in common.
Thus we have the classes Monocotyledones and Dicotyledones,
which possess certain distinctive characters in their respective
embryos, &e.

The Classes are also divided into Sub-classes, Series, Cohorts
or Alliances, and other divisions, in the same manner as the
orders, genera, and species are subdivided ; but as the names of
such divisions vary in different systems, and are all more or less
artificial, it is not necessary for us, in this place, to dwell
upon them further. The classes themselves, in different
systems, are also generally arranged in more comprehensive
groups, which have been variously named Swb-kingdoms,
Groups, Divisions, Regions, Sub-divisions, &c. But as these
are also of different extent and variously defined by botanists,
we must refer to the several systems for particulars respecting
them.

The following table will include all the more important
groups we have alluded to; those in more general use being
indicated by capitals.
GENERAL PRINCIPLES OF CLASSIFICATION 7

1. SuB-Krnepoms or Divisions.
Sub-divisions.
2. CLASSES.
Sub-classes.
Series.
Cohorts or Alliances.
3. ORDERS.
Sub-orders.
Tribes.
Sub-tribes.
4, GENERA.
Sub-genera.
Sections.
5. SPECIES.
Varieties.
Races.

Section 2.—-CHARAcTERS, NOMENCLATURE, ABBREVIATIONS,
AND SYMBOLS.

Descriptive Borany is the art of describing plants in tech-
nical language, so that they may be readily recognised when met
with by those to whom they were previously unknown, who pos-
sess a knowledge of the technical names of the different parts
and organs of plants and of their various modifications. This
subject is too extensive to be treated of here; reference must
be made to special treatises for this purpose ; but it is necessary
for us to refer briefly to the Characters, Nomenclature, Abbre-
viations, and Symbols of Plants.

1. CHaracTERS.—By the term ‘ character,’ we mean a list of
all the points by which any particular variety, species, sub-genus,
genus, sub-trobe, tribe, sub-order, order, sub-class, or class, &c., is
distinguished from another. We have also two kinds of characters,
which are called respectively essential and natural. By an essen-
tial character, we understand an enumeration of those points
only, by which any division of plants may be distinguished from
others of the same nature; such may be also called diagnostic
characters. A natural character, on the other hand, is a com-
plete description of a given species, genus, order, class, &c.,
including an account of every organ from the root upwards,
through the stem, leaves, flowers, fruit, and seed. Such cha-
racters are necessarily of great length, and are not required for
general diagnosis, although of great value when «a complete
8 MANUAL OF BOTANY

history of a plant or group is required. Those characters, again,
which refer to a species are called specific, and are taken gene-
rally from all the organs and parts of the plant, and relate
chiefly to their form, shape, surface, division, colour, dimension,
and duration; or, in other words, to characters of a superficial
nature, and without reference to their internal structure. The
characters of a genus are called generic, and are taken from the
organs of reproduction. The characters of an order are termed
ordinal, and are derived from the general structure of the plants
in such groups, more especially of the organs of reproduction ;
while the characters of a class, &c., as already mentioned, are
derived from certain important structural peculiarities which
the plants of such divisions exhibit.

2. NoMENCLATURE.—It is the object of nomenclature to lay
down rules for naming the various kinds of plants and the dif-
ferent groups into which they are arranged in our systems of
classification ; in the same manner as it is the object of termi-
nology to find names for the different organs of plants, and the
modifications which those organs present.

a. Species.—The names of the species are variously derived.
Thus the species of the genus Viola, as shown by Gray in the
following paragraphs, exhibit the origin of many such names.
‘Specific names sometimes distinguish the country which a
plant inhabits: for example, Viola canadensis, the Canadian
Violet; or the station where it naturally grows, as Viola
palustris, which is found in swamps, and Viola arvensis, in
fields; or they express some obvious character of the species,
as Viola rostrata, where the corolla bears a remarkably long
spur, Viola tricolor, which has tri-coloured flowers, Viola ro-
tundifolia, with rounded leaves, Viola lanceclata, with lanceolate
leaves, Viola pedata, with pedately-parted leaves, Viola primu-
lefolia, where the leaves are compared to those of a Primrose,
Viola asarifolia, where they are likened to those of Asarum,
Viola pubescens, which is hairy throughout, &. Frequently
the species bears the name of its discoverer or describer, as
Viola Muhlenbergit, Viola Nuttallii, &e.

Specific names are written after the generic, as indicated
above in the different species of the genus Viola, and these
together constitute the proper appellation of a plant, in the
same way as the surnames and christian names designate the
members of a family. The specific names should also in all
cases be adjectives or substantives used adjectively; in the
former case they should agree in gender and case with the name
GENERAL PRINCIPLES OF CLASSIFICATION 9

of the genus. Thus, when a speciesis named after its discoverer
or describer, it is usually placed in the genitive case, as Viola
Muhlenbergtiand V. Nuttall ; but when such names are merely
given in honour of botanists who have had nothing to do with
their discovery or description, the specific names are generally
put in the adjective form, as Carex Hookeriana, Veronica
Lindleyana : such a rule is, however, frequently departed from.
Sometimes the specific name is a noun, in which case it does
not necessarily agree with the genus in gender; such specific
names are often old generic ones, as Dictamnus Fraxinella, Rhus
Cotinus, Lythrum Salicaria, Rhus Coriaria, Dianthus Ar-
meria, Rhamnus Frangula. In such cases the specific name
should begin witha capital letter; a similar rule should also be
adopted when it is derived from a person; but in all other
instances it is better that the specific name should begin with a
small letter. The specific name was called by Linneus the
trivial name; thus, in the particular kind of Violet called Viola
palustris, Viola is the generic, and palustris the specific or
trivial name.

b. Genera.—The names of the genera are substantives, in
accordance with the rule laid down by Linneus as follows :—
Every species shall have a particular name, compounded of a
substantive and an adjective, whereof the former indicates the
genus, and the latter the species. This has already been re-
ferred to under the head of Species. The names of the genera
are derived in various ways: thus, either from the name of some
eminent botanist, as Linnza after Linneus, Smithia after Smith,
Hookeria after Hooker, Jussie after Jussieu, Tournefortia after
Tournefort, Lindleyana after Lindley ; or from some peculiarity
of structure or habit of the plants comprised in them, and from
various other circumstances. Thus, Crassula is derived from
the genus comprising plants with succulent or thickened leaves ;
Sagittaria, from its arrow-shaped leaves ; Arenaria, from grow-
ing in sandy places; Lithospermum, from its fruits (which were
formerly regarded as seeds) having a stony hardness; Campa-
nula, from its corolla being in the form of a bell; Lactwca, from
its milky juice; and so on. Others, again, have derived their
generic names from supposed medicinal properties, such as Scro-
phularia, from its former use in scrofula ; Pulmonaria, from its
employment in pulmonary disease, &c.

ce. Orders.—The names of the orders in the Artificial
System of Linneus are chiefly derived from the various charac-
ters of the gyneecium and fruit. Those of Natural Systems are
10 MANUAL OF BOTANY

usually taken from some well-known genus which is included
in any particular order, and which may be regarded as the type
of that order. Thus, the genus Ranunculus gives the name
Ranunculacee to the order to which it belongs; the genera
Papaver, Malva, Hypericum, Geranium, Rosa, Lilium, Orchis,
and Iris, in like manner, give names respectively to the orders
Papaveracee, Malvaceae, Hypericacea, Geraniacea, Rosacea,
Liliaceae, Orchidacee,and Iridacee. At other times the names
of the orders are derived from some characteristic feature which
the plants included in them present. Thus, the order Cruct-
fer@ is so named because its plants have cruciate corollas; the
order Leguminose because the fruit of its members is, with
few exceptions, a legume; the Umbellifere@ are umbel-bearing
plants; the Labiate have a labiate corolla; the Conifere are
cone-bearing plants; and so on.

d. Classes—The names of the classes are derived from
some important and permanent characters which the plants
comprised in them possess, relating either to their structure or
mode of development. Such names vary, however, according
to the views of different systematic botanists. Examples of
those which have been more commonly used in this coun-
try are Monocotyledones and Dicotyledones—terms which
are derived from the structure and characters of the reproductive
bodies in those classes respectively. The above names are used
especially in Natural Systems of Classification; while the
names of classes in the Artificial System of Linneus are derived
chiefly from the number and other characters presented by the
andreecium.

e. Sub-kingdoms, Divisions, dc.—The names of these are
generally derived from some well-marked peculiarity of typical
forms; thus we have the Bryophyta or Moss-like plants, the
Pteridophyta or Fern like plants, the Spermaphyta or plants
which produce seeds, sometimes called Phanerogamia because
their sporophylls are usually collected into evident flowers.
The other sub-divisions are variously named according to the
views of different botanists.

3. ABBREVIATIONS AND SyMBoLs.-—It is usual in botanical
works to use certain abbreviations and symbols. A few of the
more important need alone be mentioned here.

The names of authors, when of more than one syllable, are
commonly abbreviated by writing the first letter or syllable,
&e., as follows :—

L. or Linn. means Linneus; Juss.is the abbreviation for
GENERAL PRINCIPLES OF CLASSIFICATION 11

Jussieu ; DC. or De Cand. for De Candolle; Br. for Brown;
Lindl. for Lindley; Rich. for Richard; Willd. for Willdenow ;
Hook. for Hooker ; With. for Withering; Endl. for Endlicher ;
Bab. for Babington ; Berk. for Berkley, &c., &c.

It is common to put such abridged names after that of the
genus or species which has been described by them respectively.
Thus Hriocaulon, L. indicates that the genus Eriocaulon was
first described by Linneus; Miltonia, Lindl. is the genus Mil-
tonia as defined by Lindley ; Nuphar pumila, DC. is the species
of Nuphar defined by De Candolle, &e., &c.

Other abbreviations in common use are Rad. for root; Caul.
for stem ; Fl. for flower; Cal. for calyx; Cor. for corolla; Per.
for perianth ; Fr. for fruit; Ord. for order; Gen. for genus; Sp.
or Spec. for species; Var. for variety; Hab. for habitat; Herb.
for herbarium, &e.
12 MANUAL OF BOTANY

CHAPTER II.
SYSTEMS OF CLASSIFICATION.

We have already stated that Systematic Botany has for its
object the naming, describing, and arranging of plants in such a
manner that we may readily ascertain their names, and at the
same time get an insight into their affinities and general
properties. Every system that has been devised for the
arrangement of plants does not, however, comprise all the
above points; for, while some systems are of value simply for
affording us a ready means of ascertaining their names, others
not only do this, but at the same time give us a knowledge of
their affinities and properties. Hence we divide the different
systems of Classification under two heads; namely, Artificial
and Natural—the former only necessarily enabling us to
ascertain readily the name of a particular plant; while the
latter, if perfect, should comprise all the points which come
within the object of Systematic Botany. The great aim of the
Botanist, therefore, should be the development of a true
Natural System; but in past times, Artificial Systems, more
particularly that of Linneus, have been of great value.
Linneus himself never devised his system with any expectation
or desire of its serving more than a temporary purpose, or as an
introduction to the Natural System, when the materials for its
formation had been obtained.

In both artificial and natural systems, the lower divisions—
namely, the genera and species—are the same, the difference
between the systems consisting in the manner in which these
divisions are grouped into orders, classes, and other higher
groups. Thus in the Linnean and other artificial systems, one,
or, at most, a few characters are arbitrarily selected, and all the
plants in the Vegetable Kingdom are distributed under classes
and orders according to the correspondence or difference of the
several genera in such respects, no regard being had to any
other characters. The plants in the classes and orders of an
SYSTEMS OF CLASSIFICATION 13

artificial system have, therefore, no necessary agreement with
each other except in the characters selected for convenience as
the types of those divisions respectively. Hence such a system
may be compared to a dictionary, in which words are arranged,
for convenience of reference, in an alphabetical order, adjacent
words having no necessary agreement with each other, except
in commencing with the same letter. In the Natural System,
on the contrary, all the characters of the genera are taken into
consideration, and those are grouped together into orders which’
correspond in the greatest number of important characters ; and
the orders are again united, upon the same principles, into
groups of a higher order, namely, the classes and other divi-
sions. While it must be evident, therefore, that all the know-
ledge we necessarily gain by an artificial system is the name of
an unknown plant, on the other hand, by the natural system,
we learn not only the name, but also its relations to the plants
by which it is surrounded, and hence get a clue to its structure,
properties, and history. Thus, supposing we finda plant, and
wish to ascertain its name, if we turn to the Linnean System
and find that such a plant is the Menyanthes trifoliata, this
name is the whole amount of the knowledge we have gained;
but by turning to the Natural System instead, and finding that
our plant belongs to the order Gentianacee, we ascertain at
once from. its affinities that it probably has the tonic and
other properties which are possessed by the plants generally of
that order, and, at the same time, we also learn that it accords in
its structure with the same plants. It is quite true that all the
orders, as at present constituted, are by no means so natural
as that of the Gentianaceer, but this arises from the present
imperfection of our systems, and can only be remedied as
our knowledge of plants extends; a system, devised as per-
fectly as possible one day, may be deficient the next, in conse-
quence of new plants being discovered which may compel us to
alter our views, for at present the floras of many regions of the
globe are imperfectly known, and those of others almost entirely
unknown. Sufficient, however, is now known of plants to
enable us to establish certain great divisions according to a
natural method, which after discoveries are not likely to affect
to any important extent. The present imperfections of the
Natural System are, therefore, comparatively unimportant, and
will no doubt disappear as our knowledge of the flora of the
globe becomes extended.

Having now described the general characters upon which
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16 MANUAL OF BOTANY

the artificial and natural systems depend, and the particular
merits and disadvantages of the two kinds of system respec-
tively, we proceed in the next place to describe the mode
of construction of such systems, commencing with those of an
artificial nature, which, however, will be only treated of very
briefly.

Srectron 1.—ARTIFICIAL SYSTEMS OF CLASSIFICATION.

Tue first artificial system of any importance, of which we have
any particular record, is that of Cesalpinus, which was promul-
gated in 1583. Only 1520 plants were then known; and these
were distributed into fifteen classes, the characters of which were
chiefly derived from the fruit. The next systematic arrangement
of an artificial character was that of Morison, about the year
1670. He divided plants into eighteen classes, which were con-
structed according to the nature of the flower and fruit, and the
external appearance of the plants. The systems of Hermann and
others were also constructed upon somewhat similar principles,
while that of Camellus was framed from the characters presented
by the valves of the pericarp, and their number. In the system
of Rivinus, which was promulgated in the year 1690, plants were
divided into eighteen classes ; these were founded entirely upon
the corolla—its regularity or irregularity, and the number of its
parts being taken into consideration. The system of Christian
Knaut was but a slight alteration of that of Rivinus. That of
Tournefort, which was promulgated about the year 1695, was for
a considerable time the favourite system of all botanists. About
8,000 species of plants were then known, which were distributed
by Tournefort into twenty-two classes. He first arranged plants
in two divisions, one of which comprised herbs and wnder-shrubs,
and the other trees and shrubs: and each of these divisions was
then divided into classes, which were chiefly characterised ac-
cording to the form of the corolla. Many other systems were
devised which were simply alterations of the foregoing, as that
of Pontedera. Magnolius, however, framed a system entirely
on the calyx ; while Gleditsch attempted one in which the classes
were founded on the position of the stamens. All the above
systems were, without doubt, useful in their day, and paved the
way for the more comprehensive one of Linnzus.

Linnyan SystemM.—This celebrated system was first pro-
mulgated by Linneus in his ‘Systema Nature,’ published in
the year 1735; and although it was somewhat altered by subse-
SYSTEMS OF CLASSIFICATION 17

quent botanists, the Linnean System, in all its essential charac-
ters, was that devised by Linnzus himself; and although now
superseded by natural systems, it will be advisable for us to give
a general sketch of its principal characteristics.

The classes and orders in the Linnean System are taken ex-
clusively from the sporophylls; as these were considered to be
the sexual organs of the plant, this artificial scheme is commonly
termed the Sexual System.

The table (pp. 14 and 15) of the Classes and Orders of the
Linnean System will show at a glance their distinctive cha-
racteristics.

SEcTION 2..-NaTURAL SysSTEMS oF CLASSIFICATION.

The first attempt at arranging plants according to their
natural affinities was by our celebrated countryman, John Ray,
in the year 1682 ; and imperfect as any scheme must necessarily
have been at that day, when the number of plants known was
very limited, still his arrangement was in its leading divisions
correct, and has formed the foundation of all succeeding systems.
He divided plants thus :—

1. Flowerless.

2. Flowering ; these being again subdivided into
a. Dicotyledons.
6. Monocotyledons.

Ray still further grouped plants together into genera, which were
equivalent to our natural orders, many of which indicated a true
knowledge of natural affinities, and are substantially represented
at the present day by such natural orders as the Fungi, Musci,
Filices, Conifer, Labiate, Composite, Umbellifere, and Legu-
minose.

Tournefort, who flourished in France and was a contemporary
of Ray, was the first botanist to define genera as we now accept
them.

Next in order was the scheme propounded by the celebrated
author of the most perfect artificial system ever devised for the
arrangement of plants, namely, Linneus, who, about the year
1751, drew up a sketch of the natural aftinities of plants under
the name of Fragments. Many of the divisions thus prepared by
Linneus are identical with natural orders as at present defined,
among which we may mention Orchidee, Gramina, Composite
(nearly), Umbellate, Asperifolie, Papilionacee, Filices, Musci,
and Fungi.

VOL. Il. c
18 MANUAL OF BOTANY

Jussi£v’s NaTuRAL System.—To Antoine Laurent de Jussieu,
however, belongs the great merit of having first devised a com-
prehensive natural system. His method was first made known
in the year 1789. It was founded upon the systems of Ray and
Tournefort, to which he made some important additions, more
especially in considering the position of the stamens with respect
to the ovary. The following table, which requires no explana-

tion, represents his arrangement.
Class.
Acotyledons 1. Acotyledones.
Stamens hypogynous. 2. Monohypogyne.
Monocotyledons ! Stamens perigynous. 38. Monoperigyni.
( Stamens epigynous. 4. Monoepigyne.
‘Stamens epigynous. 5. Epistaminee.
Apetale | Stamens perigynous. 6. Peristaminez.
Stamens hypogynous. 7. Hypostamine.

Corolla hypogynous. 8. Hypocorolle.
Corolla perigynous. 9. Pericorolle.
10. Epicorolle Syn-
Monopetale anthere (anthers
| coherent).
Corolla epigynous. 11. Epicorolle Coris-
anthere (anthers

distinct).

Dicotyledons.

Petals epigynous. 12. Epipetale.
Polypetalie {eta hypogynous. 13. Hypopetale.

Petals perigynous. 14. Peripetale.
Diclines irregulares 15. Diclines.

 

Under these fifteen classes Jussieu arranged 100 natural
orders or families. This was the first natural arrangement in
which an attempt was made to assign characters to natural
orders, but so admirably were these drawn up, that they have
formed the basis of all succeeding systematists. Indeed, the
limits of a great many of Jussieu’s natural orders are identical
with those of the present day.

Dx CanDoLLe’s NaturaL SystemM.—The next system of note
after that of Jussieu was that of Augustin Pyramus de Candolle,
which was first promulgated in 1813, This system, modified,
however, in some important particulars, is that which is most
in use at the present day. In the first place, De Candolle
divided plants into two great divisions or sub-kingdoms, called

‘
SYSTEMS OF CLASSIFICATION 19

Vasculares or Cotyledonex, and Cellulares or Acotyledonex,
the characters of which he described as follows :—

Division 1. Vasculares, or Cotyledonew; that is, plants possessing
both cellular (parenchymatous) tissue and vessels ;
and having an embryo with one or more cotyledons.

Division 2. Cellulares, or Acotyledonea ; that is, plants composed
of cellular (parenchymatous) tissue only; and
whose embryo is not furnished with cotyledons.

The former division was again divided into two classes, called
Hxogen or Dicotyledone, and Endogene or Monocotyledonee,
the essential characters of which may be thus stated :—

Class 1. Hxogene, or Dicotyledonee ; that is, plants whose vessels
are arranged in concentric layers, of which the
youngest are the outermost and the softest; and
having an embryo with opposite or whorled cotyle-
dons.

Class 2. Endogene, or Monocotyledonee; that is, plants whose
vessels are arranged in bundles, the youngest being
in the middle of the trunk; and having an embryo
with solitary or alternate cotyledons.

These classes were again divided into sub-classes or groups.
Thus, under the Dicotyledonew were placed four groups, named
Thalamiflore, Calyciflore, Corollitlore, and Monochlamydex.
Under the Monocotyledonee two groups were placed, called
Phanerogame and Cryptogame. The latter group included
what are now called the Vascular Cryptogams, or Pteridophyta.
The Acotyledoneex were also divided into two groups, called
Folios and Aphylle. .

The following is a tabular view of De Candolle’s system.

Sub-Kingdom 1.—VascuLaREs, OR COTYLEDONER.

Class 1. Exogene, or Dicotyledonea.
{ Petals distinct, inserted with
Sub-Class 1. Thalamiflore | the stamens on the tha-
lamus.
Petals distinct or more or
less united, andinserted on
the calyx.

2. Calyciflore
ee united, and inserted

8. Corollflora on the thalamus.

Having only a single circle or
floral envelopes, or none.
C2

4. Monochlamydee
20 MANUAL OF BOTANY

Class 2. Endogene, or Monocotyledone.
Sub-Class 1. Phanerogame { es visible, regu-
eee hidden, un-

2. Cryptogame known, or irregular.

Sub-Kingdom 2. CELLULARES, OR ACOTYLEDONEA.
Having leaf-like expansions,
and known sexes.
Having no leaf-like expan-
2: Aphylia { sions, and no known sexes.

Under these sub-classes De Candolle arranged 161 Natural
Orders. The enumeration of these is unnecessary in an ele-
mentary volume ; we shall content ourselves with mentioning a
few only, as examples of the different groups. Thus, as exam-
ples of Thalamiflorae—Crucifere, Caryophyllee, and Malvacee ;
of Calyciflore—Rosacex, Umbellifere, and Composite ; of Corol-
liflore—Convolvulacee, Solanee, and Labiate ; of Monochla-
mydee—Polygonee, Urticer, and Amentacez ; of Phanerogamee
—Orchidex, Iridex, and Gramineex; of Cryptogama—Filices,
Equisetacee, and Lycopodinee ; of Foliose—Musci and Hepa-
tice ; and of Aphylle—Lichenes, Fungi, and Alge.

In this system it will be observed that De Candolle adopted
the primary divisions of Jussieu, but he reversed the order of
their arrangement; for instead of commencing with Acotyle-
dons, and passing through Monocotyledons to Dicotyledons, he
began with the latter, and proceeded by the Monocotyledons to
Acotyledons. He took a retrograde step in placing the Vascu-
lar Cryptogams with the Monocotyledons.

Since the appearance of De Candolle’s system numerous
other arrangements have been proposed by botanists, as those
of Agardh, Perleb, Dumortier, Bartling, Lindley, Schultz,
Endlicher, and many others. The important work of Robert
Brown dates from only a little later than this system of De
Candolle. In 1827 he published his discovery of the direct
action of the pollen tube on the nucellus of the ovule in
Conifere and Cycadee, which were at that time considered
to belong to the Dicotyledons. Thus began the division into
Gymnosperms and Angiosperms. At first both these were
held to be sections of Dicotyledons, and it was not understood
that the Gymmnosperms were a lower type. As all these systems,
with the exception of those of Lindley and Endlicher, were
never much used, and are not adopted in great systematic works

+  §ub-Class 1. Foliose |
SYSTEMS OF CLASSIFICATION 21

of the present day, it will be unnecessary for us to allude to
them further. But the latter having been used in important
systematic works, it will be advisable for us to give a general
sketch of their leading characters.

Enpuicuer’s Natura System.—The system of Endlicher
is adopted in his ‘Genera Plantarum,’ published between the
years 1886-1840. The following is a sketch of this system. He
first divided plants into two great divisions, which he denomi-
nated Regions, and named Thallophyta and Cormophyta.
These were again divided into Sections and Cohorts, as
follows :—

Region 1. THattoppyta. Plants with no opposition of stem
and root ; with no vessels and no sexual organs;
and with germinating spores lengthening in all
directions.

Section 1. Protophyta. Plants developed without soil;
drawing nourishment from the element in which
they grow; and having a vague fructification ;
as in Alge and Lichenes.

Section 2. Hysterophyta. Plants formed on languid or de-
caying organisms; nourished from a matrix; all
the organs developing at once, and perishing in
a definite manner ; as in Fungi.

Region 2. Cormoruyta. Plants with stem and root in opposite
directions; spiral vessels and sexual organs dis-
tinct in the more perfect.

Section 3. Acrobrya. Stem growing at the point only, the
lower part being unchanged, and only used for
conveying fluids.

Cohort 1. Anophyta. Having nospiral vessels; both sexes
perfect; spores free in spore-cases. Examples,
Hepatice and Musci.

Cohort 2. Protophyta. Having vascular bundles more or
less perfect; male sex absent. Spores free in
one- or many-celled spore-cases. Examples,
Filices and Equisetacece.

Cohort 3. Hysterophyta. Having perfect sexual organs ;
seeds without an embryo, polysporous; para-
sitic. Example, Rhizanthee.

Section 4. Amphibrya. Stem growing at the circumference.
Examples, Graminee, Liliacez, Iridacex, Orchi-
dace, and Palmacex,
22 MANUAL OF BOTANY

Section 5. Acramphibrya. Stem growing at both the apex
and circumference.

Cohort 1. Gymnosperme. Ovules naked, receiving im-
pregnation immediately by the micropyle ; as in
Conifers.

Cohort 2. Apetale. Calyx absent, rndimentary, or simple,
calycine or coloured, free or united to the
ovary. Examples, Cupulifere, Urticacee, and
Polygonez.

Cohort 8. Gamopetale. Both floral envelopes present, the
outer calycine, the inner corolline, the latter
being monopetalous; rarely abortive. Exam-
ples, Composite, Labiate, Scrophularinee,
and Ericacese.

Cohort 4. Dialypetale. Both floral envelopes present, the
outer being monosepalous or polysepalous,
free or united to the ovary, calycine or some-
times corolline ; the inner being corolline with
distinct petals, or rarely cohering by means of
the base of the stamens, and with an epigy-
nous, perigynous, or hypogynous insertion ;
rarely abortive. Examples, Umbellifere, Ra-
nunculacee, Crucifere, Caryophyllee, Rosa-
ce, and Leguminose.

Under these divisions Endlicher included 277 Natural
Orders. After Jussieu, he commenced with the simplest plants
and gradually proceeded to the more complicated, placing those
of the Leguminose at the highest point of the series.

Linpuey’s Naturau System.—To Lindley especially belongs
the merit of having been the first botanist who made any
serious attempt to introduce a natural arrangement of plants
into use in this country. The first system proposed by him in
1830 was but a slight modification of that of De Candolle. No
attempt was made in this system to form minor groups or
divisions of the tribes; but in 1833, in a new system, Lindley
arranged the natural orders in groups subordinate to the higher
divisions, which were called Nixus (tendencies). These primary
divisions were again divided into Sub-classes, Cohorts, and
Nixus or groups of nearly allied Natural Orders. In 1838,
Lindley again altered his arrangement so far as regarded
Exogens; and finally, in the year 1845, further modified his
views, and proposed the following scheme, which was that
adopted by him in his great work on ‘ The Vegetable Kingdom.’
SYSTEMS OF CLASSIFICATION 23

t

1, ASEXUAL, OR FLOWERLEsS PLANTS.

Stem and leaves undistinguishable . Class 1. Thallogens.
Stem and leaves distinguishable . . Class 2. Acrogens.

2. SExuaL, oR FLowerine Puants.

Fructification springing froma thallus Class 3. Rhizogens,
Fructification springing from a stem.
Wood of stem youngest in the
centre; cotyledon single.
Leaves parallel-veined, perma-
nent; wood of the stem always
confused : : . . Class 4. Endogens.
Leaves net-veined, deciduous ;
wood of the stem, when peren-
nial, arranged in a circle with
a central pith ; , . Class 5. Dictyogens.
Wood of stem youngest at the circum-
ference, always concentric ; co-
tyledons two or more.
Seeds quite naked . : . Class 6. Gymnogens.
Seeds enclosed in seed-vessels . Class 7. Exogens.

The Exogens were further divided into four sub-classes
thus :—

Sub-Class 1. Diclinous Exogens, or those with unisexual flowers,
and without any customary tendency to form
hermaphrodite flowers.

Sub-Class 2. Hypogynous Hxogens, or those with hermaphrodite
or polygamous flowers; and stamens entirely
free from the calyx and corolla.

Sub-Class 3. Perigynous Hxogens, or those with hermaphrodite
or polygamous flowers; and with the stamens
growing to the side of either the calyx or corolla ;
ovary superior, or nearly so.

Sub-Class 4. Epigynous Exogens, or those with hermaphrodite or
polygamous flowers, and wich the stamens grow-
ing to the side either of the calyx or corolla;
ovary inferior, or nearly so.

None of the other classes are divided into sub-classes, but
of Endogens four sections are distinguished thus :—
24 MANUAL OF BOTANY

1. Flowers glumaceous (that is to say, composed of bracts not
collected in true whorls, but consisting of imbricated
colourless or herbaceous scales).

2. Flowers petaloid, or furnished with a true calyx or corolla, or
with both, or absolutely naked ; unisexual (that is, having
sexes altogether in different flowers, without half-formed
rudiments of the absent sexes being present).

3. Flowers furnished with w true calyx and corolla; adherent to
the ovary ; hermaphrodite.

4. Flowers furnished with a true calyx and corolla, free from
the ovary ; hermaphrodite.

Under the above classes Lindley includes 808 Natural
Orders, which are arranged in fifty-six groups subordinate to
the sections, sub-classes, and classes, and which are termed
Alliances.

BENTHAM AND Hooxer’s System.—The essential features
of this system for the arrangement of the Phanerogamia, which
is adopted in their great work, ‘Genera Plantarum,’ are as
follows :—

Division I. PHAaNnsEROGAMIA,
Sub-division 1. ANGIOSPERMIA.
Class 1. Dicotyledones.
Sub-Class 1. PoLyPetTaLa.
Series 1. Thalamiflore.
2. Disciflore.
38. Calyciflore.
Sub-Class 2. GAMOPETALE or MoNnoPETALA.
Series 1. Infere or Epigyne.
2. Supere.
3. Dicarpee.
Sub-Class 3. MonocHLAMYDER or INCoMPLETAR.
Series 1. Curvembrye.
. Multiovulate aquatice.
. Multiovulate terrestres.
. Micrembrye.
. Daphnales.
. Achlamydosporez.
. Unisexuales.
. Ordines anomali.
Class 2. Monocotyledones.
Series 1. Microsperme.

9, Epigyne,

DADA WD
SYSTEMS OF CLASSIFICATION 25°

Series 3. Coronariex.
4, Calycine.
5. Nudifloree.
6. Apocarpe.
7. Glumacez.
Sub-division 2, GyMNOSPERMIA,

The series in the sub-classes Polypetale and Gamopetale of
the above system are further divided into Cohorts as follows: —

Sub-Class 1. Ponyprraua,
Series 1. Thalamiflore.
Cohort 1. Ranales.

. Parietales.
. Polygalinee.
. Caryophyllinez.
. Guttiferales.
. Malvales.
Series 2. Disciflore.
Cohort 1. Geraniales.
2. Olacales.
8. Celastrales.
4. Sapindales.
Series 8. Calyciflore.
Cohort 1. Rosales.
2. Myrtales.
8. Passiflorales.
4. Ficoidales.
5. Umbellales.
Sub-Class 2. GAMOPETALZE.
Series 1. Inferze or Epigyne.
Cohort 1. Rubiales.
2. Asterales.
8. Campanales.
Series 2. Superee.
Cohort 1. Ericales.
2. Primulales.
3. Ebenales.
Series 3. Dicarpee or Bicarpellate.
Cohort 1. Gentianales.
2. Polemoniales.
3... Personales.
4, Lamiales.

QoPr cD
26 MANUAL OF BOTANY

No division of the series of the Monochlamydee or of the
Monocotyledons is made in ‘Genera Plantarum ;’ but in the
English translation of Le Maout and Decaisne’s ‘ Traité Général
de Botanique,’ which was edited by Sir J. D. Hooker, another
classification of them is adopted as follows :-—

Sub-Class 3. MonocHLAMYDE2.
Division 1. Ovary superior (Super).
Cohort 1. Chenopodiales.
. Laurales.
. Daphnales.
. Urticales.
Amentales.
Euphorbiales.
. Piperales.
. Nepenthales.
Division 2. Ovary inferior (Infere).
Cohort 1. Asarales.
2. Quernales.
3. Santalales.

Class 2. Monocotyledones.
Division 1. Ovary inferior (Infere).
Cohort 1. Hydrales.
. Amomales.
. Orchidales.
. Taccales.
. Narcissales.
. Dioscorales.
Division 2. Ovary superior (Supera).
Sub-division 1. Ovary apocarpous (Apocarpe).
Cohort 1. Triurales.
2. Potamales.
Sub-division 2. Ovary syncarpous (Syncarpe).
Cohort 1. Palmales.
. Arales.
Liliales.
. Pontederales.
. Commelynales.
. Restiales.
. Glumales.

DAD ae wp

O oP wp

NA Qok wp

For full particulars in reference to this system, reference
should be made to Bentham and Hooker’s ‘ Genera Plantarum,’
SYSTEMS OF CLASSIFICATION 27

and to the English translation of Le Maout and Decaisne’s
‘ Traité Général de Botanique,’ edited by Sir J. D. Hooker.

Besides the above systems, others are now much used in
Germany, as those of A. Braun and Caruel of the Phanero-
gamia ; and those of Sachs and others of the Cryptogamia.

The most recent system is that put forward by Warming,
who divides the Gymnosperms into three classes instead of three
natural orders, viz. Conifer, Cycader, and Gnetacee. The
Angiosperms are then divided into Monocotyledons and Dicoty-
ledons. The sub-classes of De Candolle and his successors are
abandoned, and Dicotyledons are divided into (1) Choripetale,
with which are united the old Apetale, and (2) Sympetale. The
Choripetale are subdivided into twenty-five families; the Sym-
petale into two sections, Pentacyclice and Tetracyclice, the
former including three families and the latter eight, divided into
those with hypogynous and those with epigynous flowers.
Monocotyledons are grouped into seven families on somewhat
similar lines to those adopted in the older system of Braun,
already alluded to.

It will be seen that the Natural System now in use has been
gradually evolved through the working of many observers, ex-

- tending over many years. There is no reason to suppose that it
has yet attained anything like completeness ; indeed, many of
the groups are still variously placed by different botanists. For
the present, however, the Vegetable Kingdom may be con-
veniently divided into the following four groups :—

I. Taattopuyta, including the forms whose vegetative body
is commonly a thallus or a thalloid shoot. It rarely shows
greater morphological differentiation. The prominent form is
the gametophyte, the sporophyte not always occurring.

It is subdivided into:

Class 1. Alge.
» 2 Fungi.
» 98. Lichenes.

II. Bryopuyta, or Moss-like plants. The gametophyte is the
more prominent form, and regularly alternates with the sporo-
phyte. Differentiation of the body of the former into stem and
leaves is general, but the roots are rudimentary or absent.

It includes :

Class 4. Hepaticee.
» 5. Musei.
28 MANUAL OF BOTANY

III. Preriporxyta, or Fern-like plants. The sporophyte is
the prominent form, the gametophyte being small and not well
developed. Considerable differentiation of tissues is found in the
sporophyte, and its body exhibits stem, leaves, and roots.

It includes :

Class 6. Filicine.
» 7. Equisetine.
» 8. Lycopodine.

IV. SpeRMAPHYTA, or PHANEROGAMIA, including all plants
which produce seeds. The sporophyte is the predominant form.

The subdivisions are :

A. Gymnosperme.
Class 9. Gymnosperme.
B. Angiosperme.
Class 10. Monocotyledones.
» ll. Dicotyledones.
29

CHAPTER III.
Grovr I.
THALLOPHYTA.

Tuis group includes the Algwe, the Fungi, and the Lichens.
It embraces plants of widely different habit and complexity of
structure, both morphological and anatomical. In the lowest
forms they are characterised by extreme simplicity in both
these respects, the plant body being sometimes a single cell,
sometimes a thallus consisting of filaments or plates of cells.
In the higher forms, on the contrary, the plants are often bulky
and formed of masses of tissue showing some considerable histo-
logical differentiation; their form may display both root and
shoot, the latter exhibit-
ing stem and leaves. Again Fie. 779.
these bulky masses may ;
be distinctly thalloid.

The simplest Thallo-
phyte shows no histologi-
cal differentiation, being
only a single cell such as
Yeast, or Hematococcus. ot
Achain of cells like Nostoe ©, ad B
( Fig. 779) is almost as Fig, 779. ee sromy a Noses colony.
simple, though cells of
different appearance may be present in the chain. Usually
a filament of this kind has its cells independent, and sepa-
rated from each other by cell-walls. In a good many cases
these separating walls are not formed, and the organism consists
of a tubular body with an external wall, on the inner face
of which lie the constituent cells, whose protoplasm is con-
tinuous throughout. The composite nature of this structure
is recognised by the presence of numerous nuclei. A structure
like this is called a Cenocyte.

The filament in other cases is much like this, but some of

   
30 MANUAL OF BOTANY

the separating walls are present, so that the filament is divided
into a number of chambers, which are not cells but cenocytes.

This caenocytic structure may extend into some of the mor-
phologically most highly complex bodies. Thus the Alga
Caulerpa, which attains considerable size and whose body shows
rounded stems and much-divided leaves, is composed of only a
single coenocyte, whose cavity extends through all the ramifica-
tions of the plant. The Fungus Mucor mucedo shows a similar
structure (fig. 780).

In cases where the Thallophyte is composed of masses of

Fic. 780.

 

 

Fig, 780. Coenocyte of Mucor mucedo.

cells there may be considerable histological differentiation, or
there may be but little. In some of the brown seaweeds we find
a limiting layer, enclosing a very different internal tissue.
In some this is composed of elongated loosely arranged cells
with mucilaginous cell walls; in others it shows differentiation
into more complex structures. Thus in Macrocystis we find
under the epidermal layer a layer of thin-walled parenchyma
covering a layer of somewhat prosenchymatous cells with
thickened walls, sometimes with pits upon them. The inner
portion of this contains the well-marked sieve tubes already
referred to. Some of the large Alge of the same group as
THALLOPHYTA 31

Macrocystis, the Laminarias, show a secondary growth in
thickness of the stalk, the merismatic layer. being sometimes the
epidermal one, and sometimes one specially differentiated near
the periphery. In the latter case the growth in thickness re-
sembles that of Dracena, though the cells formed are different,
never becoming lignified nor truly vascular. There is formed
in some a kind of axial strand of elongated cells, which can
sometimes be traced upwards into the leaves. In some of the
plants of the same group certain secretory structures, the mucus
or gum passages, are differentiated. In the masses of tissue
constituting the so-called fructifications of the more bulky Fungi,
such as Agaricus, the structure is composed of filamentous cells
or hyphe arranged side by side and cohering together.

The differentiation of tissue leads also to the localisation of
the regions of growth. The growing points may be convex
or depressed, when they are apical ; or they may be intercalary.

The form in which the plant exists is always the gameto-
phyte. The sporophyte is either not produced at all, or it forms
only a small structure not detached from the gametophyte, and
sometimes consisting only of a single cell. In only a few cases
is it a separate structure. There is thus not that regular
alternation of generations which we have seen to exist in all the
forms above the Thallophytes, when sporophyte regularly gives
rise to gametophyte and is again reproduced from the latter. This
obtains, however, in some cases, particularly in the higher Alge.

The gametophyte in very many cases produces asexual as
well as sexual reproductive cells. Theseare in structure and mode
of behaviour almost exactly like the spores of the sporophyte.
To distinguish them from the latter they are often called gonidia.
In some eases both gonidia and gametes are borne upon the
same gametophyte;-in others the plant frequently produces
gonidia alone. A gametophyte in which no sexual cells arise is
spoken of as a potential one. In many cases a succession of
potential gametophytes occurs, each arising from one of the
gonidia of its parent, which succession is sooner or later
interrupted by one of the series producing sexual cells. Thus an
irregular alternation of generations arises, not between gameto-
phyte and sporophyte, but between actual and potential gameto-
phytes. This is spoken of as homologous alternation, to
distinguish it from the other kind, which is known as antt-
thetic.

A potential gametophyte must not be confused with a sporo-
phyte, though both bear only asexual reproductive cells. The

o
32 MANUAL OF BOTANY

former is capable of bearing sexual cells as well, under appro-
priate conditions; the latter is not.

As mentioned above, the result of the coalescence of two
gametes is sometimes the production of a sporophyte. Very
often, however, the process only gives rise to another gameto-
phyte.

The same plant body produces thus both sexual and asexual
cells. In this lowly class of plants the allotment of these two
varieties of reproductive structures each to its appropriate plant
body has not yet been reached.

Above this group each kind is found developed upon its
special form, and the two forms regularly alternate.

Fie. 781. Fie. 782,

 

Fig. 781. Vertical section of a female conceptacle of Fucus vesiculosus containing
oogonia and paraphyses. After Thuret.— Fig. 782. Oogonium with the oo-
spheres fully separated, and disengaging themselves from their coverings.
After Thuret.

The gametophyte is the dominant form in thegroup ; the com-
mencement of the development of the sporophyte is indicated in
the group of Algz by the zygospores of many Chlorophycex, which
produce two or four zoosporeson germination, and by the forma-
tion of the cystocarps or fruits of the red seaweeds; in the Fungi
by the behaviour of the zygote of the Myxochytridines which gives
rise to zoospores and that of Mucor which produces a rudimentary
mycelium, giving rise at once to a sporangium with its spores.

In the Thallophyta the differentiation of the sexual organs is
seldom very complex. Themalecells or antherozoids, orsperma-
tozoids, are usually developed in antheridia, often consisting of
THALLOPHYTA 33

single cells of the surface. In the Fungi the differentiation into
antherozoids, with one doubtful exception, does not take place,
and the male organ is only a swollen cell or branch of a hypha,
containing usually undifferentiated protoplasm. In most cases
the antherozoids are ciliated and consequently motile; in certain
groups of both Algse and Fungi they are non-motile. In thig
case they become sooner or later clothed with a cell-wall.

The female organ is usually an cogoniwm (fig. 782) consist-
ing of a single cell, often carried on a stalk, and containing one
or more oospheres. In other forms it is an archicarp (fig. 788)

Fra. 783.

 

Fy. 783. Section of thallus of a lichen, show-
ing archicarps, e, f— ig. 784. Procarp of
one of the Red Seaweeds. ¢r. Trichogyne.
sp. Spermatia, After Kny.

 

or procarpium (fig. 784) and does not contain any differentiated
oosphere.

The Thallophyta are divided into three classes, the Alge,
Fungi, and Lichens. The first contain chlorophyll, the second
do not. As aconsequence their habit of life is essentially dif-
ferent; the former can prepare food for themselves from the
constituents of the air and the medium in or on which they live ;
the latter are compelled to obtain them directly or indirectly
from other organisms. The members of the third class are

partly algal and partly fungal.

VOL. II.
84 MANUAL OF BOTANY

Crass I.—ALGA.

As we have already seen, there exists in this group a won-
derful variety of forms, ranging from single cells of microscopic
dimensions to immense plants showing both morphological and
anatomical differentiation. They are mainly aquatic in their habit,
being found in both fresh and salt water. Many of the humbler
of them occur not in water, but in moist situations, such as on
rocks, banks, tree trunks, &e. Some few forms are epiphytic,
living attached to other Algx by filamentous or more massive
outgrowths, which are embedded in the tissues of their hosts.
Though epiphytic they are usually not parasites.

They all contain colouring matters of some kind ; chlorophyll
is always present, but in some it is masked by the presence of
other pigments in the chromoplastids. We have blue-green,
green, brown and red Alg, and the distinguishing colouring
matters serve as a primary basis of classification in the group.

The forms that live in fresh water are chiefly green, though
there are among them a few red forms, and many which are
blue-green. A large number of microscopic forms, belonging to
the Diatoms, also inhabit fresh water. These are olive-brown
in colour.

The massive forms include representatives of all four colours :
their distribution bears a certain relationship to their hue.
Thus the seaweeds which are found near the limit of high-water
are green ; between high and low-water marks the olive-brown
forms are more prominent, while the red forms are also sparsely
represented in this area. Beyond low-water mark the olive-
green gradually give place to the red forms, and as the depth
increases the latter become predominant. They are seldom found
beyond a depth of 250 to 300 feet, so that the massive flora
oceupies a belt along the shore, extending from that depth to the
limit of high water. Some forms are attached to a substratum,
others float freely in the water.

The form which the adult plant exhibits is, as we have seen,
the gametophyte, either actual or potential. The sporophyte
rarely occurs, and then only in the higher members of the green
and red forms.

In histological differentiation the Alge are all very simple
as compared with the higher plants. Many of them are
THALLOPHYTA—ALGA 35

unicellular and multiply by ordinary fission; each cell-division
so produces a new plant. In others the cells do not separate from
each other, but the division proceeds until along filament of cells
is formed, each cell being generally physiologically independent,
though connected anatomically with the others. In other cases
the cells divide in two planes, forming a plate of cells. Some-
times the unicellular forms do not separate from each other
after division, but remain connected by a common mucilaginous
cell-wall, forming a colony or cenobium. In other Alge the
structure is a ccenocyte, no cell-walls being formed in the in-
terior of the filament, which thus appears unicellular. In the
larger ccenocytes, as Caulerpa, the cavity is often crossed by

Fic. 785.

   

ee AY
AT SCURAT I ARR

Fig. 785. Vertical section of a female couceptacle of /ucus vesiculosus con-
taining oogonia and paraphyses. After Thuret.

trabecule of modified cellulose. In the higher forms the plant is
multicellular, and shows a rudimentary differentiation of tissues ;
a kind of epidermis often being distinguishable from a central
tissue, which is sometimes furnished with sieve-tubes. In the
stalks of some Laminarias there is a secondary meristem which
increases the thickness of the part. In many of the Pheophycew
the internal cells are hypha-like, and loosely arranged with
mucilaginous walls and large intercellular spaces (fig. 785).
There is sometimes a fair amount of morphological differentia-
tion; generally the plant body is a thallus, but frequently
rudimentary roots can be distinguished, serving as organs of
attachment. The plant is often attached to its substratum by
n2
36 MANUAL OF BOTANY

special dises or outgrowths from the stem known as haptera.
The shoot in many cases may show ditferentiation into stem
and leaf, sometimes of very delicate form. Instances may be
found in Caulerpa, Chara, Sargassum, and others.

The mode of growth in length of the thallus or thalloid
shoot also varies a good deal. There are often definite growing
points, which may be either apical or intercalary. When they
are apical they sometimes consist of « simple apical cell, as
they do in the Ferns and their allies ; or they may be composed
of a number of cells. These may be disposed in a series along
the margin of the thallus, or may form a group resembling the
apical meristem of the Phanerogams. In the ccenocytes, though
these grow at their apices, no apical cell is differentiated. When
the growth in length is intercalary there is often a definite
growing zone in the frond, but sometimes this is not the case,
any cell being capable of division. Sometimes the growing point
consists of a terminal hair, or collection of hairs, the basal cells
of which are merismatic. In most filamentous forms, any cell
of the filament can divide, and so increase the length of the
filament.

Where secondary growth in thickness takes place it may be
brought about in two ways. In the stalks of some of the
Laminarias a secondary meristem or cambium is developed,
either in the epidermal cells or those immediately beneath them.
This behaves as in woody Dicotyledons, producing new tissue on
both sides. The external tissue forms a pseudo-bark or rind,
while the internal adds to the substance of the stalk. The
central stalk tissue is a dense plexus of filaments which anasto-
mose freely with each other. In Desmarestia a sort of mantle
or covering of the original axis is produced by filaments which
grow from the cells of the lateral branches originating just
below the growing point, which become united together and to
the original axis, subsequently undergoing differentiation with
cortical and internal tissues.

With the exception of the lowest group the colouring matters
are associated with definite chromatophores, which may occur
singly or in numbers in the cells. The pigments which are
formed are phycoerythrine in the red, phycoranthine and
phycopheine in the brown, and phycocyanine in the blue-green
Alge. Besides these, all the members of the group contain
chlorophyll, which is the only colouring matter in the green
forms. The other pigments may be extracted by fresh cold
water, which dissolves all but the chlorophyll. The disposition
THALLOPHYTA—ALGE 37

of the chromatophores is very constant in the several species.
In some of them curious bodies called pyrenoids are found,
which are probably connected with the assimilative processes.
The group exhibits considerable variety in its modes of sexual
reproduction. In the simplest forms that show sexuality, the
gametes are not distinguishable into male and female. In
Ulothrix (fig. 803) the contents of some cells break up into a
number of ciliated masses of protoplasm which escape from
the cell,-and, after swimming about for a while, conjugate in
pairs. In the Zygnemee and Mesocarpee the gametes are
solitary and not motile, and do not escape from the cells in

Fic. 787.

Fie. 786.

Fic. 788.

   

Fig. 786. Antheridia, a, a, on the branched hairs of the male conceptacle.
After Thuret.—/ig. 787. Oogonium with the oospheres fully separated,
and disengaging themselves from their coverings. After Thuret.—
Fig.788. An oosphere without a cellulose coat being fertilised by authe-
rozoids so as to form an oospore.

which they are formed. In Cutleria the gametes are dissimilar
in size, but both are ciliated. The larger comes to rest soonest,
and one of the smaller fuses with it. More completely differen-
tiated gametes are found in higher forms (figs. 787 and 789) ;
oospheres are developed in oogonia and antherozoids in an-
theridia. When the gametes are alike the reproduction is called
isogamous ; when they are different in size and behaviour it is
said to be oogamous. In the Rhodophyce the antherozoid is
not ciliated and there is no differentiated oosphere. Instead of an
oogonium the female organ is known as a carpogonium. It is
frequently multicellular, and fertilisation is brought about
through a filiform or elongated cell known as a trichogyne.
38 MANUAL OF BOTANY

The asexual reproductive cells are frequently borne upon
the gametophyte. They may be ciliated cells, differing but

Fic. 789.

 

Fig. 789. A. sp. Newly formed zoospore or zoogonidium of Vaucheria
sessilis escaping. 3B. Zoospore at rest after having lost its cilia.
c. First stage of germination. p. Filament of Vaucheria sessilis pro-
ducing oogonia, og, eg, and antheridium, 2. w. Hyaline root-like
process, forming a sort of mycelium, sg. Zoospore, which by germinating
has formed the filament. After Sachs.

     

-*P. little, if at all, in appearance from
the gametes. These are known as
zoogonidia, from their power of move-
ment. In other cases they are non-
jr, motile. They are at first always
j naked cells. Sometimes they are
developed in special organs, the goni-
pr dangia; in some forms any cell of
the thallus may produce them.
Where the sporophyte exists it gives
rise to spores similar in structure to
the gonidia. In many of the green
Algz the zygospore or oospore gives
rise to a number of zoospores, either
with or without preliminary cell-divi-
sion. It must in such cases be re-
garded as a very rudimentary sporo-
phyte.

F 1.790.

Fig. 790. Procarp of one af the Vegetative reproduction is very
Red Seaweeds. ¢7. Trichogyne. i ac
sp. Spermatia, After Knv. common in the lower forms; in the

unicellular Alge, each cell-division is
often followed by a separation of the cells, showing thus the
simplest example of this mode. In Sphacelaria, gemme are
THALLOPHYTA—ALGA 39

produced which are multicellular. Chara gives rise also to
peculiar structures, the embryonic branches, which are referable
to this mode of reproduction.

The main sub-divisions of the Alge are based upon the colour
of the thallus. This distinction would be of little value in itself,
but the groups so defined show peculiarities of form and of life
history which warrant their being considered as sub-classes.
The divisions are Cyanophycee (blue green), Chlorophycexe
(green), Phzophycee, and Diatomacer (olive-brown), and
Rhodophycee (red).

Sub-Class I.—CyaNoPHYCE.

The forms presented by the members of this group are very
simple. In many cases the plant is unicellular, or if it divides,
the products of the division remain surrounded by a common
cell-wall, which becomes mucilaginous and of considerable thick-
ness, so that the cells appear as if embedded in a mass of jelly.
The plane of division may be such as to cause the cells to
form a flat plate, or 4 mass more than one cell in thickness
may result. In other cases the cells divide so as to form a
filament, often of some length, sometimes tapering at its apex,
which may be either free or attached at its base to some substra-
tum. Many filaments usually are collected together, so that
the plant appears in tufts. This filamentous form is also invested
with a sheath, of similar consistence to that in the former case.
The sheath is often coloured with various tints, purple, blueish,
or red. The cells are not ciliated, but the filaments are capable
of a peculiar swaying movement, the mechanism of which is not
known. The cells are in all cases of very simple structure ; no
nucleus has been satisfactorily shown to exist, and the phyco-
cyanin or blue-green colouring matter is diffused through the
protoplasm ; no chromoplastids have been found. The cell-wall
has been stated to be formed of w substance resembling cutin,
while the sheath is always cellulose, or a modification of it. The
reproductive processes are chiefly vegetative; the filaments split
up into fragments, which, after a period of inactivity, grow out
into filaments like their parent. These fragments, which consist
of several cells, are called hormogonia. In one section of the
sub-class, to which Nostoc belongs, the cells of the filament are
of two kinds (fig. 791); here and there in the course of the fila-
ment large, almost spherical clear cells appear, which are named
heterocysts. These mark the limits of the hormogonia.

The filament sometimes branches, either regularly by the,
40 MANUAL OF BOTANY

formation of growing points placed laterally, or irregularly often
by the hormogonia not becoming completely detached, and so
growing while adhering to the filament.

In many forms spores are produced. These are single cells
of the filament or mass, which are rounded in shape, larger than

the other cells, and fur-

Fie. 791. nished with a _ strong

c thickened cell-wall. They

become detached from the

plant, and are capable of

resting for some time be-

fore germinating. In the

filamentous forms, when

germination takes place,

the wall of the spore cracks

Fig. 791, Filaments from a Nostoe colony. and cell-divisions take

After Luerssen. place in the cell in such

order that a filament is

produced much resembling an ordinary hormogonium, which

becomes set free from the spore-coating and develops into the

plant. In the other forms, the divisions of the germinating spore

are irregular and give rise to a mass of cells. Sexual reproduc-
tion is unknown in the group.

In habit, some of the Cyanophycee are free floating or-
ganisms ; others are attached by their bases to rocks or stones.
Some are embedded by their gelatinous coatings to form colonies
of various shapes. Some are endophytic and live symbiotically
with other plants. Thus Nostoc is frequently found associated
with a fungus in the thallus of alichen ; it occurs, too, in cavities
in the thallus of Azolla and in the body of Anthoceros. Others
again are epiphytic, bormg into the tissue of other Alge and
remaining attached tothem. A few of them, chiefly abundant in
hot springs, are covered with a precipitate or pellicle of carbonate
of calcium, which may wrap round the individual filaments, or
enclose the whole thallus.

Jom

   

Sub-Class II.—D1atomacem.

These plants have often been included in the next sub-class,
the Pheophycee, on account of their olive-brown colour. They
are, however, so unlike them in every other respect, while they
present no very great resemblance to any other group of Alge,
that it seems best to regard them as a separate sub-class.
THALLOPHYTA—ALGA 41

They are both fresh-water and marine in their habit, and are
extremely numerous wherever they occur.

Diatoms are unicellular plants, of very minute size, which
have their cell-walls strongly impregnated with silica, the mark-
ings upon the walls often being of great regularity and beauty.
The plants may be free, or a number of them may be grouped
together. In the latter case the colony may consist of a chain of
cells, or they may be aggregated together upon gelatinous stalks,
or may form gelatinous masses. Each diatom consists of a proto-
plasmic cell or frustule which is encased in two silicified shells
known as valves, one of which overlaps the other by its edges.
The peculiar sculpturing is found upon the flattened face of each
valve. The plant is not furnished with cilia, but is nevertheless
capable ofa peculiar gliding movement through the water, the
nature of which is at present unexplained. The colouring inatter
is deposited in chromatophores of more or less regular form, and
is not diffused through the protoplasm as in the preceding group.

The diatoms frequently undergo longitudinal fission ; the two
valves slightly separate ; the protoplasm divides, and each half
secretes a new valve between itself and its fellow, which has its
edges included under the rim of the old valve. The two valves
of a diatom are thus of different ages. In the free forms this
process of fission increases the number of the individuals; in
those which continue attached it recalls the processes of inter-
calary growth.

This repeated bi-partition gradually reduces the size of the
diatoms, each new valve being necessarily a little smaller than
the one which overlaps it. When a certain limit of size is reached
another method of reproduction occurs, which is in some cases a
sexual one. This is the formation of awxospores. The contents
of two diatoms escape from their containing valves and unite
together, growing into a new plant which secretes a pair of
valves like those of the original cells. In some cases the process
is asexual; the contents of a cell escape and grow; on a con-
siderable size being attained, new valves are secreted by the
protoplasm and the original appearance is resumed.

Certain modifications of both these methods occasionally
occur.

Sub-Class III.—Pumornyce®, or Melanophycer.

This sub-class includes those Algze which are of an olive-
brown or olive-green colour, with the exception of the Diato-
macee. Its members comprise forms of very great variety,
42 MANUAL OF BOTANY

some being microscopic while others have a plant body several
hundreds of feet in length and of considerable thickness. In
the simplest cases the body is unicellular, or forms a colony
resembling that of many of the Cyanophycesw. The colony may
be attached or not. In other cases the plants, which vary a
good deal in size, are attached to rocks by specially differentiated
roots, or by haptera. Epiphytic forms occur, filamentous
patches being seen upon other Alge; these are the free por-
tions of the epiphyte, rhizoidal appendages having penetrated
the tissues of the host.

The brown colouring matter, which is a mixture of phyco-
pheine and phycoxanthine, is localised in definite plastids or
chromatophores, instead of being diffused through the proto-
plasm of the cells. The anatomical or histological differentia-
tion is sometimes considerable, a great variety of tissues being
found in the thallus.

Asexual reproductive cells are found in some of the members
of this sub-class, which may be spores or gonidia; sometimes
these are motile, sometimes not. Some members of the group
possess only sexual reproductive cells.

The sexual organs are sometimes antheridia, containing
antherozotds, and oogonia, producing oospheres. Fertilisation
never takes place in the oogonia, the gametes of both sexes being
discharged with the water. The antherozoids are ciliated, the
cilia being two in number, attached at the side of the gamete
and pointing one towards each end.

More frequently the gametes are alike, or nearly so, when the
organ producing them is called a gametangiwm. They are then
always ciliated. i

The oogonium is always unicellular and produces one or
several oospheres; the antheridium may be unicellular or
multicellular. In the latter case each cell produces only a
single antherozoid.

There is a good deal of variety in the morphological differ-
entiation of the group. Some show only a thallus; others
present the appearance of root and shoot, and in many the latter
is distinctly leafy. In some, special branches bear the reproduc-
tive organs.

Alternation of generations can only be traced in some forms ;
the sporophyte phase is generally absent; it is represented in
some of the Cutleriacez, though sometimes the two forms are
very similar in appearance and can only be distinguished by
noticing what kind of reproductive cells they respectively produce.
THALLOPHYTA—ALGA 48

The sub-divisions of the group are very difficult to define,
and many schemes of classification have been suggested.

Several different types may with advantage be considered.
Of these the Fucaczm are most familiar. The thallus is
generally of large size and shows a copious branching. In
Cystosevra and other genera the shoot can be seen to be divided
into stem and leaves. Sargasswm exhibits also the fruiting
branches spoken of above. The branches of the thalloid shoot,
or the leaves of the leafy forms, often exhibit curious air-
chambers which serve as floats. The plants are often attached
to the substratum by suckers, or by haptera. The epiphytic
forms are secured to their hosts by haustoria, which penetrate
the tissues of the latter.

The thallus generally shows histological differentiation.
There is an external rind of closely packed cells, in which the
colouring matter is abundant. This constitutes a pseudo-
epidermis. The innermost layer of this tissue is capable of
increasing the thickness of the shoot by repeated tangential
divisions, forming in some cases almost a rudimentary bark.
Beneath this layer is some thick-walled parenchyma ; and this
covers in turn a central strand, often of considerable dimensions.
The cells of this strand are elongated and narrow, and have
their longitudinal walls pitted. They do not, however, become
woody, but their walls are usually mucilaginous and much
swollen.

Growth in length is carried out by means of an apical cell,
which is placed at the bottom of a pit or depression at the apex
(fig. 792). The branching may be lateral or dichotomous.

The reproductive organs are variously situated, but always
occur in peculiar depressions of the surface known as con-
ceptacles ( fig. 793 t). These are nearly globular cavities in the
thallus which open to the surface by small pores or apertures
known as ostioles. They are developed near the growing point.
One or more cells cease to grow, and by the continued increase
in size and number of those adjoining them a pit is formed
which becomes ultimately the cavity of the conceptacle. The
distribution of the sexual organs in the conceptacles varies in
different species. In some, antheridia or oogonia arise in each ;
in others the same conceptacle may contain both.

The cells at the bottom of the conceptacle grow out into hairs,
from some of which the sexual organs arise. The antheridia
are formed in great numbers as the terminal cells of branches
of these hairs (fig. 795). Each produces a number of bi-ciliated
44 MANUAL OF BOTANY

antherozoids, which are sometimes discharged into the con-
ceptacle and make their way out through the ostiole. In
other cases the antheridia are detached unruptured and escape
from the conceptacle, the antherozoids being subsequently
liberated.

The oogonia arise from two-celled hairs, of which the upper
cell only gives rise to the sexual organ, the lower one forming a
stalk to it (fig. 794). Each oogonium develops usually eight
oospheres, of generally spherical shape and having no cilia. The
wall of the oogonium is composed of two layers, and when the
oospheres are mature the outer layer bursts (fig. 796), and the

Fie. 792. Fie. 793.

 

Fig. 792. Growing point of Pelvetia. a. Apical cell. After Kny.—§Jlig.
793. Thallus or thallome of the common Bladder Seaweed (/ucus vesiculo-
sus). t,t Groups of conceptacles. », v. Bladders of air.

inner one, covering the oospheres, is extruded. When this bursts
later the latter are set free into the water. Fertilisation always
takes place outside the conceptacle, each oosphere becoming
surrounded by a number of the ciliated antherozoids (jig. 797),
one of which ultimately fuses with it, forming the oospore or
zygote, which then secretes for itself a cellulose covering. The
zygote generally germinates at once.

Besides the sexual organs the conceptacles contain a number
of barren hairs or paraphyses (jig. 794), which frequently are so
numerous towards the top of the cavity as to protrude through
the ostiole.
THALLOPHYTA—ALGA ‘ 45

Certain conceptacles in some of the Fucacex do not give rise
to sexual organs. These are generally known as cryptostomata.

Fic. 794.

 

Fre. 796,

Fie. 797.

   

Fig. 794. Vertical section of a female conceptacle of Fucus vesiculosus con-
taining oogonia and paraphyses. After Thuret.— /Jig. 795, Antheridia,
a, a,on the branched hairs of the male conceptacle. After Thuret.——
Fig. 796. Oogonium with the oospheres fully separated, and disengaging
themselves from their coverings. After Thuret.—/ig. 797. An oosphere
without a cellulose coat being fertilised by antherozoids so as to form an
oospore.

These cavities contain only paraphyses, which are of greater
length than those in the fertile conceptacles.
The Lamrnariace@ afford examples of the largest Alge of the
46 MANUAL OF BOTANY

Pheophycee ; they show a good deal of variety of form, including
long unbranched fronds terminating below in a thick stalk, as
well as stems which bear a series of much and variously divided
leaves. In some the stalk is so short and covered by rootlets,
while the fronds are so long, that a single plant appears like a
group of the unbranched forms. On the stalk, in some cases,
gonidiophylls are developed in addition to the ordinary fronds,
their development being acropetal. In some of the fronds
midribs and subordinate veins appear, giving them a very leaf-
like appearance. A few forms possess air-floats, something like
those of the Fucacee. The stem or stalk terminates below in
strong rootlets or haptera, which fasten the plant to a substratum
of rock or stone.

The thallus shows still more complete histological differentia-
tion than that of the Fucacee. The stalk shows epidermal,
cortical, and medullary tissue. The epidermal layer often be-
comes merismatic, though in many species the meristem is found
in the peripheral part of the cortex. This merismatic layer is
often very active and causes the stalk to become of consider-
able thickness. Like most merismatic layers, it forms new
tissue on both its faces. The inner portion of the cortex
in the stalk consists of a layer or cylinder of elongated cells
whose walls are generally pitted. In Macrocystis it contains
the peculiar sieve-tubes of which mention has already been
made.

The central strand is something like that of the larger
Fucacee, consisting of hypha-like filaments which anastomose
copiously. This layer is continued upwards into the fronds.

The mucus passages already alluded to are only found in
some of the Laminariacee. They are long tubes which branch
and anastomose, forming a network in the tissue.

The growing point is sometimes apical, sometimes inter-
calary.

The reproductive organs are not produced in conceptacles
but in sori, variously distributed over the fronds, but sometimes
confined to definite sporophylls. Each sorus consists of a
number of unilocular gonidangia, among which are found
paraphyses. The gonidangia give rise to ciliated zoogonidia or
zoospores. Some of the genera possess cryptostomata, which
bear paraphyses as in the Fucacee.

The genus Splachnidium appears to occupy an intermediate
position between Fucacee and Laminariacee. It is peculiar in
that it bears sporangia or gonidangia resembling those of the
THALLOPHYTA—ALGA 47

latter group, which are developed, not in sori, but in conceptacles
much like those of Fucus.

The CUTLERIACE# have w special interest as illustrating the
evolution of sex in the Phzeophyces. They possess two kinds of
gametes which are both ciliated, the female, generally called
oospheres, being much larger than the male. The organs in
which they arise are situated in sori on the surface of the
thallus, and the gametes are set free by a lateral aperture in the
wall. When they are liberated both kinds are freely motile ;
the female comes soonest to rest, and is fertilised by the fusion
of an antherozoid with it.

The thallus is sometimes erect and sometimes prostrate. It
grows by means of a cluster of hairs, the bases of which are
merismatic. The rows of cells produced from each hair become
united together laterally to form the tissue of the thallus.

The differentiation of the internal tissue is not so complete
as in the other groups described. In Cutleria itself three sys-
tems can be seen; the epidermal layer, which contains chromo-
plastids in abundance, a cortical layer, of clearer cells in
which a little colouring matter is present, and an axial layer of
larger cells, almost colourless. All the cells are parenchymatous,
the pseudo-vessels of the former groups not being represented.

Asexual reproductive structures are met with in the Cut-
leriaciz, which take the form of unilocular sporangia, each con-
taining several zoospores. These resemble the gametes in
being ciliated, but they are intermediate in size between the
antherozoids and the oospheres. In the genus Cutleria these
are borne upon the young plant produced from the germinating
‘zygote. The form of this sporophyte differs considerably from
the thallus which bears the sexual cells. There is thus in
Cutleria an alternation of generations. In the other genus of
the group, Zanardinia, the two forms are essentially similar.

The sexual organs are placed in sori, and originate in hair-
like outgrowths of the thallus. The hairs bearing antheridia
are often much branched, as in the case of Fucus. The sori
contain paraphyses as well as sexual organs.

The Dicryotacrs® form a group somewhat resembling the
Cutleriacee, but differ in the gametes being nonciliated. The
thallus is very varied in form, but is generally flattened. The
branching is dichotomous, and usually arises from a longitudinal
division of a small-celled apical meristem. A single apical cell
is only known in the genus Dictyota. There is not much dif-
ferentiation of internal tissue, an epidermis being however well

2
48 MANUAL OF BOTANY

marked off from a colourless internal mass. The sexual organs
are antheridia and oogonia, and are grouped together in sori. The
asexual ones are gonidangia, which occur in clusters or scattered
over the surface of the thallus. The gonidia and both forms of
gamete are nonciliated and motionless. In some forms the re-
productive cell, whether sexual or asexual, gives rise to a plant
like the parent; in others « kind of filamentous body is de-
veloped, recalling the protonema of the Bryophyta, to be de-
scribed later. The adult plant arises as an outgrowth from some
of the cells of this filament.

The spores are often produced in groups of four in the
sporangia. In this point and in the unciliated character of
the antherozoids the Dictyotacee approach the group of the
Rhodophycee.

The SyneENETIC@ form a group which is in marked con-
trast with the rest of the Pheophyceex. They are unicellular
organisms, and resemble the Cyanophycee in forming colonies
in consequence of the cells not separating after division, but
remaining surrounded by their diffluent mucilaginous cell-walls.
They have no sexual reproduction, but bear asexual spores,
which are ciliated.

Sub-Class IV.—Ruopopuycex,

This sub-class includes a large number of forms, nearly all of
which are marine. They are found growing mixed with olive-
green or brown forms at low-water mark and a little beyond,
and in deeper water they occur almost alone. The fresh-water
forms are few and belong only to two or three families. Some
marine forms are parasitic on other red Algwe; others are
epiphytic. Some members of this family have the thallus
encrusted or impregnated with carbonate of lime, forming
structures which superficially resemble the animal corals.

The morphological differentiation of the group is greatly in
excess of their anatomical complexity. They are all multi-
cellular, and generally form a much-branched thallus, which
may be flattened and spreading, or may be filamentous. The
segments of the shoot may in many cases be called leaves, and
a root can usually be found.

The histological differentiation is much slighter than in the
last group. The filamentous forms sometimes show nothing more
than a single row of cells; sometimes there are several such
rows, which may be covered by a kind of cortex composed of
small cells. In these cases the rows of the filaments do not

.
THALLOPHYTA—ALGA 49

form a true tissue, but are bound together by a kind of inter-
cellular substance, or are surrounded by a common gelatinous
coating. Each row of cells grows by division of the terminal
one, which is sometimes much larger than the others. There
is no intercalary growth of the filament by division of any of
the other cells, though lateral branches may arise from them.
The successive cells of the row or rows constituting the thallus
communicate with each other by a kind of rudimentary sieve-
plate (fig. 798), though they can hardly be described as sieve-
tubes.

Fic. 799.

 

Fiy. 798. Semi-diagrammatic longitudinal
section of an old and stout portion of
Ceramium rubrum, showing continuity
between the protoplasmic contents of
the axial or central cells, a, a, at their ends ; and laterally with the cortical
cells, b, by protoplasmic threads, and also that of the cortical cells infer se
by threads radiating from the central mass in each cell. After T. Hick.
—Fig. 799. Procarp of one of the Red Seaweeds. tr, Trichogyne. _ sp.
Spermatia. The branch to the left bears a cluster of antheridia, After Kny.

 

The flattened forms usually grow at their margins, new cells
arising from divisions in certain cells in definite positions
there. The characteristic colouring matter is red, and is found
in chromatophores in the cells. Asin the last group, chloro-
phyll is present in addition to the phycoerythrine.

The group is characterised by great peculiarity in its methods
of reproduction, which are both sexual and asexual.

The gametophyte bears sexual organs and gonidia, the latter

VOL. II. E
50 MANUAL OF BOTANY

sometimes occurring only in special forms. There is a sporophyte
developed after fertilisation of the contents of the female
organ, but this is always a very small structure, incapable of
great development, and almost at once producing its spores.

The sexual organs are antheridia and carpogonia or pro-
carpia. The antheridia are borne generally in clusters, which
are often situated at the end of a filament (fig. 799), but
which may be collected into various groups upon the surface
when the thallus is flattened. Sometimes they are found in
pits or depressions of the surface, something like the conceptacles
of Fucus. Each antheridium produces externally a number
of special cells in which the male gametes are produced singly.
The gamete is a mass of protoplasm, which at first in most cases
has no cell-wall, but which secretes one after its liberation
from the mother-cell, usually just before it reaches the female
organ. The term applied to the male gamete is pollinoid or
spermatium ; it differs from the antherozoids of the former
group in not possessing cilia. The pollinoids are discharged
from the antheridial cells by the latter opening at their apices.

Some botanists hold that the structure described above as
an antheridium is really a cluster of them, and that the true
antheridium is the special cell alluded to. On this hypothesis
the antheridia are numerous and unicellular, and give rise each
to a single pollinoid.

The female organ, or carpogonium, is peculiar in that it
never produces an oosphere, but its contents remain undifferen-
tiated. It is usually a cell with a somewhat swollen base and a
long narrow pointed apex. The latter is called the trichogyne
(fig. 799 tr), and is the part which is concerned in the act of fertili-
sation. The carpogonium proper is usually the terminal cell of a
short branch consisting of three or four modified cells which are
sometimes sunk in the thallus. When the carpogonium is mature
a pollinoid comes into contact with the trichogyne, which always
projects above the surface of the thallus, even if the whole
carpogonial branch is not exposed. The wall of the pollinoid and
that of the trichogyne become absorbed at the point of contact,
and the contents of the former pass into the cavity of the latter.
The further stages of the process have not been observed, but as
there is no differentiated oosphere it is probable that the
nucleus of the pollinoid fuses with that of the carpogonial cell.
The trichogyne becomes cut off from the rest of the carpogonium
and withers away.

Fertilisation having been thus accomplished, the further deve-
THALLOPHYTA—ALGA 51

lopment of the structure varies very greatly in different groups,
leading in all ultimately to the production of a fruit-like structure
which is known as a cystocarp, and which is really the sporophyte
phase of the plant. It consists essentially of a cluster of car-
posporangia, variously arranged and often enclosed in a definite
encasement of filaments or cells. There are five different types
of formation. The first is seen in the Nema.ionacea; here
from the fertilised carpogonium filaments known as gonimoblasts
grow out, often in dense clusters. The terminal cells of the
filaments are the carposporangia, and each produces internally
a single carpospore. The whole group constitutes the cystocarp

(fig. 800), which is consequently not enclosed in any specially
differentiated case. Some-

times the gonimoblasts arise Fre. 800.
from the upper part of the
carpogonium, sometimes
fromits side. In some of the
families the cystocarp is im-
mersed in the tissue of the
thallus. In the Gelidee the
ceils of the gonimoblast_be-
come united here and there
to certain cells of the thallus,
from which it absorbs nou-
rishment.

The second type is fur-
nished by the GIGARTINACES ; cae
in this, besides the branches Ag: eo = Aemslion,
which carry the earpogonia, 2 Gystocary cf Telos. Coupe:
other special cells are pro- spore escaping. After Kny.
duced on the thallus near
them, generally in pairs. These cells are known as aucilary
cells. When the carpogonium has been fertilised it does not give
rise at once to gonimoblasts, but puts out a short protuberance
known as an ooblastema filament. This makes its way to an
auxiliary cell, and the contents of the two fuse. The gonimo-
blasts arise from the resulting cell and branch in the interior
of the thallus, the cystocarp being thus embedded in its sub-
stance. The fruit thus arises from the auxiliary cell rather than
immediately from the carpogonium as in the Nemalionacee.

The third type, characteristic of the RHopoMENIACE®, is still
more complex. The formation of the cystocarp is indirect as in
the last case, the carpogoniwn conjugating with an auxiliary cell.

“2

  
52 MANUAL OF BOTANY

A complex procarpium is formed, consisting of carpogonial
branches and certain cells which ultimately give rise to the
auxiliary cells. The latter are not developed till after the fer-
tilisation of the carpogonium. When they are complete, conju-
gation takes place between an ooblastema filament from the
carpogonium and either the auxiliary cell or a process growing
out from it. In some cases the carpogonial and auxiliary cells
coalesce without the intervention of either outgrowth. After the
process of conjugation is accomplished, gonimoblasts grow out
from the resulting cell and form a much-branched collection of
filaments which generally protrude from the thallus. Each
gives rise to a number of carposporangia. The thallus tissue
sends out filaments which coalesce round the cystocarp, forming
a protecting wall or case (jig. 800, Lejolisia). In some cases.
where the cystocarp is formed upon a slender leaf-like branch
of the thallus the filaments proceed from near the cell which
bears the carpogonial branch and curling over the latter cover it
in. The wall generally begins to be formed as soon as the
carpogonium is fertilised. In some cases no ‘protective coating
is formed.

The most complicated typeis met within the CRYPTONEMIACER.
The fertilised carpogonium sends out a very long ooblastema
filament which branches copiously, and consists of several cells.
There are many auxiliary cells formed upon separate branches,
and one ooblastema filament communicates with several of them,
fertilising several in succession. From each of these gonimoblasts
proceed ; and these branch repeatedly, the cells of the branches
forming carposporangia, each containing a single carpospore.
The gonimoblasts ramify in the substance of the thallus, so
that the fructification is internal, and surrounded by thallus
tissue.

The CoraLtinem form a very special family of this group.
Their thallus, which is of very various form, is encrusted or
impregnated with carbonate of lime, the coating covering every
part except the reproductive organs. They bear curious cysto-
carps, which are really compound, and resemble the conceptacles
of Fucus. In the hollow of the conceptacle, which opens
apically, several carpogonia occur, each with its trichogyne.
Other filaments only produce auxiliary cells. After a carpo-
gonium has been fertilised it fuses with many of the auxiliary
cells by means of a single ooblastema filament, and a single
large cell is formed. The gonimoblasts, each of which bears
a chain of carposporangia, arise in some numbers from the
THALLOPHYTA—ALGA 53

periphery of this cell. The cystocarp is surrounded by the wall
of the conceptacle.

In the last type, that of the Banciacrm, the formation is simple
and direct, as in the Nemalionacee. The carpogonial cells are
very little specialised, and only differ from the ordinary cells of
the thallus by being a little larger. They grow outwards and
give rise to a very rudimentary trichogyne, which becomes fused
with a pollinoid as in the other groups. The fertilised
carpogonium does not put out a gonimoblast, but either becomes
at once a carposporangium, or divides into a number of cells,
each of which may be regarded as one. The cystocarp consists
merely of the cluster of sporangia, no wall being formed.

The asexual cells of the gametophyte are usually produced
in groups of four in a gonidangium. They are variously
arranged (fig. 801), sometimes
being formed in tetrads, some-
times in rows, and sometimes
being quadrants of a sphere.
They may occur within the
cortical region of the thallus,
or may be produced upon
special hair-like outgrowths.
The gametophyte in which
they occur is very frequently
a potential one, and when they
germinate each gives rise to
another potential individual.
There is thus a succession of
potential gametophytes, before Fig. 801. Tetraspores of Rhodophyces

ssc . 1. Plocaminm. 2. Dudresnaya. 3. Le
an individual appears which jolisia. (2 and 3 after Kny.)
bears sexual organs. This
kind of alternation of generations has already been alluded to as
homologous alternation.

The gonidia differ from the carpospores in not being clothed
with « cell-wall on their liberation. From their oceurrence in
groups of four they are usually termed tetraspores, or tetra-
gonidia.

Fie. 801.

 

Sub-Class V.—CHLOROPHYCES.

In many respects this group may be considered to approach
most nearly the next great division of plants, the Bryophyta,
as in the higher forms the oosphere is fertilised in the oogonium
and not after extrusion from the plant. Though as a rule both
54 MANUAL OF BOTANY

anatomical and morphological differentiation is but slight, the
peculiarities of sexual reproduction are thus more like those in
the higher plants than are those of any of the other groups of
Algee.

The plants of this sub-class are, with few exceptions, very
simple in the structure of their vegetative body. Like those of
the last group, the predominant form is the gametophyte, the
sporophyte being quite rudimentary, and consisting either of the
fertilised female gamete, or of a small body resulting from a few
divisions of the latter. They show several types of structure.
Many are unicellular, and in that case of microscopic dimensions,
Others form filaments, each made up of a single row of pre-
cisely similar cells, all of which are physiologically alike. A
third type is seen in flat plates of cells, only a single cell in
thickness ;-these may be very large and leaf-like, or they may
form a very small group, microscopic in size. A group of this
kind, in which the cells show no differentiation, or at most a
difference between the ordinary cells of the thallus and the
reproductive cells, is called a cenobium or colony. Sometimes
the eenobium is spherical, and its cells are all furnished with
cilia, giving it powers of locomotion. Ina fourth type the thallus
is coenocytic—that is, there are no internal cell-walls formed
between the constituent cells, so. that the whole plant appears
like a single large cell with many nuclei embedded in its pro-
toplasm. The ccenocyte may be a filament, or a somewhat
globular body with a branched base (fig. 804), or a branched
structure showing differentiation into stem, and leaf and root.
In some cases of ccenocytic structure the body is divided by
transverse walls in several places, so thai it may be regarded as
composed of a number of ccenocytes. Lastly, the body may
be cellular and differentiated into root and shoot, the latter
bearing branches and leaves.

In habit the Chlorophyces vary but little. They are found
in both salt and fresh water. Most forms are free; some are
attached to a substratum. A few are endophytic, inhabiting
cavities in other plants much as Nostoc does. They present
hardly any histological differentiation, with the exception of the
Characee, where the stem sometimes shows a rather curious
structure, and curious reproductive bodies are produced.

The gametophyte may produce both asexual and sexual cells,
and may reproduce itself vegetatively by simple division or by
the production of gemmez. The sexual organs are sometimes
very simple, any cell of a filament having the power to produce
THALLOPHYTA—ALGA 55

a number of bi-ciliated gametes, which are liberated by rupture
of the cell-wall. These, after a period of activity, conjugate in
pairs, the conjugating cells generally originating from two
different cells or even two different filaments. The differentia-
tion of sexuality in some of these is very slight, for if they fail to
conjugate they can still germinate as if asexual cells. In
another group, while apparently any cell of the filament can
become a gametangium, the contents are not differentiated into
ciliated free-swimming bodies, but the whole of the proto-
plasm undergoes a kind of rejuvenescence and forms a single
gamete. In other forms definite antheridia and oogonia are
produced, which furnish antherozoids and oospheres respect-
ively. In each oogonium, as a rule, only a single oosphere
is produced, and this is fertilised in situ by the entry of an
antherozoid into the

oogonium (fig. 805). ; Fria. 803.

This marks a striking
advance upon the sex-
ual process in the
Pheophycee, where
the oospheres are set
free and fertilised out-
side in the water. It
approaches to the con-
dition in the next
group, where more

 

* oe . Fig. 803. Part ofa filament of Ulothrix from which
elaborate provision 18 the gametes, g, are escaping. g'. Free gamete.

made to bring the 7, 7°. Gametes conjugating.

sexual cells together.

In the cases of conjugation of the solitary gametes in a game-
tangium, the fusion of the cells always occurs within one of
the cells or an outgrowth from it, the gametes never being set
free.

In the latter case parthenogenesis sometimes occurs, a gamete
developing into a new filament without any process of conjuga-
tion. Such gametes are called azygospores.

In one exceptional case, Sph@roplea, several oospheres are
formed in the oogonium, which is not a specially differentiated
cell. Here, too, fertilisation takes place internally, antherozoids
finding their way into the cell by an opening in the wall.

Asexual cells are produced by most, but not by all the mem-
bers of this group. They are generally free-swimming cells,
or in some cases ccenocytes, either ciliated all over their surface,
56 MANUAL OF BOTANY

or having a pair of cilia at one end, which is usually pointed,
giving them a pear-shaped appearance. They are not produced
in specially differentiated gonidangia ; apparently any cell of the
thallus can give rise to them.

The sub-class has been very variously subdivided, and at
present it is difficult to give a very minute classification.
Several types of structure may be briefly described.

Protococcacr#.—These are the simplest of the sub-class;
the plants consist of single cells or of colonies of cells united
by a common mucilaginous cell-wall. They multiply by cell-
division, or by formation of zoospores, or by the conjugation
of two free-swimming gametes. In the latter case the zygote
represents the sporophyte and gives rise to two zoospores on

germination.

Fie. 804. VoLvoccacE#.—Of these the most
remarkable plant is Volvox itself. It
consists of a hollow sphere formed of a
single layer of cells, each of which is
furnished with a pair of cilia. By
the movement of these the plant
rotates rapidly and makes its way
through the water. Some of the cells
of the sphere produce a number of
orange-coloured ciliated antherozoids ;
ANS others represent oogonia, and each

gives rise to a single oosphere. The
latter is fertilised im sitw and divides
into a number of cells, which become
sci aie arranged into a hollow sphere like
the parent. Certain other cells of the
colony, which may be taken to represent gonidia, can divide
similarly in situ, and produce within their cell-wall a miniature
Volvox. Several of these may often be seen in the interior of
the hollow sphere of the parent, into which they are discharged
from the gonidangial cell. They only escape on the death of
the parent. Other genera of this group are Pandorina and
Hudorina; the ccenobium of the former is a solid sphere, that
of the latter a hollow one. Pandorina reproduces itself by
gametes which are alike, Eudorina by antherozoids and
oospheres. The zygote of Pandorina represents the sporophyte
and produces zoospores. That of Eudorina is like that of
Volvox. Other genera produce colonies or ccenobia which are
flattened instead of spherical,

   

“yl
THALLOPHYTA—ALGAE 57

SrpHonr®.—These are the most remarkable forms of the
group, the thallus consisting of a single ccenocyte, often of very
large dimensions, or of a number of ccenocytes attached to each
other, forming a filament. The largest members of this family
belong to the genus Cawlerpa, which in many cases simulates
the different types of habit exhibited by terrestrial plants. The
stem and leaves are nearly always well represented, and the root
system is clearly differentiated. The internal cavity of the
ceenocyte is crossed by interlacing strands or trabecule formed
of a modification of cellulose, and springing from the outer wall
of the structure. A form of much humbler type, but more
familiar to us from its occurrence in fresh-water and in muddy

Fie. 805.

 

Fig. 805. A. sp. Newly formed zoospore or zoogonidium of Vaucheria sessilis
escaping. B. Zoospore at rest after having lost its cilia. c. First stage of
germination. D. Filament of Vaucheria sessilis producing oogonia, oy, og,
and antheridium, 2. w. Hyaline root-like process, forming a sort of
mycelium. sq. Zoospore, which by germinating has formed the filament.
After Sachs.

places, is Vaucheria (fig. 805), The plants are filamentous
cceenocytes, which branch irregularly or dichotomously. There
is but little differentiation, but from some of the filaments curious
root-like structures are developed for purposes of attachment.
Other forms are Acetabularia, where there are stalks crowned
by whorls of coherent leaves, and Botrydiwm (fig. 804), where a
bladder-like head is continued downwards by a slender stalk to
a much-branched root, all being a single ccenocyte. Forms
composed of several ccenocytes united into a filamentous thallus
are shown by the genera Spheroplea, Cladophora, ke. The
curious genus Hydrodictyon is sometimes referred to this

er oup.
58 MANUAL OF BOTANY

The reproductive processes of the group may be sexual or
asexual. The sexual cells are usually all alike and are free-
swimming ciliated gametes, which conjugate in pairs. Vau-

cheria is exceptional

Fie. 806. in producing anthe-

ridia and oogonia
(fig. 805), which are de-
veloped in close prox-
imity to each other
from the surface of a
filament. Each be-
comes shut off from
the rest of the cceno-
cyte by a_ cell-wall.

‘ The antheridium gives

Fig. 806. Partofafilament of Ulothrixfrom which 4+,
the gametes, g, are escaping. g'. Free gamete. rise to a number : of
g, g'. Gametes conjugating. antherozoids which

are liberated by the
rupture of the apex. The oogonium contains a single oosphere,
and when it is mature it opens at the apex, and a drop of muci-
lage is extruded. An antherozoid enters the oogonium and

 

Fie. 807.

 

Fig. 807. Conjugation in Spirogyra, Two filaments are lying side by side,
and fiom cells opposite to each other protuberances are growing out to
meet, a,a'.. Each produces a gamete,’. When the protuberances have
met and fused, one gamete passes over and unites with the other, c.
d. Adult zygospore.

effects fertilisation. There is no sporophytic form, the zygote
germinating to produce a new gametophyte.

In Spheroplea, which is composed of several coenocytes, any
segment of the body may become an antheridium or an
THALLOPHYTA—ALGA 59

oogonium. There is not thus the differentiation of the organs
seen in Vaucheria. The antheridia produce a large number of
antherozoids, and the oogonia develop several oospheres in each.
Fertilisation takes place by the entry of the antherozoids into
the oogonia through openings in the walls of the latter,
Unlike Vaucheria, this plant shows an alternation of genera-
tions, the oospore not producing at once a new Spheroplea
plant, but giving rise to free-swimming zoospores, which form
the new filament when they come to rest and germinate. The
oospore thus represents the sporophyte.

Asexual reproduction is not common; when it takes place it
is brought about by the formation of zoospores. These are gene-
rally motile and have a varying number of cilia. In Vaucheria
(fig. 805), a single zoospore or zoocwnocyte is formed at the end
of a filament, a portion of which becomes segmented off by a
wall. The protoplasm of this portion undergoes rejuvenes-
cence, and becomes ciliated all over, a pair of cilia being placed
over each nucleus of the new cceenocyte. It escapes by rupture
of the apex of the filament. In some forms the asexual gonidia
are non-motile.

CoNFERVOIDES.—The forms included in this group are either
unicellular, filamentous, or membranous; the filaments are
sometimes branched, sometimes not, the membranous ones
sometimes form flat plates, sometimes hollow or tubular expan-
sions. The growth of the filaments is generally intercalary.
They are always composed of cells and not of ccenocytes.

The processes of reproduction are both sexual and asexual.
The origination of sexuality can be traced in some members of the
group. In Ulothrix, which is a filamentous multicellular form,
the contents of certain cells of the filament give rise to a large
number of free-swimming ciliated cells, which indicate in their
behaviour the beginning of sexual differentiation. They often
conjugate in pairs (fig. 806), forming zygospores and thus indi-
cating that they are essentially gametes. If they do not succeed
in conjugating, they; still can germinate; a fact which shows
that they are much akin to ordinary zoogonidia.

A further evolution of sexuality is found in the Zygnemia,
to which Spirogyra belongs. Any cell of the filaments of the
plant can become a gametangium. In the process of conjugation
two filaments come to lie parallel with each other, and from the
middle of each cell a lateral process grows out towards the other
filament (fig. 807, wa). The opposite processes join and their
walls fuse, forming a tube which stretches across betwecn the
60 MANUAL OF BOTANY

two gametangia. The protoplasm of each undergoes rejuve-
nescence to form the gamete, and one of them passes over into
or through the tube and fuses with the other gamete, which
either enters the tube to meet the first or remains in its game-
tangium, where it is joined
Fre. 808. by the other. The first
condition is found in Zy-
gogonium, and as there
is no difference between
the gametes taking part,
we cannot speak of differ-
ence of sex. In Spirogyra
(fig. 807) the cell which
passes over through the
tube begins to be diffe-
rentiated slightly sooner
than ‘the other and. may
be held to be the male
one.

In Gdogonium sexu-
ality is completely esta-
blished, antherozoids and
oospheres being produced.
In some cases the whole
contents of the antheri-
dium forms a single an-
therozoid, which is cili-
ated.

Unicellular forms
occur in this group in
the family of the Desmids.

Fig. 808. A. Middle part of a sexual filament These are cells of bright-

of Edogonium ciliatum. og, og. Oogonia green colour and usually
fertilised by the dwarf male plants, m, m, . 3
developed from zoospores formed in the Peculiar shape. Their

cells, n (antheridium), at the upper part of i i As
the filament. 3B. Ripe oospore, c. Piece colouring matter is col

of male filament of a species of Gdogo- lected into curiously

nium, with productioa of antherozoids, z, z. .
Dr. The four zoospores resulting from an formed chlor oplasts,

oospore. . Zoospore at rest. After which May occur as
Pringshein. bands stretching _ the
whole length of the cell,

and having pyrenoids embedded in them. They multiply chiefly
by fission, as do the Diatoms, to which group they present
certain resemblances. Occasionally two individuals conjugate

 
THALLOPHYTA—ALGA 61

to form a zygospore, which germinates and produces two new
plants.

The Zygnemiz are, like the Desmids, furnished with peculiar
chloroplastids. In Spirogyra these form a spiral band which
winds round the cell; in Zygnema they form two stellate
plates ; other forms occur in other genera.

Gidogonium (figs. 808, 809) is noteworthy among the
group on account of certain
peculiarities of its reproduction. Fie. 809.
The ordinary filament produces
a number of oogonia along its
length, the cells swelling and
becoming ovoid. Each produces
a single oosphere. The anthe-
ridia may be on the same
filament as the oogonia or on a
different one. A cell of such
filament divides transversely
several times, and each cell so
formed becomes an antheri-
dium, giving rise either to a
single antherozoid or dividing
into two to form two mother-
cells, each of which produces
one. The oogonium admits
the antherozoid usually by a
perforation of the wall. Some-
times no antheridia are formed
directly on the parent filament.
Instead, special cells produced Fig. 809. A,B. Escape of the zoogonidia
a aya of an G@dogonium. c. One in free
in the same way as antheridia motion. D. The same after it has be-
set free their contents in the come fixed, and has formed the attach-

Jag a ing disc. E. Escape of the whole pro-

form of a ciliated cell known  toplasm of a germ-plant of (dogo-
as an androspore. It is much atone: of a. zoogonidiar:
like an antherozoid, but differs
from the latter in its behaviour. It becomes attached to the
wall of an oogonium and germinates, forming a very small
plant, of three or four cells, known as a dwarf male, the upper
cells of which are antheridia, and produce each a single
antherozoid. When the oosphere is fertilised it clothes itself
by a cell-wall, and the oospore so formed in due time
germinates and produces four zoospores (fig. 808 p). It thus
represents the sporophyte.

 
62 MANUAL OF BOTANY

Coleochate is a form which in some respects approaches the
red seaweeds. Its thallus is composed of much-branched
filaments forming a tufted mass which grows apically or mar-
ginally. The cells in some cases bear peculiar sheathing hairs.
The plant bears antheridia and oogonia, each of the latter bearing
a trichogyne except in a few species. The antherozoid enters
the oogonium by an opening in the trichogyne and fertilises the
oosphere.

The result of the fusion is the production of a more elabo-
rate sporophyte than in any other member of the Chloro-

phyceex. The oosphere se-
Fic. 810. cretes a cell-wall round it, and
the oogonium in which it lies
becomes surrounded by a kind
of cellular covering derived
from the cells of the thallus
near it. It thus forms a kind
of fructification which becomes
detached from the parent.
Later the oospore germinates,
‘rupturing its coating ; it only
produces a few cells, each of
which gives rise to a single
zoospore.
Fig. 810. Longitudinal section through The asexual reproductive
shoott of Chara fragitix. “Apleal ea, CUS produced by the Confer-
in which segments are formed by voidex are zoogonidia or ZOO-

septa, each segment being further = ‘
divided by a curved septum into 2 SPores, as they are produced

lower cell not further divisible, which on the gametophyte or the
develops into an internode, g, 9’, 9”, 9/”", 3
and an upper cell which produces a sporophyte respectively. They
Which "sled undergo segmentation, F@ variously ciliated, and
After Sachs. always on germination pro-
duce a gametophyte (fig. 809).
The process of asexual reproduction is not found in the Desmids
nor in the Zygnemiz.

The last type of structure is found in the Cuaraceg, repre-
sented most familiarly by the two genera Chara and Nitella.
In some respects these approach nearest in structure to the
Bryophytes ; among the Chlorophycee they are distinguished
by their relatively great degree of both morphological and
anatomical differentiation and by the complex structure of
their reproductive organs.

Chara exhibits a long slender stem, bearing whorls of leaves

 
THALLOPHYTA—ALGA 63

and branches, and consequently divided into nodes and inter-
nodes. The branches are developed in the axils of the leaves.
The lower portion of the stem gives rise to a number of adven-
titious roots, which are filamentous and multicellular.

The growth of root, stem and leaf is apical; in the stem
and branches it is carried on by an apical cell.

The nodes and internodes differ in structure; in the latter
the central core is formed by a single very elongated cell,
which in the older parts contains several nuclei. It is not a
cenocyte, the nuclei being derived from the fragmentation of
the original nucleus. This cell is covered in by a cortex
consisting of a number of rows of cells which spring from the
nodes above and below and accompany the internodal cell in
its elongation. The nodes are made up of a number of small
cells, from the external ones of which the branches and leaves
arise.

The growing point of the stem of Chara is seen in fig. 810.
When it divides it cuts off a segment by a transverse wall ;
this cell is again divided similarly into two, of which the upper
becomes a nodal and the lower an internodal cell. The nodal
cell divides by vertical walls, while the internodal one only
elongates. The peripheral ones grow upwards and downwards
to help to form the cortex of the internode above and below
it. The apical cell of the leaf is similar to that of the stem,
but it only keeps its activity for a short time. The apical cell
of the root is not differentiated.

The reproductive organs are antheridia and oogonia, and
are produced at the nodes of the stem. The antheridium is a
shortly-stalked globular body, sometimes called a globule. Its
case consists of eight cells with curious thickenings upon their
surfaces. The top cell of the stalk projects into the interior
of the antheridium between the bases of the lower cells of the
case. Each of the eight wall-cells, known as shields, bears a
long cell projecting into the interior, which is termed a manu-
brium; this is crowned by a smaller globular cell, the capi-
tulum, and this in turn gives rise to six secondary capitula,
Springing from each of these are two long filaments, divided
into a large number of cells, each of which gives rise to a single
antherozoid. The antherozoids are twisted masses of proto-
plasm, bearing two cilia at their anterior ends.

The oogonium is also stalked, the central cell being sur-
rounded by filaments which arising beneath it from the node
coil spirally round it. Each filament cuts off a small cell at its
64 MANUAL OF BOTANY

apex, so that the oogonium is covered in by a kind of neck or
crown consisting of small cells. There are usually five of these.
When the oogonium is mature these cells separate from each

Fie. 811.
Fie. 812.

   
 

 

Fic. 813.

Fig. 811. A, Portion of the axis of Chara fragilis. s. Nucule or oogonium.
a. Globule or antheridium. 0. Internode. c¢, Crown or corona of nucule.
B. Abortive leaves. ', 8’, B’. Sterile leaflets. 3B. sk. Nucule, and a, glo-
bule, both in an early stage of development. w. Nodal cell of leaf,
u. Union cell between it and basal node of globule. 7. Cavity of internode
of leaf. br. Cells of leaf covered;with cortex. After Sachs.— Fig. 812. A
portion of a filament, fil, of fig. 813, in the cells of which the antherozoids
are developed; with a 2-ciliated antherozoid by its side.—ig. 813. A
globule cut in half to show the oblong cells or manubria, c, and the septate
filaments, fil. After Henfrey.—/ig. 814. Nucule or archegonium of
Chara. a. Apices of the spirally wound cells.——/’ig. 815. Vertical seotion
of a nucule.

other, leaving a small channel through which the antherozoid
can make its way.

The oosphere is solitary in the oogonium, though as it
becomes ready for fertilisation it cuts off one or two small cells
THALLOPHYTA—ALGA 65

from near its base. These cells are separated from it by cell-

walls, but the oosphere itself remains
naked.

The oogonium does not open, but
the antherozoid makes its way
through the cell-wall, which under-
goes a sort of mucilaginous degene-
ration. The fertilised oosphere after
fusion with it becomes an oospore
with a very thick wall.

The germination of the oospore
is peculiar; a transverse wall is
formed near the apex and a small
cell is so separated from the rest.
The latter part of the oospore takes
no part in the further development,
but remains as a store of nutriment
for the young embryo. The small
cell divides into two, and from one
of these the new shoot is developed,
the primary root arising from the
other. A small pro-embryo is thus
produced which bears a single whorl
of leaves and a few adventitious
roots. The Chara plant arises as a
bud upon this, its apical cell being
differentiated among the whorl of
leaves (jig. 816, g).

In the genus Nitella the stem is
much more slender than in Chara,
and it is not furnished with a cortex.

There are no asexual cells pro-
duced, but vegetative propagation is
sometimes brought about. Certain
branches of peculiar form may be-
come detached from the parent and
grow into new plants; or gemme
may be developed upon the under-
ground nodes.

Not producing any asexual cells,

Fie. 816.

 

’

Fig. 816. Pro-embryo of Chara
Sragilis. sp, Germinating spore.
i, d, g, pl. The pro-embryo.
At d are the rhizoids, w. w’.
Primary root. g. First leaves of
the second generation, or Chara
proper. After Pringsheim.

Chara does not exhibit any alternation of generations. The

plant is the gametophyte.

VOL. Il.
66 MANUAL OF BOTANY

Cuass II.—FUNGI.

This class of Thallophytes differs from the preceding one
especially by the absence of chlorophyll from the tissues of
the plants which it comprises. In other respects there is
a great similarity between the two groups. The absence of
chlorophyll, however, makes:such a material difference to the
mode of nutrition, and leads ultimately to such great differences
in degree of development, that they are properly separated into
two distinct classes. The fungi cannot assimilate the CO, of
the atmosphere, and are therefore compelled to obtain their
carbonaceous food from somewhat complex compounds, which
have, however, « fairly wide distribution. Some fungi obtain
them from other living organisms, both animals and vege-
tables, on which they prey, their tissues entering into the
living substance of their hosts and absorbing therefrom the
food-stuffs they need. These are called parasites. Others
grow upon decaying organic matter, either in the soil or else-
where; these are known as saprophytes. Yet a third class
exists, whose members live in intimate relationship with living
green plants, the two forming together a complex organism,
partly chlorophyllaceous, partly fungal, the two constituents
playing each its own part in the nutrition of the whole. Such a
mode of life is called symbiosis; it differs from parasitism in
that the fungus does not in any way injure the green plant with
which it is in such close relationship. The best examples of
symbiosis may be found in the next class, the Lichens, where an
alga and a fungus live together. In this it is illustrated by the
micorhiza found on the roots of many of our forest trees.

In their life history the fungi show an alternation of genera-
tions, but not at all a regular one. Many species have both
gametophyte and sporophyte phases, but these rarely if ever alter-
nate with constancy. The gametophyte is always the larger and
most important form, the sporophyte being sometimes repre-
sented only by the oospore or zygospore, sometimes by a small
promycelium developed from it, sometimes by a kind of fructifi-
cation recalling the cystocarp of the red Algew. The gametophyte
usually bears spores or gonidia in addition to the gametes ; indeed
THALLOPHYTA—FUNGI 67

many gametophytes are only potential ones, usually producing
gonidia alone. Many generations of these may occur in suc-
cession before an actual one with sexual organs is formed.
Hence we get often, as in the Alge, in the life history an alterna-
tion, generally very irregular, of potential with actual gameto-
phytes, in addition to the alternation of sporophyte with gameto-
phyte, which is also very irregular. The former has been called
homologous, the latter antithetic alternation.

Again, some of the gametophytes have lost the power of

Fie. 817.

 

 

fig. 817. Coeenocyte of J/ucor Mucedo, bearing asporangium or gonidangium,
k, This is more highly magnified in the fig. to the right. m. Columella.
2. Gonidia or spores.

producing sexual cells at all, probably in consequence of the
degeneration of structure that has accompanied the parasitic or
saphrophytic modes of nutrition. They thus never produce any
reproductive cells but gonidia, and can only be distinguished as
gametophytes by a careful study of their homologies.
Polymorphy is very wide-spread among the Fungi. As we
have seen, the plant body is in most cases the gametophyte. It
may be unicellular, consisting of separate cells of various shapes,
rounded, oval, or irregular. It may be a ccenocyte (fig. 817),
when the appearance it presents is that of a number of white
F2
68 MANUAL OF BOTANY

interlacing filaments, or hypha@, with no separating transverse
walls, but with many nuclei embedded in the protoplasm which
lines them. This network of hyphx, which is characteristic of
most fungi, is known as the myceliwm. Often the mycelium is
septated into segments, each of which is a small ceenocyte. In
one group, the Myxomycetes, the plant body is a plasmodiwm
(fig. 818), consisting of an aggregation of cells which possess no
cell-walls, but are capable of amceboid movements. The plasmo-
dium is of course a form of ccenocyte.

Fie. 818.

  
   
    
  
  
   

ERR LID

UASU EV
Ca ae ISO
AVETIRA
REO VARN)
Satan may
ANS

So

  

Fig. 818. A. Plasmodium of a Myxomycete (x 300). B. A fructification still
closed. c. After rupture of the wall p, and extension of the capillitium.
After De Bary x 20.

The degree of differentiation which is shown by the plant
body varies a good deal. Some are always single cells, others
by division of these form strings or chains of cells; others form
the mycelia already noticed, and in many cases the hyphe of
these, combining in various ways as they grow, produce large
masses of tissue.

In nearly all cases but the first two, the body can be seen
to be composed of parts which may be calledroot and shoot. In
THALLOPHYTA—FUNGI 69

many the former is much the greater in extent and forms the
larger part of the mycelium, being buried in the substratum on
which the fungus is growing. In such cases the shoot is com-
posed of a few hyphe, bearing the reproductive organs. In
other cases the shoot is large and bulky. In some parasitic
forms the root hyphe take the form of haustoria, or sucking
organs, which penetrate into the cells of the host plant (jig. 819),
the rest of the mycelium being found only between the latter.
Sometimes, instead of forming a feltwork of mycelium, the root
hyphez are gathered into bundles. The shoot, especially when
bulky, is of curious and varied form and never bears anything
that can be called a leaf.

Corresponding with this rudi- Fra. 819.
mentary morphological differentia-
tion, the anatomical structure is very
simple. The long chains of cells are
produced by ordinary cell-division ;
the elongated hyphe grow at their
apices; in the masses of tissue of the
more bulky forms a transverse sec-
tion shows the appearance of a kind of
parenchymatous tissue. It is not a
true parenchyma, however, being
composed of hyphz which run side
by side, cohering together. The
outer layers of such a mass form a
kind of cortex, which is more com-
pact than the inner parts. Occa- _
sionally some of the hyphe ave “#0 Powrceliotpetto plan,
modified to form a system of latici- Hypha running between the

a ° a cells and sending haustoria, a,
ferous tissue, and a kind of gland is into their interior.
formed in some other species. These
forms are found generally in the most complex group, the
Basidiomycetes.

The cell-walls of the fungi are composed of a modification
of cellulose, characterised by not turning blue when treated
with iodine and sulphuric acid. This modification, known as
fungus cellulose, has recently been shown to resemble in some
respects the chitin found in some animal organisms.

The reproductive structures found in the fungi are very
varied. Sexual reproduction is represented in several of the
groups, but in others it is unknown, the gametophytes being
always potential and not actual. In many a somewhat elaborate

 
70 MANUAL OF BOTANY

sexual apparatus is formed, but it is doubtful how far actual
fusion of the gametes takes place.

The gametes may be alike. In this case they are never set
free from the gametangia, but the walls of the latter coalesce and
fusion takes place inside the structure so formed, a zygospore
being the result (fig. 820). These isogamous fungi form the
group of the Zygomycetes.

In other cases both male and
female gametes are found. The
female is usually an oosphere,
contained either singly or in
numbers inside a structure that
may be called an oogonium (jig.
821). In this case the male
usually consists of a mass of
naked protoplasm, which occurs
in a special branch of one of
the hyphe, in close proximity
to the oogonium. This branch
is known as a pollinodium (fig.
821,an). In another section the
male gametes are differentiated
and are set free. They are small
rounded cells, clothed with a cell-
wall, and known as spermatia.
They are produced by abstriction
from the apex of aspecial filament,
the sterigma, a number of these
being developed in « special re-
PENS er ae fas ceptacle, the spermogonium. The

into contact at their apices, andeach female organ, which is known as

has cut off from itself a cell. xyg. . :
Zygospore resulting from the fusion an archicarp (fig . 783), contains

of these cells. zyg'. Adultzygospore no differentiated female cell, and
after germination. py. Promycelium =
bearing a sporangium. sp. corresponds to the procarpium of
the Rhodophycer. This some-
times has a trichogyne, as in the latter group.

In some forms which bear an archicarp the male cell is not
differentiated either, but is much like the gamete of the group
last mentioned, being produced by a hypha close to the
archicarp. The product of fertilisation in the last two cases is
known as an ascocarp, and is the sporophyte of the plant.

The spores or gonidia of fungi are borne in great numbers, and
receive different names according to the organs in or on which

Fie. 820.

 
THALLOPHYTA—FUNGI 71

they are produced. The sporophyte rarely occurring, it follows
that they generally arise upon the gametophyte. In most cases
they are small rounded bodies, each with its cell-wall. They
may be produced singly in a cell, as in the Schizomycetes, or
in groups of four or eight, as in the Ascomycetes. In most
Phycomycetes they are produced in great numbers in globular
or club-shaped sporangia or gonidangia (fig. 823) borne upon

special aerial hyphe, termed gonidiophores. In other cases the

Fic. 821.

99.

 

Fig. 821, A. Branched mycelium of Cystopus with young oogonia, og, og.
B. Portion of mycelium bearing oogonium, og, with the oosphere, os ; and
antheridium or pollinodium, av. ¢. Mature oogonium, with os, the
oospore. D. Mature oospore. F, F. Formation of swarm-spores or 200-
spores, G, from the oospores. 7,7. Protruded endospore. After De Bary.

spores are never in a sporangium, but are produced from
special hyphe by a process of abstriction or budding, leading to
the formation of strings of them, called stylogonidia (fig. 824).
Usually each spore ultimately becomes free. In one group, the
Uredinew, they remain together, in number two or more
( fig. 825), each of which can germinate while associated with the
others. These are sometimes looked upon as compound spores,
though each one is actually independent. This form is known
as a telewtospore, There is some doubt as to whether the
72 MANUAL OF BOTANY

bodies described above as spermatia are not a form of the stylo-
gonidia, and not sexual cells at all. In some cases they have been

Fie. 822.

 
 
  
 
 
  
 
 
 
 
 
 
 
 
 
   

Fig. 8:2, Oogonia and an-
theridia of Achlya ligni-
cola. The letters a to Er
indicate the course of
development. The pro-
toplasm of a cell or
branch of a cell collects
into a globular form
A, B, and by the forma-
tion of a septum, D g,
becomes an independent
cell (the oogonium).
The protoplasm then
breaks up into two or
more parts, D, ¢ @
(oospheres), which
quickly become spheri-
cal, as seen in D, secrete
a cell-wall E, and be-
come oospores. After
Sachs.— Fig. 823. Oo

found to be capable
of germination, pro-
ducing a mycelium
without any sexual
fusion.

In a few families,
such as the Sapro-
legnias, the spores are
not clothed with a cell-
wall, but are ciliated
free-swimming bodies.
They are produced in
great numbers inside
special terminal spo-
rangia (fig. 826).

Fie. 823. f

 

nocyte of Afucor Mucedo bearing a sporangium or gonidangium. &. This is more
highly magnified in the fig. to the right. m. Columella. 7, Gonidia or spores.

The sporangia or gonidangia may be produced singly or in
groups. In the latter case the gonidiophores which bear them may
be collected into special receptacles which are known as pycnidia,
THALLOPHYTA—FUNGI 73

Besides these sexual and asexual modes of reproduction, vege-
tative reproduction very commonly occurs. In forms such as
Bacteria and yeast it is much the most general method, and
consists only of ordinary cell-divisions, the daughter cells at
once separating from the one which gives rise to them. Some-
times in yeast this separation does not at once take place, with
the result that chains of cells are produced (fig. 827).

Fie. 824. Fra. 825.

  

Fig. 824. Stylogonidia or stylospores of Eurotium, formed by repeated abstric-
tion from the basal cell. After Dodel-Port.— Fig. 825. Teleutospores of
Paccinia graminis bursting through epidermis of straw. After Dobel-Port.
—Fig. 826. Two gonidangia of Achlya, A. Closed. 8B. Ruptured, and
allowing the zoogonidia a to escape. b. Mother cells of the latter after
escape of e, the zoogonidia, from them.— ig. 827. Two yeast cells bud-
ding,

In other cases a hypha divides by the formation of transverse
septa into a number of cells, each of which becomes rounded
off, and the chain breaks up into single cells which are capable
of immediate germination. They are often called oidiwm cells.
More complex forms are the bodies known as sclerotia, which are
composed of a mass of hyphe closely felted together and covered
by a pseudo-cortex. These separate from the mycelium which
74 MANUAL OF BOTANY

gives rise to them, and remain dormant for a longer or shorter

period, ultimately putting out hyphe like those of the original

mycelium.

The fungi have been classified in various ways by different
writers. The system which is now usually adopted divides them
into six groups as under :—

1. Schizomycetes, including those bodies commonly spoken of as
microbes, or bacteria. They are sometimes unicellular,
sometimes filamentous and composed of chains of cells.
They have no sexual reproduction.

2. Myxomycetes. The body of the fungus is a plasmodium or
aggregation of amceboid cells with no cell-wall. They
produce spores, but have no sexual reproduction.

3. Phycomycetes. These have usually a mycelium composed of
a much-branched ccenocyte with no septa. They are often
erroneously described as unicellular, a condition which,
however, does occur in some cases. They reproduce
sexually and asexually, zoospores and ordinary non-motile
spores occurring in different orders. The sexual reproduc-
tion isa process of conjugation or fertilisation, leading to
the recognition of two groups accordingly, the Zygomycetes
and the Oomycetes. In the former the zygote is a zygo-
spore, in the latter an oospore.

4, Ascomycetes. The ccenocytic structure is found in this
group also, but the whole plant is usually not a single
ceenocyte, but incompletely septated, forming a number of
them. The female organ is a carpogonium, containing no
differentiated gamete; the sporophyte is inconspicuous, but
represented by the so-called fructification.

5. Alcidiomycetes. The mycelium has the same structure as in
the last group. There is no sexual reproduction known.
Several kinds of spore are borne. There is an elaborate
structure produced called an ecidiwm, which may possibly
represent the sporophyte, but the homologies are doubtful.

6. Basidiomycetes. The mycelium is much like those of the last
two groups. No sexual reproduction is known. The
mycelium produces a massive structure, on certain parts of
which the spores are produced by abstriction from special
cells, known as basidia.

Sub-Class I.—ScuH1zomycEtEs.

The members of this group are very small, and almost struc-
tureless. The unicellular forms have various shapes, some being
THALLOPHYTA—FUNGI 75

spherical (Micrococcus), some more elongated or rod-shaped
(Bacterium), some forming a spiral (Spirillum). The multi-
cellular forms are filaments, branched or unbranched, or small
masses of cells, They are extremely polymorphic, one organism
passing through several forms in its life history. Some are
furnished with cilia, by which they move rapidly in the medium
in which they live (fig. 828).

The cells are of w very simple structure, consisting of a cell-
wall enveloping a mass of protoplasm. In this is found a body
capable of staining more deeply than the rest of the cell-
contents, and hence thought to be a nucleus. The protoplasm
often contains deeply staining granules, sometimes regularly
disposed round the cell. The true nature of the staining

Fie. 828.
f Fig. 828,
2 1. Sarcine.
oer é 2. Bacteria.
: eco 3. Spirilla,
ar) 4. Spirillum, show-
a , ing flagelle,

Micrococei in

strings, singly
and in groups.
After Cohn
and Sachs.
(Very highly
magnified. )

 

FU

 

material is, however, not yet accurately ascertained. Many of
these cells contain various pigments.

In the course of their life history, most of the Schizomycetes
become embedded in a jelly-like substance which holds great
numbers of them together. This isknown as the zooglwa stage.
The zooglea may form a membrane or scum on the surface of
the liquid in which the organism is living, or may occur in the
shape of masses of various forms.

The reproductive processes are either vegetative or asexual.
In the former case the multiplication takes place with enormous
rapidity by ordinary cell-division. In the second case spores
are formed, one in a cell, by a process of rejuvenescence. A
filament may thus give rise to a chain of spores, which ulti-
mately become separate by the degeneration of the original cell-
76 MANUAL OF BOTANY

wall. The spores have their own proper coats, which are much
thicker and more resistent than the ordinary cell-wall. The
zooglea stage is generally the one in which the plant forms its
spores.

It is to these organisms chiefly that the processes of fermen-
tation and putrefaction are due, though other fungi take part in
similar phenomena.

Sub-Class II.—Mryxomycetes.
This curious group is distinguished by the fact that, except at
a particular time in its life, it possesses no cell-walls. Originating
Fie. 829.

   

Fig. 829. A. Plasmodium of a Myxomycete (x 300). 3B. A fructification still
closed. c. After rupture of the wall, y, and extrusion of the capillitium.
After De Bary x 20.

from spores, the contents of the spore escape as a naked mass
of protoplasm, which in some forms is capable of active move-
ment by means of a cilium, and in others can only creep about
slowly, by means of protrusions which it can put out from its
substance. These are called psewdopodia. In the first case,
the freely motile body passes over later into this stage, so that
THALLOPHYTA—FUNGI 77

the myxomycete is at some time characterised by this behaviour
which recalls the condition of the form of animal known as the
Amba. While the separate masses are still motile they can
multiply by cell-division, which has been ascertained to be pre-
ceded by karyokinesis. Ultimately the amcboid masses collect
into a plasmodiwm, without fusion of the nuclei, so forming a
kind of cceenocyte (fig. 829, 4). Like the constituent cells, the
plasmodium can creep about by means of pseudopodia. A
familiar example of this fungus is the so-called ‘flowers of tan’
(Ethaliwm), which is found in the form of jelly-like lumps in
tan yards.

The plasmodiwm in time comes to rest, and gives rise to
one or more sporangia. In the latter case it divides into as
many pieces as sporangia. The whole of the mass shrinks up
into a rounded body which shows differentiation into a hardened
outer portion or wall, and an inner mass which gives rise to
spores. The substance of the inner portion produces a peculiar
protoplasmic network of filaments, the capillitium (fig. 829, c),
among which are formed the spores, these being furnished with
a cell-wall which each secretes independently. Sometimes the
sporangium is stalked, sometimes not ; occasionally a protrusion
of the stalk into the sporangium forms a kind of columella.
The spores are, after a time, liberated, or scattered by the elastic
capillitium, and give rise to the amcboid masses already
described.

Sub-Class III.—PHYcoMYCETES.

In this group we have the only undoubted cases of sexual re-
production, which may take the form of conjugation, or fertilisa-
tion, thus giving rise to two sections, the Zygomycetes and the
Oomycetes. In both groups the mycelium is unseptate, or in-
completely septate, being a cenocyte.

Zygomycetes.—The form most generally known in this group
is the common mould, Mucor Mucedo, found generally on dung
and other decaying organic matter. The spore gives rise to a
copiously branched mycelium, which ramifies very freely in the
substratum. When well established it throws up aerial branches
which terminate in globular heads or gonidangia. A septum is
formed close to the apex of the hypha, cutting off a small head
which grows and becomes globular. The lower cell grows also,
and projects into the swollen portion, forming a columella (fig.
823, m). ‘Che contents of the terminal cell break up into a
78 MANUAL OF BOTANY

number of spores or gonidia. The wall of the gonidangium
usually becomes impregnated with crystals of oxalate of calcium.
The sexual reproduction is carried out by means of undifferen-
tiated gametes. Two hyphe from the vegetative part of the
mycelium approach each other, and a septum cuts off from each
a small cell, which is the gametangium. The two gametangia
come into contact, and the walls between them are absorbed, so
that the gametes, which are the
undifferentiated protoplasm of
the gametangia, fuse together,
forming a zygospore (fig. 830).
This grows into a globular body
which secretes round itself a
thick cuticularised wall. After
a period of rest this body ger-
minates, pulling out a small
mycelium, calleda promycelium,
which gives rise to a sporangium
(fig. 830, sp) much like that
borne upon the ordinary fungus
body. This promycelium repre-
sents the sporophyte, the ordi-
nary form being the gameto-
phyte. In some species of Mucor
the gametangia are single and
conjugation does not take place ;
the body produced partheno-
genetically by such a gametan-
gium is called an azygospore.
Under unfavourable condi-
Fig. 830. Conjugation in Mucor tions of nutrition, as when the

Mucedo. h. Two hyphe which have i : ee
come into contact at their apices, hyphe are immersed in liquid,

and each has cut off from itself a :
cell. zyg. Zygospore resulting from the my celium of Mucor may

the fusion of these cells. zyg'. Adult divide up into a number of
zygospore after germination. p. +4: : :
Bromycelium bearing a sporau. Oidium-like cells much like yeast
gium, sp. cells. This is called the Torula
form ; it is capable, like yeast,
of setting up alcoholic fermentation in a sugary fluid. Some-
times the separate cells are large and thick-walled, when they
are known as Chlamydospores.
There are two other groups in this sub-class, the Chytridiacese
and the Entomophthoracez. The former produce zoospores in

ordinary sporangia or gonidangia, and in special thick-walled

 
THALLOPHYTA—FUNGI 79

sporangia, after a period of rest. Zygospores are also formed,
but the differentiation of the sexual organs is not so complete as
in the Mucorine. The Entomophthoracexe are parasitic on
insects. They differ from Mucor chiefly in the mycelium being
incompletely septate, being thus composed of a number of
cenocytes, instead of a single one.

Oomycetes.—The chief members of this group are the
Peronosporee and the Saprolegnie. The former are chiefly
parasitic, causing many of the diseases of Phanerogamic plants,
though saprophytic forms occur. <A typical instance of them is
the fungus Phytophthora infestans, which causes the potato
disease. The hyphe ramify usually
between the cells of the plants, Fie. 831.
sending haustoria into their interior
and so absorbing their nutritive
juices (fig. 831). The mycelium
sends out hyphe through the sto-
mata of the leaves, which bear
gonidangia at their apices. In
Phytophthora these hyphe are
branched and bear several goni-
dangia; in Peronospora each bears
w single one. In some cases the
gonidangium gives rise to zoogo-
nidia,in others it behaves like a
gonidium and puts out a hypha
directly.

The sexual reproduction of this _
group is seen best in such forms as * ie aoe Bete:
Pythiwm and Cystopus. A hypha — phthora. 6. Hypha running be-

° e tween the cells and sending
cuts off a cell at its apex, which haustoria, a, into their interior.
becomes swollen and rounded and
forms an oogonium. Its contents give rise to a single oosphere,
part of the protoplasm only being concerned in its formation
while the rest forms a peripheral layer, the periplasm. The
male organ or pollinodiwm is produced in a similar manner
from a hypha, which sometimes springs off as a lateral branch
from that which bears the oogonium and sometimes from an
adjacent one. The pollinodium becomes closely applied to the
oogonium and penetrates its wall by means of a delicate tube
which serves to conduct the male cell into the oogonium, where
it fuses with the oosphere, forming the oospore, which secretes
a cell-wall round it. After a period of rest the latter germinates.

 
80 MANUAL OF BOTANY

In Cystopus (jig. 882) the germination takes the form of the
production of a number of zoospores, which are set free. In
Pythium and other genera it results in the production of a small
promycelium, which in time gives rise to spores.

The Saprolegnie all live in water, being parasitic in some
cases, though often saprophytic. The Salmon disease is due to
one species of this group. The gonidangia are here club-shaped
and give rise to zoospores (fig. 834). The sexual organs are

Fie. 832.

 

Fig. 832. A. Branched mycelium of Cysfepus, with young oogonia, og, og.
B. Portion of mycelium bearing oogonium, og, with the oosphere, os ; and
autheridium or pollinodium, an. c. Mature oogonium, with os, the
oospore. D. Mature oospore. E, F. Formation of swarm-spores or z00-
spores, G, from the oospores, 7, 4. Protruded endospore. After De Bary.

similarly produced to those of the last group, but the oogonium
contains usually several oospheres (jig. 833). In their formation
there is no periplasm left. The pollinodia usually send tubes
into the oogonium, but there is no passage of the male gamete.
The oospheres become oospores without fusion with the latter,
that is parthenogenetically.

Inthe Oomycetes, as in the Zygomycetes, antithetic alterna-
tion of generations occurs, but the sporophyte is always small and
inconspicuous. It is represented by the oospore itself in such
THALLOPHYTA—FUNGI 81

forms as Cystopus, where it at once gives rise to zoospores; in
Pythium, &e., the promycelium is the sporophyte. Some forms
have apparently no such alternation, as the oospores give rise to
sexual plants.

Sub-Class [V.—AscomycETEs.

In this group the mycelium is made up of a number of
ccenocytes, each of the apparent cells into which the hyphe are

Fic. 833. Fie. 834.

    

Fig. 833. Oogonia and antheridia of Achlya lignicola. The letters 4 to BE
indicate the course of development. The protoplasm of a cell or branch
of a cell collects into a globular form A, B, and by the formation of a
septum, Dg, becomes an independent cell (the oogonium). The proto-
plasm then breaks up into two or more parts, D, ¢, @ (oospheres), which
quickly become spherical, as seen in D, secrete a cell-wall E, and become
oospores. After Sachs.—Fig. 834. Two gonidangia of Achlya. a. Closed.
B. Ruptured and allowing the zoogonidia, a, to escape. 0. Mother-cells of
the latter after escape of e, the zoogonidia, from them,

divided containing several nuclei. The mycelium is thus in-
completely septate. The fungi are both saprophytic and para-
sitic. Sexual reproduction is said to occur in some forms, but
it is not undisputed. In many cases complex organs occur
which suggest sexuality, but it may be that, as in the Sapro-
VOL. II. G
82 MANUAL OF BOTANY

legniz, the actual process does not take place. It is, however,
convenient to describe these structures as sexual, while reserving
the question of actual fusion of the gametes.

The group derives its name from the fact that whether pro-
duced after sexual fusion, or parthenogenetically, the spores
arise in closed cells known as asci. There is much variety in
the mode of origination of the latter, but they agree in that there

Fic. 835. Fic. 837.

 

c Fig. 835, Section of upper portion
’ of thallus of a lichen, showing
archicarps. a,b. Trichogynes.
e, f. Coiled basal portion of
archicarps, c. Nostoc filaments.
d. Fungal hyphe. After Kny.
— -Fig. 836. Section of spermo-
gonium ofa lichen. a. Hyphe of
the thallus, 0. Algal cells. ¢
Sterigmata.—— ig. 837, Highly
magnified fragment from the
wall of a spermogonium of Par-
melia parietina, sp. Articulated
sterigmata or spermatophores.
s. Spermatia. gon. Algal cells.

 

is no case of a differentiated female gamete giving rise to them.
The fungi of this group in this respect resemble the Rhodo-
phycee of the group of Algez.

The sexual organs show a great deal of difference in degree
of complexity. The female organ is usually an archicarp
consisting of a coiled portion, known as a carpogoniwm, with
sometimes an elongated part, called a trichogyne (fig. 885). In
THALLOPHYTA—FUNGI 83

many forms the trichogyne is wanting, and only the coiled por-
tion is found. The male organ is sometimes a pollinodium,
much like that of the preceding group, and produced in the
immediate neighbourhood of the carpogonium. Sometimes it is
a filament producing small cells by abstriction. These fila-
ments are known as sterigmata, and are borne in special
depressed receptacles called spermogonia (figs. 836 and 887). The
separate cells correspond to antherozoids, but are incapable of
motion and clothed with a cell-wall. They are known as sper-
matia. The result of the union of the contents of the pollinodium
or spermatium with those of the carpogonium is a fructification
called the ascogoniwm, which is the sporophyte of the fungus.
In the simplest case, which is that of Eremascus, two hyphe
coil round each other. These correspond to the carpogonium
and the pollinodium respectively. Their contents are said to
fuse, and as the result a large globular body is produced at the
apex of the coil, the contents of which divide into eight spores.
In Eurotium Aspergillus (fig. 888) a little more difference
is found between the two hyphe. The female forms a coil, and
from the base of it the pollinodium arises. It becomes closely
adpressed to the carpogonium, and fusion of the contents of the
two is said to occur. From the base of the carpogonial filament
other filaments arise which grow round and envelop it. The
coiled carpogonium becomes septated, and from each segment a
little protrusion arises which enlarges and becomes an ascus and
forms in its interior eight spores. The investment becomes
also septated, and forms a thick wall to the whole body. From its
cells ingrowths arise which gradually fill up the spaces between
the coils of the carpogonium, forming a solid mass of pseudo-
parenchyma. The body so formed is then known as the ascogo-
nium or ascocarp. From the fact that it remains closed and pro-
duces its spores internally, it is sometimes calledacleistothecitum.
The fungus Collema, which is generally found in symbiotic
relation with an Alga, may be taken as an illustration of another
type. The female organ is a septated coiled filament embedded
a little below the surface of the organism (fig. 835). Its upper
end is prolonged into a tapering filament, the trichogyne, which
projects above the surface. A spermatium liberated from the
spermogonium is floated passively to the trichogyne and becomes
attached to it. The walls deliquesce at the point of contact, and
fusion of the contents takes place. The trichogyne then withers
and the carpogonium develops and pushes its way to the surface,

where it expands into w flattened disc which is known as an
G2
84 MANUAL OF BOTANY

apothecitum. Hyphe from the sterile tissue are interwoven
with the filaments from the carpogonium, so that the apothecium
is derived from both. The surface layer of the apothecium is

Fig. 838 Fie. 840.

 

Fig. 838. Development of thecleistothecium of Eurotium. a. Pollinodium.
6. Carpogonium. ec. The carpogonium beginning to form asci. After
Kny.— Fig. 839. Mature cleistothecium of Eurotium. e. Wall. d. Asci
containing ascospores. After Kny.—-Fig. 840. Hymenial layer of the
mycelium or hyphex of Peziza converula. a,b, c, d, e, f. Successive stages
of development of the asci and ascospores intermixed with slender para-
physes. After Sachs.—Jig. 841. Perithecium of Peziza (natural size),
with section showing hymenial layer (slightly magnified), After Kny.

known as the hymenial layer (figs. 840 and 841). It consists of
a number of asci derived from the carpogonium, and of sterile
filaments springing from the vegetative hyphe. These are
THALLOPHYTA—FUNGI 85

called paraphyses. Each ascus develops eight spores from part
of its protoplasm, the rest remaining as epiplasm.

In some species the fructification is in the form of a deep or
shallow cup, sometimes nearly closed. This is called a perithe-
cium (fig. 841).

The group of the Saccharomycetes is now generally referred to
this sub-class. These plants are represented by the Yeasts, which
have the power of setting up alcoholic fermentation in sugary
fluids. They are simple cells of rounded or ovoid form which
multiply with great rapidity by a
process of budding. When growing Fic. 842.
rapidly, sometimes chains of cells are
formed, owing to the budding taking
place before separation of the cells.
Under certain conditions, usually
when badly nourished, the yeast cell
forms four spores by free cell-forma-
tion in its interior. There is, how-
ever, no sexual apparatus ever pro-
duced. Each such cell may be looked
upon as an ascus and the four spores
as ascospores.

Besides these so-called sexual pro-
cesses, most of these fungi can pro-
duce gonidia in great numbers.
They are borne upon erect aerial
hyphe by a process of abstriction
from their terminal cells called
sterigmata (fig. 842). Each  ste-
rigma can thus produce a chain of
gonidia, Sometimes the aerial
hypha or gonidiophore terminates in Fig. 842. Stylogonidia of Eurotium,
a single sterigma, sometimes it aes absuriction» trom
branches near the apex, forming
several. Sometimes the gonidiophores are found in numbers in
special receptacles called pycnidia.

We have thus an alternation of generations in most members
of the group, the ordinary mycelium being the gametophyte, and
the ascocarp the sporophyte. Homologous alternation almost
always occurs, many gametophytes in succession bearing only
gonidia, till one appears which produces the sexual organs. In
a few genera, however, no gonidia are found.

A curious case of homologous alternation occurs in some

 
86 MANUAL OF BOTANY

forms where two kinds of gametophyte are met with. The
fungus producing Ergot (Claviceps) is an example of this. The
first form consists of a feltwork of mycelium, filling the ovary
of the Rye or Wheat plant, and giving rise by abstriction to

Fic. 843. Fie. 844.

oe

      
    

sph

 

Fig. 843. Young sclerotium, c, of Claviceps growing up and supplanting the
old sphacelia, sph.Fig. 844. Section through the junction of the
sphacelia with the sclerotium of Claviceps, showing formaticn of gonidia.

Fic. 845. Fie. 846.

 

Fig, 845. Portion of the horn-shaped sclerotium of Claviceps purpurea, or the
Ergot Fungus, bearing four stromata,—— /"ig. 846. Longitudinal section of
a stroma, magnified, showing the perithecia. After Tulasne.

numbers of gonidia (fig. 844). This form is known as the
Sphacelia. Later in the year the mycelium becomes very dense
and hard, and protrudes from the ear as a black elongated body
which is known as a sclerotiwm (fig. 848). After a period of rest
extending through the winter, the sclerotimm germinates, putting
THALLOPHYTA—FUNGI 87

out a number of short protrusions, each composed of a number of
hyphe. These, which are called stromata, bear each a rounded
head, which is covered by a number of depressions. In each of
these is developed a perithecium (figs. 845, 846, and 847), the
asci of which develop each eight filiform ascospores (fig. 848).
These, when they germinate on the flowers of the host-plant,
again produce the sphacelia form.

Sub-Class V.—AMcIDIOMYCETES.

In this group are included two orders of parasitic plants,
which are characterised by a still further degradation of the
sexual processes. Indeed it is doubtful if any sexual organs

Fic. 847. Fic. 848.

 

Fig. 847, A single perithecium of Claviceps purpurea, magnified, showing the
contained asci. After Tulasne.— Fig. 848, Asci of the same, containing
the long slender ascospores. After Tulasne.

exist, though a peculiar form of fructification, the ecidiwm,
occurs in some of the members, which is thought by some
botanists to be homologous with the ascogonium of the preceding
group. The gametophyte is consequently potential and not
actual, in most if not in all cases. It is very polymorphic, and
bears several different kinds of gonidia, all produced by abstric-
tion.

The most characteristic fungus of this group is Puccinia
graminis, which forms the rust of wheat. It has a very peculiar
life history, inhabiting two host plants in different stages of its
existence. In the first of these it is found infesting the stems
and leaves of Wheat and other grasses, whose tissues are pene-
88 MANUAL OF BOTANY

trated by an incompletely septate mycelium. During the
summer this mycelium produces patches of gonidia, each borne
upon a short stalk. These develop underneath the epidermis
of the host, and, being of a yellow or reddish colour, give the part
a rusty appearance. These are known as wredospores or
uredogonidia. These escape by rupture of the epidermis (fig.
849, a), and are blown upon other grass plants, where they ger-
minate, and the hypha penetrates the host through a stoma. In
the interior a mycelium is produced, which again produces
patches of uredospores.

Towards the end of the summer the same mycelium gives

Fie. 849. Fic. 850.

 

Fig. 849, A. Grass leaf infested with Puccinia graminis, showing the uredo-
spores bursting through the epidermis of the leaf. 3B. Teleutospore ger-
minating and producing promycelium with sporidia.—Fig. 850. Teleuto-
spores of Puccinia graminis bursting through epidermis of straw. After
Kny.

origin to black patches which are visible upon the straw. These
are composed of numbers of compound gonidia, two together
upon a single stalk, developed as before by abstriction (fig. 850).
These, which are called teleutospores, or teleutogonidia, have
thick black walls and are very resistent. They remain quiescent
till the spring, when one or both of the cells germinates, produ-
cing a small promycelium, usually of four cells. Each cell puts
out a small gonidiophore, from which a small gonidium, called a
sporidium, is developed by abstriction (fig. 849, B). From a re-
semblance to the cells which abstrict the spores in the next group,
these cells are sometimes called proto-basidia. The sporidium
is a very small thin-walled structure, and from its lightness it is
THALLOPHYTA—FUNGI 89

easily transported by the wind. It is incapable of developing
a mycelium upon the grass, but if it falls upon the leaf of the
Barberry, it germinates, sending a hypha through the epidermis,
instead of penetrating a stoma like the uredospore. The myce-
lium resulting from this hypha forms a dense network in the inter-
cellular spaces of the leaf. At particular spots upon the leaf
brown pustules make their appearance, in which two kinds of
receptacles appear. Some on the upper surface of the leaf are
much like the spermogonia of the Ascomycetes, and bear the

Fic, 851. Fig. 852.

 

Fig. 851. Group of three uredospores, uw, and one teleutospore, ¢, springing
from mycelium sh.—Fig. 852. Section through leaf of the Barberry
infested with Puccinia graminis. o. Epidermis of upper surface of leat.
sp. Spermogonia. p, p. Layers of cells (peridium), surrounding a, a, the
ecidium fruits. After Sachs.

same name. They produce spermatia in the same way as the
latter. Upon the under surface large spherical bodies are formed
(fig. 852), containing a hymenial layer of sterigmata which
cut off from their apices a succession of spores known as
e@cidiospores. There are large numbers of chains of these thus
produced in the globular mass, which is known as an ecidium
The whole excidium has a wall derived from the sterile hyphe
When mature it ruptures and the spores escape. These are
carried in their turn to other grass plants, and there germinating,
reproduce the uredo form, entering the grass through the stomata.
 

90 MANUAL OF BOTANY

This plant and those like it, which thus inhabit two host-
plants in their life cycle, are called hetereciows.

There are many of these rusts, which vary in several ways.
The compound teleutogonidia sometimes have more than two
-cells. Sometimes the ecidium form inhabits the same host as
the uredo form, when the fungus is said to be awtecious.
Sometimes again one or the other phase of the life cycle does
not occur.

Though the xcidium is held by some to correspond to the
ascocarp or ascogonium of the Ascomycetes, no sexual process
causing its development has been discovered.

The rusts constitute the family of the Uredinex, named from
the uredo form of the fungus.

The other family included in this sub-class is that of the
Ustilaginee or smuts. They differ from the Uredinex in not
producing ecidia. Like them the mycelium infests the tissue
of grasses, ultimately making its way into the ovary of the
latter, replacing its normal contents by a mass of black resting
gonidia. These when liberated germinate, forming a small
promycelium on which sporidia of curious shape are borne. These
sporidia sometimes coalesce in pairs, sometimes remain separate.
On germination they either produce the original form of my-
celium, or give rise to another promycelium bearing sporidia.
The latter then produce the first form.

Sub-Class VI.—Basip1omycETEs.

This group includes the Mushrooms, Puff-balls, &c. It is
characterised by the entire absence of sexual reproductive
organs. The mycelium, which is incompletely septate, burrows
throughout the substratum on which the fungus grows, and
sends up above the surface large fructifications which bear the
spores or gonidia. These are formed by abstriction from special
cells known as bastdia, which give the name to the group. The
form of the fungus is always that of a potential gametophyte,
but the power of producing gametes is absent.

The distinguishing feature of the group is the large sub-aerial
fructification or gonidiophore. Several varieties of this are
found, of which the most familiar is that produced by the common
mushroom (Agaricus campestris) (fig. 853). A conical or pear-
shaped outgrowth appears upon the mycelium, consisting of a
number of hyph closely cohering together and growing at
their apices. The direction of the growth soon changes, the
hyphe spreading outwards to form a prominent head which
THALLOPHYTA—FUNGI 91

extends centrifugally. An annular cavity is formed in this
near its lower part, which increases in size as the head extends.
The head can now be recognised as distinct from the lower portion
of the hyphal mass, and is known as the pilews, the lower part
or stalk being called the stipes. In the air cavity a number of
plates or lamelle are developed, which radiate from the centre
to the circumference. These form the gills of the mushroom,
and on them the spores or gonidia are developed. As the growth
of the stipes proceeds, the part of the pileus below the air cavity

Fic. 853.

 

Fig, 853. Development of the Mushroom. c. Mycelium. 0}. Early stage of
the development of the gonidiophore. d@. Later stage, showing origina-
tion of the gill-chamher. «. Later stage, showing commencement of
formation of the gills. Aiter Sachs.
becomes very much stretched and forms a membrane, extending
from the stipes to the lower margin of the pileus. It ultimately
ruptures and leaves the gills exposed. This membrane is
known as the velum partiale. The gills are composed of
hyphe, which run parallel along their length, ultimately curving
slightly outwards. These constitute the tram ( fig. 854, f), and
are covered by the hymenial layer, which is composed of short
cells derived from the hyphe of the trama, set at right angles
to its long axis. These cells are of two kinds, sterile ones, or
92 MANUAL OF BOTANY

paraphyses, and those which give rise to the spores, the basidia.

Fach basidium puts out four delicate outgrowths, closely

resembling those of the promycelium of the Uredinee, and

from each of these a single gonidium or spore is abstricted.

These, from their mode of

Fie. 854. origin, are known as bast-

diospores or basidiogonidia
(fig. 854, ©, 9).

The form of the fructifi-
cation varies a good deal in
different groups. In some
the hymenium is exposed
from its first formation ; in
others it is covered for a
time by the velwm partiale ;
in yet others it is always
surrounded by a membrane,
which is then known as the
peridiwm, as in the Gastero-
mycetes, or the velum uni-
versale, as in some Aga-
ricine. The hymenium is
also variously arranged ; in
the true mushrooms it
covers the gills as described ;
in the family Polypore it
lines pits or tubes on the
under surface of a flattened
expansion ; in the Gastero-
ENO, oI mycetes it is formed in the
\ : interior of the fructification

J

   

in a number of chambers.
The basidia are usually

Fig. 854, A. Section of five gills of the Mush- unicellular, but in one
room, B. One gill more highly magnified. h acai
jf. Trama, e, Hymenial layer. c. Hymenial SYOUup, the Protobasidiomy-

sndiea t Pobevan. ebay Seem hey Se Gieided fy
menial layer. After Sachs. : septa, sometimes  trans-
verse, sometimes longitu-
dinal, forming four cells, each of which produces a single goni-
dium. These forms approach the promycelium of the Uredinee
very closely.
Vegetative reproduction occurs in this group, by the forma-
tion of gemme, which commonly arise on the vegetative
THALLOPHYTA—FUNGI 93

mycelium as oidium cells (page 73). Some of the Basidio-
mycetes also produce sclerotia, masses of closely matted hyph
which may become detached from the mycelium and germinate
after a period of quiescence.

In recent years the investigations of Brefeld and his pupils
have led to a different classification of the Fungi, for which
there is much to be said.

The Myxomycetes are taken out of the group and made a
separate class, of equal position to the Alge and Fungi, great
stress being laid on their resemblance to the animal Mycetozoa
or Rhizopods.

The Fungi proper are subdivided into three classes, and
these into sub-classes as under :—-

Cuass J. PHycoMYcETEs.
Sub-Class 1. Zygomycetes.
Sub-Class 2. Oomycetes.
Crass II. Mesomycetes.
Sub-Class 1. Hemiasci.
Sub-Class 2. Hemibasidii.
Cuass III. Mycomyceress.
Sub-Class 1. Ascomycetes.
Series 1. Exoasci.
2. Carpoasci.
Additional. Ascolichenes.
Sub-Class 2. Basidiomycetes.
Series 1. Proto-basidiomycetes.
2. Auto-basidiomycetes.
Additional. Basidiolichenes.
Additional. Fungi imperfecti.

According to this school these groups can be arranged in the
form of a tree, indicating the probable line of descent or succes-
sion of forms. The Phycomycetes are held to be the primitive
type and to be descended from sporangia-bearing Chloro-
phycee.

Phycomycetes

Zygomycetes Oomycetes
|

Hemiasci Hemibasidii . . Mesomycetes.

Ascomycetes Basidiomycetes . Mycomycetes.
94 MANUAL OF BOTANY

The Phycomycetes form the lowest group and include all
the forms which as well as asexual show sexual reproduction
by fusion of differentiated gametes. They thus include the
Mutvorini, the Peronosporee, and the Saprolegniacex.

The Mesomycetes comprise the intermediate forms between
the Phycomycetes and the Ascomycetes and the Basidiomycetes
respectively. They approach the latter in their vegetative organs,
especially their incompletely septate mycelium. They differ from
them in not possessing definite asci or basidia. They have no
sexual organs, differing thus from the Phycomycetes.

The Hemiasci are a small and comparatively unimportant
group; the Hemibasidii include the Ustilaginex, or smuts.

Through the Mesomycetes the line of descent passes to the
Ascomycetes on the one side and the Basidiomycetes on the
other, which together form the group of the Mycomycetes.
These have septate hyphe, and produce their spores at some
time or other in asci or on basidia. Sexual reproduction is un-
known.

The Ascomycetes embrace, generally speaking, the forms
included under the same name in the older classification, except
that the Saccharomycetes are excluded. The Ascolichenes are
held to belong to this group and are not put into « separate
class. The Ascomycetes are divided into two series, the
Exoasci, where the asci are simple and free, and the Carpoasci,
where they are gathered into the various forms of fructification
already described. :

The Basidiomycetes are a larger group than in the old
system, as the Aicidiomycetes are included in it. The latter
are referred to the series Protobasidiomycetes on account of the
mode of germination of the teleutospore, which gives rise to
what was formerly called a promycelium on which were borne
sporidia. This promycelium is held to be a protobasidiwm,
from each cell of which a basidiospore is segmented. The Auto-
basidiomycetes comprise what under the older system were
called Basidiomycetes, except the Auriculariacee and the Tre-
mellacer, which form with the Uredinee the first series.

The Basidiolichenes are held to be members of this group,
though not referable to either of the two series.

Finally, the Saccharomycetes are separated from the rest on
the ground that their life history is very imperfectly known,
and that they probably are only stages in the life cycle of some
polymorphic form of the higher Fungi. They are classified as
an additional group under the name Fung? imperfecte.
THALLOPHYTA—LICHENES 95

Cuass ITI.—LICHENES.

The propriety of considering the Lichens as a separate class
is perhaps open to discussion. Before their true nature was
understood they ranked as such, but when they were ascertained
to be largely fungal in their composition, and to contain alge in
their tissues, they were perhaps hastily relegated to the Fungi,
assuming them to be parasitic on the alge within them.
Further study has shown them to be symbiotic organisms, the

Fic. 855.

 

Fig. 855. A. Usnea barbata, a fruticose lichen (natural size). B. Sticta pul-
monacea, a foliaceous lichen. «a. Apothecia. After Sachs.

alga and the fungus living together to the mutual advantage
of both. The constituents may also sometimes vary, the same
alge growing with different fungi and vice versa. They may
consequently be restored to something of their old position.

The lichens are thallophytes of various form, living on old
trees, rocks, &c., and presenting always a peculiar withered
appearance. According to their habit, they may be divided into
fruticose, foliaceous, and crustaceous lichens.
96 MANUAL OF BOTANY

The fruticose forms have an erect thallus, which branches in
a somewhat shrubby fashion. A typical lichen of this type is
Usnea barbata (fig. 855, a). The foliaceous ones are flattened
and grow closely and pressed to the substratum. The thallus is
wavy and its margin lobed. The crustaceous forms are usually
very indistinct, their outline indefinite, and only their fructi-
fication distinctly seen. They become so attached to their sub-
stratum that they cannot be detached from it completely with-
out injury (fig. 856).
In composition the thal-
Fie. 856. lus consists of a fungoid
mycelium, which is very
closely matted together.
It includes in its substance
certain alge, which may
be distributed throughout
it or confined to a definite
layer near the upper surface,
constituting the homotome-
rous and heteromerous kinds
respectively. In the former
case the alge generally be-
long to the Cyanophycer,
and in the latter to the Chloro-
phycee. This distinction is,
however, by no means abso-
Inte. The fungal constituents
are chiefly referable to the
\ sub-class Ascomycetes, and
Fig, 856. A,B. Graphis elegans, a crustaceous 80 great is their prominence
lichen growing on the bark of the Holly. that the whole group has
Perini Walfeni, another erustaceous BY Some botanists been de-
lichen (slightly magnified). After Sachs. geribed as a family of this
sub-class. Other fungi, how-
ever, are now known to enter into the symbiotic relationship
with alge, especially several belonging to the Basidiomycetes.
The proof of the true character of the lichens is based upon
the facts that the two organisms can be cultivated separately,
and that if the spores of one of the fungi be sown amongst some
of the alge the composite organism can be produced.
A section of the body of one of the heteromerous foliaceous
lichens is shown in fig. 857, where the distribution and
character of the fungal mycelium are shown. g is the layer of

 
THALLOPHYTA —LICHENES 97

algee which are symbiotic with the fungus. In the fruticose
forms the centre of the branches is occupied by a dense strand of
hyphe running longitudinally. This is surrounded by a looser
layer which is in turn enclosed by a compact cortex. The alge
are found in the loose tissue.

The reproductive organs of the lichen are always produced
by the fungal constituent. The fructification is usually an
apothcecium produced after the fusion of a spermatium with the
trichogyne of an archicarp, as described in the case of Collema
(page 82).

The hymenial layer of
the fructification of the form
into which a basidiomycete OOACECO SS

niters has basidi . SRILA CETTE FOC SY
enters has basidia and para : cunle ey Ha ae eKo
ave |

Fie. 857.

   

physes like those of the
ordinary Basidiomycetes.

The mode of growth of
the lichen is in most forms
determined by the fungus
constituent, the alge divid-
ing and multiplying as the
thallus extends. In some
cases the alge are more
prominent, the fungus-hy-
phe being very fine and
delicate. The alge occupy
nearly the whole substance
of the branches, and are
covered by a gelatinous en-
velope derived from their
cell-walls. In this the deli- Fig. 857. Transverse section of the thallus of
cate fungus-hyphe ramify. Sticta fuliginosa (x300). 0. Cortical layer

The lichens reproduce itachine fires’ wn, Medullary layer, oon:
themselves vegetatively by sisting of fungal hyphe. g. The algal cells.
forming peculiar gemmeze
termed soredia. These are composed of a small bundle of
fungal filaments investing a few algal cells. They are cast off
from the surface of the thallus and speedily reproduce it.

The Alege which take part in the composition of lichens are
usually very simple unicellular or filamentous forms, such as
Nostoe, Chroococcus, Scytonema, Protococcus, &c. Rarely
higher forms are found, such as members of the Coleo-
chetacer.

VOL. IL. u
98 MANUAL OF BOTANY

CHAPTER IV.

Group II.
BRYOPHYTA.

Tue plants of this group show a great advance in complexity
of structure when compared with the Thallophyta. There is a
well-marked antithetical alternation of generations, the gameto-
phyte giving rise to the sporophyte uniformly as the result of
the fertilisation of a female sexual cell. The spore on germina-
ting always produces a gametophyte.

The gametophyte is the body which is usually termed the
plant, the sporophyte is a stalked spherical or ovoid structure
which arises upon it and never has a separate existence. The
gametophyte shows considerable morphological differentiation ;
in the lower forms it is a thallus; in some a little higher it is a
thalloid stem bearing a few rudimentary leaves ; in the highest
forms it is a leafy shoot. There are never any true roots, but
a number of unicellular root-hairs, or multicellular filaments,
attach it to the soil. It always contains chlorophyll, the
arrangement of the plastids presenting considerable variety.

The gametophyte consists of two parts. When the spore
germinates it does not at once produce what we recognise as
the plant, but gives rise to a structure called the protonema
(fig. 858), which is sometimes a flattened plate-like body and
sometimes a much-branched filament. Upon this protonema
the plant arises usually as a lateral bud, which grows up into the
form of the adult gametophyte.

The protonema contains chloroplastids in all its cells; it
exists usually for a short time only, though in some of the
Mosses it persists for a long period. Generally in the Hepatica
the protonema gives rise to only one plant; in the Mosses, on the
other hand, several may spring from it.

The anatomical differentiation of the gametophyte is not
very great. The tissue is nearly all parenchymatous, but in
some of the Mosses there is in the axis an indication of vascular
BRYOPHYTA 99

tissue occuping the centre. This is, however, very rudimentary,
true vessels or tracheids never being found. A similar tissue
occursin the midribs of the leaves in some species. The epidermis
is not completely differentiated and bears no stomata. The
apical meristem is usually well defined, and consists sometimes
of a single apical cell and sometimes of a group of such cells.
The sexual organs, borne only on the gametophyte, are of
two kinds, antheridia giving rise to antherozoids or spermato-
zotds, and archegonia, containing each an oospherc. In most
cases they arise in groups, often on special receptacles, or at the
apices of leafy shoots. They are generally surrounded by some

Fie. 858.

   

cK

Fiy. 858. Protonema of Moss. a. Early stages of germination of spore.
B. Developed protonema on which young bud, & w, is formed, which will
give rise to the moss plant. After Sachs,

arrangement for protection, being either embedded in the tissue
of the receptacle or furnished with foliaceous investments. The
antheridia are club-shaped, spherical, or ovoid bodies, furnished
with a stalk ( figs. 859 and 866). They consist of a wall composed
of a single layer of cells, and a mass of cells in the interior, each
of which gives rise to a spirally coiled body furnished with two
long cilia and known as a spermatozoid or antherozoid. The
cells in which the latter bodies are developed are known as
mother cells. When the antheridium is mature it bursts, and
the mother cells escape, the spermatozoids being discharged
from thei later ( fig. 860, 4). Hach antheridium produces a large

number of the latter.
H2
100 MANUAL OF BOTANY

The archegonia are flask-shaped bodies, provided with a short
stalk and a long neck (fig. 867). The swollen portion at the
base is the venter and contains the oosphere. The wall of the
venter is continued upwards to form the neck. The axis of the
archegonium is occupied by a number of cells, the lowest one of

Fie. 859.

 

Fig, 859. Apex of fertile shoot of Moss (Polyfrichum) bearing autheridia,
ant, and paraphyses, par. J. Leaves of the shoot.—/7g. 860. A. Anthero-
zoids of Moss (x1200). B. Antherozoids of Fern ( x 700).

which gives rise to the oosphere and the remainder are known
as the neck-canal-cells. Before forming the oosphere the lowest
cell divides into two, of which the upper one is the smaller, and
is known as the ventral canal-cell. The other one is the
oosphere. The terminal cells of the neck separate when the
archegonium is mature. The neck-canal-sells and the ventral
BRYOPHYTA 101

canal-cell become converted into a kind of mucilaginous material,
so that a spermatozoid can make its way down the neck to the
_oosphere, and, fusing with it, form the zygote or oospore.

The process of fertilisation is rendered possible by the fact
that the surface of the plant is generally moistened by rain or
dew. The liberated spermatozoid can make its way about in
this moisture, swimming by means of its cilia. It appears to be
attracted to the archegonium by the mucilaginous contents of
the neck, which escapes when the lid-cells of the neck separate.
This is said to contain a sugar, possibly cane-sugar, which is the
attractive matter.

The oospore germinates at once, without becoming detached
from the archegonium. It divides into two cells by a wall,
known as the basal wall, forming an epibasal and a hypobasal
half. The former gives rise, by further segmentation and
division, to the body of the sporophyte, which is a capsule known
as the sporogonium. The hypobasal cell usually in a similar
way develops a structure known as the foot, which attaches the
young sporogonium tothe gametophyte. There is no continuity
of tissue, however, between the two; the foot forms a means of
attachment only, and serves to absorb nutriment from the
gametophyte. In some forms the foot is not developed from
the hypobasal cell, which does not divide at all, but remains
rudimentary and functionless. Then a foot is derived from the
lower part of the mass which is of epibasal origin. In the
Ricciew there is no foot, but both hypobasal and epibasal cells
go to form the capsule. Sometimes the capsule is developed
only from the upper part of the epibasal mass, the lower part
forming a more or less elongated seta or stalk.

As this development takes place from the oospore in situ,
the growth of the sporophyte is attended by changes which
take place in the archegonium. The venter of the latter grows
as the sporophyte increases and forms an investment to it which
in the forms with sessile sporogonia, remains surrounding it till
the spores are ripe. In the stalked forms it is ruptured by the
elongation of the seta and carried up on the top of the capsule.
This investment is known as the calyptra. When it is ruptured
the part which remains at the base of the seta and forms a
sheath to it, is known as the vaginula.

The body of the sporogonium soon shows a differentiation
into an external portion known as the amphitheciwm and an
internal part called the endotheciwm. In the higher forms an
air space arises in the inner part of the amphithecium, which is
102 MANUAL OF BOTANY

bridged over by strands of cells. The amphithecium gives rise
generally only to the wall of the capsule, but in one or two
families the sporogenous tissue is derived from it. In most
eases the latter springs from either the whole or part of the
endothecium. In the latter case a central portion of the tissue
remains sterile and constitutes the columella.

The spores are derived from a mass of cells which are early
marked off by the richness and granularity of their contents.
These are known as the archesporium. In most cases in the
Hepatice the whole of the endothecium becomes sporogenous ;
in the remainder (Anthocerotacez) the archesporium is the inner
layer of the amphithecium. In the Mosses it is generally the
outer layer of the endothecium ; the Sphagnacee forming an
exception, behaving like Anthoceros. In the genus Archidium
of the Mosses the sporogenous tissue is found in the endothecium,
butis not regularly arranged as in the other groups.

Inthe Hepatice the archesporium consists of cells which are
of two kinds, some sporogenous, giving rise to spores, others
sterile, generally becoming elongated and narrow, with a peculiar
spiral thickening on their walls. These are known as elaters ;
they help to disperse the spores when the capsule opens, becoming
suddenly elongated by virtue of the longitudinal extension of the
spiralband. Elaters are absent from one family of the Hepatice.
the Ricciez, where all the archesporial cells are sporogenous.

The sporogenous tissue of the archesporium consists of a
number of cells with granular contents. Sometimes a good deal
of cell-division goes on in this area, sometimes not. Eventually
what are known as the mother cells of the spores constitute its
substance. In each of these four spores are produced by free cell-
formation in the way already described. They are situated at
points corresponding to the four angles of a tetrahedron, and the
groups are often spoken of as tetrads. Before the spores are
fully developed the mother cells separate from each other, and
later the spores themselves are set free from the latter, each
being now a mass of protoplasm, covered by a cell-wall of two
coats which the latter has secreted round itself.

The spores are liberated by the rupture of the capsule or its
decay. When rupture takes place it may be irregular, or by
splitting into valves, or by the separation of the upper portion in
the form of a lid known as the operculum.

The sporogonium thus formed shows a certain morphological
differentiation, there being in the segmentation of the zygote an
indication of the formation of root and shoot, the latter being the
BRYOPHYTA 103

result of the development of the epibasal cell while the root is
represented by the body developed from the hypobasal one (see
vol.i.p. 11). The shoot is not differentiated morphologically,
always being a thallus and never bearing leaves.

Besides the regular sexual reproduction, leading to antithetical
alternation of generations as described, the gametophyte may and
often does reproduce itself vegetatively, giving rise to a kind
of homologous alternation also. It rarely possesses the power of
forming gonidia, which we have seen to be so common among

Fia. 862.
Fie. 861. A

 

Fig. 861. Section of cup-shaped receptacle
of Marchantia, in which gemme, a, are

being developed. Fig. 862, A. Aulo- < nt
comnion androgynum, showing gemme oN

borne upon a long stalk. B. Collection ye fe
of gemme magnified. for

a

 

 

the Thallophytes. It often, however, produces gemmce upon some
part ofits surface. These gemme have a very varied distribution ;
in many Hepatice they arise in cup-shaped receptacles upon the
upper surface (figs. 861 and 866); in others they are developed
upon the leaves ; in the Mosses a collection of them is sometimes
found upon a long stalk (Aulocomnion) (fig. 862), or they may
oceur upon the axis or on the root hairs. They are generally
flattened masses of cells, sometimes with definite growing points.
Most mosses can put out protonemal filaments from various parts
of their surface, which can develop new plants as did the original
protonema. Frequently branches are separated from the plant
by the dying away of the older tissue at their bases, and these
then become fresh plants.

The Bryophyta include the two classes of the Hepatice or
Liverworts and the Musci or true Mosses. ;
104 MANUAL OF BOTANY

Cuass IV.—HEPATICH (LIVERWORTS).

The differences which are met with between this group and
the succeeding one chiefly concern the sporophyte. In the
Hepatice the sporogonium is never set free from the calyptra
till the spores are mature; the calyptra is never carried up as a
cap to the sporogonium, but the whole of it remains as a
vaginula; there is no gradual elongation of the seta. Except in
the Anthocerotacee there is no columella in the sporogonium,
but the whole of the endothecium becomes the archesporium ;
except in the Ricciee sterile cells, generally elaters, are developed
as well as spores from the archesporial tissue. The vegetative
body is less differentiated anatomically than in the Mosses ;
there is never any vascular tissue indicated in either sporophyte
or gametophyte, nor are stomata present in the epidermis of the
former, except in Anthoceros.

There are two types of structure found in the group, in one
of which the gametophyte is a thallus or thalloid shoot, in the
other it is a leafy shoot. These are spoken of as thallose and
foliose respectively. The former include the two orders
Marchantiacee and Anthocerotacee, the latter are found among
the Jungermanniacez.

THALLOSE Liverworts.—A typical representative of the
thallose liverworts is Marchantia polymorpha, the structure of
which may be described in detail. From the spore there is
developed a small protonema, which, at first filamentous, expands
into a flat cellular plate, on which arises by budding the body of
the plant. This has a thick creeping dichotomously branching
thalloid stem, from the under side of which a number of root hairs
or rhizoids are given off. It also bears on the lower surface two
rows of scaly leaves. The upper surface is somewhat corrugated
and bears the sexual organs on special receptacles or gameto-
phores; it also gives rise to a number of circular gemme cups or
cupules, in which the gemme arise from superficial cells (fig. 866),

The shoot is dorsiventral, the two surfaces showing marked
differences in structure.

The upper surface is marked by somewhat indistinct lines,
dividing it into a number of lozenge-shaped or rhomboidalareas, in
the centre of each of which is a pecuhar opening or pit leading
into an air-chamber, which is bounded above by a single layer
BRYOPHYTA—HEPATICA 105

of cells forming the upper epidermis. From the bottom of this
cavity arise a number of short filaments which contain numerous
chloroplastids (jig. 863). The pit or opening is bounded by a
number of tiers of cells, constituting what is sometimes called a
stoma. It is not, however, a true stoma, as the cells have no
power of opening or closing the aperture (fig. 864).

Below the layer of air-chambers the thallus consists of
several layers of elongated thin-walled or but slightly thickened
parenchymatous cells which have no intercellular spaces and
which contain few chloroplastids. These cells become smaller
and more compact as the ventral surface is approached. The
outer layer of these is not especially marked off as a lower
epidermis.

The root hairs or rhizoids are long and unbranched. Some

Fig. 863.

 

Fig. 863. Section through an air-chamber of the surface of the thallus of
Marchantia, showing chlorophyllaceous tissue and stoma, After Kny,

of them contain peculiar peg-like projections of cellulose in their
interior. ,

The thallus grows by the divisions of a group of apical cells
which are situated in a depression at the anterior end. The
branching is truly dichotomous.

The cupules bearing the gemme# spring from the air-
chamber layer, of which they are outgrowths. Their walls show
similar air-cavities to those of the rest of the shoot (fig. 865).
The gemmez themselves arise from single cells of the epidermis
of the base of the eupule, which elongate upwards and segment
into two, of which the lower forms a stalk, while the former
develops into a somewhat circular plate, with a conspicuous
notch or depression on each side. In these depressions the
106 MANUAL OF BOTANY

growing points are formed. Each gemma is several cells thick
in the centre, but the layers thin out towards the margin, where
it is only one cell thick. When it falls to the ground after
liberation from the cup, the lower surface puts out root hairs
and the upper takes on the structure already described. There
is at first no difference in structure between the two sides;
whichever happens to come in contact with the ground becomes
the ventral one. The gemma contains chloroplastids.

Marchantia is a dicecious form; some shoots give rise to an-
theridia, others to archegonia.

Both these organs are borne on special gametophores, which
spring from the upper surface of the thallus. The antheridiophore

Fic. 865.

  

Fig. 864. Surface view of the so-called stoma of Marchantia (x 250). After
Kuy.—V’ig, 865. Receptacle of Marchantia with gemme, a.

(fig. 866, d) is a thick fleshy stalk which spreads out at the summit
into a somewhat flattened circular disc, which is lobed at its
margins. The disc has several growing points, each producing
antheridia, in acropetal succession, which are seated in de-
pressions on its upper surface. The surface of the disc contains
air-chambers like those of the rest of the thallus. The antheridia
have the structure already described; the depressions in which
they are seated are flask-shaped, and only communicate with
the exterior by a narrow canal.

The archegoniophore is somewhat more complex. Like the
antheridiophore, it is a long stalked body, crowned by a disc.
The latter is not a flattened structure, but consists of eight
arms or branches radiating from the centre of the stalk, some-
BRYOPHYTA—HEPATICA 107

what like the ribs of an umbrella. The archegonia are
developed on its under surface in the angles between the ribs
and the stalk (figs. 867 and 868).

The elongation of the stalk is proceeding while the arche-

Fic. 866.

   
 
  
  
    
    
  
  

Spa
ry
zi =

RHEIN,

aS

or

Sr

Sy

Sao eo ss

ae
ee

SSeS

Fig. 866. Thallus of Marchantia with gemme cups, }, and antheridiophore, d.
The upper figure is a section through part of d. a, b, c, d, e, f. Antheridia
in depressions in successive stages of development. After Kny.
gonia are being developed, and they do not spread out freely till
fertilisation is effected.

The structure of the archegonia has been already described.
They are not embedded in the tissue of the receptacle as are
the antheridia, but they are invested by a peculiar outgrowth
from it, called the pertchetiwm, which often surrounds a group
108 MANUAL OF BOTANY

of them. This springs from the air-chamber layer, but thins
out as it grows, forming a membranous structure which is very
much dissected or lobed. Besides this perichetium, another
membrane, the perigynium, grows up from the base of each

Fie. 867.

i
ai

——— :
a

Se

—

eee eee ee a ee

 

Fig. 867. Archegoniophore of Marchantia, bearing archegonia on under sur-
face, 2, 3, 4, 5, 9. 10,11. Successive stages in development of archegonia,
14. Root hair with characteristic thickening on the walls. After Kny.

archegonium itself, surrounding it as a kind of open sac as it
approaches maturity.

Both the antheridiophore and the archegoniophore are com-
pound, being composed of two coherent branches, the ventral sur-
faces of which are consequently internal, From these ventral sur-
BRYOPHYTA—HEPATICAs 109

faces root hairs are originated which may be found, on section
of the structure, passing down the centre of the stalk.

The sporophyte or sporogonium arises in the manner de-
scribed for the whole group. After the division of the oospore

Fic. 868.

 

SS
Fig. 868. 1. Thallus of Marchantia bearing archegoniophores. a, b, c, d, f.
Successive stages in their development. 2,3. Upper and under appear-
ances of archegoniophore when the sporogouia are mature. 6. Young
sporogonium. 7. Adult sporogonium dehiscing and discharging the
spores. 8, Elater, with mother cells of spores adhering to it. After Kuy.

into epibasal and hypobasal segments, two other walls are
formed at right angles to each other and to the basal wall,
dividing the oospore into octants. The hypobasal octants
give rise to a somewhat bulky foot, while the epibasal ones
110 MANUAL OF BOTANY

develop the capsule. All the cells of the endothecium go to
form the archesporium, which gives rise to the spore mother
cells and to the elaters. The latter are very hygroscopic, and
assist in the disseminating of the spores when the capsule
opens. When mature, the capsule is forced out of the calyptra
by the elongation of a short seta, or stalk, developed from the
hypobasal region by intercalary growth. It then opens longi-
tudinally by a number of fissures, and the spores are liberated.

Other members of the thallose group show certain differ-
ences from Marchantia. In the lower forms the sexual organs
are not borne upon special gametophores, but arise from the
ordinary dorsal surface of the thallus. In some the plants are
not dicecious, the same thallus producing both antheridia
and archegonia ; in some Riccias both organs occur together in
the same sorus.

In Anthoceros and Blasia, chiefly on the under surface of
the shoots, various cavities occur which are filled with mucilage.
In these, quantities of the Alga Nostoc live symbiotically. The
cavities become irregularly septate in consequence of filamen-
tous outgrowths from the cells of their walls.

Anthoceros is peculiar also in the fact that its chloro-
plastids contain pyrenoids like those of the Algw.

The sporogonium of Anthoceros is peculiar in two respects.
Its endothecium is sterile and forms a columella, while the
archesporium is developed from the inner layers of the amphi-
thecium. It continues to elongate by basal growth, forming a
long pod-like body which dehisces from the apex downwards by
two valves.

Foutose Liverworts.—The foliose liverworts have a dorsi-
ventral axis bearing leaves which are generally of two kinds.
The ventral surface produces a row of very rudimentary ones,
which are known as amphigastria, while on the lateral faces are
developed the ordinary foliage leaves. Root hairs also spring
from the ventral side, and mucilaginous secreting hairs occur
near the growing point.

The growth in length is carried out by a single apical cell,
which is sometimes two-sided, and hence cuts off two series of
segments. In some forms the apical cell is a three-sided pyra-
mid. Each segment produces a leaf and also contributes to the
increase of size of the stem. The branching of the axis is
usually monopodial.

Vegetative reproduction is carried out by means of gemme,
as in Marchantia, but the gemme are, as a rule, simpler in
BRYOPHYTA—HEPATICAH 111

structure, often being composed of only one or two cells. They
arise either from the margins of the leaves or from the axis near
its apex.

The antheridia are stalked somewhat globular bodies which
are not sunk in the tissue as in Marchantia, but arise singly
or in groups on the shoot near its apex, in the axils of the
leaves.

The archegonia are developed later, sometimes from the
same shoot as the antheridia. They are sometimes solitary, some-
times in groups, and are surrounded by a kind of involucre formed
either by the cohesion together of the youngest whorl of leaves,
or by a perichetial outgrowth resembling that of Marchantia.
They are produced
directly from the apical
cell or its youngest
segments, so that they
are terminal in their
position. Usually each
archegonium is pro-
tected also by a peri-
gynium.

The histological
differentiation of the
shoot is very slight.
The stem possesses an
axial strand of cells
which have thin walls,
while the cortex is
made up of fairly thick-
walled cells. There is
no indication of any-
thing like vascular Fig. 869. Sporogonium of J i
tissue. The leaves are a. Thigpies 3 Falee foot, After Bache
simple plates of cells
of uniform substance, being only one cell thick.

The sporophyte is mainly derived from the epibasal cell of
the first division of the oospore, the hypobasal one often not
developing at all, but remaining in an atrophied condition at
the base of the stalk of the capsule. The epibasal mass then
can be differentiated into the capsule and a bulky stalk or seta,
the lower end of which swells and forms a false foot (fig. 869).
The archesporium is co-extensive with the endothecium and
produces spores and sterile cells, usually elaters. When it is

Fic. 869.
a H

  

a

    
112 MANUAL OF BOTANY

mature the capsule dehisces, sometimes regularly by valves,
sometimes irregularly.

A calyptra is formed during the growth of the embryo or
sporophyte, much as in Marchantia. When the capsule is
mature, a rapid growth of the short seta ruptures it at the apex,
and the sporogonium is exposed. It then dehisces as described.

According to Goebel, there is a possible link between the
Hepatice and the Chlorophycex in the genus Anewra, from the
thallus of which certain cells are liberated which may be com-
pared with the zoospores of the latter. On liberation each
divides into two cells, and ultimately gives rise to a new gameto-
phyte. They differ from zoospores in not possessing cilia.
BRYOPHYTA-—-MUSCI 113

Crass V.-MUSCI (MOSSES).

In the group of the true mosses a still further advance, espe-
cially in the direction of anatomical differentiation, is seen. The
gametophyte is always foliose, and bears rhizoids instead of
simple root hairs. The sporogonium escapes from the calyptra
before the spores are mature ; it never contains elaters, and always
possesses a well-defined columella. The plants are of small size,
and grow upon the earth, rocks, trees, or old walls; some are
saprophytic, growing on decaying wood, &c. A few are aquatic.

Fic. 871.

 

 

Fig. 870. Protonema of Moss. A. Early stages of germination of spore.

B. Developed protonema on which young bud, & 2, is formed, which will
give rise to the moss plant. After Sachs,

The protonema is in most cases a filamentous structure,
copiously branched. The septa are usually arranged obliquely
across the filament. Generally part of it ramifies below the
surface of the soil and is colourless, while the remainder con-
tains chloroplastids. Each filament grows by segmentation
of a single terminal or apical cell.

The shoot is rarely dorsiventral as in the Liverworts. It grows
by means of an apical cell, which is usually three-sided, and
gives rise by its segmentation to three rows of leaves. It is
frequently branched, the branches arising not in the axils of the
leaves, as in the Phanerogams, but either beside or below them.

VOL. II. I
114 . MANUAL OF BOTANY

The branching is usually monopodial, but sometimes cymose.
From the base of the shoots a number of rhizoids spring and
affix it to the substratum. The plant is not supplied with water
exclusively by these, the leaves having the power of absorbing
liquid.

The shoot is differentiated into stem and leaves. The
anatomical structure of the stem is interesting as giving the
first indication of a central stele, which, is, however, very
rudimentary. The outer layers form a cortex of somewhat
prosenchymatous cells with thick walls. This gradually passes
into a thin-walled parenchyma. In some forms the axis is
occupied by a strand of
small rather thin-walled
cells or tracheids (fig.
872). In others there is
a rudimentary vascular
stele consisting of a num-
ber of cells, which are
partly parenchymatous
and partly prosenchy-
matous. The latter cells
are tyracheids, as are
those of the first type;
true vessels are never
developed. This central
group of cells, partly thin-
walled, partly thick -
Fig. 872. Section of stem of gametophyte of walled, corresponds to the

ean ceuenacainomes cn the Stele Th ts

al epidermis. After Sachs, ae Eales cells,
which correspond to phloém. There is no pericycle and no
endodermis.

The leaves which are developed on the stem are simple in
most mosses, consisting often of a single layer of cells. Some
forms are furnished with a midrib, chiefly composed of thick-
walled cells almost prosenchymatous in shape. In some the
midrib is penetrated by rudimentary vascular strands, which
enter the stem and join its axial stele. The cells of the leaf all
contain chloroplastids.

The leaves of the bog-mosses (Sphagnum) show a peculiarity in
containing cells of two kinds (fig. 873) ; some are large, broad and
almost lozenge-shaped, empty of contents, and marked by curious

Fie. 872.

 
BRYOPHYTA—MUSCI 115

spiral thickenings ; others, which form a network between the
large ones, are small and tubular and contain chloroplastids.

Fie. 873.

   

The antheridia and arche-
gonia are usually borne amid
clusters of leaves at the apex of
a shoot. Most generally there
are several together, though this
is not always the case. Some-
times a shoot bears only an-
theridia, sometimes only arche-
gonia, sometimes archegonia in
the centre of the sorus or collec-
tion, and antheridia around the
periphery. We may thus have
monecious, dicscious, or herma-
phrodite arrangement.

The sorus is invested with

Fig. 873. Leaf of Sphagnum. a. Sur- leaves of rather different cha-

face view. B. Section.

racter from the ordinary foliage

Fic. 874,

 

Fig. 874. Apex of fertile shoot of Moss (Polytrichum) bearing antheridia,
ant, aud paraphyses, par. 1. Leaves of the shoot.

leaves; the innermost of them at any rate growing up in a sort
of perichetial fashion round the base of the capsule as it begins

To
116 MANUAL OF BOTANY

to develop. There is no special perichetium produced as in the
liverworts.
Among the sexual organs are developed hairs of peculiar
form known as paraphyses. These are multicellular, and often
terminate in a globular head.
Fie. 875. They are singular in that their
cells often contain chloroplastids.
The antheridia differ but little
from those of the Hepatice ; they
are club-shaped or rounded bodies,
mounted on short stalks, and con-
sist of a wall surrounding a cavity
in which are the antherozoids.
They open in the mosses by split-
ting across the apex. The mother
cells of the antherozoids escape
before emitting the antherozoids.
They are attached to each other
by a sort of intercellular mucilage
derived from the cell-walls. This,
however, dissolves as soon as it
comes into contact with water.
The archegonia have the same
general structure as those in the
preceding group (fig. 875). There
is a body or venter, and a long
generally twisted neck. The body
or venter is usually thicker than in
the liverworts, and consists of two
layers of cells. It contains, as in
other cases, an oosphere, while the
neck is filled with mucilage derived
from the disintegration ofits canal-
cells and of the ventral canal-cell
cut off in the formation of the

 

Fig. 875. A. Apex of shoot of Funaria
with two archegonia. B. Neck of oosphere.

archegouium, showing mode of The vegetative reproduction of
separation of the cells. c. Immature E &
archegonium. After Sachs. the gametophyte is very varied.
The chief feature of it is the ease
with which almost any part of the plant can produce
protonemal filaments, even root hairs doing so if exposed
to light in a moist atmosphere. Similar outgrowths may

spring from the rhizoids, or from the leaves, or frcm
BRYOPHYTA—MUSCI 117

the summits of the shoots which produce the reproductive
organs.

Besides these protonemal outgrowths leaf-buds are sometimes
formed which become detached and grow at once into moss
plants. They may arise on different parts of the plant, but
seem to be most easily developed upon root hairs. Some mosses
multiply by the separation of branches, or by the production of
stolons.

Definite gemme like those in the Marchantiacee are also of
frequent occurrence. They are stalked flattened bodies of more
or less circular shape, and consist of a single layer of cells. Many
of them are developed together at the end of a long support-
ing axis in Awlocomnion androgynum (fig. 876) ; in Letraphis
pellucida they are produced in a terminal cup, which is composed
of severalleaves. When detached from the plant and transported
to moist soil they germinate, putting out a protonema, on which
a new gametophyte arises by the formation of a lateral bud.

It is in the structure and development of the sporogonium
that the mosses chiefly show a great advance upon the liver-
worts. A sporogonium typical of most mosses is that of
Funaria hygrometrica, the structure of which may be examined
in some detail.

The first division of the oosphere is, as before, caused by the
appearance of the basal wall, dividing it into epibasal and
hypobasal segments. The latter takes little part in the subse-
quent development, not dividing more than once in most cases.
In some of the less highly organised mosses, such as Sphagnuin,
it gives rise to a foot, but this absorbing organ in the higher
forms is developed from the end of the seta.

The segmentation of the epibasal cell into octants is unusual.
Instead, by a succession of oblique divisions, an apical cell is
soon produced, and by the repeated division of this the embryo
grows. When it has reached a fair degree of development,
being fusiform in shape, the upper end swells to form the
capsule or theca, and the remainder continues elongating to
form the stalk or seta. As it elongates it ruptures the tissue of
the archegonial wall which still surrounds it. This breaks
across irregularly, and the withered neck with part of the venter-
wall is carried up by the elongating stalk and is recognised as
an easily detachable cap over the capsule. It is called the
calyptra( fig. 877, B 0).

When the capsule has become slightly swollen the tissue of
its substance differentiates into amphithecium and endothecium.
118 MANUAL OF BOTANY

An air space or cavity arises in the former, which extends in-a
cylindrical fashion all round the capsule, being crossed by
strands or filaments of cells forming a number of bridles.

The endothecium gives rise to the archesporium, its outer
layer being transformed into it. The remainder of its tissue,
consisting of large cells, forms the columella. The archesporium
is cylindrical and does not extend across the top of the colu-
mella. The walls of the capsule contain chloroplasts.

The arrangements for causing and regulating the escape of

Fic. 876. Fic. 877.

 

Hig. 876, A, Aulocomnion androgynum, showing gemmex borne upon a long
stalk. mr. Collection of gemmz more magnified. Vig. 877. Funaria
hygrometrica. A, Young sporogonium. c. Capsule. 3B, Adult condition of
the gametophyte. s. Stalk or seta of the sporogonium. f. Capsule or theca.
o. Ca'yptra.- ¢. Section of a sporogonium x80. d. Operculum. yp. Peri-
stome. h. Air space. s. Sporogenous layer. After Sachs.

the spores from the capsule are the operculum and the peristome.
The former is the apical portion of the amphithecium. It is
detached from the rest of the capsule by the swelling of the
walls of a ring of epidermal cells, the annulus, situated at the
point of rupture. This swelling causes the separation of the
operculum from the rest of the theca, and the lid falls off.

The peristome is also developed from the amphithecium just
below the operculum, so that when the latter falls off it forms
a kind of fringe round the margin of the opening. The cells of
BRYOPHYTA—MUSCI 119

the innermost amphithecial layer, situated just above the
termination of the cylindrical air-chamber, undergo thickening
and cuticularisation on their external and internal faces. The
lateral and part of the transverse walls connecting the others
remain unchanged. These, as the peristome dries, break away
from the cuticularised walls, and the latter separate longitudinally
into several strips (fig. 878). There are thus two rows of cuti-
cularised membranous teeth formed, which, so long as the oper-
culum is in position, curve over and meet at a point in the centre.
The outer ones are known as the teeth of the peristome, the inner
ones, which are less strongly thickened, are called cilia. The
number of teeth varies from 4 to 64, according to the number of
longitudinal divisions of the cells. When the operculum falls
off, these teeth uncoil in virtue of their elasticity and remain as
a kind of fringe round the opening.

The base of the capsule below the
air-space is slightly dilated, forming a Fic. 878.
mass of cells known as the apophysis.
This is furnished with stomata, and con-
tains «a large amount of assimilating
tissue.

There is a good deal of variety in
the formation of the peristome in diffe-
rentgenera. Insome, as Gymnostomum,
none is developed. In Tetraphis the
layer giving rise to it is two cells in _ Peristome, p, of Funaria.
thickness, and all their walls become
thickened, forming a plate of tissue. When this is released it
splits into four valves or segments. In Polytrichum the develop-
ment is different. The teeth are formed not of simple pieces of
membrane, but of bundles of thick prosenchymatous cells. A
plate of cells unites the top of the teeth and remains after de-
hiscence of the theca as a structure called the epiphragm.

As the spores mature the rest of the contents of the capsule
dry up and shrink ; when they are ripe nearly everything else has
disappeared, so that the spores lie loose in the cavity of the theca.

Some species show important differences of structure from
the type of Funaria. In Sphagnum the archesporium which
. is developed from the inner layer of the amphithecium is a
hemispherical or dome-shaped band extending across the top
of the capsule and covering the columella. In Polytrichum a
second air-chamber is formed in the endothecium on the inner
side of the archesporium. In a few mosses there is no operculum.

 
120 MANUAL OF BOTANY

The advance in histological differentiation which marks the
gametophyte is also seen in the structure of the sporophyte.
There is a well-marked epidermis furnished with rudimentary
stomata. The seta contains a strand of pseudo-vascular tissue
similar to that described as occurring in the stem. The tissue
of the sporogonium also contains chloroplastids.

The phenomenon of apospory, which is not uncommon in

shies
ged
zB
dean
Sas
a,
oUs
ese
See
xag
563
sac
548
Rg8
33
ga
5
g i:
o
$
Loa
Ee

Columella. d. Sporogenous

the rim of the capsule after the opercul
above these form the annulus.

b. Peristome. ¢.
es

Fig. 879. Upper portion of capsule (sporogonium) of
in

 

the next group, the Pteridophyta, occurs also in some mosses.
Under favourable conditions some of the cells of the sporogonium
put out protonemal filaments which give rise by budding to
new gametophytes. We get thus the formation of the latter
from the sporophyte without the production of spores. This
may be taken as a case of vegetative reproduction, which we
have seen to be so common in the gametophyte generation.
121

CHAPTER VY.

Group III.
PTERIDOPHYTA.

TuIs group, which is sometimes known as the group of the
Vascular Cryptogams, includes the Ferns, the Equisetums or
Horsetails, and the Lycopodine or Club-mosses. They are
called Vascular Cryptogams, to indicate that their tissues con-
tain well-differentiated vascular structures, which we have seen
to be almost entirely unrepresented in the preceding two groups.
The life history embraces two phases, as in the case of the
Bryophyta, but the order of their greater prominence is reversed.
The gametophyte is small, cellular, and usually of very short
duration ; the sporophyte forms what is commonly called ‘the
plant,’ and may persist for many years. It shows considerable
morphological and histological differentiation.

Comparing the group with that of the Bryophyta we note
especially the retrogression in size of the gametophyte, and the
great advance made by the sporophyte. Further, that the
sporophyte does not remain all its life parasitic on the gameto-
phyte, but that it develops roots and leaves, and soon becomes
independent of the latter, which usually perishes as soon as
the sporophyte becomes well established. The latter generally
persists many years, producing its spores annually.

In describing the forms which are included in the group, it
is well to begin with the sporophyte on account of this predomi-
nance.

It shows considerable morphological differentiation, possess-
ing, with few exceptions, root and shoot, the latter consisting of
stem and leaves. The stem is often of considerable size; its
growth may be sub-aerial, but it frequently takes the form of a
rhizome.

The leaves are of very various sizes; in the ferns as a rule
they are large and compound ; in the club-mosses much smaller
and more numerous; in the horsetails reduced to scales closely
122 MANUAL OF BOTANY

surrounding the stem. They are of two kinds ; some are ordinary
foliage or scale leaves ; others bear sporangia, and are known as
sporophylls, as in the higher plants. In the ferns there is
usually no difference between the two, but in the other groups
the sporophylls are often much modified. In the Equisetine
and some of the Lycopodine they are collected together at the
apices of special shoots, forming cones or flowers.

The sporophylls bear the sporangia usually in clusters,
known as sori, which may be exposed to the air, or variously
covered in for purposes of protection. In some cases the
sporangia arise directly from the stem in the axil of the sporo-
phyll. In the ferns and horsetails the sporangia are on the under
or dorsal surface ; in the club-mosses on the upper one.

The primary roots are shortlived, soon being replaced by
adventitious secondary ones. Salvinia has no primary or
secondary roots, nor, so far as we know, have some species of
the isosporous ferns and some of the club-mosses.

A peculiar feature makes its appearance in the Pteridophyta,
which persists throughout all the higher plants. This is the
production by the sporophyte of two kinds of spore, each of which
gives rise to its appropriate gametophyte. The two kinds of
spore differ from each other chiefly in size, some, called
microspores, being very small, and others, macrospores, much
larger. Each is produced in its appropriate sporangium, so that
we distinguish micro- and macrosporangia. The peculiarity of
producing both kinds is called heterospory; we speak thus of
asosporous and heterosporous Vascular Cryptogams.

It some cases all the sporangia of a sorus are closely attached
together as if coherent. They are so developed, never being
free from each other. The resulting body appears like a multi-
locular sporangium, but it is better to regard it as compound
and call it a synangiwm.

A similar multilocular appearance is afforded by the sporangia
of Isoetes, but in this case it is due to bands of the archesporial
tissue becoming sterile, and crossing the sporangium in the form
of a number of trabecule.

Sporangia are classed in two categories, according to the
manner of their development. In some plants, as in many
ferns, they arise each from a single superficial cell. These are
known as leptosporangiate forms. In others, asin the Marattias
and Isoetes, the sporangia arise from a group of cells of the
superficial and sometimes deeper layers as well. These forms are
called ewsporangiate.
PTERIDOPHYTA 123

The anatomical differentiation of the sporophyte shows a
great advance on that of the sporogonium of the Bryophyta.
The epidermal and cortical or fundamental tissue systems are

Fic. 880.

 

Fig. 880. Section through prothallium, p p, and young fern plant. FR. The
latter attached to the former by the foot. «a. Archegonia of the prothal-

lium. A. Root hairs of same. After Sachs.

clearly distinguishable, and the axisis either mono-, schizo- or
polystelic. The stele consists of xylem and phloém, in vascular
bundles, with circumferential pericycle in most cases. There

is often a very marked development
of sclerenchyma either in bands or
patches. The leaves range from very
simple structures to others almost as
well differentiated as the leaves of
Phanerogams; but their mesophyll is
not so well divided into palisade and
spongy parenchyma, and the epidermal
cells contain chloroplastids.

The growth in length of the stem,
root, and leaf is usually effected by the
segmentation of apical cells. In some
cases, instead of a single apical cell
there is a group of them, especially in
the higher forms, where we have indi-
cated an approach to the Phanerogams.
Growth in thickness of the axis rarely
takes place ; there is, however, a modi-
fied cambium in Isoetes and in some
ot the Ophioglossacee. Some of the
fossil forms of this group showed con-
siderable cambial activity, the axis be-
coming of very considerable diameter.

Fie. 881.

 

Fig. 881. Prothallium, p, p, of
Adiantum — Capillus-Veneris
seen from below, showing the
Fern-plant developed from
the fertilised germ-cell of the
archegonium. 0b, First frond.
w,! wv. Roots. h. Root hairs.
After Sachs.

The secondary roots are not developed from the pericycle,
but from the endodermis of the axis; in the horsetails from its
124 MANUAL OF BOTANY

inner layer. They thus originate in the periblem and not in the
plerome.

The growth of the sporophyte from the oospore or zygote
shows considerable variety. Epibasal and hypobasal segments
are produced, as in the Bryophyta, by the formation of a basal
wall. In the ferns and horsetails this is followed by segmenta-
tion into octants. From the epibasal octants the stem and either
one or two primary leaves or cotyledons are then produced, while
from the hypobasal ones proceed the primary root, and w foot
which, as in the Bryophytes, serves to attach the sporophyte to
the tissue of the gametophyte (figs. 880 and 881). The foot is

Fic. 882.

gy
Ln

te
aero
ee PS,

 

Fig, 882, Prothallium (gametophyte) of Fern. After Kny,

in this group a transitory structure, which perishes as soon as
the sporophyte is capable of an independent existence. In the
club-mosses the hypobasal segment gives rise to a suspensor, as
it does in Phanerogams (page 184). This is only composed of a
single cell, or a chain of a few cells in length.

The gainetophyte arises from the germination of the spore, in
most cases becoming free from it (fig. 882), but in certain cases
remaining partly or almost entirely in its cavity (fig. 888). In
the former case it is usually a small thallus composed only of
cells and containing chloroplastids. Its morphological character
is, however, varied; it may be a filamentous much-branched
body, somewhat recalling a protonema, or it may be tuberous
PTERIDOPHYTA 125

and fleshy (fig. 917, »), when it is developed underground and
contains no chlorophyll. It is always known as the pro-
thallium.

In the heteroporous forms there are two kinds of prothallia
formed, one from the microspore, and the other from the
macrospore. Inneither case do we get the prothallium entirely
set free from the spore. They are not very strongly developed,
only sufficiently so indeed to
permit of the production of Fie. 883.
the sexual organs. The pro-
thallium from the microspore
gives rise to antheridia ; that
from the macrospore to arche-
gonia. In some of the iso-
sporous forms the prothallia,
which are all alike as to their
vegetative features, are mo-
necious, producing both an-
theridia and archegonia; in
others, as in the equisetums,
they are dicecious, only bear-
ing one or other of them.

The antheridia are either
immersed in the substance of
the prothallium, as in the
tuberous forms, or project
from the surface as in the
flattened ones. They are
superficial always in their
origin, and consist of a wall
of a single layer of cells, which jig, gg3, Gametophyte produced by the
encloses a number of spirally midcroepare of Salvinia. Bre Etoshallinm
coiled ciliated antherozoids pringsheim. > i
(fig. 860, 8). The archegonia
are also superficial, having a venter embedded in the tissue of
the prothallium, and a slightly projecting neck consisting of only
a small number of cells (fig. 897). The structure is otherwise
like that of the Bryophytes. Fertilisation is effected in the
same way as in the latter group. The number of archegonia
produced often depends upon whether or no the oospheres of
the first-formed ones become fertilised. If not, others are
developed.

Vegetative reproduction of the gametophyte is not uncommon

 
126 MANUAL OF BOTANY

it takes place by means of gemme, or by branches which be-
come detached. Similar reproduction of the sporophyte is
brought about by the development of adventitious buds, arising
on either the petiole or the lamina of the leaf in many ferns.
In some of the equisetums some of the underground shoots
form tubers, which may remain dormant for some time and
ultimately produce new stems. A similar formation is found
in some of the club-mosses.

The phenomenon of apospory is not infrequent. A specially
interesting form of it occurs in Athyrium Pilix-feemina, where
sporangia produced in the normal position grow out into pro-
thallia instead of forming spores. In other cases the prothallia
spring from the tips of the pinne of the leaves.

The converse process, the production of a sporophyte from
the prothallium without the formation of an oospore, is occasion -
ally seen. The prothallium in this case sometimes produces
sterile archegonia; sometimes none at all. The sporophyte in
either case arises as an adventitious bud upon it. This phe-
nomenon is known as apogamy.

The Pteridophyta are usually arranged in three groups or
series, being thought to have arisen by separate lines of develop-
ment from a common Bryophytic ancestor. These three classes
are the Filicine, the Equisetine, and the Lycopodine.
PTERIDOPHYTA-—-FILICIN & 127

Ciass VI.—FILICINA.

The usual classification of the forms included in this class is
as under :—

Sub-Class IsosporE#.—One kind of spore only is produced ;
on germination it gives rise to a free pro-
thallium.

Section 1. Leptosporangiate.—Each sporangium is pro-
duced from a single epidermal cell.
This section includes most of the Ferns
proper.
Section 2. Husporangiate.—Each sporangium arises
from a group of epidermal cells.
This section includes the Ophioglos-
sacee and Marattiaceer.
Sub-Class HeTERosporEx.—The spores are of two kinds,
microspores and macrospores or megaspores.
The prothallia do not become free from the
spores on germination. The microspore produces
a prothallium bearing an antheridium, the
macrospore develops one bearing archegonia.
Neither form of prothallium is ever free from
the spore. :
Section 1. Leptosporangiate.—EHach sporangium arises
from a single epidermal cell.
This section includes the water ferns,
Hydropteridez, sometimes called the Rhizo-
carps.
Some botanists place .a second section here to include the
Isoetacer, which are eusporangiate. They are, however, gene-
rally included among the Lycopodine.

Section 1.—Isosrorous LEPTOSPORANGIATE FERNS.

The sporophyte of this group is the plant usually termed a
Fern. It has generally « conspicuous body, morphologically
differentiated into stem, roots, and leaves.

The stem is usually a creeping underground rhizome, though
in some cases it is borne upon the surface of a tree, and in
others, as in the tree ferns, it grows vertically into the air. It
usually gives off a number of adventitious roots and bears a
128 MANUAL OF BOTANY

relatively few large, often pinnate, leaves. In some ferns the
stem branches normally, the branch system being lateral and not
dichotomous as in the lower groups; in others the branching is

Fic. 884.

 

 

Fig. 884, Polystelic stem of Fern. st, Steles. sc. Bands of sclerenchyma.
hy. Hypodermal sclerenchyma, ep. Epidermis.——/ig. 885. Stele of stem
of Fern, composed of three fused concentric bundles. en. Endodermis.
pe. Pericyle. ph. Phloém. px. Groups of protoxylem.

adventitious. The roots are always adventitious, for though a
primary root is always developed it never persists in the adult
fern. The adventitious roots are small and often branched,
arising in great numbers from the stem or the leaf stalks. The
PTERIDOPHYTA—FILICINE 129

leaves are sometimes of three kinds, the foliage leaves, some-
times entire, but usually much and repeatedly pinnate; the
sporophylls, which in many ferns are exactly like the foliage
leaves in appearance, but. in others are much modified; and
scaly leaves, rarely found, and then only on subterranean
rhizomes. The vernation of the leaves is very markedly circin-
ate, the main axis and all its branches or pinne emerging from
the earth rolled up with their lower surfaces outwards. The
stem and bases of the leaf stalks are furnished when young with
numerous scaly hairs, called ramenta, which are multicellular
and sometimes glandular.

The growth in length of the stem is always brought about
by the divisions of a pyramidal apical cell of either two or three
sides, the apex of the pyramid being directed inwards. It soon
shows a differentiation into dermatogen, periblem, and plerome.
At first the stem is always monostelic, but this condition in
most cases soon gives way to polystely, which persists throughout
its length (jig. 884). The separate steles are usually gamodesmic,
the bundles of which they are composed being completely
united together, presenting the appearance of a central mass
of wood with two or three strands of protoxylem, almost sur-
rounded by bast, though not entirely, as the latter does not
wrap round the narrow end of the woody mass. The whole is
enclosed by a pericycle and an endodermis, the latter belonging
to the fundamental tissue (jig. 885). Sometimes a stele will
consist only of a single bundle ( fig. 886), though generally fusion
takes place. The steles as viewed in longitudinal section of the
stem, or better, as isolated by maceration, are found to anasto-
mose together very irregularly, forming a meshwork, from the
angles of which branches go off to enter the leaves. The nature
of the anastomosis is largely determined by the number and
size of the leaves.

The bundles are said to be concentric. As they are usually
placed two or three together in the stele and fused laterally, this
is not very apparent, the whole stele seeming rather to deserve
this name, the fused bast masses surrounding the fused wood
masses. Asingle bundle, however, when found free (fig. 886), is
seen to be concentric; and a stele is usually composed of two or
more placed so close together that the bast is not developed on
their contiguous faces. The lateral fusion of bast and wood of the
original bundles thus gives rise to the mass of wood in the stele
with its peripheral envelope of bast. The steles should perhaps
be called bi-collateral rather:than concentric, as the bast is not

VOL. IT. K
130 MANUAL OF BOTANY

continuous round the narrow ends of the wood masses ( jig.
885).

The monostelic arrangement persists in a few families
(Osmundacee, Hymenophyllacee, &c.); the bundles in the stele
are then sometimes collateral.

The pericycle is absent from the stele of some of the Poly-
podiacee, being then replaced by an inner layer of the endo-
dermis, as in the root of Equisetum.

The stem of the fern is usually well supplied with scleren-
chyma, which is developed in various forms in the ground

Fic. 886.

 

fig. 888. Concentric bundle from Fern stem. en. Endodermis. p. Peri-
cycle. ph. Phloém. pz. Protoxylem. a. Xylem.

tissue. It is often found as a strong hypodermal sheath, deep
brown in colour, and consisting of several layers of cells with
very greatly thickened walls. Isolated bands of greater or less
extent are common in the inner part of the ground substance
(fig. 884).

The tissue of the wood and bast is generally characteristic.
The wood is chiefly made up of large tracheids thickened in a
scalariform manner. True vessels are rare, and there is not
much wood parenchyma. The sieve-tubes of the bast (jig. 887)
PTERIDOPHYTA—FILICINA 131

are long, narrow tubes with bluntly pointed ends, and have their
sieve-plates more or less regularly arranged along their whole
length, being thus marked out into very characteristic areas.
They have no companion-cells and no callus.

Except in the monostelic stems the bundles are cauline.
They are always closed, cambium not being present.

Fic. 887.

 

 

    
  

     

 

 

 

 

 

 

 

 

2 &
eS 2
8. LU a
Say
pe : a
= = Y
2; == = Sa ©
WY 2 ey
key e
S a
Ss q
(e)
"
| Se
gy 30
@
BD
¢ Bl
ep. sts

ig. 887. Section of stele of Fern. The upper part is transverse, the
lower longitudinal. e. Endodermis. p. Pericycle. s. ¢. Sieve-tube.
x. Xylem. f. Fibres of bast.

The primary root is in all cases developed, but it usually
soon perishes, and its work is taken over by adventitious roots
which are produced in great numbers from the stem or the
leaf-stalks. Each originates in the endodermis of one of the
steles, opposite to a xylem bundle. By the formation of two
walls a pyramidal apical cell is cut out of one of the cells of the

endodermis, and by successive divisions it gives rise to the
K2
132 MANUAL OF BOTANY

adventitious root, which grows out through the fundamental
tissue in the way already described (jig. 888). Occasionally, as
in Osmwnda, there may be a group of initial cells at the apex,
instead of the usual pyramidal one.

The root is monostelic, the stele containing sometimes two,
sometimes three bundles; the pericycle may consist of a single
layer of cells or of many, and sometimes it is irregular, being one
layer of cells thick in part of its course and more than one layer
thick in the remainder.

When the roots branch the new root springs from the old
one in the same way as the latter did frcm the stem.

The foliage leaves arise each from a single superficial cell of

the growing point of

Fig. 888. the stem. They grow

in most cases by
means of a two-sided
apical cell. In verna-
tion they are strongly
curled up owing to the
greater growth of the
under surface. Later
the region of growth
changes to the upper
surface and the leaves
expand. In structure
fig. 888. Longitudinal section through root of they resemble the
Pleris hastata, showing apical region. vw. Apical leaves of Angiosperms,
cell, from which are developed the tissue of the but the differenti ation

substance of the root, 0, c, and the root-cup,
k,l,m,n. After Sachs. of the mesophyll into

palisade and spongy
parenchyma is not so well marked. The epidermal cells as a
rule contain chloroplastids. The vascular cylinder is generally
monostelic in the petiole, but becomes schizostelic in the leaf
blade. The stele joins one of the steles of the stem as already
described.

In some Ferns the sporangia are borne upon leaves that
cannot be distinguished in appearance from ordinary foliage
leaves. In others, as in Osmunda, Aneimia, &ke., there are
definite, specialised sporophylls. These show various shapes, the
pinne generally being narrower than those of the foliage leaves.
In the most specialised, the upper or lower branches of the
phylopodium are scarcely at all winged, the edges being covered
by clusters of sporangia.

 
PTERIDOPHYTA—FILICINA 133

The sporangia occur usually in groups on the lower or dorsal
surface of the sporophylls (fig. 890), or in some cases in a band
along their margins, being situated on a kind of placental
outgrowth. They are sometimes quite exposed to the air,
sometimes partially protected by hairs or paraphyses which
arise among them from the placenta. Generally, however, the
sorus is more or less covered by a definite membrane called the
indusium, which springs from the epidermis of the leaf. Where
the sorus is marginal, as in Pteris, the edge of the leaf curves
over it, forming a false indusium, which sometimes is supple-
mented by a kind of membrane springing from the leaf along
the inner side of the sorus.

Fie. 889. Fie. 890. Fie. 891.

 

Fig. 889. A portion of a frond of the common Polypody (Polypodium vul-
gare), showing two sori springing from its veins. The sori are naked,
and consist of a number of sporangia or capsules, sp, in which the spores
are contained.— Fig. 890. Portion of a frond of the Male-fern (Aspidium
Filix-mas), with two sori, s, s, covered by an indusium.—-fig. 891.
Portion of a frond of the Royal or Flowering-fern (Osmunda regatis),
with its sporangia or capsules arranged in a spiked manner on a branched
rachis.

The sorus (fig. 892) consists of a number of sporangia, often
mixed with a number of hairs or paraphyses, which are some-
times glandular. Each sporangium is an ovoid or globular
body placed upon a long stalk. It originates from a single
superficial cell of the placenta, which grows outwards and
becomes divided into two. The upper one gives rise to the
body of the sporangium, the lower one to the stalk. As the
upper one grows, there are formed in it three oblique walls, which
cut out of it a somewhat tetrahedral cell with its base uppermost.
A further wall is formed across its base, so that the structure
consists of a wall and a central cell. Divisions parallel to the
134 MANUAL OF BOTANY

first ones cut off from the latter four protective cells which
form the tapetum, an investing nutritive layer, which by subse-
quent divisions of its cells becomes multicellular. The central
cell so formed is the archesporium.

Changes now take place in both inner and outer parts of the
growing organ. The four peripheral cells undergo repeated
division by anticlinal walls, so that the outer coating of the
sporangium becomes multicellular, remaining one cell thick. A
special band of cells forming part of this wall, rmmning in some
cases longitudinally and in some obliquely or transversely, becomes
peculiarly thickened, as in fig. 892, and constitutes the annulus.

Fie. 892.

 

Fig. 892. Section of sorus of Fern, consisting of a number of sporangia borne
upon a placental outgrowth from the under side of the Jeaf and covered
by an indusium. Each sporangium has running nearly round it a row of
thick-walled cells, the annulus. After Kny.

Its walls are strongly cuticularised, more so than the walls of the
rest of the cells, which, however, undergo cuticularisation to some
extent. The annulus in most cases does not extend completely
round the sporangium, but leaves a few thin-walled cells between
itself and the stalk, which cells form the stomium, where
eventually the sporangium opens. The tapetum becomes multi-
cellular and for a time invests the archesporium, its cells being
filled with very granular protoplasm. The archesporium divides
repeatedly till it consists of sixteen cells, which are the mother
cells of the spores. When this stage is reached, the tapetal cells
become disorganised and give rise to a mucilaginous fluid in
PTERIDOPHYTA—FILICINA 135

which the archesporial mass remains. Each mother cell then
divides by free-cell formation into four cells, usually but not always
arranged at the four angles of a tetrahedron, so that the result-
ing cells are pyramidal in form. Each undergoes rejuvenescence
and surrounds itself with a new cell-wall, forming a spore. The
walls of the original mother cells then disintegrate as did those
of the tapetum, and the spores, sixty-four in number, lie free in
the cavity of the sporangium. The development is shown in
Jig. 893.

In some cases the stalks of the sporangia are not developed,

Fic. 893.

 

Fig. 893. Development of the sporangium of the Fern. The figures indicate
the successive stages. a. Archesporium. ¢. Tapetum. ap. Sporogenous
tissue. After Kny.

so that those organs are sessile; in others the stalk gives rise to
a glandular hair (jig. 893, 7 h).

When the sporangium is ripe, the drying of the cells of the
annulus leads to great tension in the stomium, which ruptures,
and the annulus recoils with some force, scattering the spores.

In the Tree ferns the annulus extends all round the sporan-
gium, so that it includes the stominm.

Different genera show a certain variety in the position of
the annulus, and consequently in the direction of the rupture.
The dehiscence is, however, brought about in a similar manner
in all.

The gametophyte in the Ferns is always a thallus, having
136 MANUAL OF BOTANY

no differentiation into members. It is known as the pro-
thallium, and is usually a green flattened expansion of small
size. Its cells contain chloroplastids. From the under side
a number of root hairs are developed which attach it to the
soil.

Sometimes the prothallium has a central somewhat thickened
portion known as the cushion. Sometimes it is almost fila-
mentous, recalling the protonema of a moss.

It always becomes quite free from the spore.

On the under side of the prothallium the sexual organs are
developed, the anthéridia lying to the basal end and the

Fic. 894.

eee

"
e

CP

RS

SiR

 

Fig, 894, Prothallus (gametophyte) of Fern. After Kny.

archegonia, which are formed later, towards the anterior or
apical region. In a few cases a prothallium develops only
one or other of the sexual organs, but generally both are to be
found in the relative positions described.

‘When the spore germinates, the outer coat ruptures and the
inner one grows out into a green filament consisting of a single
row of cells ( fig. 895, 1-4). The end cell of the row soon divides
longitudinally, and the plate-like prothallium becomes recog-
nisable. The growth is soon continued by the formation of an
apical cell (fig. 895, 5), which after a while is found to lie ina
sort of notch or depression in the anterior margin.
PTERIDOPHYTA—FILICIN A 137

The cushion is formed by the cells in the middle line in the
anterior region then dividing in a plane parallel to the surface
so that the mass becomes several cells in thickness there. This
cushion bears the archegonia and may in a way be compared to
the archegoniophore of the liverworts. The antheridia do not
arise on the cushion, but towards the posterior margin.

The antheridiwm is always superficial in origin (fig. 896).
An epidermal cell grows out and is divided into two, the
upper one of which produces the organ.

It divides into two cells, the lower of Fie. 895.
which forms a stalk-cell. The upper one
divides repeatedly, so as to form a wall
surrounding a central cell, in which the
mother cells of the antherozoids are pro-
duced by repeated cell-divisions. In each
mother cell a single antherozoid is pro-
duced, which is a coiled filament furnished
with cilia at its anterior end (fig. 860, B).
When the antheridium is mature it
ruptures, and the mother cells, containing
the antherozoids, escape, the antherozoids
being liberated a little later. The whole
of the protoplasm of the mother cell is
not used up to form the antherozoid, so
that when the latter escapes it has usually
attached to it a vesicle of protoplasm, the
rest of the contents of the mother cell.

The development of the archegonium
(fig. 897) is also from a superficial cell of
the prothallium, which segments into two,
an upper anda lower. The neck is de-

 

Fig. 895. 1-5, Successive

rived from the former by a succession stages in the early de-

of divisions. It is much like the neck velopment of the pro-
‘ thallus (gametophyte) of

of the archegonium of the moss, but the Fern. After Kny.

much shorter, consisting of only a few
tiers of cells. The lower cell grows upwards into the neck,
separating its cells somewhat and forming the neck-canal-cell,
which remains single. The neck-canal-cell is cut off from
the remainder, which then constitutes the central cell of the
archegonium. This next cuts off a small ventral-canal-cell, and
the remainder rounds itself off into an ovoid mass of protoplasm,
which is the oosphere.

Later the ventral-canal-cell and the neck-canal-cell become
138 MANUAL OF BOTANY

mucilaginous, and the neck of the archegonium opens by the
separation of its cells.

Fertilisation is effected by the entry of an antherozoid
into the neck of the archegonium and its ultimate fusion with
the oosphere at its base. The mucilaginous matter ejected from

 

Fig. 896. 1-8. Development of the antheridium of the Fern. 5. Anthero-
zoidsescaping. After Kny.—Fig. 897. Development of archegonium in
the Fern. The figures indicate successive stages. 3 and 6 are transverse
sections of the neck in two stages. After Kny.

the archegonium is said to contain a substance, probably malic
acid, which has an attraction for the antherozoid, enabling
the latter to find its way to the canal of the neck.

When fertilisation has been effected the oosphere clothes
itself with a cell-wall, and becomes the zygote, or oospore. It
PTERIDOPHYTA—FILICINA 189

is soon segmented into epibasal and hypobasal parts by the
formation of a basal wall parallel to the axis of the archegonium.
Each gives rise by further divisions to four octants. In
further development the epibasal octants give origin to the stem
and first leaf, or cotyledon, of the young sporophyte; the hypo-
basal ones form the primary root and a special organ, called the
foot, which attaches the young fern to the prothallium, from
which it draws a supply of nutrient’ material. The foot becomes
a somewhat bulky structure and occupies the space formed by
the venter of the archegonium (fig. 880).

The primary root soon disappears; the cotyledon also lasts
but a short time, and is succeeded by the foliage leaves, arising
from the stem. The foot also disappears as soon as the young
fern has become capable of absorbing its nutriment from its
environment independently of the gametophyte.

The prothallium seldom lives longer than is necessary to
produce a single sporophyte. The sporophyte, on the contrary,
may produce spores for many years, each being able to give rise
to a gametophyte. Sometimes the gametophyte lives longer, in
some cases for more than a year.

The vegetative reproduction of ferns occurs in both genera-
tions. The gametophyte may give rise to branches or to gemme,
either of which can develop into prothallia. The sporophyll may
produce adventitious buds, generally on the petioles of its leaves
where they are below the soil.

Both apospory and apogamy may occur in this group.

SEcTION 2.—Isosporous EvspoRANGIATE FERNS.

In this section are comprised two orders of Ferns, the
Ophioglossacesw and the Marattiaceew, which have much in
common with the previous group, but differ in that their spo-
rangia are derived each from a group of superficial cells instead
of from a single one.

OPHIOGLOSSACEE.

The affinities of the Ophioglossacee have lately been much
discussed, and many doubts have been suggested as to their
being properly included among the ferns, certain points in their
structure suggesting an affinity with the Lycopodine. For the
present, however, it will be well to give them their old position.

The sporophyte is generally a short erect rhizome bearing a
few leaves which are not circinate in vernation. Generally
140 MANUAL OF BOTANY

only one appears above ground each year.

Between this leaf

and the apex of the stem the rudiments of four other leaves

may generally be found, so that it
takes five years for a leaf to attain
its full development.

The sporangia are borne upon a
peculiar outgrowth from the ventral
surface of the petiole of the sporo-
phyll, which has the appearance of
being branched, one branch bearing
an ordinary foliage lamina and the
other an elongated, sometimes
branched, spike-like structure, em-
bedded in or placed upon which
are the sporangia, arranged in two
rows, one on each side of its axis, or
variously clustered upon its surface
(fig. 898).

The stem is very short and pre-
sents some peculiar features in its
interior. There is usually present
none of the sclerenchyma, so cha-
racteristic of the Ferns; the ar-
rangement of the vascular structures
is different also, the Ophioglossaceze
being schizostelic and the bundles of
the steles being collateral. Ophio-
glossum itself has no pericyle in
its steles. The genera Botrychium
and Helminthostachys possess
cambium in their collateral bundles,

Fig. 898. Ophioglossum vulgatum. a. Sporangia.

but it does not give rise to much secondary tissue.

occurs in the cortex of these stems.

Fic. 898.

 
 
 
 
 
 
 
 
 
 
 
 
  
  
 
 
 
 
 
 
 
 
 
 
  

bd. Foliage leat.

Cork also
PTERIDOPHYTA—FILICINE[ 141

The sporangia, situated as described above, are usually
quite independent of each other, not being arranged in sori.
They are often embedded in the tissue of the sporophyll and
open when ripe by valves or slits. Each contains numerous
spores.

The gametophyte is best known in Ophtoglosswm pedun-
culosum and Botrychium Lunaria. In the former it is a
tuberous body growing underground and devoid of chloroplastids.
From it springs a cylindrical gametophore, which grows up
through the earth and becomes green. It bears antheridia and
archegonia. In the latter it is again tuberous and subterranean ;
it has root hairs, and bears antheridia and archegonia, the latter
being chiefly on its lower and the former on its upper surface.

MARATTIACEAE.

The stem of the sporophyte, as in the last case, is generally
a rhizome, which is sometimes branched, and bears numerous

Fie. 899.

 

Fig. 899, Synangia, s, of A, Angiopteris, B, Marattia; c, section of synan-
gium of B. After Sachs.

leaves. The latter resemble those of the true ferns, from which
they differ by bearing well-marked stipules. The roots branch
considerably, the branching being lateral.

The histology of the stem recalls that of the true ferns, the
arrangement of the vascular tissue being polystelic, and the
bundles of the steles concentric. There is more variety in regard
142 MANUAL OF BOTANY

to the selerenchyma, which is never very prominent and is in
some cases absent. Gum passages of probably schizogenous
origin are found in many parts.

The sporangia are arranged in sori, but the several sporangia
of each sorus are coherent instead of being developed separately.
They thus form a body, at first sight suggesting a compound
sporangium. This is known asa synangium. They are filled
with numerous spores and dehisce when ripe by a slit or an
apical pore (fig. 899).

The gametophyte is a flattened green prothallium, much
like that of the true ferns. It has a cushion in the centre, on
which both antheridia and archegonia are borne. It grows by
an apical cell. The sexual organs have the same structure as
in the ferns.

SEcTIoN 3.—HETERosPoROUS LEPTOSPORANGIATE FERNS.
(Rhizocarps or Hydropteridee.)

This group, which has much in common with the isosporous
ferns, introduces a difference which becomes more and more
important as we go higher and higher in the scale. The plants
bear spores of two kinds, the microspores and the macrospores
or megaspores. Each of these in turn produces a special form
of gametophyte, and those which are derived from the macro-
spores never become free from the spore, being largely developed
in its interior. As we pass upwards from this point this
peculiarity becomes more and more marked, until we find the
prothallium always completely endosporous. The great im-
portance of this is seen in that it leads ultimately to the
production of the body known as the seed, which is the dis-
tinguishing feature of Phanerogamic plants.

The Hydropterideex or Rhizocarps were till comparatively
recent times considered as a separate group. It is usual now to
include them with the Ferns, to which they show considerable
resemblance. They are all of aquatic habit, and are hence
named Hydropteridea. The group comprises four genera,
Salvinia, Azolla, Pilularia, and Marsilea, which according to
the arrangement of their sporangia are divided into the two orders
Salviniacee and Marsileace. Salvinia and Azolla float freely
upon the surface of water; each has a horizontal rhizome,
sometimes copiously branched. Upon the rhizome are borne
numerous leaves arranged in-rows, which in Azolla are all alike,
but in Salvinia are of two kinds, floating and submerged.
PTERIDOPHYTA—HYDROPTERIDE™ 143

Azolla bears numerous adventitious roots; Salviniais altogether
rootless.

In Salvinia the phyllotaxis is whorled, three leaves being
produced at each node. Of these, two are broad, somewhat
rugose, entire floating leaves, placed opposite each other. The
third is divided into a number of filamentous branches which
hang down freely into the water (jig. 900) and function as roots.
In Azolla the leaves are alternate and are arranged in two
rows on the upper surface of the rhizome. Each leaf is two-
lobed, one lobe floating while the other is submerged. Pilularia
and Marsilea have perennial rhizomes and are attached to the
substratum. They are found in bogs or marshes. From the

Fic. 900.

 

fig. 900. Part of a plant of Salvinia. 7. Floating leaves. w. Submerged
leaves. s. Sori. &. Apex of stem. B. Longitudinal section through three
sori of Salvinia. 7,7 Two with microsporangia. a. One with macro-
sporangia, After Sachs.

rhizome the leaves grow vertically upwards, being arranged
alternately on the stem. In the former genus the leaf is un-
branched and somewhat cylindrical ; in the latter it is compound,
bearing four leaflets at the end of a long petiole (figs. 901, 908).

Both Pilularia and Marsilea produce adventitious roots from
the rhizome.

In Salvinia and Azolla the stem is monostelic, the stele being of
very small dimensions. Itis not furnished with a pericycle, but
is surrounded by a two-layered endodermis. In the other genera
the stem is at first polystelic, but eventually becomes gamostelic
from the fusion of the separate steles to form a ring (jig. 902).
This ring encloses some fundamental tissue which simulates a
144 MANUAL OF BOTANY

pith. It can be distinguished from the latter by the fact that
there isan endodermal band on both sides of the ring of bundles.
The bundles are concentric in all four
Fic. 901. genera. The fundamental tissue contains

large intercellular spaces or lacune.

The growth in length of both stem
and root is carried on by means of an
apical cell, which is either two-sided or
tetrahedral.

A curious feature of the leaf of
Azolla is the occurrence of a pit or
cavity in the tissue of the dorsal lobe
in which small colonies of Nostoc fila-
ments are found, much as in Antho-
ceros. This is a case of symbiosis, as
in the latter plant.

The two orders Salviniacee and
Marsileacew differ from each other in
the arrangement of their sporangia.
They agree in having them placed in

Fic. 902.

   
          

b i=

4 yaaye
wee
A Tea eee

 

 

Fig. 901. Plant of Marsilea. &. Rhizome. 6. Leaves. jf. Sporocarps
springing from the leaf stalks at. After Sachs. Lig. 902. Stele of -
Marsilea, showing gamostelic structure. a. Outer endodermis. 0. Inner
endodermis. c. Fused xylem bundles. «@ A point at which the fusion
does not extend to the wood. e. Fundamental tissue isolated by the
fusion of the steles. f. Cortex.

 

curious globular or ovoid bodies, which occur in Salvinia and
Azolla on the submerged leaves or lobes of leaves; in Marsilea
PTERIDOPHYTA—HYDROPTERIDEH 145

.

on stalks springing from the petioles of the leaves much as in
Ophioglossum ; and in Pilularia from the rhizome on the ventral

side of a leaf.

In Salvinia and Azolla, the two genera of the Salviniacex, the

structure is a sorus of
sporangia, covered in by
a cup-shaped indusium,
which differs from the
corresponding structure in
the ferns by being com-
posed of two layers of cells,
separated in Salvinia by
an air space (jig. 900, B),
and by completely closing
over the sorus. In Azolla
the walls of the upper part
of the indusium become
lignified. At the base of
the globular chamber so
formed there is a cellular
placenta, from which the
sporangia spring. Hach
sorus consists either of
microsporangia or macro-
sporangia, but never con-
tains both. The number
of microsporangia in a
sorus in both genera is
considerable. The macro-
sporangia are less nume-
rous, the sorus of Salvinia
containing not more than
twenty-five, while that of
Azolla contains only a
single one.

In the Marsileacee
(Pilularia and Marsilea)
the sporangia are borne in
acomplex structure known
as a sporocarp. This is

Fie. 903.

 

Fig. 903. Pilularia globulifera. A. Natural
size. B. End of shoot (enlarged). s. Apex
of stem, b. Leaves. w. Roots. f. Sporocarps.

a modified leaf-branch, as shown in fig. 901. It is an oval or
globular body with a very hard wall; its interior is divided into
a number of chambers, each of which contains a sorus. The sori

VOL. It.

L
146 MANUAL OF BOTANY

contain both micro- and macrosporangia.

In Marsilea there is

in each a single row of the latter in the middle, and a double

row of the former on each side of it.

ment is not so definite.
The sporocarp is
made to rupture by the
mucilaginous character of
the internal tissue, which
absorbs water and causes
the wall of the sporo-
carp tosplit. In Pilularia
the rupture begins at the
apex, in Marsilea it takes
place along the side. In
the sporocarp of the latter
is a band or ring of mu-

Fia. 904.

 

Fig. 904. Transverse section
of the sporocarp of Pilu-
laria globulifera. After
Henfrey.

cilaginous tissue, to which
the walls of the chambers
containing the sori are at-
tached. When the sporo-
carp ruptures by the swell-
ing of this ring, the latter
protrudes through the
opening, and still swelling
drags out with it the sori
ina kind of string or chain
(fig. 905, Bc). When free
from the sporocarp the
walls of the sori-chambers

 

In Pilularia the arrange-

Fic. 905.

Fig. 905. Marsilea salvatrix, A. A sporocarp

(natural size). 3B. A sporocarp which has
burst its water and is protruding its gelati-
nous ring. After Hanstein. c. The ring
ruptured and extended, showing the sepa-
rated €ori, s7. D. A sorus showing macro-
sporangia and microsporangia. E. A sorus
from a ripe sporocarp. After Sachs.

and those of the sporangia disintegrate, setting free the spores.

The spores in this group of plants are characteristic.

Instead

of possessing only two walls and lying free in the sporangia, as
PTERIDOPHYTA—HYDROPTERIDEA 147

in almost all other cases, they either have a third coat, derived
from the epiplasm of the disorganised tapetal cells, or they
are by this epiplasm agglutinated together into one or more
spore masses. The conditions differ in the different genera. In
Salvinia all the microspores of a sporangium are fastened to-
gether; in Azolla there are from two to eight of such masses in
a sporangium, each being known as a massula. A delicate skin
surrounds each massula, and this in some species is furnished
with a number of hairs bearing barbed processes, known as
glochidia, at their free ends. In the Marsileacee the microspores
are free from each other, but each is coated by its epispore or
perinium, derived from the tapetal epiplasm.

In Salvinia, Pilularia, and Marsilea the macrospores are
similarly invested, but each one is free. The outer layer of the
epispore in the last two genera is capable of swelling enormously
on being wetted, surrounding the apex of the spore with a mu-
cilaginous coating.

In Azolla the epispore on the lower surface of the macrospore
is developed into large spongy masses which serve as floats,
enabling it to drift about after partially escaping from the
sporangium. The upper surface is firmer and bears filamentous
outgrowths. The apex of the spore is generally furnished with
a number of delicate filaments extending between the floats.
The glochidia of the massulz of microspores generally catch in
these filaments, so that the massule are anchored to the macro-
spore.

The microspores are not set free from the microsporangium
in Salvinia, but germinate in situ. In Azolla the separate
massule escape and float about in the water, those that have
glochidia usually becoming entangled in the filaments developed
from the perinium of the macrospore.

The gametophyte in this group shows considerable reduction
when compared with that of the ferns. The heterospory, as
already pointed out, involves the production of two kinds of
gametophyte, one from each kind of spore. We have from the
microspore one that bears only male organs, antheridia, and
from the macrospore one that bears only female organs,
archegonia. In neither case does the gametophyte become
entirely free from the spore which gives it origin; in some
cases a good part of it remains enclosed within the spore.

In Salvinia the microspores germinate by putting out a
tubular protrusion of the endospore, which pierces the mucila-
ginous matter in which they are embedded and makes its way

L2
148 MANUAL OF BOTANY

through the wall of the sporangium. It then forms a septum at
the end, cutting off a terminal cell which later divides into two.
The tube constitutes the prothallium, and its two end cells after
farther divisions form a rudimentary antheridium, in which are
produced four antherozoids (jig. 906).

When the antherozoids are mature, the antheridium ruptures
as in other cases, and the antherozoids, each in its mother-cell,
escape into the water. Only part of the protoplasm of the
mother-cell is used in the formation of the antherozoid, as in the
ferns.

Azolla produces a similar male gametophyte. In the Marsi-

leacee the latter’ is

Fre. 906. formed within the

microspore. ‘The first
division of the spore
produces a small basal
vegetative cell and w
larger apical one,
which forms an anthe-
ridium. By successive
divisions this comes to
consist of eight cells
surrounded by a pa-
rietal layer or wall.
The central cells pro-

paths : _ duce each four anthero-
Fig. 906. Germination of microspores of Salvinia. zoids. Throughout the

After Sachs. 1. The mass of spores putting out

tubular prothalli. 2. A prothallus, with anthe- group the male pro-

ridium, a. 3. Antherozoids in mother-cells, . . :

4. Ruptured antheridium, thallium is destitute of
; chloroplastids.

The formation of the female prothallium is a good deal
alike in all the genera, showing small differences in the extent
of its protrusion from the spore, from which it is never free.
The macrospore begins to germinate before its coats rupture; it
first cuts off a small cell at its anterior end or apex, bya wall
known as the diaphragm, which thus divides the spore into
two. The small cell at the apex continues to divide, forming a
sinall celled tissue which soon protrudes through the spore-
coats, owing to the rupture of the latter. The emerging tissue
develops chloroplastids and becomes green; it constitutes the
prothallium. In Salvinia it is somewhat triangular in shape and
bears two winged appendages (fig. 907). In the Marsileacex only
a small part of it protrudes from the opening of the spore.

 
PTERIDOPHYTA—HYDROPTERIDE 149

The lower cell takes no part in the formation of the
prothallium, but remains almost unchanged, becoming filled with

various reserve materials for
the nutrition of the young
embryo developed later on the
prothallium. In Azolla its
nucleus divides repeatedly,
but no cell-walls are formed
in it.

The archegonia are de-
veloped at the apex of the
prothallium, three being
usually formed in Salvinia,
but only one in the Mar-
sileacere and Azolla. Ifnone
of the first formed ones be-
come fertilised, more are de-
veloped later. The structure
is similar to that of the ferns.

In the germination of the
zygote or oospore Salvinia
shows some peculiar features.
It segments into octants as
in the Ferns, but all the
hypobasal cells go to form
the foot. No root is developed.
The first leaf or cotyledon,
developed from two of the
epibasal cells, is of curious

Fic. 907.

 

Fig. 907. Gametophyte produced by the
macrospore of Salvinia. pro. Prothallium
bearing a, young sporopbyte. After
Pringsbeim.

shape. It is known as the scutiform leaf. In the other three
genera there are two cotyledons, stem, and root, as well as foot.
150 MANUAL OF BOTANY

Cuass VII.—EQUISETINA.

The plants included in this class, which only includes the genus
Equisetum, are characterised by a peculiar habit; they gene-
rally have a much-branched subterranean rhizome, from which
sub-aerial shoots are given off which rise erect and may attain a
height of six or seven feet. These aerial shoots are of two kinds,
one purely vegetative and the other ultimately becoming termi-
nated by a cone-like collection of sporophylls, forming a flower.
The shoots are surrounded at every node by a ring of small scale-
like leaves cohering together at their bases, in the axil of each
of which a branch is produced, causing a succession of whorls of
branches to appear. Each of these has the same structure as
the stem from which it arises (fig. 909).

The roots are adventitious and are produced from the nodes
of both rhizome and sub-aerial stem. In the former case they
grow into elongated structures, but in the latter they remain
rudimentary and never grow out from the tissue of the stem.

Ina few species the flowering shoot is different from the
form described above; it either does not produce branches, or
very few occur upon it, or they are not developed till the spores
are shed. In one or two cases the sub-aerial shoot, whether
sterile or fertile, remains almost or quite unbranched.

The green colour of the plant is due to the stem, the leaves
being brown and scaly.

The sporophylls are gathered together at the apex of the
fertile shoot, and they form a conical mass which may properly
be considered as a flower. Its structure is a thin cylindrical
axis on which a number of peltate leaves are arranged close
together ina succession of whorls. Each leaf or sporophyll
consists of a thick flattened head, to the centre of which a stalk is
attached at right angles. On that side of the peltate head or
blade which is turned towards the axis, there are a number of
sessile sporangia. Each leaf may bear from five to ten, all of which
contain numerous spores (jig. 908).

Just below the flower there is a ring of curiously modified
leaves, forming what is known as the annulus.

Equisetum grows by means of an apical cell, as do the ferns.
Such a cellis to be found at the apex of stem, branch, and
root (fig. 910).
PTERIDOPHYTA—EQUISETINAE 151

A transverse section of the rhizome, taken a little way
from the growing point, shows its exterior divided into ridges
and furrows. Opposite to each furrow there is, a little

Fie. 908.

Fig. 908. Fertile stem of Lguisetum bearing a
flower or cluster of sporophylls— lig. 909.
Sterile shoot of Equisetum.

 

way from the surface,
a large lysigenous
intercellular cavity.
These together are
known as vallecular
cavities. They, are
interrupted at the
nodes, where a sheet
of parenchymatous
tissue stretches across
them.

Fie. 910.

an

os ’

Fig. 910. Growing point of
shoot of Lquisetum arvense.
x 250. a. Apical cell.
b, c. Successive segments
cut off from it.

A little internal to
these cavities are the
several steles, the plant
being schizostelic.
These are arranged
differently in different
species, and we may
distinguish three va-
rieties. In EH. litorale
(fig. 911, A), the steles
are all separate, each
is clothed with peri-
152 MANUAL OF BOTANY

eyele and endodermis, and they are arranged in aring round the
stem. In H. silvaticwm the separate steles fuse together late-
rally, forming a gamodesmic mass. The pericycle and endoder-
mis are then absent from the sides of the steles, and the portions
remaining behind and in front of each stele fuse together, form-

Fie. 911.

 

  
  

Fig. 911. Diagram of stem in two
species of quisetum. A. EE.
litorale. s. The separate
bundles or schizosteles, each
with its endodermis. B. ZL.
silvaticum. The schizosteles, s,
have their endodermis fused
laterally. In both figures 7=
cortical lacune. After Pfitzer.
—Fig.912. Section of vascular
bundle of Lquisetum limosum.
en. Endodermis. pe. Pericycle.
w. Xylem. ph. Phloém. J. La-
cuna. After Dippel.

ing two continuous bands, one surrounding the whole collection
and the other forming an internal lining to it (fig. 911, 8). In
. palustre the inner endodermal layer is not well marked,
the cells not thickening in the same way as those of the outer.
This rhizome appears to be monostelic, though it is not really so.

The centre of the rhizome is in most cases filled with paren-
PTERIDOPHYTA—EQUISETINEA 153

chymatous tissue, forming a kind of pith. In some it is a large

air-cavity.

There is considerable development of sclerenchymajust under
the epidermis, forming a very strong hypoderma.
Each stele consists of a single closed collateral bundle, the

wood of which is much reduced.

protoxylem and two groups of
tracheids (fig. 912, x). In the
region of the wood it contains
always a conspicuous air space,
the carinal cavity, into which
the elements of the wood often
protrude (fig. 912, 1).

The sub-aerial shoots differ
from the rhizome by always
having a very large central
cavity, extending as_ before
through the several internodes
and being interrupted at the
nodes. The arrangement of the
steles is the same as in the
underground stem. The cortex
shows similar lacune, but it
contains a number of bands of
tissue with chloroplastids, which
are situated opposite to the fur-
rows. The sclerenchyma is
developed in strands opposite to
the ridges. The epidermis con-
tains in its cell-walls copious
deposits of silica.

The vascular bundles pursue
a straight course down the inter-
nodes. At every node, each
bundle bifurcates and the two
halves diverge; each half unites

Generally it consists of the

Fie. 913.

\ A

 

 

 

 

 

 

 

 

Fig. 913. Diagram of the course of
the fibrovascular bundles of Zqui-
setum through two nodes and one
internode.

with half of the next laterally placed bundle, the conjoint bundle
passing then down the next internode in the same manner. At
each point of junction of two half-bundles a strand from a leaf
joins the united portions (fig. 913), so that the bundles are

common.

The leaf is very rudimentary, having only a single small
154 MANUAL OF BOTANY

vascular strand passing up the centre. It contains no assimi-
lating tissue.

The vascular cylinder of the root is monostelic; the stele
contains three wood and three bast bundles and is invested by a
double-layered endodermis, from the innermost layer of which
the lateral branches spring. There is no pericycle.

The sporangia are ovoid bodies, arranged with their long axes
pointing towards the stem. Each is derived from several
epidermal cells, the Fquisetine being eusporangiate. The
wall of the sporangium is one layer of cells deep, and these have
peculiar thickenings similar to those of the anthers of the higher
flowering plants.

The spores are all alike, the Equisetine being isosporous.
A perinium, or epispore, is developed, resembling somewhat that
of the spores of Marsilea. When the spores are mature, this
coating splits up into four bands which coil round the spore,
being attached to one point of its surface. These are known as
elaters, and they aid in the dissemination of the spores by virtue
of their hygroscopic qualities.

When the spore germinates it produces a gametophyte or
prothallium very much like that of the Ferns, but somewhat
more irregular in contour.

The prothallia are generally dicecious, producing antheridia
or archegonia, but not both. Both antheridia and archegonia
closely resemble in structure and development the corresponding
organs in the Fern.

The embryo produced from the zygote has two cotyledons,
contrasting with that of the Ferns, which has only one. The
octants, with this exception, behave much as in the latter group.

The Equisetine were represented in Carboniferous times by
a very prominent group of plants now known under the name of
Calanuites. Some of these were heterosporous. Though much
like the existing forms, they showed a certain variety in the
mode of arrangement of the sporophylls. They differed very
greatly in anatomical structure on account of the bundles being
open instead of closed. The band of cambium gave rise to
considerable amounts of secondary wood and bast, so that the
Calamites increased in thickness as do now the Dicotyledonous
flowering plants.
PTERIDOPHYTA—LYCOPODINZ 155

Cuass VIII.—LYCOPODINA.

Like the Filicine, this class embraces both isosporous and
heterosporous forms, and is divided accordingly. The plant is
the sporophyte, and all the plants of the class are eusporangiate.
Though of a somewhat higher type than the Ferns and Horse-
tails with regard to their processes of reproduction, their vegeta-
tive body is usually not so conspicuous, though in this respect
there is a great deal of variety. The development of the embryo
from the zygote, so far as it has been followed in the group, is
much more like the process found in the flowering plants. The
foot, so prominent in the embryo of the Ferns, is replaced by a
cell or filament of cells known as a suspensor, and a special
absorbing structure is developed from the epibasal portion of
the embryo, which is often erroneously spoken of as a foot.
It functions in the same way as a true foot, but is developed
from an altogether different part of the embryo. We have,
indeed, in the action of the foot in the Ferns and of this new
organ in the Lycopodine an instance of the same physiological
function being discharged by different morphological members.

Section 1.—Isosporous LycoPopin2.

Included in this section are two Natural orders, Lycopodiacee
and Psilotacez, each of which comprises two genera, Lycopodium
and Phylloglossum, Psilotum and Tmesipteris.

Lycopodium is much the largest genus, comprising many
species of very varying external appearance. Generally there is a
very much-branched wiry stem, sometimes growing underground,
sometimes creeping on the surface, sometimes erect. It is
closely covered with variously arranged small, pointed leaves,
which are very numerous. The stem sometimes branches dicho-
tomously, sonietimes monopodially.

Besides the foliage leaves the plant bears sporophylls, which
are often very different in appearance from the former, and are
collected into flowers at the end of the branches. The flowers
are cones, consisting of spirally arranged leaves bearing the
sporangia in their axils or on the upper surface of the leaf-stalk
(fig. 916). In some species the collection of the sporophylls into
cones is not so obvious, and then the sporophylls closely resemble
the foliage leaves. The roots are all adventitious, and in many
cases arise from superficial cells of the stem.
156 MANUAL OF BOTANY

Phylloglossum has a tuberous stem, from the apex of which
about six leaves spring. These are longer than in Lycopodium
and form a sort of rosette, from the centre of which arises a pe-
duncle bearing the single flower. This is a small simple cone, the
upper leaves of which do not bear sporangia. The whole plant
is only a few inches in height.

Psilotum is very much branched, and in appearance resembles
a very small bush. It has a much-branched subterranean
rhizome, from which arise numerous sub-aerial stems. There
are no roots, the subterranean shoots discharging their functions.
The foliage leaves are
very much reduced,
being very small and
sparsely distributed.
The sporophylls are
bilobed and stalked.

Tmesipteris grows
upon the trunks of tree
ferns, the stems being
pendulous and clus-
tered. Each stem is
slender and crowded
with linear _ sessile
foliage leaves, among
which occur sporo-
phylls much like the
former, but stalked and
bearing sporangia.

The anatomy of

the stem in this group
Fig. 914. Lycopodium inundatum, Marsh Club-moss- presents some very
The stem is creeping, and bears numerous small waft.
seSuile imbricate leaves: characteristic features.
The apical cell of the
lower Cryptogams becomes replaced by a small-celled meristem
resembling that of the apical growing point of the Phanerogams.
In a few cases, but only exceptionally, an apical cell occurs. The
stem is monostelic, and its vascular bundles are arranged radially
as in most roots (fig. 915). There are generally anumber of wood
and of bast bundles, the protoxylem and protophloém of which
are placed alternately in a circle round the stele, abutting on the
pseudo-pericycle. As the wood develops the separate bundles
become united together, fusing into masses of irregular pattern,
between which lie masses of bast similarly formed by fusion of the

Fie. 914.

 
PTERIDOPHYTA—LYCOPODIN A 157

primary bundles. In their downward course the fused masses of
wood are found to separate again and rejoin in other ways, the
anastomoses causing the transverse section of the stem to pre-
sent different patterns at different levels. The endodermis is
usually thick-walled, and surrounds a layer which occupies the
place of a pericycle, but which is really cortical and not stelar
in its origin. This layer gives rise to the adventitious roots.
The root is similar in structure to the stem, but it contains

Fie. 915.

 

 

 

 

 

 

 

 

 

 

Fig. 915. Section of stem of Lycopodium. ep. Epidermis. en. Enudodermis.
pe. Pseudo-pericycle. pr. Groups of protoxylem. ph. Phioém. After Sachs.

fewer bundles of wood and bast. Its apical meristem is com-
posed of small cells.

The stem or tuber of Phylloglossum contains little vascular
tissue. Bundles from the leaves and roots anastomose where
they enter it, and from the network a single strand passes
up to the peduncle of the cone.

Both Psilotum and Tmesipteris agree with Lycopodium in
being monostelic, with bundles arranged radially. The cortex of
158 MANUAL OF BOTANY

the stem of Lycopodium can be divided into two areas, composed
of thick-walled woody cells with small intercellular spaces.
The cells of the inner area have very thick walls. The cortex
is crossed by bundles passing out from the stele to the leaves.
The sporangia in Lycopodium and Phylloglossum are simple
and stalked. They arise on the leaves near their insertion

Fie. 916, Fie. 917.

 

Fig. 916. Longitudinal section of cone of Lycopodium, showing the sporangia
in the axils of the sporophylls.—Jig. 917. Lycopodium annotinum.
p. Prothallium. 7. The young plant. w. Its root. After Funkhauser,

(fig. 916). They arise from several cells instead of from a single
one as in the ferns. They show no special peculiarity in their
development. The spores are all microspores.

In Psilotum and Tmesipteris the sporangia are bilocular
or trilocular, being synangia, as in the Marattias. They are
stalked bodies, borne upon the upper surface of the bilobed sporo-
phyll at the junction of its two lobes.
PTERIDOPHYTA-—-LYCOPODINA 159

The gametophyte or prothallium (fig. 917, p) is only known in
the genus Lycopodium, and shows considerable variety of form.
In some species it is a small tuberous body, with a colourless base
from which root hairs spring and an apex which is divided into
several green lobes; in others it is altogether tuberous. In other
species again it is larger and is a cylindrical branched body
bearing gametophores. It bears both antheridia and archegonia,
which resemble the corresponding organs in the eusporangiate
Ferns. The antherozoids do not exhaust the protoplasm of the
mother cells in which they are developed, but a small portion of
it remains attached to them on their liberation as in the Ferns.
They are biciliate.

The development of the sporophyte from the zygote is only
known in DL. Phlegmaria. The first division gives, as before,
epibasal and hypobasal segments. The hypobasal cell does not
as a rule divide, but elongates slightly to form the swspensor.
The epibasal cell gives rise to the embryo, which consists of a
primary stem, bearing a single cotyledon. The part of the axis
below the cotyledon becomes the pseudo-foot already spoken of.
It is really a hypocotyl. There is no primary or true root, but
an adventitious one speedily arises from below the cotyledon.

In two other species (L. cernwwm and L. inundatum) the
later stages in the development have been followed, but the early
ones are unknown. In them the appearance of the primary stem
is preceded by the development of a tuberous body which bears
the cotyledon and subsequently the stem at its apex. From its
base adventitious roots arise exogenously.

Besides these modes of reproduction the vegetative method
is not uncommon. Some species of Lycopodium multiply by
gemme, others by tuberous outgrowths from the roots, others by
the detachment of branches. Phylloglossum produces annually
a single branch, which ‘develops into the tuber of the succeeding
year. Psilotum sometimes bears gemme on its rhizomes.

Section 2._-HETEROSPOROUS LYCOPODINE.

In this section we have two genera grouped together, about
whose close affinity there issome doubt. These are Selaginella
and Isoétes. Of the relationship of the former to the isosporous
Lycopodine there can be no doubt, but some authorities lean to
the view that the affinities of Isoetes are rather to the Ferns than
to the present group. This view is based upon its general habit,
the large leaves and the small stem being much more like the
160 MANUAL OF BOTANY

Ferns than the Lycopods; its embryogeny, the hypobasal cell
not giving rise to a suspensor; the isolated position of its
sporangia, and the form of its antherozoids. On the other hand,
it shows relationship to the Lycopods in the occurrence of the
sporangia on the upper surface of the leaf near the base; in the
peculiar features of the gametophyte arising from the macrospore,
which approaches the condition obtaining in the Gymnosperms
even more closely than that of Selaginella ; in the occurrence of
a peculiar outgrowth of the leaf close to the sporangium, which
is shared only by Selaginella; and in the structure of its apical
meristem. The adventitious nature of the first root also
supports this view of its position. a :

The heterosporous Ly-

Fic. 918. copodine have sometimes
been called the Ligulata,

(} from the occurrence of the
particular outgrowth re-

terred to, which is known
as the ligule. Selaginella
is the best known repre-
sentative, and in many
respects is the highest type
represented in the group.
Its form shows more
variety than that of any
other genus; the stem is
slender, herbaceous, and

- sometimes erect, some-
Fig. 918. Selaginella helvetica. s, Stem. o. c BN
Small leaves of upper surface. «. Larger times creeping ; almost

leaves of lateral flanks. always showing a bilateral
symmetry, which is very
evident when it is much branched ; the branches spread out ina
flattened manner, and show an evident difference between the
upper and under sides. The branching is apparently dichotomous
and the stem asympodium. Recentinvestigations tend to the view
that the dichotomy is only apparent, and that it is really lateral.
The stem bears numerous small leaves of very simple struc-
ture. They are arranged in pairs, which are of unequal size, one
leaf being much smaller than the other. The successive pairs
decussate with each other, and in many cases, by some distortion
in growth, the small leaves come to lie on the upper surface of
the stem, while the larger ones are on the lateral flanks (fig. 918).
Each leaf bears the peculiar ligule spoken of above.

 
PTERIDOPHYTA—LYCOPODINA 161

The roots are adventitious asin other cases, even the primary
root proceeding from the epibasal half of the zygote. This pri-
mary root soon perishes; the adventitious roots which succeed
it spring from the lower surface of the stem, or from peculiar
naked branches termed rhizophores, which grow down into the
soil and develop roots from their apices.

The sporophylls are usually aggregated at the ends of certain
ofthe branches ; they form their flowers much as in Lycopodium,
but there is not quite so sharp a distinction between the flowers
and the foliage leaves as in the latter case. The sporangia, which
are of two kinds, spring from the axils of the sporophylls, or
in some cases from the surface of the stem just above the inser-
tion of the latter.

The macrosporangia usually contain four macrospores; the
number of microspores is generally large.

In the details of its anatomy Selaginella presents some very
characteristic appearances. The apical meristem is sometimes
small-celled and stratified, but in some species there is a definite
apical cell. In others there is a group of two or three large cells
which behave like apical cells. The stem as seen in section
(fig. 919) is composed of parenchymatous or prosenchymatous
cells, embedded in which are one to three steles, the polystelic
condition being the most usual. There is no sclerenchyma,
and but few intercellular spaces; sometimes, indeed, the latter
are absent altogether. Each stele is enclosed in a large air-
chamber, and this chamber is crossed by delicate rows of cells
or trabecule, which attach the stele to the walls. The steles
are gamodesmic, and consist of a variable number of bundles
which have their protoxylem groups external, abutting on the
pericycle. A frequent number of bundles in the stele is two of
xylem and two of phloém; in such case the structure much
resembles the stele of the fern stem, but it differs in the proto-
xylem being on the outside instead of being internal. The
structure is really of the same kind as in Lycopodium, the
bundles being originally disposed radially. Not being so nume-
rous as in the latter case, the subsequent fusions do not lead
to so complicated a woody mass.

The leaves contain a single bundle, which in like manner is
slung in an air-chamber. The base of the leaf is sometimes
dilated into a kind of pulvinus, which is chiefly occupied by the
air-cavity. The intercellular space system being so much
reduced, the stomata of the leaf open into these air-chambers.

The tissue of the root is more compact, there are no air-

VOL, IL. M
162 MANUAL OF BOTANY

chambers, and usually a single central stele. The structure of
the rhizophore resembles that of the root.

The sporangia are developed much as in Lycopodium ; the
macrosporangia differ from the microsporangia in the number
of divisions that take place in the cells of the archesporium.
In the latter case many mother-cells are produced, each giving
rise to four tetrahedral microspores ; in the former case not so
many are formed, and only one of them as a rule divides to
form spores. Hence the mature macrosporangiuin contains four
macrospores.

Fic. 919.

 

fy. 919. Section of stem of Selaginellu showing three steles, a, b, air claambers.

The male gametophyte arises from the microspore, and is
very similar to that of Marsilea. The spore divides into two cells,
a small vegetative one at the apex, and a large basal one which
by repeated divisions produces a single antheridium, having a
wall enclosing the mother-cells of the antherozoids. The micro-
spore does not rupture until the antherozoids are developed.

The germination of the macrospore gives rise to a prothal-
lium which is very largely endosporous. The spore contains a
PTERIDOPHYTA—LYCOPODINA 163

small amount of protoplasm surrounding a large central vacuole.
By free cell-formation a small primary prothallium is formed at
the apex of the spore, which is soon separated from the remainder
of the spore-cavity by thickening of the cell-walls of its lower
layer, forming a diaphragm not unlike that of Salvinia. The
protoplasm of the lower part of the spore increases till the cavity
is filled with it. By free cell formation it develops a tissue
much like that of the primary prothallium but with larger cells.
This has been called the endosperm. The upper portion of the
prothallium is after its formation exposed to light and air by the

Fie. 920.

 

Lig. 920, Germination of macrospore of Selaginellu. After Pfet¥er. arch.
Archegonium. em, em’. Young embryos,

rupture of the macrospore at its apex; it then becomes green
from the development of chloroplastids. Generally it bears only
one archegonium, always only a limited number. Frequently
the number produced depends upon whether the first becomes
fertilised. They have the same structure as those of the euspo-
rangiate ferns.

The archegonia have the usual structure found in the group.
Fertilisation of its oosphere is also normal.

‘When the zygote is formed and its germination begins, the
process is similar to that of Lycopodium. The hypobasal seg-
ment becomes the suspensor, which by its elongation forces the

M 2
164 MANUAL OF BOTANY

young embryo down into the tissue filling the cavity of the spore,
the so-called endosperm. The epibasal cell forms four octants,
and from these arise the growing points of the stem and of two
cotyledons. As the growth of the embryo proceeds, a pseudo-foot
is developed from the hypocotyledonary region, and the direc-
tion of growth of the axis becomes changed, so that the stem
gradually curves upwards to emerge from the spore at the crack
at its apical region, through which the prothallium is partially
protruding. The foot remains embedded in the tissue of the
endosperm and absorbs
its contents. The first
root is developed from
cells in the interior of
the hypocotyl between
the foot and the sus-
pensor.

The other member
of this section, Isoétes,
differs from Selaginella
very markedly in its
habit. It has a short
tuberous stem some-
what lobed externally,
from which spring
numerous leaves in a
cluster. The leaves
are long and narrow,
some of the cluster be-
ing fertile and some
sterile. The fertile
leaves bear large spo-

Fiy. 921, ILsotles lucustris, Lake Quill-wort. The rangia in a kind of pit
stem is small and corm-like, and bears its leaves, h
which are linear-cylindrical, in tufts. upon the upper surface

at their base. The
microsporophylls are developed later than the macrosporophylls.:
Each leaf bears a ligule as in Selaginella, Numerous roots
spring from the under side or base of the tuberous stem, and
these branch dichotomously.

The stem is monostelic, and grows by a meristem, which con-
sists of several large so-called apical cells. The stele is com-
posed of a number of fused collateral bundles, which are common
and run out into the leaves. Outside the bast of the bundles is
a merismatic ring, which forms vascular tissue internally, and

Fie. 921.

 
PTERIDOPHYTA—LYCOPODIN A 165

externally adds to the cortex of the stem. Isoétes thus increases
in thickness, but somewhat irregularly, the distribution of the
new cortical tissue being interrupted at places in the ring, so
causing the furrows noticeable on its exterior.

The leaves have a single bundle, which is of a somewhat re-
duced type. It runs down the middle of the blade into the stem,
and joins the ring of the stele. Four large air-spaces run down
the whole length of the leaf in the parenchymatous tissue (fig.
922).

Fic. 922.

 

Fig. 922. Transverse section of leaf of Zscétes lacustris. a. Air-chamber. 0.
Fibrovascular bundle,

The root differs from the stem in having a small-celled
stratified apical meristem. Its stele contains only one or two
bundles of xylem and phloém.

The sporangia are much more bulky than in any other of the
Lycopodine. They arise in a depression or pit on the upper
surface of the leaf just above its base, a little below the insertion
of the ligule. Isoétes is eusporangiate, the sporangium arising
from a group of cells. In the microsporangium the archesporial
tissue, which becomes bulky, has its cells arranged in radial rows,
springing from a sort of pad or cushion at its base. There takes
166 MANUAL OF BOTANY

place in the archesporium then a process of sterilisation of
certain of these cells, recalling the formation of the elaters in the
Liverworts. The sterile cells extend as trabecule or strands
across the interior of the sporangium, so that in transverse
section it appears to be septate. In the microsporangium other
cells also sterile, though derived from the archesporium, form
tapetum, which surrounds the mass of microspores. In the
macrosporangium there is a similar formation of trabecule, but
the arrangement of the rest of the archesporial tissue is different.
There are fewer cells, which are consequently larger, and a tape-
tum is formed round each mother-cell.

The sterilisation of the tissue forming the trabecule, like that
of the tapetum, is probably due to the need of distributing
nourishment for the spores throughout the large sporogenous
mass.

The gametophytes of Isoétes closely resemble those of
Selaginella. The prothallium derived from the macrospore is
even more completely endosporous, the development being
advanced to the stage of maturity of the archegonia before the
spore splits. The prothallium consequently never becomes
green. The antheridia and archegonia resemble in all points
those of Selaginella.

The development of the young sporophyte from the zygote
recalls that of the ferns. Both epibasal and hypobasal segments
divide to form the octants; the hypobasal ones all combine to
form the foot, but the first root is developed from the epibasal
segments, which also give rise to the stem and the single
cotyledon. The root is consequently adventitious, as in
Selaginella.

Like the Equisetine, the Lycopodine were represented in
Carboniferous times by very massive forms which showed great
cambial activity in the development of their trunks and roots.
Of these Lepidodendron is the best known example.
167

CHAPTER VI.

Group IV.
SPERMAPHYTA OR PHANEROGAMIA.’

Tuts group of plants, so long considered as one standing apart
from and above all others, or corresponding in classificatory
value to the whole of the Cryptogams, is now held to be properly
only upon an equal footing with the other groups already dis-
cussed. The gradual increase of complexity of structure of
the sporophyte, associated with the progressive degradation of
the gametophyte, reaches its maximum in this group, which
appears as the fourth member of the series into which the
Vegetable Kingdom is now divided.

The heterosporous character of the sporophyte, which we
have seen to appear irregularly in the Pteridophyta, is here
constant. The microspores are developed in much the same
way and in about the same numbers as in the latter group ; the
macrospores show a considerable degradation, and the macro-
sporangia never become free from the parent plant until some
time after their gametophytes are mature, not indeed until the
young sporophyte or embryo produced by each of the latter has
attained a considerable degree of development. The result is
that a peculiar structure known as the seed makes its appearance
for the first time in this group of plants. As its development
shows some variability, it will be well, for the present, to defer
its consideration. On account of its constant occurrence, the
group is sometimes called the Spermaphyta.

The general morphology and anatomy of the group have
formed the subject of the greater part of the first two sections of
this manual, and need not, therefore, be treated of at length in the
present, chapter.

~-“--Piie chief remaining points calling for attention in connection
with the Phanerogams are the structure of the sporophylls; the
development of their sporangia, and spores; the gametophyte
generation ; and the embryogeny of the sporophyte.
168 MANUAL OF BOTANY

The arrangement ot the sporophylls has been discussed in
connection with the morphology of the reproductive organs
(Vol. I. Chapter IT.), where their collection with other leaves
into special branches, called flowers, has been fully treated of.

This development of a special branch system in connection
with the occurrence of spores has been seen in the previous
groups, especially in the Pteridophyta, not to be peculiar to the
Phanerogams, but to be clearly indicated in the Kquisetine and
the Lycopodine. What is, however, exceptional in the lower
forms becomes in the Phanerogams a constant and characteristic
feature of their life.

It has been already pointed out that in the Phanerogams the
sporangia, though usually borne upon leaves, are sometimes axial
in their origin (fig. 923). This is seen in the case of both micro-
sporangia and macrosporangia.
When borne upon leaves, these
are known as microsporophylls
and macrosporophylls respec-
tively. The microsporophylls
are also called stamens, or
staminalleaves; while the macro-
sporophylls are termed carpels,
or in some cases carpellary
leaves or scales.

E ; ; The microsporangia, often
ae Eigse areal ee called pollen-sacs, are situated at
sporangia. different places upon the stamen
or staminal leaf. In the Gymno-
sperms they are upon the under side; in the Angiosperms
upon both surfaces. The macrosporangia, or ovules, arise from
a special parenchymatous cushion already described as the
placenta, which in the Gymnosperms is usually on the ventral
surface of the sporophyll or carpellary scale, but in the Angio-
sperms is almost always a development of the margin of the
carpel. The carpel, or frequently the collection of carpels in a
flower, forms by various cohesions at their bases in the latter
case a closed chamber or ovary in which the macrosporangia are
concealed.

Based on this latter point we have the classification of the
Phanerogams into two large divisions, Gymnosperme, in which
the ovules are exposed, and Angiospermae, in which they are
enclosed in an ovary. Each of these large groups presents
important peculiarities, the Gymnosperms approaching the

 
PHANEROGAMIA 169

Pteridophyta much more nearly than the other forms, especially
in the structure of the gametophyte and the differentiation of the
sexual organs.

Tue MIcROSPOROPHYLLS, AND THEIR SPORANGIA.—The micro-
sporophyll varies a good deal in its form; in the Gymnosperms
it may be a flattened leaf with sporangia on its under surface ;
it may be a peltate scale, something like that of the flower of
Equisetum, or it may be a short branched axis bearing a variable
number of anther lobes. In the Angiosperms it is the structure
already described as a stamen, consisting of a filament, carrying
at its apex a swollen head or anther.

The Microsporangia are distributed in various ways upon the
sporophyll; in most cases in groups which are to be considered
as sori, corresponding to the sori in the Ferns and their allies.
In the Gymnosperms the flattened staminal leaf of the Conifers
has a sorus of two sporangia on its back; the sporophylls of
the Cycads bear a number of groups of sporangia, each group
representing a sorus. The anther of the Angiosperms contains
a sorus of four sporangia, the pollen-sacs. The indusium or
membrane covering the sorus in the Ferns is represented
doubtfully in the Cupressinex, where the sporangia when young
are covered by an outgrowth of the under surface of the sporo-
phyll.

Whether the sporangia arise upon a sporophyll or upon the
axis, their mode of development is the same. They are
eusporangiate, that is, they originate in a group of several cells.
In the young anther, at four places, corresponding to the anther
lobes, a row of hypodermal cells is seen to be somewhat
different from the rest in their mode of dividing. In a trans-
verse section of the anther they appear as four cells, as the row
runs longitudinally. The hypodermal cell so seen in transverse
section cuts off a cell from itself on its exterior face; this
division is followed by another one parallel to the first, so that
the original cell or archesporium is replaced by a row of three,
of which the innermost has come to lie more deeply in the
tissue. The outer two take no part in the development of the
spores, which arise from the inner one. The one lying next to
this is the first-formed part of a nutritive layer which is made to
extend round the sporogenous cell by divisions taking place in
the tissue next it. This layer is known as the tapetwm and
has only w transitory existence. The outermost of the three
cells becomes similarly extended, and the walls of those cells.
which are towards the exterior become thickened spirally, con-
170 MANUAL OF BOTANY

stituting the external wall of the pollen sac. Both these layers
become composed of many cells, owing to radial or anticlinal
divisions of those first formed. The innermost cell divides into
a variable number of cells, which are the mother cells of the
microspores or pollen grains. Each mother cell gives rise to four
special mother cells; in the Monocotyledons by ordinary cell-
division twice repeated, the plane of the second division being at
right angles to that of the first: in the Dicotyledons the four
special mother cells are arranged at the four angles.of a tetra-
hedron, as described in the case of the ferns. Each special
mother cell gives rise to a pollen grain, or microspore, by a
process of rejuvenes-

Bras 28: cence. The a

3 1 and frequently the

walls of the original
mother cells, become
disorganised, forming
a sort of mucilagi-
nous fluid in which
the spores float. As
they mature their
walls are thickened
from within and usu-
ally form two coats,

the intine and the

Fig. 924, Development of pollen in the exine. The exine
stamen of Lavatera. 1, 2. Young stages. 2 a
1, Transv>rse, 2. Longitudinal, section of is often curiously

anther. a,d. Tapetum. 0, c, Sporogenous i 7
cells, 3. Later stage. f. Tapetum. e¢. Four marked with spines

special mother cells of the pollen. After or ridges, due to

Deer ron the deposition of
matter upon it from the disorganised tapetal cells. Eventually
the spores lie free in the cavity of the sporangium.

Dehiscence is secured by the hygroscopic character of the
wall of spirally thickened cells described above, which under
different atmospheric conditions ruptures either by longitudinal
or transverse slits, or occasionally by a pore at or near the apex.

The microspore so formed is a rounded, or oval, or rarely an
elongated body, containing protoplasm and nucleus, anda quantity
of reserve food material consisting of proteids, starch, oil, &e. It
has usually two coats, of which the outer is hard and thickened,
the inner thin and delicate. In some of the Gymnosperms the
outer coat is expanded at two places at the base of the spore to
form two bladder-like bodies which are filled with air,

 
PHANEROGAMIA 171

The two coats are usually distinct from each other, but in
some pollen grains they are adherent, except at special spots, at
which the exine will rupture when the spore germinates. In
some cases there is no exine, particularly in some aquatic
plants.

The microspores do not always become free from each
other; in the Mimose they are bound together by the special-
mother-cell walls into groups of four or more; in the Orchids
and Asclepias the whole mass is usually coherent, forming the
pollinium.

THE MacrosPoropHYLLs anD THE Macrosporancia.—The
appearance of the macrosporophylls has already been described.
In the Angiosperms they are the carpels, and may be either
free or coherent together. Inthe Conifers of the Gymnosperms
they are flattened, scale-
like leaves, each of which Fie. 925. Fie. 926.
bears two sporangia on
its upper face. In some
of the Cycads they are
small pinnate leaves, the
lower pinnz only bearing
the sporangia. In others
they are peltate scales
with the latter on their
under side, much resem-
bling the microsporo-
phylls.

The development of
the macrosporangium or
ovule takes place by the
division of certain hypodermal cells of the placenta, whether
the latter be upon a sporophyll or upon the axis. These
cells divide repeatedy periclinally till the young sporangium
appears as a little protrusion of tissue, whose cells are arranged
in radial rows (fig. 927). In the most usual case the terminal
cell of the central row becomes the archesporium. The growth
of the mass of the sporangium, known as the nucellus, has
already been described (Vol. I. p. 207) and its various shapes
mentioned. From its base arise the integuments, usually two in
number, which accompany it in its growth and finally surround
it, except at the apex, where the micropyle is left.

While this development is proceeding changes take place in
the interior. The original archesporium, which is a single cell,

Fig. 925. A mature carpel or
scale of the Scotch Fir
(Pinus sylvestris), with two
winged naked seeds at its
base. mic. Micropyle. ch.
Chalaza.— Ty. 926. A
seale of the Larch, bearing
one naked winged seed ; the
other seed has been re-
moveil,

 
172 MANUAL OF BOTANY

cuts off one or sometimes two cells at its apex, the innermost of
which represents the tapetum. These tapetal cells sometimes
divide repeatedly, especially in the Gymnosperms, so that the
innermost cell often comes to lic deep in the tissue of the
nucellus. This is often, in the same group, secured by ad-
ditional multiplication of cells derived from the epidermis

Fie. 927.
a,
SRS

a
= os

~~}
Far tTys

 

Fig. 927, Yarly development of the anatropous ovule of Viola. 1-6. Succes-
sive stages. a,b. Inncr integument. c,d. Outer integument. F.s. Em-
bryo sac. After Kny.

of the nucellus over the apex of the archesporium. The
innermost cell produced by the archesporial divisions now
enlarges to a considerable extent. It represents the mother
cell of the spores of the microsporangium. Instead of dividing
to form special mother cells as in the latter, it becomes itself
PHANEROGAMIA 173

the single spore. It was formerly described as the embryo sac,
as the embryo ultimately makes its appearance in it. During
its growth, which is very considerable, it absorbs the cells around
it, often to such an extent that it leaves nothing of the original
nucellar tissue. It may even encroach upon the integuments.
It then forms a large cell, clothed only by the integuments of
the sporangium. If the absorption of the nucellus is not
complete, the remainder of its cells form the tissue already
alluded to as the perisperm.

The nucellus of the ovule is seen thus from its development
to be the macrosporangium of the Phanerogam, and to corre-
spond to the macrosporangium of Selaginella. It differs from
the latter in that the mother cell of the spore becomes itself the
spore, whereas in Selaginella the corresponding cell divides
twice, forming four macrospores. It differs further in not
secreting a thickened coat, its wall always remaining thin and
delicate, except in the Cycadex, where it is double.

The integuments of the ovule correspond to the indusium,
which in Salvinia and Azolla has been shown to be two-layered
and to grow over and enclose the sporangia. The integuments
do not completely close over the ovule, while in the former case
they shut the sporangia in entirely.

The structure in the Phanerogams recalls the condition in
Azolla more than in Salvinia. In Azolla the sorus of macro-
sporangia consists only of one, and this one is invested by the
indusium just as the ovule is surrounded by its integuments.
The macrosporangia in the Phanerogams are thus solitary as in
Azolla, or in other words the sorus is monosporangiate.

Though this is the usual course of development in the
Phanerogams, there are many variations of the process known.
More than one row of cells in the nucellus may give rise to
archesporia, and consequently more than one embryo sac or
macrospore may be produced. Eventually only the central one
becomes mature, the others perishing early. In some cases,
instead of a single spore mother cell occurring, this divides into
a number of sporogenous cells, of which again several may begin
to develop into macrospores, though ultimately only one of
them matures. In a few plants the original archesporium does
not cut off any tapetal cells.

The features of the gametophyte generation and the embryo-
geny of the sporophyte differ considerably in the Gymnosperms
and the Angiosperms, and will be best described in connection
with those respective groups.
174 MANUAL OF BOTANY

DIVISION A.—GYMNOSPERMA.
Cuass IX.—GYMNOSPERM A.

The plants included in this class are distinguished by their
macrosporophylls never forming an ovary, the carpels being
usually flattened and bearing the macrosporangia on their upper
surfaces. In habit they are shrubs or trees, generally of consider-
able size. In our climate they are chiefly represented by the
Coniferous trees, Firs, Larches, &c., which have a monopodially
branched stem, bearing usually long branches, on which dwarf
shoots are thickly placed, the latter consisting of small fascicles
of two to several elongated green leaves springing from a short
axis and surrounded at their base by minute withered or brown
seales. The long branches bear no foliage leaves except what
arise from their dwarf shoots.

The stem in other members of the group is a short thick
trunk, bearing large pinnate leaves; in Welwitschia it is very
short and bears only two leaves, which are very long.

A few forms have a bushy habit, with wiry stems which
bear no foliage leaves, but only a number of scales.

The sporangia are of two kinds, as already stated. The micro-
sporophylls are usually collected into cones, and bear the
sporangia on their lower surfaces. The macrosporangia are
axial in Taavus and in the Gnetacee ; in the other cases they are
borne on sporophylls. These, like the microsporophylls, are
generally arranged in cones, but the sporangia are on the upper
surface at the base of the sporophyll, sometimes upon a large
placental scale. In Cycas the sporophyll is a pinnate leaf, the
lower pinne of which are replaced by macrosporangia. A cluster
of these sporophylls is developed at the apex of the stem among
the foliage leaves.

The development of the sporangia and of the spores has
already been described.

A few features of the histology are remarkable. The stem
is of the same type as the Dicotyledons, but is peculiar in that
the wood formed by the cambium, except in the Gnetacex, always
consists of fusiform tracheids with bordered pits upon their
radial walls. The sieve tubes, like those of the Pteridophyta,
have no companion cells. There is a great development of
GYMNOSPERMA 175

secreting ducts in most cases, the secretion being either resin or
mucilage.

Tue Gametoruyte.—As there are two kinds of spore, there
are two forms of gametophyte, the male organs occurring on the
one developed from the microspore, the female on that proceed-
ing from the macrospore.

The pollen grain generally begins to germinate before it is
set free from the microsporangium. It divides into two, one of
which is much larger than the other. The smaller is known as
the antheridial cell, the larger as the vegelative one. In some
species more than one small cell is produced, the whole series of
them being then looked upon as a rudimentary prothallium, and
the last formed being the antheridial cell. After escaping from
the sporangium the vegetative cell grows out into a long fila-
mentous body, known as the pollen tube ; it is composed only
of the intine of the spore, the exine rupturing to give it exit.

The antheridial cell divides into two, a stalk cell and a
generative cell. The generative cell and the nucleus of the
vegetative cell both make their way down the pollen tube ; the
vegetative nucleus breaks up and disappears; the generative
cell divides into two, which represent the mother cells of anthero-
zoids of the Pteridophyta. The antherozoid is, however, not
differentiated. In some forms there is a still further division of
the generative cells at the apex of the pollentube. The ultimate
cells, whether the divisions be one or many, are naked cells and
constitute the male gametes. They are eventually extruded
from the pollen tube.

The prothallium which is produced from the macrospore is
sometimes called the endosperm. It is never exposed as in the
Pteridophyta. The nucleus of the macrospore divides repeatedly
till a large number of nuclei are present; these are arranged in a
layer in the protoplasm lining the spore; then between them
cell-walls are formed, and a peripheral cellular layer is thus
constituted. The cells of this layer by ordinary cell-division
produce a tissue which fills the spore. This is the prothallium.
Archegonia are developed at its apical end, having almost the
same structure as in the Pteridophyta. They arise from
superficial cells, and have a neck and a venter, in which lie the
neck-canal-cells, ventral-canal-cells, and oosphere respectively.

Fertilisation is brought about by the microspore germinating
upon the apex of the macrosporangium. The pollen tube pene-
trates the latter by the micropyle and bores its way into the
tissue of the nucellus during its development, as described above.
176 MANUAL OF BOTANY

The apex of the tube comes to the summit of the macrospore,
where the necks of the archegonia are situated. It pierces the
coat of the spore and either enters the neck of a single arche-
gonium or spreads over several. A male gamete is extruded
from the tip into the oosphere or oospheres as the case may be,
and the nuclei of the two gametes fuse to form the nucleus of the
new zygote.

This is the general arrangement throughout the group; but
variations are found in some
forms, particularly in the
Gnetacee.

The fate of the zygote differs
a good deal in the different
Natural Orders of the group.
The Conifere are the most
regular, and may be first dis-
cussed. The embryo is derived
from only part of the zygote;
its nucleus goes down to the base
of the cell and divides into two,
and each again into two; the
four nuclei become four cells by
protoplasm aggregating round
them and cell-walls being formed
between them. Tach cell of the
four divides twice transversely,
so that instead of four cells there
are four tiers, each tier consist-
ing of three cells. Each of the
middle cells grows out into a

Fie. 928.

 

Fig. 928, Macrosporangium (ovule) of
Pinus at maturity. After Dodel-
Port. mac. Macrospore. end. Ga-
metophyte or prothallium. arch.
Archegonia. p.g. Pollen-grain or
microspore, which has been trans-
ported to the micropyle of the ovule
and has put out its prothallium, the
pollen-tube, p.2.

suspensor, the top cells of each
tier attach the suspensor to the
rest of the zygote, while the
terminal cells give rise to four
embryos.

This mode of development

is that characteristic of the
Abietinee ; in the Cupressinee a single tier of three cells is first
formed ; in Thuja only the two upper cells undergo longtitudinal
division, so that a single embyro is found, furnished with four
suspensor cells ; in Juniperus all three divide as in the Abietinex.
Picea excelsa of the Abietinee resembles Thuja in only forming
one embryo instead of four. In the Cupressinex the elongation
GYMNOSPERMA 177

to form the suspensor takes place in the top cell as well as the
middle one.

In the Cycadex the embryo is formed by a process of free-
cell formation leading to the construction of a mass of cells, the
lower part of which grows out into the tissue of the prothallium
forming a suspensor, at the end of which an embryo is developed.
Ephedra of the Gnetacee behaves similarly, but each embryonic
cell grows out separately in the same way, and so a number of
embryos are formed; in Ginkgo the mass of cells formed in the
zygote constitutes the embryo, and there is no suspensor. Other
modifications occur in Welwitschia and Gnetwm.

In most cases the zygote gives rise to a number of embryos ;
in the ripe seed, however,
only one is usually present,
the others perishing in the
course of development.

The seed is always albu-
minous; a good deal of the
prothallium persists, forming
an endosperm, and a certain
amount of the original nucel-
lus is also present, forming
perisperm. The embryo is
found embedded in the endo-
sperm : it consists of an axis,
with plumule and radicle,
and bears a variable number Fig. 929, Beginning of development of
of cotyledons, sometimes SPS Aus. Mheright hand ovum
only one, sometimes as many
as fifteen. The growing point of the root is peculiar, being
differentiated in the body of the embryo, some distance from its
lower end. The integument of the macrosporangium becomes
hard and woody and forms the testa of the seed.

The macrospore remains in the sporangium orovule all the
time these changes are proceeding, and the sporangium does
not become detached from the sporophyte from which it origi-
nated. The resulting structure is the seed whose composition
has just been described. In this body we have consequently
three generations represented. From the original sporophyte
are derived the testa, the perisperm or nucellus of the macro-
sporangium, and the embryo sac or macrospore. From the
gametophyte we have the endosperm or prothallium. From
the zygote, the commencement of the new sporophytic genera-

VOL. II. N

Fie. 929.

 
178 MANUAL OF BOTANY

tion, we have the embryo, which is the young sporophyte
itself,

The Gymnosperms are subdivided as under :—

Order 1. CoNIFER&% or PINACES, the Coniferous or Pine
Order.—Character.—Resinous trees or evergreen shrubs, with
branched continuous stems. Leaves linear, acicular or lanceo-
rate, parallel-veined, fascicled or imbricate alternate. lowers
naked, moncecious or dicecious. Male flowers arranged in
deciduous amenta. Stamens 1 or several, in the latter case
monadelphous; anthers 1- or more-celled, opening longitudinally.
Female flowers in cones, consisting of flattened imbricate carpels
or scales arising from the axil of membranous bracts; ovules
naked, 2 or more, on the upper surface of each carpel. Frutt a

io Fie. 930. Fie. 931. Tia. 932.

ip

Fig. 930, A ripe cone of the
Larch (Pinus (Abies) Larix).
—Fig. 931. <A mature
carpel or scale of the Scotch
Fir (Pinus sylvestris), with
two winged naked seeds at
its base. mie. Micropyle. ch.
Chalaza.— Fig. 982, A
seale of the Larch bearing
one nakell winged see ; the
other seed hag been removed.

 

woody cone or agalbulus. Seeds naked with a hard crustaceous
integument, albuminous ; cotyledons 2 or many.
Division of the Order and Illustrative Genera.—This order
has been subdivided as follows :—
Sub-order 1. Abietee.—Ovules inverted, with the micropyle
next the base of the carpel. Pollen curved.
Iilustrative Genera :—Pinus, Linn.; Araucaria, Juss.
Sub-order 2. Cupressee.—Ovules erect, with micropyle superior.
Pollen spheroidal. Illustrative Genera :—Juniperus, Linn. ;
Cupressus, Tourn.
The order Taxacee is now frequently included in the
Conifera, forming the tribe or sub-order Taxee or Taxinea.
Distribution and Numbers.—The plants of this order occur
GYMNOSPERMAi _ 19

in all parts of the world; but they abound most in temperate
climates. There are about 250 species.

Properties and Uses.—They possess very important proper-
ties. Many supply valuable timber, and most of the species
contain an oleo-resinous juice or turpentine, which is composed
of a volatile oil and resin.

Ordcr 2. Taxacem, the Yew Order.—Character.— Trees or
shrubs, with continuous branches. Leaves usually narrow,
rigid, and veinless; sometimes broad, with forked veins.
Flowers unisexual, naked, bracteate. Male flowers several
together, each with one or several stamens, which, in the latter
case, are united or distinct; anthers bursting longitudinally.
Female flowers solitary, and consisting of a single erect naked
ovule, which is either terminal or placed in the axil of a bract.
Seed small, usually more or less surrounded by a cup-shaped
fleshy mass or aril, albuminous; embryo straight. This order

Fie, 933. Fie. 934.

Fig. 933. Male flower of the
Common Yew (Zaxus bac-
cata), with numerous mo-
nadelphous stamens.
Fig. 984. Vertical section
of the seed of the same. ar.
The succulent cup-shaped
mass which surrounds the
seed. pl. Embryo. alb. Al-
bumen. ch. Chalaza. mr.
Mieropyle.

 

  

is now frequently included in the Conifere, forming the tribe
or sub-order Taree or Ta-rinee.

Distribution and Numbers.—Natives of the mountains of
tropical countries, and of temperate regions. Illustrative
Genera :—Taxus, Linn.; Salisburia, Smith. There are about
50 species.

Properties and Uses.—In their general properties they re-
semble the Conifers.

Order 3. Gnetacn@, the Jointed Fir Orden: —Character.
Small trees or shrubs, with usually jointed stems and branches.
Leaves opposite, entire, net- or parallel-veined, or sometimes
small and scale-like. Flowers unisexual or rarely hermaphro-
dite, in catkins or heads. Male flowers with a 1-leaved calyz ,
anthers 2—8-celled, with porous dehiscence. Female flowers

naked or surrounded by 2 more or less combined scales; ovules
x2
180 MANUAL OF BOTANY

1— 2, naked, pointed by a style-like process. “ Seed succulent ;
embryo dicotyledonous, in the axis of fleshy albumen.

Distribution and Numbers.—These plants occur in both
tropical and temperate regions. There are 3 genera-—Ephedra,
Linn.; Welwitschia, Reichb.; and Gnetum, Linn. ; and about
30 species.

Properties and Uses.—Unimportant. The seeds and leaves
of several species are eaten. Some Ephedras are astringent.

Order 4, CycaDAcEa, the Cycas Order.—Character.—Small
Palm-like unbranched or occasionally dichotomous érees or
shrubs, with their surface marked by the scars of fallen leaves.
Leaves clustered at the summit, pinnate, parallel-veined, hard
and woody ; leaflets sometimes circinate in vernation. Flowers
quite naked, unisexual, diccious. Male flowers in cones, con-
sisting of scales, from the under surface of which 1-celled
pollen sacs arise. Female flowers consisting of naked ovules
placed on the margins of altered leaves, or of ovules arising from
the base of flat scales or from the under surface of peltate ones.
Seeds hard or succulent, with 1 or several embryos contained in
fleshy or mealy albumen.

Distribution and Numbers.—Natives principally of the tem-
perate and tropical parts of America and Asia; and occasionally
of the Cape of Good Hope, Madagascar, and Australia. Illus-
trative Genera :—Cycas, Linn.; Zamia, Lindl. There are
about 50 species,

Properties and Uses.—The stems and seeds of the plants of
this order yield mucilage and starch.

Artificial Analysis of the Orders in the GyMNosprRM™.

1. Stem jointed, branched . , , Fi + Gnetacee.
2. Stem not jointed. *
Branched. Leaves simple.

Carpels ccllected in cones . . Conifere.
Seed solitary, usually menantiled bya a suc-
culent coat ‘ . . Taxacee.

Not branched or dichotomous. “Deéavenpinnate Cycadacea.
ANGIOSPERM 181

DIVISION B.—ANGIOSPERMZ.

In this division the evolution of the flower reaches its highest
point; the micro- and macrosporophylls are usually found in
the same flower; the former are, as a rule, much modified in
shape, and their foliar character lis at first sight difficult to
grasp; they form the structures described already as stamens,
each consisting normally of a filament and an anther, the
latter bearing the microsporangia or pollen-sacs. The macro-
sporophylls are carpels, and are either distinct or coherent to-
gether. In either case the ovules or macrosporangia are con-
tained in a closed cavity, or ovary, formed by the cohesion in
various ways of the carpellary walls. Each ovary is crowned
by a stigma, which is often separated from the ovary by a
filiform structure called the style.

The pollen grain, instead of entering the micropyle of the
ovule and germinating there, falls upon the stigma and there
develops its gametophyte, which penetrates the tissue of the style
in the form of the pollen tube and makes its way into the cavity
of the ovary, ultimately reaching the ovules. It generally enters
the latter at the micropyle and so makes its way to the gameto-
phyte of the macrospore or embryo sac, which is situated just
below the micropyle. In a few cases it finds its way to the
female cell by burrowing through the tissue of the ovule and of
the gametophyte from the chalazal end. This, however, is
exceptional, and only occurs in a few families.

The gametophyte produced by the macrospore is always com-
pletely internal or endosporous, and is very much reduced. It
bears the female cell or oosphere at its micropylar end, and this
cell is not enclosed in an archegonium (jig. 935).

Histologically the group shows an advance upon the structure
of the Gymnosperms in the greater variety of the elements com-
posing the wood and bast. The wood contains true vessels, which
show the varieties of thickening already described. The sieve
tubes always have companion cells. The development of the
spores takes place in the way already described. In a few cases
modifications of the process arefound. In Asclepias and Zostera
the mother cells of the pollen do not form four special mother
cells, but each becomes a microspore.
182 MANUAL OF BOTANY

Tur GAMEToruyTe.—As in the Gymnosperms we have two
forms of the gametophyte, the one coming from the microspore,
the other from the macrospore.

The prothallium developed from the microspore is more
reduced than in the last group. When the spore is shed, or
sometimes while it is still in the sporangium, the nucleus divides
into two, but this division is not followed by the formation of a
cell-wall. The protoplasm of the spore aggregates round the two
nuclei, forming two primordial or naked cells, one of which is
the generative, the other the vegetative cell. The exine ruptures,
often at particular spots, but sometimes irregularly, and the
intine grows out into a long tube, the pollen tube. In some
cases, as in the Malvacer, several tubes arise from different
points on the spore.

The pollen tube is derived from the larger of the two cells,
the vegetative one, as in the Gymnosperms. The generative cell
passes into the tube, as does the vegetative nucleus. As they
proceed down the tube, the generative cell divides into two,
forming two gametes, which correspond to the antherozoids of
lower forms, but they are never differentiated as in the latter
case. The vegetative nucleus becomes disorganised and disap-
pears.

By the time that the pollen tube has reached the gametophyte
of the macrospore the process is complete, and the tube remains
with its two gametes at or near its apex. The protoplasm of the
tube is richly vacuolated, and the granules it contains show ex-
tensive movements of circulation.

The macrospore produces its gametophyte in its interior as
in the Gymnosperms, but the prothallar tissue is very much
smaller (fig. 985). The nucleus of the macrospore divides into
two, and each travels to one end of the spore. Each then divides
into two, and each of the daughter nuclei repeats the process, so
that at that stage the spore contains two groups each of four
nuclei, one at the micropylar and the other at the chalazal end.
One nucleus from each of these groups then travels to the centre
of the spore, and the two fuse together, constituting what is known
as the definitive nucleus of the embryo sac. A certain amount
of protoplasm aggregates round each of the three nuclei at the
two ends, forming two groups of three cells each. Those at the
chalazal end secrete cell-walls and form the antipodal cells,
which take no further part in the development; those at the
micropylar end remain naked and constitute the egg apparatus.
One of these, whose nucleus is the sister nucleus of the one
ANGIOSPERM A 183

which descended to help form the definitive nucleus, is the female
gamete, or oosphere, while the other two are known as the
synergide. In some few cases the definitive nucleus is consti-
tuted by only the one from the chalazal end; there are then
two oospheres, of which only one becomes fertilised. In
rare cases the synergide are fertile gametes, though this very
seldom happens.

At this stage the development of the prothallium remains
suspended, and nothing further takes place unless the oosphere
becomes fertilised. The
egg apparatus lies almost Fic. 935.
always immediately below
the micropyle, and is thus
not covered by a mass of
tissue as in the Gymno-
sperms. The pollen tube
reaches the micropyle as
already described; its apex
becomes more or less muci-
laginous, as does the wall
of the embryo sac, and one
of the male gametes makes
its way through to the
oosphere, with which it
fuses, nucleus with nucleus
and protoplasm with pro-
toplasm. The fertilised
oosphere, now become a
zygote, surrounds _ itself
with a cell-wall, and the ig. 935. Macrosporangium (ovule) of an
synorgide hecome disor  AMSiOsREM. ran, Macrorpor, "es,
ganised and disappear.

The further fate of the zygote differs in the two classes into
which the Angiosperms are divided and will be discussed later.
The embryo sac becomes filled with a tissue known as the endo-
sperm, which has, however, a different morphological value from
the tissue in the macrospore of the Gymnosperms, though it bears
the same name.

This so-called endosperm is derived from the definitive
nucleus of the embryo sac. This body divides repeatedly, form-
ing a number of nuclei which become disposed in a layer all over
the surface of the wall of the embryo sac. Round each of
these an aggregation of protoplasm takes place, so that the sac

 
184 MANUAL OF BOTANY

has a lining of naked or primordial cells. These become sepa-
rated from each other and from the cavity of the spore by cell-
walls, and the cells so formed divide repeatedly till, in most
cases, the part of the embryo sac not occupied by the body
resulting from the divisions of the zygote becomes filled with a
mass of tissue which is the endosperm. In a few cases the
endosperm does not completely fill the spore, but leaves a hollow
cavity in the centre.

The young embryo, derived from the zygote in’a manner still
to be explained, together with the endosperm and the remains
of the microsporangium and its coats, forms the body frequently
alluded to above as the seed. The coats or integuments of the
macrosporangium generally become hard and form the testa of
the seed.

In some cases the endosperm is not formed by free-cell-for-
mation as described above, but by ordinary cell-division, walls
being developed after each nuclear fission.

In some plants this condition of things persists, and the
embryo in the ripe seed is embedded in the endosperm. In
others the embryo grows vigorously, and in its enlargement
absorbs the contents of the endosperm cells. The seed then shows
only the embryo surrounded by the testa. Generally the seed
leaves or cotyledons are the parts which form the bulk of the
embryo in such cases.

When fertilisation has been effected, and the zygote is
formed, it at once commences its further development. There
is no pause between the maturity of the gametophyte and the
origination of the new sporophyte. A resting period occurs later,
when the young plant has attained a certain size and when the
endosperm has been formed and perhaps absorbed. The zygote
divides into two by a transverse wall, and the two cells so formed,
which correspond to the epibasal and hypobasal cells of the
Pteridophyta, give rise, as in the latter case, to different structures.
The hypobasal segment, which is the one nearest to the micro-
pylar end of the embryo sac, develops into a chain of cells known
as the suspensor, a structure noticed as occurring in a similar
manner in the embryogeny of the Lycopodine. The suspensor
does not become free from the protoplasm of the embryo sac, in
which the oosphere was originally placed, and hence attaches the
embryo to the embryo sac ina way indicated by thename suspensor.
The suspensor, as a rule, soon perishes, so that only traces of it
can be seen in the seed ; sometimes, however, it grows to great
length. In the Orchidacee cases occur where it assumes such a
ANGIOSPERMZ: 185

size as to make its way out of the embryo sac through the micro-
pyle and to ramify in the interior of the ovary and the tissue
of the placenta. In some Dicotyledons a somewhat similar
behaviour is found. In such cases it recalls physiologically as
well as morphologically the foot of the Ferns and their allies,
absorbing nutriment for the support of the embryo.

The suspensor contributes a cell to the formation of the
embryo in a manner to be described below.

The epibasal cell, often termed the embryo cell, divides very
differently. In it three walls are formed successively at right
angles to each other, dividing it into eight octants. The octants
in this group, it will be noticed, all proceed from the epibasal
cell only and not from the whole zygote as in the Ferns, &c.
The recent separation of the hypobasal cell causes the epibasal
one not to be a sphere as is the zygote, so that the octants next
the suspensor are flattened somewhat and abut upon the latter
in a somewhat truncated fashion. The subsequent divisions differ
somewhat in the Dicotyledons and the Monocotyledons. In the
former group the anterior octants give rise to the upper por-
tion of the axis, but the posterior ones only form the hypo-
cotyl, the primary root being formed from the last cell of the
suspensor, the so-called hypophysis. In the latter group this
cell gives rise to the growing point of the laterally produced
stem, and the root originates in the segment of the hypophysis
next to the rest of the suspensor.

When the octants have been formed, the next step in the
development is the formation of the dermatogen by walls
parallel to the surface of the embryo. At first the dermatogen
is incomplete, the periclinal walls only being formed in the
octants. Soon it is continued across the hypophysis, which
has by this time grown up in a slightly bulging fashion at the
base of the embryo (jigs. 936 and 937). Of the cells so formed
from the hypophysis the internal one gives rise to the periblem
of the root, while the latter forms its dermatogen, which soon
becomes many-layered and constitutes the root cap. The fur-
ther growth of the embryo soon gives rise to the three systems
of tissue already described, the dermatogen, periblem and
plerome. %

In the Monocotyledons the terminal cotyledon is developed
from the octants, the hypophysis dividing to form a row of cells,
of which the anterior ones give rise to the stem while the pos-
terior one forms the root, as the whole hypophysis does in
Dicotyledons. The order of division of cells is very similar,
186 MANUAL OF BOTANY

and the embryo becomes differentiated histologically in the
same way. The young stem is derived from the upper cell
of the two resulting from the first division of the hypophysis,
and as it assumes its form it turns out laterally from below the
cotyledon.

This division of the Phanerogamia includes the two classes
of Monocotyledons and Dicotyledons, which are distinguished
from each other by the following points :—

Fie. 936.

 

 

 

 

 

Fig, 936. Successive stages in development of the embryo of Brassica.
After Kny.

MonocoryitEpons.—The embryo has a single cotyledon, which
is placed at its apex, while the plumule arises laterally; the
flower is usually trimerous; the vascular bundles do not con-
tain cambium and are small and arranged in a scattered
manner in the stele; the foliage leaves usually have parallel
venation.

DicotyLepons.—The embryo has two cotyledons, between
ANGIOSPERM Ai 187

which the plumule is developed; the vascular bundles are
arranged in a circle in the stele and usually increase in thick-

Fic. 987.

 

Fiy. 937. 1,2, 8, 4, 5,6. Suecessive stages in the development of the Mono-
cotyledonous embryo of Alisma. h. Hypophysis and the cells derived
from it. f. Segment of the hypophysis which gives rise to the root.
7, Mature embryo. a. Apex of stem, After Sachs.

ness by means of a cambium layer; the flower is either
tetramerous or pentamerous; the foliage leaves usually have
reticulate venation.
188 MANUAL OF BOTANY

Ciass X.—-MONOCOTYLEDONES.

The general histology as well as the morphology of this group
has been already treated of in some detail.

The class is divided by Bentham and Hooker into the
following seven series, each including several natural orders.

Series 1.—Microsperme.

Characters.—aAt least the inner whorl of the perianth peta-
loid. Ovary inferior, 1-celled with 3 parietal placente, or rarely 3-

celled with axile placente; seeds very small, numerous, exal-
buminous.

Order 1. Hydrocharidacee.
2. Burmanniacee.
3. Orchidaces.
4, Apostasiaceze.

Series 2.—_Epigyne.

Characters.—At least the inner whorl of the perianth peta-
loid. Ovary inferior, except in a few genera of Bromeliacez and
Hemodoracee. Albumen copious.

Order 5. Zingiberacew or Scitaminacer.

6. Marantaceze or Cannacee.
7. Musacew.
8. Bromeliacee.
9. Heemodorace.

10. Iridacee.

11. Amaryllidaces.

12. Taccaciz.

13. Dioscoriacee.

Series 3.—Coronaria.

Characters.—At least the inner whorl of the perianth peta-
loid. Ovary free, or very slightly adherent at base. Albumen
copious.

Order 14, Roxburghiacee.
15. Liliaces.
16. Philesiaces.
17. Melanthacee or Colchicacex.
18. Similacez.
MONOCOTYLEDONES 189

19. Pontederiace.
20. Philydraces.
21. Xyridacer.

22. Mayacee.

23. Commelynacez.

Series 4.—Calycine.

Characters.—Perianth herbaceous; inner whorl small;
very rarely sub-petaloid. Ovary free. Albumen copious.
Order 24. Juncacee.
25. Palmacez.

Series 5.—Nudiflore.

Characters.—Perianth absent or reduced to seales or setas.
Ovary superior with a solitary carpel, or if of many carpels then
syncarpous. Ovules 1-co. Seeds most frequently albuminous.

Order 26. Pandanaces.
27. Typhacez.
28. Aroidacese or Aracez.
29. Lemnacez.

Series 6.—Apocarpe.
Characters.—Perianth uniseriate or absent. Ovary supe-
rior. Carpels distinct or solitary. Seeds exalbuminous.
Order 30. Triuridacez.
31. Alismacez.
32. Butomacezx.
33. Naiadacez.
34. Juncaginacere.

Series 7.—Glumacee.

Characters.—Flowers in capitula or spikelets, disposed
under bracts or glumes; very often imbricated, sessile ; segments
of perianth small, scale-like, glumaceous or absent. Ovary either
with one ovule, or divided into monovulate loculi. Seeds al-
buminous.

Order 35. Eriocaulacee.
36. Desvauxiacese.
37. Restiacee.
38. Cyperacee.
39, Graminacex.,
190 MANUAL OF BOTANY

Series 1.—Microsperme.

Order 1. Hyprocuaripace®, the Hydrocharis or Frog-bit
Order.—Character.—Aquatie plants. Flowers spathaceous,
regular, unisexual or polygamous. Pertanth superior, in 1 or 2
whorls, each composed of 3 pieces, the inner petaloid. Stamens
few or numerous. Ovary inferior, usually 1—6-celled ; placen-
tation parietal. Fruit indehiscent. Seeds numerous, exalbu-
minous.

Distribution, Numbers, and Properties.—Inhabitants of fresh
water in Europe, North America, East Indies, and New Holland.
Illustrative Genera:—Anacharis, Rich.; Vallisneria, Mich.
There are about 25 species. Their properties are unimportant.

Order 2. BuRMAnntace®, the Burmannia Order.—Cha-
racter.—Herbaceous plants, without true leaves, or with tufted
radical ones. Flowers hermaphrodite, regular. Perianth peta-
loid, tubular, regular, superior, usually with 6 divisions. Sta-
mens distinct, inserted into the tube of the perianth, either 3
with introrse anthers, and opposite the inner segments of the
perianth, or 6 with extrorse anthers. Ovary inferior, 1-celled
with 3 parietal placentas, or 3-celled with axile placentas ; style
1; stigmas 3. Fruit capsular, 1—3-celled. Seeds numerous,
very minute ; embryo solid.

Distribution and Numbers.—They are principally found in
the tropical parts of Asia, Africa, and America. Illustrative
Genera :—Burmannia, Linn.; Thismia, Griff. According to
Miers, there are 38 species. Their properties are unimportant,
but some are reputed to be bitter and astringent.

Order 8. ORcHIDACER, the Orchis Order.—Character.—
Herbs or shrubs, terrestrial or epiphytical. Roots fibrous or
tuberculated; no true stem or a pseudo-bulb. Leaves entire
generally sheathing. Flowers irregular, solitary or numerous,
with a single bract, hermaphrodite. Perianth superior, usually
petaloid and composed of six pieces, which are commonly
arranged in two whorls; the owter whorl, s, sl, sl, formed of
three pieces (sepals), more or less united below or distinct;
one, s, being anterior, or when the ovary is twisted posterior,
and two, sl, sl, lateral; the inner whorl usually consists of three
pieces (petals), (or rarely of but one), alternating with the pieces
in the outer whorl; one (the labellwm or lip) posterior, or by the
twisting of the ovary anterior, usually longer and larger than the
other pieces, and altogether different from them in form, often
MONOCOTYLEDONES 191

spurred; sometimes the labellum exhibits a division into three
regions, of which the lowest is then termed the hypochiliwm,
the middle the mesochiliwm, and the upper the epichilium.
Andrecium united to the style (gynandrous ) and forming with
it a central column (gynostemium) ; the column usually bearing
one perfect anther and two lateral abortive ones, or in Cypri-
pedium two lateral perfect anthers and one abortive anther in
the centre. Pollen powdery, or more or less collected into
grains or waxy or mealy masses (pollinia) ; the masses free, or

Fria. 938. Fic. 939. Fie. 940.

 

Fig. 988. Front view of the flower of the Tway-blade (Zistera ovata),
showing the bifid labellum at the anterior part of the flower, and the
other five divisions of the perianth; the one stamen ard three styles
forming a column (gynostemium).—Sig. 939. Diagram of the flower of
an Orchid. s, sz, sl. The three outer divisions of the perianth ; s being
anterior or inferior, sZ, s2, being lateral. pl, pi. The two lateral divisions
of the inner whorl of the perianth. ys. The superior or posterior division
(labellum) of the inner whorl ; this by the twisting of the ovary becomes
ultimately inferior or anterior. e. The fertile stamen, with two anther
lobes. c. Transverse section of the ovary, with three parietal placentas.
—Fig. 940. Fruit of an Orchid dehiscing by three valves, each valve
bearing a placenta and numerous very minute seeds. Fiy, 941. Seed
of an Orchid, with a loose reticulated testa.

 

attached by their stalk, ¢ (caudicle), to a gland or glands
(retinacula) at the apex (rostellun) of the stigma. Ovary
inferior, 1-celled, with 3 parietal placentas bearing a number of
anatropous ovules; style united with the andrcecium and form-
ing with it « column or gynostemium ; stigma w viscid space
in front of the column. Fruit usually capsular, 3-valved, the
valves bearing the placentas in their middle, and separating
when the fruit is ripe from the central parts or midribs of the
component carpels, which are left as an open framework ; or
192 MANUAL OF BOTANY

rarely fleshy and indehiscent. Seeds very minute and nume-
rous, with a loose netted or rarely hard crustaceous testa, ex-
albuminous; embryo a fleshy solid mass.

Diagnosis.—This order is readily known by its irregular
flowers; by the peculiar form which the labellum in many
cases asstumes, so as to cause the flower to resemble some
insect, reptile, bird, or other living object; by its gynandrous
stamens ; its frequently more or less coherent -pollen; and by
its 1-celled inferior ovary with three parietal placentas. .

Division of the Order.—This order has been divided by
Lindley and others into several tribes, the characters being de-
rived from the number and position of the anthers, the number
and nature of the pollen-masses, and other characters; but the
description of these does not come within the scope of this
volume.

Distribution and Numbers.—They are more or less abun-
dantly distributed in nearly all regions of the globe, except in
those which have a very cold or dry climate. Some species are
terrestrial and occur chiefly in temperate regions ; others are
epiphytical and are confined to hot climates. Illustrative
Genera :—Malaxis, Swartz; Dendrobium, Swartz; Oncidium,
Swartz; Stanhopea, Frost; Orchis, Linn. ; Cypripedium, Linn.
The order contains about 5,000 species, 2,000 being in cultiva-
tion.

Properties and Uses.—These plants, which present so much
interest from the singularity, beauty, and fragrance of their
flowers, are of little importance from an economic or medicinal
point of view. Some are aromatic and fragrant, and are used
as flavouring agents, several possess nutritious roots, and a few
are antispasmodic and aphrodisiac.

Order 4, AposTasIAcEm, the Apostasia Order.—Character.
Herbs, with regular hermaphrodite flowers. Perianth superior,
regular, with 6 divisions. Stamens 2 or 3, united by their
filaments with the lower part of the style into a column;
anthers sessile upon the column, 2 or 3. Ovary inferior, 8-
celled, with axile placentation ; ovules numerous; style united
below with the filaments into a column, but prolonged above
into a filiform process. Capsule 8-celled, 3-valved. Seeds very
numerous. By Bentham and Hooker this order is included in
Orchidaceae.

Distribution and Numbers.—Natives of damp woods in
tropical India. Illustrative Genus :—Apostasia, Blume. There
are about 5 species. Their properties are altogether unknown.
MONOCOTYLEDONES 193

Series 2.— Epigyne.

Order 5. ZINGIBERACEZ or ScrTaMiNacem, the Ginger
Order.—Character.—Aromatic herbs, with creeping rhizomes,
and broad simple, stalked, sheathing leaves, with parallel
curved veins springing from the midrib. Flowers arranged in
a spiked or racemose manner, and arising from among spatha-
ceous membranous bracts. Perianth superior, irregular, each
whorl consisting of 3 pieces. Stamens 6, in 2 whorls, all
abortive except the posterior one of the inner whorl; anther 2-
celled ; filament not petaloid. Ovary inferior, 3-celled; placen-
tas axile; style filiform. Fruit 1—3-celled, capsular or baccate.
Seeds numerous, albuminous ; embryo enclosed in endo-
sperm. ,

By Bentham and Hooker the two succeeding orders, Maran-
tacee and Musacea, are included in Zingiberacee.

Distribution and Numbers.—Chiefly natives of tropical
regions. Illustrative Genera :—Zingiber, Gdrtn.; Curcuma,
Linn.; Elettaria, Rheed. There are about 250 species.

Properties and Uses.—They are principally remarkable for
the stimulant aromatic properties possessed by their rhizomes
and seeds, owing to the presence of resins and volatile oils; hence
several are used as condiments, and in medicine as aromatic
stimulants and stomachics. Some contain starch in large quan-
tities, which when extracted is employed for food.

Order 6. MarantacE®& or CANNACES, the Maranta Order.—
Character.—Herbaceous plants, without aromatic properties.
They have a close resemblance to the Zingiberacee. Their
distinctive characters are, in their more irregular perianth ; in
one of the lateral stamens of the inner whorl being fertile, and
the other two abortive ; in the fertile stamen having a petaloid
filament, an entire or 2-lobed anther, one lobe of which is
sterile, and the anther therefore 1-celled; in the style being
petaloid or swollen; and in the embryo not being enclosed in
endosperm.

Distribution and Numbers.—Exclusively natives of tropical
regions. Illustrative Genera :—Maranta, Plum.; Canna, Linn.
There are about 160 species.

Properties and Uses.—The rhizomes of some species contain
starch, which when extracted is extensively used for food.

Order 7. Musacem, the Banana Order.—Character.—
Herbaceous plants, often of large size. Leaves large, with

VOL. II. 0
194 MANUAL OF BOTANY

parallel curved veins springing from the midribs, and long
sheathing petioles, which together form by their union a spurious
aerial stem. Flowers irregular, spathaceous. Perianth irregular,
6-partite, petaloid, superior, arranged in 2 whorls. Stamens 6,
inserted upon the divisions of the perianth, some abortive ;
anthers 2-celled. Ovary inferior, 3-celled. Fruit capsular,
dehiscing loculicidally, or succulent and indehiscent, 3-celled.
Seeds usually numerous, rarely 3, without endosperm.

Distribution and Numbers.—Generally diffused throughout
tropical and sub-tropical regions. Illustrative Genera :—Musa,
Tourn. ; Ravenala, Adans. There are about 20 species.

Properties and Uses.—The fruits of some species and
varieties form important articles of food in tropical regions.
Others yield valuable textile materials; and the large leaves of
many are used for various purposes, such as to form a kind of
cloth, and as thatching for cottages, &c. The seeds and fruits of
others are used as dyeing agents in some countries.

Order 8. Bromeiaceam, the Bromelia Order.—Charac-
t ev.—Herbs or somewhat woody plants, commonly epiphytical.
Leaves persistent, crowded, channelled, rigid, sheathing at the
base, and frequently scurfy and with spiny margins. Flowers
showy. Pertanth regular, superior, or nearly or quite inferior,
arranged in two whorls, the outer of which has its parts
commonly united into a tube; and the inner has its parts dis-
tinct, imbricate, and of a different colour from those of the outer
whorl. Stamens 6; anthers introrse. Ovary 8-celled; style 1.
Fruit capsular or indehiscent. Seeds numerous; embryo
‘minute, at the base of mealy albumen, with the radicle next
the hilum.

Distribution and Numbers.—They are mostly found in the
tropical regions of America, West Africa, and the East Indies.
They appear to have been originally natives of America and the
adjoining islands, but are now naturalised in West Africa and
the East Indies. Illustrative Genera :—Ananassa, Lindl. ;
Tillandsia, Linn. There are about 180 species.

Properties and Uses.—They are chiefly important for yielding
edible fruits and useful fibrous materials. Some are anthel-
mintic, and others contain colouring matters.

Order 9. Hammoporacrs, the Blood-root Order.—Charac-
ter.—Herbs or rarely shrubs, with fibrous roots. Leaves usually
equitant, ensiform. Perianth more or less superior, tubular, 6-
partite, regular, the divisions usually scurfy or woolly on their
outside Stamens 8 or 6 when 8 they are opposite the inner
MONOCOTYLEDONES 195

segments of the perianth ; anthers introrse. Ovary inferior, or
partially so, 3-celled. Fruit dehiscent or indehiscent, covered by
the withered perianth. Seeds few or numerous, with carti-
laginous albumen, and radicle remote from the hilum.

Distribution and Numbers.—Natives of America, ithe
Cape of Good Hope, and Australia. Illustrative Genera :—
Hemodorum, Smith; Vellozia, Mart. There are about 50
species.

Properties and Uses.—The roots of some species are used as
dyeing agents in North America, others are edible, and a few are
bitter and astringent.

Order 10. Inipaces, the Iris Order.—Character.—Herbs,
usually with bulbs, corms, or rhizomes. Leaves with parallel
venation, generally equitant. Flowers spathaceous. Perianth
superior, petaloid, 6-partite, in two whorls, which are equal or
nearly so, or unequal, in the size of their segments; or some-
times the parts are entirely distinct; convolute in xstivation.
Stamens 8, inserted on the outer segments of the perianth;
anthers 2-celled, innate, extrorse. Ovary inferior, 3-celled,
with axile placentation; style 1; stigmas 8, often petaloid.
Frwit capsular, 3-celled, 3-valved, with loculicidal dehiscence.
Seeds numerous with horny or fleshy albumen.

Diagnosis.—Herbs. Leaves with parallel veins. Flowers on
scapes, spathaceous. Perianth petaloid, superior, 6-partite, or
rarely the parts are quite distinct, in two equal or unequal
whorls. Stamens 3, distinct or monadeJphous ; anthers innate,
extrorse. Ovary 3-celled, with axile placentation, inferior.
Fruit capsular, with loculicidal dehiscence, 3-celled, 3-valved.
Seeds numerous, albuminous.

Distribution and Numbers.—Chiefly natives of temperate
and warm climates. They are found in various parts of the
globe, but are most abundant at the Cape of Good Hope.
Illustrative Genera :—Iris, Linn. ; Gladiolus, Towrn.; Crocus,
Linn. There are about 560 species.

Properties and Uses.—The rhizomes of several species
possess acrid properties, which causes them to be purgative,
emetic, &. Some are poisonous, and a few have fragrant
rhizomes. Others are employed as colouring agents, and some
are commonly regarded as antispasmodic, carminative, Xc.
Many contain starch in large quantities, but as this is usually
combined with acridity, they are not generally available for
food, although some are stated to be thus employed in Africa.

Order, 11. AmaryLLipace&, the Amaryllis Order.—Cha-

02
196 MANUAL OF BOTANY
racter.—Bulbous or fibrous-rooted plants, without any aerial
stem, or sometimes with a woody one. Leaves with parallel

venation, and usually linear-ensiform, sometimes dry and harsh.

Fic. 942. Fie, 943.

   
 

Fie, 944,

 

Fig. 942. Diagram of the flower of a species of Jris, showing solitary
bract below, six divisions to the perianth arranged in two whorls, three
stamens, and a three-celled ovary with axile placentationn—Fig, 943. A
flower of the Spring Crocus (Crocus vernus) cut open to show the three
extrorse stamens attached to the outer segments of the perianth.—— Fig.
944. The three petaloid stigmas of the same with the end of the style.
—Vig. 945. Vertical section of the flower of ris germanica. ce, ce. Two
of the external and larger divisions of the perianth. ci. One of the internal
and smaller divisions. ¢. Tube formed by the union of the divisions of
the perianth. ¢, e. Stamens, covered by the petaloid stigmas, s,s, 0. In-
ferior ovary, with numerous ovules, g, attached to placentas in the axis.
—Fig. 946. Vertical section of the seed of the same. /. Integuments of
the seel. p, Albumen. e. Embryo. m. Micropyle. From Jussieu.

Flowers usually on scapes, and spathaceous. Perianth regular
or nearly so, petaloid, superior with six divisions, and with or
without a corona; estivation imbricate or valvate. Stamens 6,
MONOCOTYLEDONES 197

inserted on the perianth or summit of the ovary; anthers 2-
celled, introrse. Ovary inferior; 38-celled; placentas axile.
Fruit capsular, 8-celled, 3-valved, with loculicidal dehiscence
and numerous seeds; or baccate, with 1—3 seeds. Seeds with
fleshy or horny albumen, sometimes carunculate; embryo
with the radicle turned to, or remote from, the hilum.

Fig. 948.

 

fig. 947. Diagram of the flower of the Spring Suowflake (Amaryllidacece),
with six divisions to the perianth arranged in two whorls, six stamens,
and a 3-celled ovary with axile placentation.—/ig. 948. The perianth of
the Daffodil (Narcissus Pseudo-narcissus) cut open in a vertical manner.
t. Tube bearing six stamens. 7. Limb of the perianth. ». Corona,—
Fig. 949. Vertical section of the flower of the Spring Snowflake (Leucojum
vernum),—§Fg. 950. Vertical section of the seed of the same.

Diagnosis.—Leaves with parallel veins. Flowers spatha-
ceous. Perianth superior, petaloid, commonly regular, 6-partite,
frequently with a corona. Stamens 6; anthers introrse. Ovary
inferior, 3-celled, with axile placentation. Fruit capsular, 3-
valved, with loculicidal dehiscence, or baccate. Seeds numerous,
albuminous.

Distribution and Numbers.—Natives of many parts of the
world, but, like the Iridacew, most abundant at the Cape ot
198 MANUAL OF BOTANY

Good Hope. Illustrative Genera :—Galanthus, Linn.; Ama-
ryllis, Linn. ; Narcissus, Linn.; Agave, Linn. ; Hypoxis, Linn.
There are above 460 species.

Properties and Uses.—Several plants of this order possess
poisonous qualities. This property is especially evident in
Hemanthus toxicarius, the juice of which is used by the Hot-
tentots to poison their arrow-heads. Some yield excellent fibres.
The juice of some few species is saccharine, and is employed in
the preparation of fermented liquors. Starch may be obtained
from certain species of Alstremeria. Some are bitter and aro-
matic. Medicinally, several have been used as emetics and
purgatives.

Order 12. Taccacum, the Tacca Order.—Character.—
Perennial herbs, with fleshy roots. Leaves large, with parallel
veins, radical, stalked. Flowers hermaphrodite. Perianth
tubular, regular, 6-partite, superior. Stamens 6, inserted into
the base .of the divisions of the perianth, with petaloid fila-
ments, incurved and hooded at the apex; anthers 2-celled,
placed in the concavity below the apex of the filaments. Ovary
inferior, 1-celled, with 8 parietal placentas projecting more or
less into the interior; styles 3. Fruit baccate. Seeds nume-
rous, with fleshy albumen.

Distribution and Numbers.—Natives of mountainous re-
gions in India, the Malayan Archipelago, the Philippines, Aus-
tralia, Polynesia, Madagascar, Guiana. According to Hance,
there are three genera—Tacca, Forst.; Ataccia, J. S. Presl;
and Schizocapsa, Hance—which contain twelve or more
species.

Properties and Uses.—The roots are bitter and acrid, but
when cultivated they become larger and lose in some degree
their acridity and bitterness, and contain much starch, which
when separated is used for food.

Order 13. Dtoscorgaces, the Yam Order.—Character.—
Climbing herbs, or small shrubs, with twining stems rising
from tuberous rootstocks or tubers, placed above or under the
ground. Leaves net-veined, stalked. Flowers unisexual,
dicecious, small, bracteate. Male flower :—Perianth 6-clett.
Stamens 6, inserted at the base of the perianth-segments.
Female flower :-_Perianth superior, 6-partite. Stamens some-
times present, but very short and abortive. Ovary inferior, 3-
celled; styles 3, distinct, or 1, and then deeply trifid ; ovwles 1—2
in each cell, suspended. Fruit dehiscent and compressed, or
MONOCOTYLEDONES 199

fleshy and indehiscent, 1—8-celled. Seeds albuminous; embryo
small, in a cavity in the albumen.

Distribution and Numbers.—Chiefly tropical plants.
Tamus communis is, however, found in Britain and other
temperate regions. Illustrative Genera:—Tamus, Linn.;
Dioscorea, Linn. There are above 150 species.

Properties and Uses.—The plants generally contain an acrid
principle. The tuberous rootstocks of many species of Dioscorea
are, however, when boiled, used for food in tropical countries.

Series 3.—Coronarie.

Order 14. RoxBurRGHIACEs, the Roxburghia Order.—Cha-
racter.—Twining shrubs with tuberous roots. Leaves net-
veined, leathery, broad. Flowers large and showy, solitary,
hermaphrodite. Perianth inferior, with 4 petaloid divisions.
Stamens 4, hypogynous, with enlarged connectives; anthers
introrse, apicilar. Ovary superior, 1-celled, with a basal pla-
centa; stigma sessile. Fruit 2-valved, 1-celled. Seeds nume-
rous, in 2 stalked clusters, anatropous; embryo in the axis of
fleshy albumen.

Distribution, Numbers, and Properties.—They are natives
of the hotter parts of the East Indies. There is but one genus,
Roxburghia, Dryand., which mcludes 4 species. Their proper-
ties are unimportant.

Order 15. Littacem, the Lily Order.—Character.— Herbs,
shrubs, or trees, with bulbs, rhizomes, tubers, or fibrous roots.
Stem simple or branched. Leaves with parallel or rarely
reticulated veins, sessile or sheathing, sometimes succulent.
Flowers regular, variously arranged or solitary. Perianth
green or petaloid, inferior, usually regular and 6-leaved or 6-
partite. Stamens 6, or rarely more, or 8 in Ruscus, inserted on
the perianth, or rarely on the thalamus: anthers intyorse.
Ovary superior, 3-celled, or very rarely 4—6-celled, with nu-
merous ovules on axile placentas ; style 1, or very rarely 3 or
more, or absent; stigma generally simple or 3-lobed. Fruit a
loculicidal capsule, or succulent and indehiscent, usually 3-
celled. Seeds with fleshy albumen, numerous.

Diagnosis.—Leaves with usually parallel straight veins, or
succulent. Perianth inferior, generally 6-leaved or 6-partite,
and regular. Stamens 6, or rarely more, or 3 in Ruscus ;
anthers introrse. Ovary superior, with axile placentation : style
1, usually undivided, or very rarely divided, and sometimes
200 MANUAL OF BOTANY

absent. Fruit indehiscent or a loculicidal capsule. Seeds

numerous, albuminous. ,
Division of the Order and Illustrative Genera :—This order

has been divided by Baker into three tribes as follows :—

   

Fie. 951.

  

Fig. 954.

Fig. 951. Diagram of the flower of a species of Lily. s. The three outer
divisions of the perianth. p. The three inner. +. The stamens. ¢. Three-
celled ovary,— Jig. 952. Raceme of flowers 7, and portion of the succu-
lent leaf J, of a species of Aloe.—~ig. 953. Flower of the Crown Imperial
(Fritillaria imperialis) with half the perianth removed. Fig. 954.
Vertical section of the flower of the Solomon's Seal (Polygonatum multi-
Jorum).— Jig. 955. Transverse section of the ovary of the White Lily

 

(Lilium candidum). ig. 956. Vertical section of the seed of the Crown

Imperial.

Tribe 1. Lilece.—Anthers introrse. Styles united. Fruit a
loculicidal capsule. Illustrative Genera:—Lilium, Linn. ;
Tulipa, Linn. ; Scilla, Linn.

Tribe 2. Colchiceea.—Anthers extrorse. Styles separate. Fruit
MONOCOTYLEDONES 201

a septicidal capsule. This tribe forms the order Melanthacee
or Colchicacee of this volume.

Tribe 8. Asparagee.—Fruit baccate. Illustrative Genera :—
Asparagus, Linn. ; Convallaria, Linn.

By Bentham and Hooker this order has been divided into
20 tribes arranged in 8 series, and includes the Colchicacea,
Smilacea, and Philesiacee of this volume.

Distribution and Numbers.—They are widely distributed
throughout the temperate, warm, and tropical regions of the
globe. There are over 1,360 species.

Properties and Uses.—The plants of this order frequently
possess important properties, but there is no great uniformity
in them. Some are purgative; others emetic, diuretic, dia-
phoretic, stimulant, acrid, &c. Several yield astringent sub-
stances, and many produce valuable fibres. The bulbs, young
shoots, roots, and seeds of others are highly esteemed, and
largely consumed as articles of food and condiments.

Order 16. PuitEstacem, the Philesia Order.—Dzagnosis,
éc.—The plants of this order are closely allied to the Rox-
burghiacex, from which, however, they are readily distinguished
by their hexamerous perianth and andrecium, perigynous
stamens, parietal placentation, long style, and semi-anatropous
ovules. They are natives of Chili. There are 2 genera—
Philesia, Commers.; and Lapageria. R. et P.--and 2 species.
In their properties they are said to resemble Sarsaparilla. (See
Smilax.) This order is included in Liliacee by Bentham
and Hooker.

Order 17. CoLcHIcacks®, or MELantHACcE®.—The Colchicum
Order.—Character.—Herbs, with bulbs, corms, tubers, or
fibrous roots. Flowers regular, usually hermaphrodite, or rarely
unisexual. Perianth inferior, white, green, or purple, 6-partite
or 6-leaved. Stamens 6, anthers extrorse. Ovary superior or
nearly so, 3-celled, with axile placentation; style 3-partite ;
stigmas 3. Fruit 8-celled, 3-valved, with usually septicidal.
dehiscence. Seeds numerous; embryo minute, in fleshy al-
bumen.

By Bentham and Hooker the plants of this order (see
Lilvacee) are now placed, according to the views of Baker, in
the Liliacee.

Diagnosis.—Herbs. Flowers regular, hermaphrodite or
rarely unisexual. Perianth inferior, 6-partite or 6-leaved.
Stamens 6; anthers extrorse. Ovary superior; style 3-partite.
202 MANUAL OF BOTANY

Fruit a septicidal or very rarely a loculicidal capsule, 3-celled,
3-valved, membranous. Seeds numerous, albuminous.

Distribution and Nwmbers.—Generally diffused, but most
abundant in Europe, North America, and the northern parts of
Asia. Illustrative Genera :—Colchicum, Linn.; Tofieldia, Hud-
son. There are about 150 species.

Properties and Uses.—The plants of this order are almost
universally poisonous, owing to the presence of powerful alka-
loids. But in proper doses several are valuable medicines, pos-

Fig. 957. Fie. 958.

 

Fig. 957. Flowering plant of the Colchicum or Meadow Saffron (Colchicum
autumnale).—Fig. 968. Diagram of the flower of the same, with six
divisions to the perianth arranged in two whorls, six stamens, and a
3-celled ovary.—/Sig. 959. Transverse section of the capsule-—Fig.
960. Vertical section of the seed.

sessing emetic, purgative, diuretic, acrid, and narcotic proper-
ties.

Order 18. Sminaceas, the Sarsaparilla Order.—Charac-
ter.—Herbs or shrubs, more or lessclimbing. Leaves petiolate,
net-veined, articulated. Flowers regular, unisexual and dic-
cious, or hermaphrodite. Perianth inferior, 6-partite, with all
its divisions alike. Stamens 6, perigynous or rarely hypogynous;
anthers introrse. Ovary superior, 3- 5- or rarely 1-celled, with
orthotropous ovules; stigmas 38. Fruit baccate, few or many-
seeded. Seeds with a minute embryo, in hard albumen. This
MONOCOTYLEDONES 203

order, as we have already noticed, is included in Liliaceae by
Bentham and Hooker.

Distribution and Numbers—The species of this order are
scattered over various parts of the world, both in tropical and
temperate climates; they are, however, most abundant in
tropical America, Illustrative Genera :—Smilax, Linn.;
Ripogonum, Forst. These are the only genera; there are pro-
bably about 120 species, but some botanists make the number
considerably more.

Properties and Uses.—The plants of this order generally
possess alterative properties.

Order 19. PontEpERIACEm, the Pontederia Order.—Cha-

Fic. 961.

 

Fig. 961. Portion of a branch, with leaves and fruit, of Smilax
papyracea.

racter.—Aquatic herbs. Leaves sheathing at the base, with
occasionally dilated petioles. Flowers hermaphrodite, irregular,
spathaceous. Perianth inferior, 6-partite, petaloid, tubular,
persistent, rolling inwards after flowering. Stamens 3 or 6,
inserted on the segments of the perianth ; anthers introrse.
Ovary superior; style 1; stigma simple. Fruit capsular,
occasionally somewhat adherent to the persistent perianth.
Seeds numerous, with mealy albumen. :

Distribution, Numbers, and Properties.—They are natives of
the East Indies, Africa, and America. Illustrative Genera :—
Leptanthus, L. C. R.; Pontederia, Linn. There are above 30
species. Their properties are unimportant.

Order 20. Puintypracea, the Water-wort Order.— Charac-
204 MANUAL OF BOTANY

ter.—Herbs, with fibrous roots. Leaves equitant, ensiform
sheathing. Flowers surrounded by a spathaceous persistent
bract, hermaphrodite. Perianth inferior, 3-partite, petaloid,
the two upper segments united so that it appears to consist of 2
segments. Stamens 3, 2 of which are barren and petaloid, and
all united to the anterior lebe of the perianth; pollen united in
masses of four. Ovary superior, 3-celled, with axile placentas ;
style simple; stigma capitate. Fruit a loculicidal capsule.
Seeds numerous, with an embryo in the axis of fleshy
albumen.

Distribution, Numbers, and Properties.—They are natives
of China, Cochin China, and Australia. There are 2 genera
(Philydrum, Banks, and Heteria, Endl.) and 2 species.
Their properties and uses are unknown.

Order 21. Xyripacge#, the Xyris Order.—Character.—
Sedge-like herbs. Leaves radical, sheathing, ensiform or filiform.
Flowers hermaphrodite, in scaly heads. Perianth inferior, 6-
partite, arranged in two whorls,—the outer sub-glumaceous or
scaly, distinct, and opposite the carpels; the inner petaloid,
regular, and united. Stamens 8, inserted into the base of the
outer lobes of the perianth, or sometimes 6; anthers 2-celled,
extrorse. Ovary superior, 1-celled, with parietal placentas.
Capsule 1-celled, 8-valved. Seeds numerous; embryo minute,
in fleshy or mealy albumen.

The genus Rapatea is sometimes made the type of a distinct
order—Rapateacea.

Distribution and Numbers.—Exclusively natives of tropical
and sub-tropical regions. Illustrative Genera :—Xyris, Linn. ;
Rapatea, Aubl. There are about 70 species.

Properties and Uses.—Unimportant. The leaves and roots
of some species of Xyris have been employed in cutaneous
affections.

Order 22. Mayacem, the Mayaca Order.—Diagnosis.—
Small Moss-like plants growing in damp places. They are
closely allied to Commelynacez, from which they differ in their
habit ; their 1-celled anthers; their 1-celled ovary and capsule
with parietal placentas ; and in their carpels being alternate to
the outer segments of the perianth.

Distribution, Numbers, and Properties.—They are found in
America from Brazil to Virginia. Mayaca, Aubl., is the only
genus, of which there are 4 species. Their properties and uses
are unknown.

Order 23. COMMELYNACE®, the Spiderwort Order.—Cha-
MONOCOTYLEDONES 205

racter.—Herbs, with flattened, narrow, usually sheathing
leaves. Perianth inferior, more or less irregular, in six parts
arranged in two whorls; the outer parts being green, persistent,
and opposite to the carpels; the inner petaloid. Stamens 3 or 6,
some generally abortive, hypogynous ; anthers 2-celled, introrse.
Ovary 3-celled, superior ; style 1. Capsule 2—3-celled, 2—3-
valved, with loculicidal dehiscence and axile placentation.
Seeds few, with a linear hilum ; embryo shaped like a pulley,
remote from the hilum, in dense fleshy albumen.

Distribution and Numbers.—They are chiefly natives of
India, Africa, Australia, and the West Indies. Illustrative
Genera :—Commelyna, Dill. ; Tradescantia, Linn. There are
above 260 species.

Properties and Uses.—Their properties are unimportant.

Fie. 962. Fic. 963.

  

Fig. 962. Flower of a species of Wood-rush (Luzula), having an inferior
perianth with six divisions, 6 stamens, and a superior ovary with 1 style
and 3 stigmas.—/ig. 963. Vertical section of the seed of the same.

The rhizomes of some species, as those of Commelyna tuberosa,
C. angustifolia, and C. striata, contain much starch, and when
cooked are edible. Others have been reputed astringent and
vulnerary, and some emmenagogue, kc.

Series 4.—Calycine.

Order 24. Juncacem, the Rush Order.—Character.—
Sedge- or grass-like herbs, rhizomatous or with tufted or fibrous
roots. Leaves with parallel veins, fistular or more or less
flattened and grooved. Flowers regular. Perianth inferior, 6-
partite, scale-like or coriaceous, greenish or brown, persistent.
Stamens 6, or rarely 8, perigynous; anthers introrse, 2-celled.
Ovary superior, 1—3-celled; style 1, stigmas 3 or 1. Fruit a
loculicidal capsule, 3-celled, 8-valved, and with 1 or many seeds
206 MANUAL OF BOTANY

in each cell; rarely 1-celled, 1-seeded, and indehiscent ; embryo
very minute, in fleshy or horny albumen ; radicle inferior.

Distribution and Numbers.—A few are found in tropical
regions, but most of the order inhabit cold and temperate
climates. Illustrative Genera :—Juncus, DC. ; Luzula, DC.
There are about 200 species.

 

Fic. 964. Fic. 965. Fie. 966.

   

DD
om,

 

Fic. 967. Fic. 968. Fia. 969.

Fig. 964. Diagram of a staminate flower of the Fan Palm (Chamerops),
with six divisions to the perianth, and six stamens.— Jig. 965. Diagram
of a pistillate flower of the same, with six divisions to the perianth, and
a 3-celled ovary.m—/F'ig. 966. Hermaphrodite flower of the Blue Palmetto
(Chamecrops hystrix), with the perianth removed. ov. Carpels, sf. Sta-
mens,—/ig. 967. The same, with three of the stamens removed, so
as to exhibit more completely the three carpels composing the pistil.
st, Stamens. ¢. Carpels.——Jig. 968. Vertical section of the fruit of the
Cocoa-nut Palm (Cocos nucifera). a. The two outer layers or husk of the
pericarp. b. Endocarp or inner layer. c. Albumen. ¢d. Cevity in the

albumen. e. Embryo.— Fig. 969. Vertical section of the seed of the
Fan Palm.

Properties and Uses.—Their medicinal properties are unim-
portant, although some have a reputation as anthelmintics and
diuretics.

Order 25. Patwacres®, the Palm Order.—Character.—Trees
or shrubs, with simple unbranched, or rarely dichotomously
branched trunks. Leaves terminal, large, mostly compound,
with sheathing stalks. Flowers hermaphrodite or unisexual,
MONOCOTYLEDONES 207

arranged generally on a branched spadix, which is enclosed by
aspathe. Perianth usually green, inferior, in two whorls, each
of which is composed of three parts. Stamens usually 6, hypo-
gynous or perigynous. Carpels 1—8, generally united, but
sometimes distinct ; ovary superior; ovules solitary, or rarely
2. Fruit nut-like, baccate, or drupaceous. Seeds with a minute
embryo, in a pit of the albumen; albumen fleshy or horny,
often ruminated.

Distribution and Numbers.—-Most of the plants are tropical,
but a few occur in temperate regions. Illus/rative Genera :—
Areca, Linn.; Chamerops, Linn.; Attalea, Humb.; Cocos,
Linn. There are above 600 species.

Properties and Uses.—Of all orders of plants there is none,
with the exception of that of the Grasses, so valuable to man,
as regards their dietetical and economic applications, as the
Palm Order. These plants supply him with sugar, starch, oil,
wax, wine, resin, astringent matters, and also edible fruits and
seeds. Their terminal leaf-buds, when boiled, are eaten as a
vegetable. Their leaves are applied in various ways, as for
thatching, materials for writing upon, and in the manufacture
of hats, matting, &c.; their wood is applied to many useful pur-
poses; the fibres of their petioles and fruits supply materials
for cordage, cloth, and various other textile fabrics; and the
hard albumen of their seeds is applicable in many ways.

Series 5.—Nudiflore.

Order 26. PANDANACEX, the Screw-pine Order.—Charac-
ter.—Palm-like trees or shrubs. Leaves amplexicaul, linear-
lanceolate, and then imbricate, and spirally arranged in 3 rows ;
or pinnated or fan-shaped. Flowers unisexual or polygamous,
numerous, arranged on a simple or branched spadix, with many
spathaceous bracts. Perianth absent or scaly. Stamens
numerous; anthers 2—4-celled. Ovaries 1-celled; ovules soli-
tary or numerous, on parietal placentas. Fruit consisting of a
number of 1-seeded fibrous drupaceous carpels, or baccate, and
many-celled, and many-seeded. Hmbryo minute, embedded at
the side near the base of fleshy albumen. By Bentham and
Hooker this order is separated into two orders, the Pandanacee
and the Cyclanthacee.

Distribution and Numbers.—Kixclusively tropical plants.
Illustrative Genera :—Pandanus, Linn. fil.; Carludovica,
R.et P. There are about 75 species.
208 MANUAL OF BOTANY

Properties and Uses.—None possess any very active proper-
ties.

Order 27. TypHace®, the Bulrush Order.—Character.—
Herbs growing in watery places. Leaves rigid, linear, sessile,
parallel-veined. Flowers moncecious, arranged on a spadix, or
in heads, without a spathe. No true pertanth, merely scales
or hairs. Male flower with 1—6 distinct or monadelphous
stamens, with long filaments, and innate anthers. Female

Fie. 970. Fie. 971.

Fie. 972.

i
g

Fie. 973.

  

Fig. 970. A plant of the Cuckoo-pint (Arum
maculatum) in fruit. 6.Corm. J. Leaf. s.
The remains of the spathe. ¢. Fruit.——V'ig.
971. The spadix of the same with the spathe
removed ; the flowers are all naked and uni-
sexual, a number of pistillate flowers or
ovaries being below ; above which are some
rudimentary ovaries, then a number of sessile
anthers, and above theseare some staminodes
or abortive stamens.— Fig. 972. Vertical
section of the ovary of the same.—— Fig, 973.
Vertical section of the seed.

 

flower a solitary 1-celled carpel, with a single pendulous ovule.
Fruit indehiscent. Seed with mealy albumen; embryo axile;
radicle next the hilum.

Distribution and Numbers.—A few are found in tropical
and warm climates, but they are most abundant in the northern
parts of the world. Illustrative Genera :—Typha, Linn.;
Sparganium, Linn. These are the only genera ; they include
about 18 species.
MONOCOTYLEDONES' 209

Properties and Uses.—Unimportant.

Order 28. AroIpacem®, the Arum Order.—Character.—
Herbs or shrubs, with commonly an acrid juice, and subter-
ranean tubers, corms, or rhizomes. Leaves sheathing, usually
net-veined, simple or rarely compound. lowers unisexual and
monecious, or hermaphrodite, arranged on a spadix within a
spathe, or the spathe is absent. Perianth none, or composed of
scales which are inferior. Male flower :—Stamens few or
numerous; anthers extrorse, sessile or upon very short filaments.
Female flower :—Ovary 1- or more-celled, superior. Fruit
succulent. Seeds pulpy, with abundant mealy, horny, or fleshy
albumen, or rarely exalbuminous ; embryo various.

Diagnosis.—F lowers on a spadix, and with or without a true
spathe. Flowers naked, unisexual and monecious; or herma-
phrodite, and then frequently with a scaly inferior perianth.
Anthers extrorse. Fruit succulent.

Division of the Order and Illustrative Genera.—The order
may be divided into two sub-orders as follows :—

Sub-order 1. Aroide@ or Aracee.—Flowers unisexual, mone-
cious. Spadix surrounded by a spathe. Perianth none.
lllustrative Genera :—Arum, Linn.; Caladium, Vent.

Sub-order 2. Acoree@ or Orontiee.—F lowers hermaphrodite.
Spadix surrounded by a spathe or naked. Perianth absent,
or more generally present, and then scaly. Illustrative
Genera :—Acorus, Linn.; Orontium, Linn.

Distribution and Numbers—They abound in tropical
countries, but also occur in cold and temperate regions. There
are about 250 species.

Properties and Uses.—The plants of this order are all more
or less acrid, and often highly poisonous. But this acrid prin-
ciple is frequently volatile, or decomposed by heat; hence it
may be in some cases more or less destroyed by drying or ex-
posing to heat the parts in which it is found. The best method
of getting rid of the acridity is, however, by boiling in water,
as the acrid matter is also commonly soluble in that fluid.
Starch is usually associated with the acrid principle, and when
extracted, may be used for food like other starches. The under-
ground stems or corms of many species, when cooked, are eaten
in different parts of the world. Some are aromatic stimulants ;
others expectorant, antispasmodic, or diaphoretic.

Order 29. LemnacE®, the Duckweed Order.—Character.—
Floating aquatic plants, with lenticular or lobed leaves or
fronds. Flowers 2 or 8, enclosed in a spathe (jig. 974),

VoL. I. P
210 MANUAL OF BOTANY

monecious, placed on the margin or surface of the frond, or in
the axils of leaves. Perianth none. Male flower with 1 ora
few stamens, which are often monadelphous. Female flower
consisting of a 1-celled ovary, with 1 or more erect ovules.
Fruit 1- or more-seeded, membranous or baccate, indehiscent
or sometimes dehiscent. Embryo straight, cleft, in the axis of
fleshy albumen.

Distribution, Numbers, and Properties.—They inhabit cool,

Fic. 974. Fie. 975.

 

Fig. 974. A moneecious head of flowers of a species of Duckweed (Lemna
minor ), consisting of two male flowers, each of which is composed of a
solitary stamen with a quadrilocular anther ; and one pistillate flower in
the centre; the whole surrounded by a spathe.——/’ig. 975, Vertical
section of the pistil of the same.

temperate, and tropical regions. Illustratwe Genera :—Lemna,
Linn.; Pistia, Linn. There are above 20 species. Their pro-
perties are unimportant.

Series 6.—Apocarpe.

Order 80. Triuripacem, the Triuris Order.—Diagnosis.—
This is a small order of plants allied to Naiadacee, but usually
to be distinguished by its PURIEenGAEy embryo. The flowers
are also sometimes perfect.

Distribution, Numbers, and Piensa found
in warm and tropical regions. Illustrative Genera :—Triuris,
Miers; Sciaphila, Blume. There are 8 species. Their pro-
perties and uses are unknown.

Order 31. Atismace@, the Alisma Order—Character.—
Swamp or floating plants. Leaves narrow or with an expanded
MONOCOTYLEDONES 211

lamina, parallel-veined. Flowers hermaphrodite or very
rarely unisexual. Perianth inferior, arranged in two whorls,
each consisting of three parts; the outer whorl herbaceous, the
inner coloured. Stamens few or numerous; anthers introrse.
Carpels distinct, several; ovaries superior, 1-célled; ovules
solitary or 2 superposed ; placentas axile or basal. Fruit dry.
Seeds without albumen ; embryo undivided, curved.

Distribution and Numbers.—These plants are principally
found in the northern parts of the world. Illustrative Genera:
—Alisma, Juss.; Actinocarpus, R. Br. There are about 50
species.

Properties and Uses.—Of little importance. Many have
fleshy or mealy rhizomes, which are edible when cooked. Others

Fig. 976. Fic. 977,

 

Fig. 976. Flower of a species of Alisma, with an inferior perianth arranged
in two whorls each consisting of three parts, six stamens, and numerous
separate carpels—- ig. 977. Vertical section of the same flower.

possess astringent properties. Alisma Plantago had formerly a
reputation as a remedy in hydrophobia.

Order 32. BuTomacEes, the Butomus Order.— Character.—
Aquatic plants with parallel-veined leaves, sometimes milky.
Flowers hermaphrodite, showy. Perianth inferior, of six
pieces, arranged in two whorls (fig. 978), the inner being
coloured. Stamens few, or numerous. Carpels 3—6, or more,
more or less distinct ; ovaries superior ; ovules numerous, ar-
ranged all over the inner surface of the ovaries. Fruit many-
seeded, separating more or less when ripe into as many parts as
there are component carpels. Seeds without albumen. This
order is included by Bentham and Hooker in Alismacee.

Distribution and Numbers.—A few plants of this order
occur in tropical countries, but the greater number inhabit the

P2
212 MANUAL. OF BOTANY

northern parts of the world. Illustrative Genera :—Butomus,
Tourn. ; Limnocharis, H. et B. There are 7 species.
Properties and Uses.—Of little importance. Butomus wmbel-
latus, the Flowering Rush,
possesses acrid and bitter
properties, and was at one
time used in medicine. The
roasted rhizomes are edible.
Order 33. NAIADACEA,
the Pondweed Order.—Cha-
racter.—Aquatic plants
with jointed cellular stems.
2 Leaves with interpetiolar
Fig. 978. A flower of the Flowering Rush membranous stipules.
(Butomus umbellatus), with an inferior :
perianth arranged in two whorls, nine Flowers small, unisexual
Were eotlon chika cdot the miae, Wie PEO emndl 981), mutne.
cious or dicecious, solitary
or in spikes. Perianth either wanting, or present and com-
posed of 2 or 4 parts, which are then free and scale-like.
Stamens 1 or few, hypogynous; pollen globose or tubular.

Fie. 978. Fic. 979.

 

Fic. 980.

  

Fie. 981. Fie. 982.
“ Fic. 983.

Fig. 980, Two flowers of the Horned Pondweed (Zannichellia palustris), one
staminate, the other pistillate—— Jig. 981. The gyncecium of the same,
composed of four perfect carpels, and one imperfect.——Irig. 982, Vertical
section of one of the carpels.—/‘ig. 983. Vertical section of the fruit aud

seed. All magnified. After Lindley.

Carpels 1 or more, distinct, with superior ovaries (fig. 981) ;
ovule solitary (fig. 982). Fruit 1-celled, 1-seeded (fig. 983).
Seed exalbuminous; embryo with a lateral cleft.
MONOCOTYLEDONES 213

Distribution.—They are widely distributed, but are chiefly
found in extra-tropical regions. Illustrative Genera :—Naias,
Willd. ; Zannichellia, Michel; Zostera, Linn.

Properties and Uses.—Their properties are of little impor-
tance.

Order 34. JuncacinacEs, the Arrow-grass Order.—Cha-
racter.—Herbs, growing in marshes. Leaves with parallel
veins. Flowers hermaphrodite, whitish or greenish. Perianth
small, more or less scaly, inferior, in two whorls, each containing
three pieces. Stamens 6, perigynous, anthers usually extrorse.
Carpels 3—6, separate or more or less united; ovules 1—2.
Fruit dry, ultimately separating into as many parts as there are
carpels. Seeds attached to axile or basal placentas, exalbumi-
nous ; embryo straight, with a lateral cleft. This order is in-
cluded by Bentham and Hooker in Naiadacee.

Distribution and Numbers.—The plants of this order are
found more or less in nearly all parts of the world, but are most
abundant in temperate and cold regions. Illustrative Genera:
—Triglochin, Linn.; Potamogeton, Linn. There are about 50
species.

Properties and Uses.—Of little importance.

Series 7.—Glumacee.

Order 35. ERtocauLace®, the Eriocaulon or Pipewort Order.
Character.—Aquatic or marsh plants. Leaves clustered, linear,
usually grass-like. Flowers minute, unisexual, in dense heads,
each flower arising from the axil of a membranous bract.
Perianth membranous, tubular, 2—3-toothed or -lobed. Stamens
26; anthers 2-celled, introrse. Ovary superior, 2—3-celled.
Fruit dehiscent, 2—8-celled, 2—8-seeded. Seeds pendulous,
albuminous, hairy or winged; embryo lenticular, at the end
of the albumen remote from the hilum.

Distribution, Numbers, and Properties.—Mostly natives of
tropical America and the North of Australia. One species is
found in Britain, Eviocaulon septangulare, With. The order
contains about 200 species. Their properties are unimportant.

Order 36. DesvauxIAcE@, the Bristlewort Order.—C harac-
ter._Small sedge-like herbs, with setaceous sheathing leaves.
Flowers glumaceous, enclosed in a terminal spathe. Glwmes1
or 2. Palee none, or 1 or 2 scales parallel with the glumes.
Stamens 1 or very rarely 2; anthers 1-celled. Carpels 1—18,
distinct or partially united, with 1 stigma and 1 pendulous ovule
214 MANUAL OF BOTANY

in each ovary. Fruit composed of as many utricles as there are
carpels. Seeds albuminous ; embryo lenticular, terminal.

Distribution, Numbers, and Propertics.—Natives of Aus-
tralia and the South Sea Islands. Illustrative Genera :—
Desvauxia, R. Br.; Aphelia, R. Br. There are about 15 species,
Their properties and uses are unknown.

Order 87. RestiacE®, the Restio Order._-Character.—
Herbs or undershrubs. Leaves simple and narrow, or entirely
absent. Stems stiff, either naked, or more commonly with slit
convolute leaf-sheaths. Flowers with glumaceous bracts, spiked
or aggregated, generally unisexual. No true perianth, its place

Fie. 985. Fie. 986.
Fie 984.

 

Fig. 984. A portion of the angular stem of a species of
Carex, with a closed sheath.—JS%g. 985. Staminate
flower of a species of Curer. sf, Stamens, with long
filaments and pendulous innate anthers. g. Glume.
—-fq. 986. Pistillate flower of a species of Carez,
consisting of a glume at the base, and a pistil sur-
rounded by an urn-shaped tube (perigynium), u.
st. Style, terminated by three stigmas.

 

being usually supplied by 2--6 glumes. Stamens 2—8, adherent
to the inner glumes, or the latter are sometimes absent ; anthers
generally 1-celled. Ovary 1—3-celled, with 1 pendulous ovule
ineach cell. Fruit capsular or nut-like. Seed solitary, pendu-
lous, albuminous ; embryo lenticular, terminal.

Distribution and Numbers.—Natives principally of South
Africa, South America, and Australia. Some are also found in
the tropical parts of Asia; but none occur in Europe. Illustra-
tive Genera :—Leptocarpus, R. Br.; Restio, Linn. There are
about 180 species.

Properties and Uses.—Unimportant. The wiry stems of
MONOCOTYLEDONES 215

some species have been used for basket-making, &c., and for
thatching.

Order 88. CyYpPERACE®, the Sedge Order.—Character.—
Grass-like or rush-like, usually perennial herbs. Stems solid,
without joints or partitions, frequently angular. Leaves without
ligules, and with entire or closed sheaths round the stem.
Flowers spiked, imbricate, hermaphrodite or unisexual, each
arising from the axil of 1—3 bracts or glumes. (The lowermost
glumes are frequently empty, that is, without flowers in their
axils.) Perianth absent, or existing in the female flowers in the
form of a tube ( perigyniwm), or as hypogynous scales or bristles.

Fic. 988. Fie. 989.

 

Fig. 987. Hermaphrodite flower of a species ot
Club-rush (Scirpus), the glume having been
removed. b. Hypogynous setz or bristles form-
ing a kind of perianth. st. Hypogynous stamens
with 2-celled innate anthers. 0. Ovary. s. Style.
stig. Stigmas.—J%g. 988. Vertical section of
the fruit of aspecies of Carer. s. Pericarp. ¢e.
Integuments of the seed. «aly. Albumen. pi.
Embryo.—/g. 989. Embryo of a species of
Carex removed from the albumen. a. Lateral
swelling. 7. Radicle. c. Cotyledon. f. Slit
corresponding to the plumule.

 

Stamens hypogynous, 1—12, commonly 3; anthers 2-celled,
innate. Ovary 1-celled, superior, with 1 erect anatropous ovule.
Fruit indehiscent, 1-seeded. Seed with fleshy or mealy albumen ;
embryo lenticular, enclosed in the base of the albumen.

Diagnosis.—Grass-like or rush-like herbs with solid and
usually angular stems. Leaves without ligules and with entire
sheaths. Stamens few, hypogynous; anthers innate, 2-celled.
Ovary superior, 1-celled; ovule solitary, erect, anatropous.
Fruit indehiscent, 1-celled, 1-seeded. Embryo enclosed in the
base of the albumen.

Distribution and Numbers.—Natives of all parts of the
216 MANUAL OF BOTANY

world, and found especially in marshes, ditches, and about
running streams. Illustrative Genera :—Carex, Linn. ; Cyperus,

Linn.; Scirpus, Linn. There are about 2,000 species.
Properties and Uses.—Although closely allied in their bota-
nical characters to the Graminacez, the Cyperacee are alto-
gether deficient in the nutritive and other qualities which
render the plants of the Graminacee so eminently serviceable
to man and other animals. Indeed the order generally is
remarkable for the absence of any
Fic. 990. important properties. Some of the
plants are slightly aromatic, sto-
machic, and diaphoretic, others
demulcent and alterative, and a few
have been used for economic pur-
poses. The underground stems of
certain species are edible when
roasted or boiled. Some of the
species by spreading and interlacing
their subterranean stems through
the sand of the sea‘shore, and thus
binding it together, prevent it from
being washed away by the receding
waves, and in*this way protect the
neighbouring coast from encroach-
ments of the sea. (See also Pro-
perties and Uses of the Grami-

nacee.)

Order 39. GRAMINACER, the
eke wae aan Grass Order.-Character.-Herbs,
of the Cat’s-tail Grass (Phiewm shrubs, or arborescent plants, with
nee a we round, commonly hollow, jointed
sheath. stems. Leaves alternate, with
parallel veins and split sheaths, and
with a ligule at the base of the lamina. Flowers herma-
phrodite or unisexual, arranged in spiked, panicled, or racemose
locusts ; or solitary. No true perianth, its place being supplied
by imbricate bracts, of which there are commonly 2, called
glumes, or rarely 1 ( fig. 992); these glumes are placed at the
base of the solitary flower, or at the base of each locusta.
Occasionally the glumes are altogether absent. Tach flower is
also usually furnished with two other alternate bracts (palee)
(or sometimes the inner palea, pi, is wanting), the outer
palea is frequently termed the flowering glume; and 2 or 3
MONOCOTYLEDONES 217

hypogynous scales (lodicule, sqwamule, or glumellules) ; these
scales also are occasionally absent. Stamens 1—6, usually 3
Julaments capillary ; anthers 2-celled, versatile. Ovary superior
1-celled, with a solitary ascending ovule; stigmas feathery or

Fic. 991. Fie. 992.

 

Fig. 991. Diagram of a spikelet of the Oat (Avena). (From Le Maout.) gi,
gl. Two glumes, enclosing two hermaphrodite flowers, and one, a, abortive.
b. The outer palea or flowering glume. },b. The inner palea. p, p. Two
scales (sqguamule or glumellules); the dotted curved line on the right
marks the position of a third abortive scale. e. Stamens. c. Ovary.
Fig. 992. A spikelet (locusta) of the Oat (Avena sativa). ge. Outer glume.
gi. Inner glume. pe, Outer palea or flowering glume of the fertile flower.
pi. Inner palea of the same. e¢. Stamens, o. Ovary. fa, and a. Abor-
tive flowers.—J'ig. 993. Fertile flower of the Oat, without the pale.
p. Lodicules, e. Stamens. o, Ovary. s, s. Feathery stigmas.— Fig.
994. One of the florets of a species of Meadow Grass (Poa pratensis ).——
Fig. 995. One of the florets of the Hard Fescue Grass (Festuca duriuscula).
— Fig. 996.. The embryo of the Oat. a. Lateralswelling. ¢. Cotyledon.
r. Radicle. f. Slit corresponding to the plumule,

hairy. Fruit acaryopsis. Seed with mealy albumen; embryo
lenticular, lying on one side of the base of the albumen.
According to the views of some botanists, the palee represent
218 MANUAL OF BOTANY

a calyx and correspond to the outer whorl of the perianth in
Liliacew. This is supported by the fact that the upper pale is
two-pointed as if composed of two leaves laterally united. Ina
species of Bromus it is cleft to the base, so that there are three
palew in the whorl. The lodicules are held to represent the
corolla. :

Other writers regard the lodicules as the only representatives
of the perianth, and consider the pales to be bracts.

Diagnosis.—Leaves alternate, with split sheaths, and a
ligule at the base of the lamina. Flowers generally arranged in
spikelets or locuste, or rarely solitary. Flowers glumaceous;
palee usually 2 in each flower. Stamens hypogynous, few,
usually 3, with capillary filaments, and versatile anthers. Ovary
superior, with a solitary ascending ovule; stigmas feathery or
hairy. Fruit a caryopsis. Seed with mealy albumen, with the
embryo on one side at the base.

Distribution and Numbers.—Grasses are universally dis-
tributed over the globe. In temperate and cold climates they are
herbaceous and of moderate height, while in tropical countries
they become shrubby and arborescent, and sometimes grow to the
height of 50 or 60 feet. Grasses usually grow together in large
masses, and thus form the verdure of great tracts of soil, and
hence have been termed social plants. Illustrative Genera :—
Panicum, Linn.; Anthoxanthum, Linn.; Phleum, Linn. ;
Agrostis, Linn.; Dactylis, Linn.; Bromus, Linn. There are
over 4,000 species.

Properties and Uses.—Of all the orders in the Vegetable
Kingdom this is the most important to man, as it affords the
various fruits, commonly known as Cereal Grains, which supply
the principal material of his daily bread in most countries
of the world; besides being eminently serviceable in other
respects, by supplying fodder for cattle, and yielding sugar and
other very useful products. It is a remarkable fact that the
native countries of our more important Cereals or Corn-produ-
cing plants are altogether unknown. A few of the Grasses yield
fragrant volatile oils. Paper has long been made from the
bamboo in India, China, and some other parts of the world;
and straw is now largely employed for a like purpose in this
country and elsewhere. Other Grasses have also, within the
last few years, been used to a great extent for making paper.
Almost all Grasses are wholesome, but one or more species
of Bromus have been erroneously reputed to be purgative,
and one, Loliwm temulentum, is said to be narcotic and
MONOCOTYLEDONES 219

poisonous. Some of the species serve to bind together the sand
on the seashore, and thus prevent the encroachment of the sea
on the neighbouring coast. (See also Properties and Uses of
the Cyperacee.)

Artificial Analysis of the Orders in the Class.

MonocoTyLEDONES,

(Modified from Lindley.)

Sub-Class I.—PrraLomwea.

1. FLOWERS WITH AN EVIDENT PERIANTH.
A. Ovary inferior (Infere or Epigyne).

a. Flowers gynandrous.
Ovary 1-celled. Placentas parietal . : » Orchidacee.
Ovary 3-celled. Placentas axile . . . Apostasiacee.

b. Flowers not gynandrous.

1. Veins of leaves diverging from the midrib,
and parallel to each other.
Embryo enclosed in endosperm.
Anther 2-celled. Filament one, not pe-

taloid . ‘ . Lingiberacee.
Embryo not enclosed in 5 exlomgerrits
Anther 1-celled. Filament one . Marantacee.

Anther 2-celled. Filaments morethanone Musacee.

2. Veins of leaves diverging from the base, and
parallel to the midrib.

Stamens 38.
Anthers extrorse : Fi é fi . Tridacee.
Anthers introrse és i & Burmanniacee.
Stamens 6.
Anthers extrorse ‘ ‘ . Burmanniacee.
Anthers introrse.
Leaves equitant ‘i : p . Hemodoracee.
Leaves flat.
Fruit 1-celled 6 é . Taccacee.

Fruit 3-celled.
Outer whorl of the perianth petaloid Amaryllidacee.
Outer whorl of the ee not pe-
taloid : . Bromeliacee.
Stamens more than 6 é ; ‘ . Hydrocharidacee,
220

3. Veins of leaves reticulated.
Hlowers unisexual

B, Ovary superior (Suwpere).
veined.

Leaves parallel-

w. Outer whorl of the perianth herbaceous or
glumaceous.

Carpels more or less distinct.
Seeds attached over the whole inner walls of
the fruit. i
Seeds attached to sila or asad placentas:
Flowers conspicuous. Embryo curved,
without a slit
Flowers inconspicuous.
with a lateral slit
Carpels combined.
Inner whorl of the perianth different from
the outer.
Placentas axile. Anthers 2-celled. Oe
sule 2—8-celled .
Placentas parietal.
Anthers 2-celled. -Capsule 1-celled
Anthers 1-celled. Capsule 1-celled
The outer and inner whorls of the perianth

Embryo straight,

alike.
Flowers on a spadix. Embryo with a la-
teral slit 3 3 i A
Flowers not on a spadix. Embryo with-
out a slit dee ates | “ae

b. Outer whorl of the perianth petaloid, or the
whole petaloid when only one whorl is
present.

Carpels more or less distinct.
Seeds solitary. Flowers on a spadix
Seeds numerous. Flowers not on a spadix.
Anthers extrorse
Anthers introrse.
Perianth of 6 parts.
bumen
Perianth of 2 parts. ‘Seeds with albumen:
Carpels combined.
Flowers on a spadix .
Flowers not on a spadix.
Perianth rolled inwards after flower-
ing. Aquatics.
Perianth not rolled inwards atten) flower-
ing, conspicuqus

Seeds without al-

MANUAL OF BOTANY.

Dioscoreacee.

Butomacee.

Alismacee.

Juncaginacee.

Commelynacee.

Xyridacee.
Mayacee.

Aroidacee.

Juncacee.

Palmacee,
Colchicacece,
Butomacee.
Philydracee.

Palmacee.

Pontederiacee.

Liliacee.
MONOCOTYLEDONES 221

C. Ovary superior. Leaves net-veined.

a. Placentas basal. i : 4 . . Roxburghiacee.
b. Placentasazile . ‘ . Smilacee.
ve. Placentas parietal . ‘ . Philesiacee.

2, FLOWERS EITHER NAKED, OR WITH A WHORLED SCALY PERIANTH,
GENERALLY UNISEXUAL.

A. Flowers on a spadix.
a. Flowers bisexual.

Embryo cleft. ' ' . Aroidacee.
Embryo solid. Pandanacee.
b. Flowers unisexual.
Embryo solid a Pandanacee.
Embryo cleft on one side.
Flowers with a true spathe. Fruit succulent.
Anthers sessile, or nearly so Fi « Aroidacee.
Flowers without a true spathe. Fruit dry..,
Anthers on long filaments ‘ . Typhacee.
B. Flowers not arranged on an evident spadix.
a. Flowers bisexual.
Ovary superior Juncaginacee.
Ovary inferior . ‘ ‘i . Hydrocharidacee.
b. Flowers unisecual.
Ovules erect.
Embryo perfect.
Seed without albumen Naiadacee.
Seed with albumen . . Pistiacee.
Embryo rudimentary . 3 . Triuridacee.
Ovules pendulous.
Carpel solitary.
Seed without albumen.
Pollen globose or tubular . Naiadacee.
Seed with albumen Restiacee.
Carpels several, distinct.
Anthers 2-celled . i a 7 ‘ . Naiadacee.
Anthers 1-celled . . Desvauxiacece.
Carpels several, combined.
Anthers 1-celled.
Stamens 2—3 . i » Restiacee.
Stamen 1 é 7 . Desvauxiacee.
Anthers 2-celled. Placentas axile.
Seeds with rows of hairs . Hriocaulacee
Seeds without rows of hairs ‘ . Restiacee.

Anthers 2-celled. Placentas parietal . Xyridacee.
222

Sub-Class II.— Guumacea.

Stem solid. Leaf-sheaths not slit. Hmbryo ba-
silar, within the albumen.

Stem hollow. Leaf-sheaths slit. Embryo basilar
outside the albumen

Synopsis of the British Natural Orders

MonocoryLEDONES.
A. Leaves net-veined.
1. Floral envelopes whorled.

Perianth inferior. Flowers perfect . {

Perianth superior. Flowers dicecious

2. Perianth absent: Flowers on a ee
(moneecious) . "

B. Leaves parallel-veined, persistent.
1. Floral envelopes whorled or absent.

a. Ovaries more than one, with styles or stig-
mas distinct.

Perianth 4-parted or 0, or inconspicuous {

Perianth 6-parted.
Placentation diffuse .
Placentation axile or basal.

Flowers conspicuous
Flowers inconspicuous .

b. Ovary single.
Ovary inferior.
Stamen 1. Flowers gynandrous
Stamens free from the style.
Perianth petaloid.
Stamens 3, anthers extrorse
Stamens 6, anthers introrse’*
Three outer segments of perianth hes:
baceous
Ovary superior.

Perianth hextpetaloid. Flowers ag
Perianth conspicuous ;
Perianth scale-like

Perianth more or less elemetebas, or

partly coloured, or wanting.
Flowers perfect. Perianth 6-parted,
stamens 6 . y é

MANUAL OF BOTANY

Cyperacee.

Graminacee.

of Class X.

Liliacee
(L'rilliacece).
Dioscoreacee.

Aroidacee
(Aroidee).

Naiadacee
(Potamogetonee).

Butomacee.

Alismacee.
Juncaginacee.

Orchidacee.
Iridacee.
Amaryllidacee.

Hydrocharidacee.

Liliacee.
Aroidace@ (Acore@).

Juncacee.
MONOCOTYLEDONES

Flowers moncecious.
Flowers on a spadix.
Spadix thick. Spathe absent

Spathe present {

Flowers not on a spadix.
Flowers capitate. Stamens 2—5 .
Flowers 2 in a spathe,1 g,1 9
Flowers in two rows on one side of
the spathe, enclosed by a fold of the
leaf; or solitary
2. Floral envelopes imbricated, bract- Tika.
Leaves with entire sheaths, stems solid
Leaves with split sheaths, stems hollow

223

Typhacee.
Aroidacee
(Aroidea).

Eriocaulacee.
Lemnacee. -
Naiadacee.

Cyperacee.
Graminacee.
224 MANUAL OF BOTANY

Cuass XI.—DICOTYLEDONES.

The plants comprised in this group are usually now divided
into three sub-classes as under :—

Sub-Class I.—MonocHLAMYDEZ.

The towers have never more than a single whorl of perianth
leaves, which may be petaloid or sepaloid. Very frequently there
is no perianth. The flowers are very frequently unisexual.
Bentham and Hooker, in the ‘Genera Plantarum,’ divide them
further into eight series, each comprising several Natural Orders
as under :—

Series 1.—Curvembryea.

Characters.—Endosperm frequently farinaceous. Embryo
curved, eccentric, lateral or peripheral, rarely straight. Ovules
most frequently 1 in the ovary or 1 in each loculus. Flowers 8,
or in some genera unisexual or polygamous. Petals very rare;
stamens equal in number to the segments of the perianth ; rarely
fewer or more.

Order 1. Nyctaginez.
. Amarantacez.
. Chenopodiacee.
- Basellacex.
. Phytolaccacex.
. Petiveriaces.
. Batidacee.
. Polygonacez.

DMAID ao w vo

Series 2.—Multiovulate aquatica.

Characters.—Aquatic herbs, submerged. Ovary syncar-
pous, ovules numerous in each loculus or on each placenta.
Order 9.—Podostemacee.

Series 3.— Multiovulate terrestres.

Characters.—Terrestrial trees or shrubs. Ovary syncar-
pous; ovules numerous in each loculus or on each placenta.
Order 10. Nepenthacee.
11. Cytinaceer.
12. Rafflesiacee.
18. Aristolochiacex.
DICOTYLEDONES 225

Series 4.—Micrembryee.

Characters.—Ovary syncarpous, monocarpous, or apocarp-
ous. Ovules generally solitary in each carpel, rarely 2 or more,
Endosperm copious, fleshy, or rarely farinaceous. Embryo very
minute.

Order 14. Piperaces.
15. Saururacee.
16. Chloranthaceze.
17. Myristicacee.
18. Monimiacez.
19. Atherospermacez.

Series 5.—Daphnales.

Characters.—Ovary monocarpous, very rarely syncarpous,
with 2 to 4 loculi; ovules solitary or in pairs in the ovary or in
each loculus. Trees or shrubs, very rarely herbs. Flowers
generally 9. Perianth perfect, sepaloid, 1—2-seriate. Stamens
perigynous, equal in number to the lobes of the perianth or
double the number : rarely fewer.

Order 20. Lauracez.
21. Proteacer.
22. Thymelacez.
23. Aquilariacez.
24. Penxacez.
25. Eleagnaces.

Series 6.—Achlamydosporee.

Characters.—Ovary unilocular with 1—8 ovules; ovules
most frequently poorly developed before flowering. Seeds albumi-
nous, but without a testa, either free in the pericarp or attached
to its walls. Perianth generally perfect, sepaloid or petaloid.

Order 26. Loranthacee.
27. Santalacee.
28. Balanophoracez.

Series 7.—Unisexuales.

Characters.—Flowers unisexual; ovary syncarpous or
monocarpous; ovules solitary or in pairs in the ovary or ineach
loculus. Endosperm copious, fleshy, scanty, or absent. Trees
or shrubs, rarely herbs. Stipules generally present. Perianth
sepaloid, or minute, or absent. Styles equal in number to the
carpels ; not infrequently lobed.

VOL, II. Q
226 MANUAL OF BOTANY

Order 29. Euphorbiacee.
80. Scepacer.
31. Stilaginacez.
32. Urticacer.
33. Moracer.
84, Cannabinacee.
35. Artocarpacee.
86. Ulmacez.
387. Platanaceer.
88. Juglandacez.
39. Myricacez.
40. Casuarinacee.
41. Cupulifere.
42. Betalaces.

Series 8.—Ordines anomalt.

Order 42. Salicacez.
43. Lacistemacex.
44. Empetracez.
45. Ceratophyllacez.

Sub-Class 1I1.—PotypetaLa@.

Flowers with both calyx and corolla, the latter usually con-
sisting of free petals. Both stamens and pistil usually
present.

Series 1.—THALAMIFLOR&.

The calyx generally consists of free sepals; the petals often
more numerous than the sepals: stamens nearly always hypo-
gynous, the pistil syncarpous or apocarpous.

Bentham and Hooker divide the Thalamiflore into Cohorts
as under :— : :

Cohort 1.—Ranales.

Characters.—Flowers generally acyclic or hemicyeclic;
perianth usually 2-seriate; stamens commonly ©, gynecium
apocarpous, monocarpous, or rarely syncarpous.

Order 46. Ranunculacee.
47. Dilleniacee.
48. Calycanthacee.
49. Magnoliacee.
50. Anonacee.
DICOTYLEDONES 227

Order 51. Menispermacez.
52. Berberidacee.
53. Nymphzacer.

Cohort 2.—Parietales.

Characters.—Flowers with calyx and corolla, sepals free,
petals free, stamens definite or », pistil syncarpous; ovary with
parietal placentation.

Order 54. Sarraceniacee.
55. Papaveracee.
56. Fumariacee.
57. Crucifere.

58. Capparidacee.
59. Resedacee.

60. Cistaces.

61. Violacez.

62. Sauvagesiacez.
63. Canellacese.
64. Bixaceer.

Cohort 3.—Polygales.
Characters.—Gyneecium syncarpous; ovary usually 2—3-
celled; placentation generally axile, or very rarely parietal.
Order 65. Pittosporacee.
66. Tremandracez.
67. Polygalacer.
68. Vochysiacee.

Cohort 4.— Caryophyllales.
Characters.—Gynecium syncarpous; ovary ultimately
1-celled, with free-central placentation, or very rarely parietal.
Order 69. Caryophyllacez.
70. Paronychiacee.
71. Portulacacez.
72. Tamaricacez.
73. Reaumuriacee.

Cohort 5.—Guttiferales.

Characters.—Gynecium syncarpous; ovary 1—many.
celled, placentation usually axile.
Order 74. Elatinacezx.

75. Hypericacee.
Q2
228 MANUAL OF BOTANY

Order 76. Guttiferse ‘or Clusiacee.
77. Ternstreemiaces or Camelliacee.
78. Marcgraviacer.
79. Rhizobolacee.
80. Dipterocarpex or Dipteracer.
81. Chlenacez.

Cohort 6.—Malvales.

Characters.—Calyx with valvate xstivation. Stamens
usually ©. Placentation axile or sutural.
Order 82. Malvacez.
83. Sterculiacere.
84. Tiliacez.

Series 2.—DIsciFLOR&.

The sepals are free or coherent, petals usually in a single
whorl; the stamens are hypogynous or attached to a dise which
is sometimes perigynous ; the ovary is generally syncarpous.

According to Bentham and Hooker, the Discifloree comprise
the following Cohorts:— / :

Cohort 1.—Geraniales.

Characters.—Flowers with their parts arranged in fives;
frequently two whorls of stamens which are then obdiplostemo-
nous; dise often conspicuous, but sometimes absent. Stamens
hypogynous, pistil syncarpous.

Order 85. Linacez.
86. Humiriacee.
87. Malpighiacee.
88. Zygophyllacee.
89. Geraniace.
90. Balsaminaces.
91. Vivianiaces.
92. Tropolacez.
93. Limnanthacee.
94. Oxalidacee.
95. Rutacesx.
96. Simarubacee..
97. Ochreacez.
98. Burseracez.
99. Meliacez.
100. Cedrelaces.
101. Chailletiaces.
DICOTYLEDONES 229

Cohort 2.—Olacales.

Characters.—Calyx imbricate. Gynccium syncarpous,
ovules suspended, raphe dorsal. Seeds albuminous. -
Order 102. Olaccacee.
103. Icacinacer.
104. Cyrillacee.
105. Phytocrenacez.
106. Aquifoliacez or Ilicacez.

Cohort 3.—Celastrales.

Characters.—Calyx imbricate or valvate. Gyncecium
syncarpous; ovules erect, raphe ventral. Seeds usually
albuminous, radicle inferior. Nearly always trees or shrubs.

Order 107. Celastracez.
108. Hippocrateacee.
109. Stackhousiacezx.
110. Rhamnacee.
111. Vitacer.

Cohort 4.—Sapindales.

Characters.—Calyx imbricate; gyncecium usually syn-
carpous or rarely apocarpous; ovules generally ascending with
raphe ventral. Seeds usually exalbuminous. Trees or shrubs,
rarely herbs.

Order 112. Sapindacee.
113. Aceraces.
114. Staphyleacez.
115. Sabiacezx.
116. Anacardiacee.

Anomalous Orders.
Order 117. Coriariacez.
118. Moringacee.
Series 3.—CaLYCIFLOR&.

The calyx is usually gamosepalous, stamens perigynous or
epigynous; gyncecium apocarpous or syncarpous. Bentham and
Hooker divide this group into the following Cohorts :—

Cohort 1.—Rosales.

Characters.—Stamens perigynous or epigynous. Gyne-
cium usually simple or apocarpous ; rarely syncarpous. Ovary
230

MANUAL OF BOTANY

superior or inferior; placentation usually marginal or axile;

styles generally solitary

or distinct; rarely united, seeds

albuminous or exalbuminous.

Order 119.
120.
121.
122.
128.
124.
125.
126.
127.
128.
129.
130.
1381.
182.
183.
184,
135.

Connaracez.
Leguminose.
Rosacee.
Saxifragacer.
Francoacee.
Escalloniacez.
Philadelphacez.
Hydrangeacez.
Hensloviacer.
Cunoniacez.
Ribesiacex.
Crassulacee.
Droseracez.
Hamamelidaces.
Bruniacez.
Haloragaceer.
Callitrichacee.

Cohort 2.—Myrtales.

Characters.—Gynecium syncarpous; style usually un-
divided; ovary inferior, or included within the calyx tube;

placentation generally axile.

nearly always simple.
Order 136.
187.
138.
139.
140.
141.
142.

143.

144,
145.

Seeds exalbuminous. Leaves
Rhizophoracee.
Combretacez.
Myrtacezx.
Lecythidacez.
Barringtoniacez.
Chamelauciacee.
Belvisiacer.
Melastomacez.
Lythracee.
Onagracee.

Cohort 3.—Passiflorales.

Characters.—Gynecium syncarpous ; ovary usually 1-
celled or sometimes spuriously 3-celled; placentation parietal ;
ovules-numerous. _ Seeds albuminous or exalbuminous. Leaves

simple.
DICOTYLEDONES 231

Order 146. Samydacee.
147. Homaliacez.
148. Loasacez.
149. Turneracez.
150. Passifloracee.
151. Malesherbiacez.
152. Papayacee.
1538. Cucurbitacee.
154. Begoniacere.
155. Datiscaces.

Cohort 4.—Ficoidales.

Characters.—Stamens generally numerous, epigynous or
perigynous. Leaves simple when present; exstipulate. Stem
usually fleshy.

Order 156. Cactacee. ;
157. Mesembryanthacee or Ficoidaceex.

Cohort 5.—Umbellales.

Characters.—Stamens few, epigynous. Gyncecium syn-
carpous, ovary inferior, ovules solitary, pendulous; styles sur-
rounded at the base by an epigynous disc. Seeds albuminous.
Leaves exstipulate.

Order 158. Umbellifere.
159. Araliacez.
160. Cornacee.
161. Garryaceer.
162. Alangiacez.

Sub-Class III.—GamorETsL& oR CoROLLIFLORAE.

The petals are coherent and the stamens are in nearly all cases
attached to the tube of the corolla. Ovary usually syncarpous.
This sub-class is divided by Bentham and Hooker into 8 series,
each comprising Cohorts and Natural Orders as under :-——

Series 1.—InFER& oR EPiIcynz.

Ovary Inferior.

Cohort 1.—Rubiales.

Characters.—Stamens epipetalous and alternate with the
lobes of the corolla. Ovary 1- or more-celled, but usually 2-
celled. Cells of the ovary with 1—many ovules. Seeds
albuminous. Leaves generally opposite. :
232 MANUAL OF BOTANY

Order 163. Caprifoliaces.
164, Rubiacee.

Cohort 2.—Asterales.

Characters.—Stamens epipetalous and alternate with the
lobes of the corolla when equal to them in number. Ovary 1-
celled, ovule solitary. Fruit dry and indehiscent. Seeds
usually exalbuminous. Leaves exstipulate.

Order 165. Valerianacez.
166. Dipsacee.
167. Calyceracee.
168. Composite.

Cohort 3.—Campanales.

Characters.—Stamens epigynous, usually free from the
corolla. Ovary generally 2—6-celled, with numerous ovules in
each cell. Fruit capsular. Seeds albuminous. Mostly herbs,
rarely shrubs. Leaves usually alternate, exstipulate.

Order 169. Stylidiacez.
170. Goodeniacez.
171. Campanulacez.
172. Lobeliacez.

Series 2,_SurpeR= oR HETEROMERA.

Ovary superior except in Vacciniacex ; stamens epipetalous,
but sometimes attached so near the base of the petals as to
appear almost or quite free and hypogynous.

Cohort 1.—Ericales.

Characters.—Stamens generally hypogynous, except in
Vacciniacer, and twice the number of the lobes of the corolla ;
or equal in number and then alternate with the lobes. Ovary
usually with more than 2 cells; placentation generally axile ;
style undivided.

Order 173. Vacciniaces.
174. Ericacee.
175. Monotropacee.
176. Epacridacee.
177. Diapensiacez.
178. Stilbaceex.

Cohort 2.—Primulales.

Characters.—Stamens generally epipetalous, equal in
number to the lobes of the corolla and opposite to them. Ovary
DICOTYLEDONES 233

1-celled, with free-central placenta and numerous ovules, or with
a solitary ovule suspended from a long funiculus arising from
the centre of the cell at the base.
Order 179. Plumbaginacee.
180. Primulacee.
181. Myrsinacee.

Cohort 3.—Ebenales.

Characters.—Stamens epipetalous, equal in number to and
opposite the lobes of the corolla or separate petals; or more
numerous. Ovary more than 1-celled, placentation axile.
Fruit fleshy, seeds 1 or few, large. Trees or shrubs; leaves
alternate.

Order 182. Sapotacee.
183. Ebenacee.
184. Styracex.

Series 38.—BicaRPELLATS.
Ovary superior, usually of two carpels. Stamens epipetalous.

Cohort 1.—Gentianales.

Characters.—Corollaregular, stamens generally epipetalous,
equal in number to and alternate with the lobes of the corolla;
rarely fewer. Leaves usually opposite and entire; rarely
compound; very rarely alternate.

Order 185. Oleacee.
186. Salvadoracee.
187. Apocynacez.
188. Asclepiadacee.
189. Loganiacee.
190. Gentianaces.

Cohort 2.—Polemoniales.

Characters.—Corolla regular or nearly so. Stamens
epipetalous, equal in number to and alternate with the corolla
lobes. Leaves alternate or rarely opposite; usually simple and
entire ; or sometimes lobed and rarely compound; always ex-
stipulate.

Order 191. Polemoniacee.
192. Hydrophyllaces.
193. Boraginacez.
194. Ehretiacee.
195. Cordiacez.
234 MANUAL OF BOTANY

Order 196. Convolvulaces.
197. Nolanacez.
198. Solanacez.

Cohort 8.—Personales.

Characters.—Flowers generally heteromerous. Corolla
usually irregular. Stamens epipetalous; posterior one often
suppressed or appearing as a staminode; generally four and
didynamous; sometimes five or two. Ovules generally numerous
or two superposed.

Order 199. Scrophulariacee.
200. Orobanchacee.:
201. Lentibulariacee.
202. Columelliacee.
203. Gesneracee.
204. Bignoniacee.
205. Crescentiacer.
206. Pedaliacee.
207. Acanthacee.

Cohort 4.—Lamiales.

Characters.—Flowers generally heteromerous. Corolla
usually irregular. Stamens epipetalous, posterior one commonly
suppressed; usually four and didynamous, or rarely two. Carpels
or cells each with one ovule or two collateral ones. No stipules.

Order 208. Selaginacez.
209. Verbenacex.
210. Myoporacez.
211. Labiate.

Anomalous Order.

Order 212.-—Plantaginacez.
DICOTYLEDONES—MONOCHLAMYDE 235

Sub-Class I.—MonocHLaMyYDE#, oR INCOMPLETA.

Series 1.—Curvembryea.

Order 1. Nycoracinacem®, the Marvel of Peru Order.—
Character.—Herbs, shrubs, or trees, with the stems usually
tumid at the joints. Leaves generally opposite and entire.
Flowers with an involucre. Calyx tubular or funnel-shaped,
often coloured, plaited in estivation, contracted towards the
middle, its base persistent and ultimately becoming indurated
and forming a spurious pericarp. Stamens 1 or many, hy-
pogynous. Ovary superior, 1-celled; ovuwle solitary; style 1;
stigma 1. Fruit a utricle, enclosed by the hardened persis-
tent base of the calyx. Seed solitary; embryo coiled round
mealy albumen, with foliaceous cotyledons, and an inferior
radicle.

Distribution and Numbers.—Natives exclusively of warm
regions. Illustrative Genera :—Mirabilis, Linn. ; Pisonia,
Plum. There are about 100 species.

Properties and Uses.—Chiefly remarkable for the presence
of a purgative property in their roots; which is especially the
case with those of Mirabilis Jalapa and M. longiflora. M.
dichotoma, Marvel of Peru, is commonly known by the name
of the Four-o’clock Plant, from opening its flowers in the
afternoon. Boerhaavia diffusa is said to possess expectorant
properties.

Order 2. AmMARANTACES, the Amaranth Order.—Charac-
ter.—Herbs or shrubs. Leaves simple, exstipulate, opposite or
alternate. Flowers crowded, spiked or capitate, bracteated,
hermaphrodite, or occasionally unisexual. Calyx of 3—5 sepals,
dry and scarious, inferior, persistent, often coloured, imbricate.
Stamens 5, hypogynous and opposite to the sepals, or a multiple
of that number; anthers 2- or 1-celled. Ovary free, 1-celled,
with 1 or more ovules; style 1 or none; stxgma simple or
compound. Fruita utricle or caryopsis, or sometimes baccate.
Seeds 1 or more, pendulous ; embryo curved round mealy albu-
men; radicle next the hilum.

Distribution and Numbers.—The plants of this order are
most abundant in tropical regions, and are altogether unknown
in the coldest climates. Illustrative Genera :—Celosia, Linn. ;
Amarantus, Linn. There are nearly 500 species.

Properties and Uses.—Unimportant. Amarantus spinosus
and other Indian species possess mucilaginous properties.
236 MANUAL OF BOTANY

Another Indian species, Achyranthes aspera, is also reputed to
be astringent and diuretic. Gomphrena officinalis and G.
macrocephala are used in Brazil in intermittent fevers, diarrhea,
and some other diseases. Some of the species have bright-
coloured persistent flowers, and are hence cultivated in our
gardens, as Amarantus caudatus, Love-lies-bleeding ; Amaran-
tus hypochondriacus, Prince’s-feathers ; Celosia cristata, Cocks-
comb; and others.

Order 3.—CHENOPODIACEA, the Goosefoot Order.—Charac-
ter.—Herbs or wndershrubs, more or less succulent. Leaves
exstipulate, usually alternate, rarely opposite. Flowers minute,
greenish, usually [ebracteate, hermaphrodite or unisexual.
Calyx persistent, usually divided nearly to the base, imbricate.
Stamens equal in number to the lobes of the calyx and opposite
to them, or rarely fewer, hypogynous or inserted into the base
of the lobes; anthers 2-celled. Ovary superior or partly
inferior, 1-celled, with a single ovule attached to its base; style
usually in 2—4 divisions, rarely simple. Frwit usually an
acheenium or utricle, or sometimes baccate. Seed solitary ; em-
bryo coiled into a ring or spiral, with or without albumen;
radicle towards the hilum.

Diagnosis.—They are chiefly distinguished from the Nycta-
ginacee by their habit and commonly ebracteate flowers.

Distribution and Numbers.—More or less distributed over
the globe, but most abundant in extratropical regions. Illus-
trative Genera :—Salicornia, Tourn.; Beta, Towrn.; Salsola,
Linn. There are above 500 species.

Properties and Uses.—Several plants of this order inhabit
salt-marshes, and yield by combustion an ash called bariila, from
which carbonate of soda was formerly principally obtained ; but
their use for this purpose has much fallen off of late years, in
consequence of soda being more readily extracted from other
sources. The plants which thus yield barilla principally
belong to the genera Salsola, Salicornia, Chenopodium, and
Atriplex. Many plants of the order are esculent, as Beet and
Mangel-Wurzel or Mangold Wurzel ; and some are used as pot-
herbs, as Spinach or Spinage (Spinacia oleracea), Garden Orache
or Mountain Spinach (Atriplex hortensis), and English Mercury
(Chenopodium Bonus-Henricus). The seeds of others are nutri-
tious; and several contain volatile oil, which renders them
anthelmintic, antispasmodic, aromatic, carminative, or stimu-
lant.

Order 4. BaseLLace®, the Basella Order.—Diagnosis.—
DICOTYLEDONES—MONOCHLAMYDEE 237

This is a small.order of climbing herbs or shrubs closely allied
to Chenopodiacee, but chiefly distinguished by its plants having
two rows of coloured sepals, and by their stamens being evi-
dently perigynous. There are about 12 species, all of which
are tropical plants. This is made a sub-order of Chenopodiacee
by Bentham and Hooker.

Properties and Uses.—Basella rubra and B. alba are used in
the East Indies as a substitute for Spinach. From the former
species a purple dye may be also obtained. The fleshy roots of
Ullucus tuberosus or Melloca tuberosa are largely used in Peru
and some of the adjoining countries as a substitute for the
Potato.

Order 5. Puytouaccacem, the Phytolacca Order.—C ha -
racter.—Herbs or undershrubs. Leaves alternate, entire, ex-
stipulate. Flowers hermaphrodite or very rarely unisexual,
racemose. Calyx 4—5-partite. Stamens nearly or quite hypo-
gynous, either equal in number to the divisions of the calyx
and alternate with them, or more numerous; anthers 2-celled.
Ovary superior, composed of 2 or more carpels, distinct or more
or less combined ; styles and stigmas distinct, equal in number
to the carpels. Fruit dry or succulent, each carpel of which it
is composed containing 1 ascending seed ; embryo curved round
mealy albumen ; radicle next the hilum.

Distribution and Numbers.—Natives principally of America,
India, and Africa. Illustrative Genera :—Giesekia, Linn. ; Phy-
tolacca, Towrn. There are about 80 species.

Properties and Uses.—An acrid principle is more or less dif-
fused throughout the plants of this order; but this is frequently
destroyed by boiling in water. Some are emetic and purgative.

Order 6. Prritvertacea#, the Petiveria Order.—Diagnosis,
&c.—This is a small order of plants, which is included by some
botanists, as Bentham and Hooker, in Phytolaccacee, with
which it agrees in many particulars. It is distinguished from
that order by having stipulate leaves, an ovary formed of a
single carpel, exalbuminous seeds, and a straight embryo with
convolute cotyledons. These plants are natives of tropical
America. There are about 12 species in this order.

Properties and Uses.—Most of the species are acrid, and
some have a strong alliaceous odour.

Order 7. Batrpace®, the Batis Order.—This supposed dis-
tinct order only contains a single plant, the Batis maritima, a
succulent shrubby species, with opposite leaves, and unisexual
flowers arranged in amenta ; it is a native of the West Indies,
238 MANUAL OF BOTANY

where it is occasionally used as an ingredient in pickles. Its
ashes also yield barilla. Some authors regard this genus as
belonging to Chenopodiacez.

Order 8. Ponyaonacem, the Buckwheat Order.—Cha-
racter.—-Herbs or rarely shrubs. Leaves alternate, simple, com-
monly with ochreate stipules above the swollen joints (nodes) of
the stem, or rarely exstipulate. Flowers perfect, or sometimes
unisexual. Calyx inferior of from 3—6 sepals, more or less per-
sistent, imbricate. Stamens few, hypogynous or rarely peri-
gynous ; anthers dehiscing longitudinally. Ovary superior,
1-celled ; styles and stigmas 2—3; ovule solitary, orthotropous.
Fruit usually a triangular nut, and commonly enveloped in the
persistent calyx. Seed solitary, erect; generally with farina-
ceous alhumen.

Diagnosis.—Usually herbs with ochreate stipules. Leaves
simple, alternate. Calyx inferior, persistent, imbricate. Stamens
definite. Ovary 1-celled; styles and stigmas 2—3. Fruit

Fic. 997. Fie. 998.

Fig. 997. Flower of
a species of Polygo-
num—Fig. 998.
Pistil of a species
of Rumex.

  

triangular. Seed solitary, erect, usually with mealy albumen,
radicle superior.

Distribution and Numbers.—Generally diffused over the
globe, and more particularly so in temperate regions. Illus-
trative Genera :—Rheum, Linn.; Polygonium, Linn. ; Coceo-
loba, Jacg.; Rumex, Linn. There are about 500 species.

Properties and Uses.—Chiefly remarkable for the presence
of acid, astringent, or purgative properties. The acidulous
character is principally due to the presence of salts of oxalic
acid. The fruits and roots of several species are more or less
nutritious.

Series 2.—_Multiovulate aquatica.

Order 9. PopdostEMAcEz%, the Podostemon Order.—
Character.—Aquatic herbs with the aspect of Mosses or
Liverworts. Leaves minute and densely imbricate, or finely
DICOTYLEDONES—MONOCHLAMYDEA 239

divided. Flowers minute, generally hermaphrodite, or very
rarely unisexual, spathaceous. Calyx absent, or of 3 sepals.
Stamens 1 or many, hypogynous; anthers 2-celled. Ovary
superior, 2—3-celled ; stigmas 2—8; ovules ascending, numerous.
Fruit capsular, ribbed, with parietal or axile placentation. Seeds
numerous, exalbuminous, with a straight embryo.

Distribution and Numbers.—Principally natives of South
America. Illustrative Genera :—Hydrostachys, Thouars ; Podo-
stemon, L. C.R. There are about 120 species.

Properties and Uses.—Unimportant. Some species of Lacis
are used for food on the Rio Negro, &c., in South America;
and other plants of the order are eaten by cattle and fish.

Series 3.—Multiovulate terrestres.

Order 10. NeEPENTHACES, the Pitcher-plant Order.—Cha-
racter.—Herbs or somewhat shrubby plants. Leaves alternate,
and when perfect, terminated by a pitcher which is provided with
an articulated lamina. Flowers terminal, racemose, unisexual,
diecious. Calyx inferior, with four divisions. Stamens usually
16, united into a column; anthers 2-celled, extrorse. Ovary
superior, 4-angled, 4-celled. Fruit a capsule, 4-celled, with
loculicidal dehiscence. Seeds very minute, numerous, albu-
minous ; embryo with an inferior radicle.

Distribution, Numbers, and Properties.—Natives of swampy
ground in China and the East Indies. Nepenthes, Linn., is the
only genus; it includes about 14 species. Their properties are
unknown ; but they are remarkable from their pitchers entrap-
ping and digesting insects and other animal matters, in conse-
quence of the formation of a digestive ferment by their glands.

Order 11. Cyvtnaces, the Cistus-rape Order.—Character.
—Root-parasites destitute of chlorophyll, and with a fungoid
texture. Flowers hermaphrodite or unisexual, and either soli-
tary and sessile or clustered at the end of a scaly stem. Calyx
tubular at the base, 3—6-partite. Anthers sessile, opening
longitudinally. Ovary 1-celled, inferior; ovules very nume-
rous; placentas parietal. Fruit 1-celled, with numerous seeds
embedded in pulp. Seeds with or without albumen; embryo
minute, amorphous or dicotyledonous. This and the next order
are frequently combined together in one order, Cytinacee.

Distribution and Numbers.—Parasitic on the roots of Cistus,
and upon fleshy Euphorbiacee and other succulent plants.
They oceur in the South of Europe and Africa. Illustrative
240 MANUAL OF BOTANY .
Genera :—Cytinus, Linn.; Hydnora, Thunb. There are about
7 species.

Properties and Uses.—Some have astringent properties, as
Cytinus Hypocistis. A kind of extract is made from this
plant in the South of Europe, and used, under the name of
Succus Hypocistidis, in diarrhoea, and for arresting hemor-
rhage.—Hydnora africana has a putrid-animal odour, but when
roasted it is eaten by the native Africans at the Cape of Good
Hope.

Order 12. RaFrLEstacEm, the Rafilesia Order.---Charac-

ter.—Root-parasites, devoid of chloro-

Fic. 999. Fic. 1000. phyll, without evident stems or leaves,
and with a fungoid texture. These plants
consist essentially of flowers sessile upon
the branches of trees, and surrounded by
scaly bracts. The flowers are herma-
phrodite, or unisexual and dicecious.
Calyx 5-partite, tubular ; the throat sur-
rounded by a number of thickened scaly
processes, which are either distinct from
each other or unitedintoaring. Anthers
placed upon » column which adheres to
the calyx, 2-celled; and either distinct,
and each opening by a pore, or united
into a many-celled body, and opening by
a common pore. Ovary 1-celled, inferior ;
ovules very numerous ; placentas parietal.
Fic. 1001. Fruit indehiscent. Seeds very numerous,

Pig. 999. Vertical section With or without albumen ; embryo amor-
of the flower of thecom- phous or dicotyledonous. This order, as

i ti istolo- . . . *
ee mentioned above, is sometimes included

 

1000, The gynwcium 47 Cytinacea.
foreplay oe Distribution and Numbers.—Parasitic
pees section of  ypon the stems of Cissiin the East Indies,
and on Leguminous plants in South
America. Illustrative Genera :—Rafflesia, R. Br. ; Brugmansia,
Blum. There are about 16 species.

Properties and Uses.—Some have styptic and astringent
properties. They are chiefly remarkable for their flowers, some
of which are‘of gigantic size.

Order |18. ArtsToLocHIAcE®, the Birthwort Order.—Cha-

‘yacter.—Herbs or climbing shrubs. Leaves alternate. Flowers
axillary, hermaphrodite, dull-coloured, regular or irregular.
DICOTYLEDONES—MONOCHLAMYDEA 241

Calyx tubular, superior, with a valvate estivation. Stamens
6—12, arising from the top of the ovary, and more or less
attached to the style; anthers adnate, extrorse. Ovary inferior,
3—6-celled with numerous ovules; style simple; stigmas
radiating, and corresponding in number to the cells of the ovary.
Fruit capsular or succulent, 3—6-celled. Seeds numerous,
albuminous ; embryo very minute.

Distribution and Numbers.—Sparingly distributed in several
parts of the world, but most common in tropical South America.
Illustrative Genera :—Asarum, Tourn. ; Pa Tourn.
There are about 180 species.

Properties and Uses.—These plants contain a ‘bitter prin-
ciple and a volatile oil, and generally possess tonic, stimulant,
and acrid properties. Many of the species are regarded in
various parts of the world as useful in the treatment of snake-
bites.

Series 4.—Micrembryee.

Order 14. PreERAcE®, the Pepper Order.—Character.—
Herbs or shrubs with jointed stems. Leaves opposite, whorled,
or alternate, and with or without stipules. Flowers spiked,
hermaphrodite or sometimes unisexual, achlamydeous, brac-
teate. Stamens 2 or more; anthers 1—2-celled. Ovary
simple, 1-celled, with one erect orthotropous ovule; stigma
sessile. Fruit more or less fleshy, 1-celled, 1-seeded. Seed
erect; embryo embedded in endosperm at the apex of the seed,
and on the outside of abundant perisperm.

Distribution and Numbers.—Natives exclusively of tropical
regions, especially in America and the islands of the Indian
Archipelago. Illustrative Genus :—Piper, Linn. There’ are
above 600 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for acrid, pungent, aromatic, and stimulant pro-
perties. These qualities are principally found in their fruits, and
are essentially due to the presence of an acrid volatile oil and
resin. Some are narcotic, and others are reputed to be astrin-
gent and febrifugal.

Order 15. SauRuRACEa, the Saururus Order.—Character,
—Marshy herbs. Leaves entire, alternate, stipulate. Flowers
spiked, achlamydeous, hermaphrodite. Stamens 3—6, hypogy-
nous, persistent. Ovaries 3—4, usually more or less distinct,
and each with a solitary erect ovule, or sometimes united and
with a few ascending ovules. Fruct either consisting of 4

VoL. Il. R
249, 7 “MANUAL OF BOTANY

fleshy indehiscent acheznia, or capsular and 3—4-celled. Seeds
ascending, with « minute embryo in fleshy endosperm on the
outside of hard mealy perisperm, This order is included by
Bentham and Hooker in Piperacee as the tribe Saururea.

Distribution and Numbers.—Natives of North America,
Northern India, and China. Illustrative Genera :—Saururus,
Linn.; Houttuynia, Thunb. There are about 7 species.

Properties and Uses.—They have acrid properties, and are
reputed to be emmenagogue. Some are also astringent.

Order 16. CHLoRANTHACER, the Chloranthus Order.—
Character.—Herbs or undershrubs with jointed stems, which
are tumid at the nodes. Leaves simple, opposite, sheathing,
with small interpetiolar stipules. lowers in terminal spikes,
achlamydeous, -with scaly bracts, hermaphrodite or unisexual.
Stamens 1, or more and united. Ovary 1-celled with a solitary
pendulous ovule. Fruit drupaceous. Seed pendulous, with a
minute embryo at the apex of fleshy endosperm; radicle
inferior. :

- Distribution and Numbers.—Natives of tropical regions.
Illustrative Genera :—Hedyosmum, Swartz; Chloranthus,
‘Swartz. -There are about 15 species.

Properties and Uses.—Aromatic stimulant properties are the
principal characteristics of the plants of this order.

Order 17. Mynisticacrm, the Nutmeg Order.—Character.
—Trees. Leaves alternate, exstipulate, entire, dotted, stalked,
leathery. Flowers unisexual. Calyax inferior, leathery, 8—4-
cleft; in the female flower, deciduous; estivation valvate.
Male flower with 83—12 stamens, or rarely more numerous;
filaments distinct or monadelphous; anthers 2-celled, extrorse,
distinct or united, with longitudinal dehiscence. Female flower
with 1 or many superior distinct carpels, or rarely 2; each
carpel with 1 erect ovule. Fruit succulent. Seed arillate,
with copious oily-fleshy ruminated albumen; embryo small,
with an inferior radicle.

Distribution and Numbers.—Natives of tropical India and
America. Illustrative Genera :—Myristica, Linn.; Hyalo-
stemma, Wall. There are above 40 species.

Properties and Uses.—Aromatic properties are almost uni-
versally found in the plants of this order, and more especially
‘in their seeds. The bark and the pericarp are frequently acrid.

Order 18. Mowimtacez, the Monimia Order.—Diagnosis.—
Trees or shrubs, with opposite exstipulate leaves. Flowers
axillary, unisexual. The flowers generally resemble those of the
DICOTYLEDONES—MONOCHLAMYDEA 243

Atherospermacee, but they differ in always being unisexual;
in the longitudinal dehiscence of their anthers; in the absence
of feathery styles to the fruit; and in their ovules and seeds
being pendulous. :

Distribution and Numbers.—They are principally natives of
South America, but are found also in Australia, J: ava, Mada-
gascar, Mauritius, and New Zealand. Illustrative Genera :—

’Monimia, Thowars ; Peumus, Pers. There are about 40 species.

Properties and Uses.—They are aromatic fragrant plants, but
their properties are of no great importance.

Order 19. ATHEROSPERMACER, the Plume Nutmeg Order.—
Character.—Trees, with opposite exstipulate leaves. Flowers
axillary, racemose, bracteate, unisexual or rarely perfect.
Calyx inferior, tubular, with several divisions. Male flowers
with numerous perigynous stamens;
anthers 2-celled, opening by recurved Fic. 1002.
valves. Female flowers usually with
abortive scaly stamens. Carpels superior,
numerous, distinct, each with a solitary
erect ovule; styles and stigmas as many
as the carpels. Fruit consisting of a ()
number of achzenia crowned with the per-
sistent feathery styles, and enclosed in
the tube of the calyx. Seeds erect, witha
minute embryo at the base of fleshy albu- Fig. 1002, Vertical section

; : 3 e of the female flower of
men. This order is combined with Zaurus nobilis, the Sweet
Monimiacea by Bentham and Hooker. Bay.

Distribution and Numbers.—Natives
of Australia and Chili. There are but 3 genera: namely, Athero-
sperma, Labill., and Doryphora, Hndl., from Australia; and
Laurelia, Juss., from Chili. These include four species.

Properties and Uses.—They are fragrant plants. The
achenia of Laurelia somewhat resemble common Nutmegs in

their odour.

Series 5.—Daphnales.

Order 20. Lauracem, the Laurel Order.—Character.—
Aromatic trees or shrubs (parasitic and twining in Cassytha).
Leaves simple, exstipulate, usually alternate, sometimes dotted
(Cassytha has scales instead of foliage leaves). Flowers generally
hermaphrodite or sometimes unisexual. Calyx inferior, deeply
4—6-cleft, coloured, in two whorls, the limb sometimes obsolete ;

estivationimbricate. Stamens perigynous, definite, some always
: R2
244 MANUAL OF BOTANY

sterile ; filaments distinct, the inner ones commonly with glands
at their base; anthers adnate, 2—4-celled, 1, 1, dehiscing by
recurved valves, v. Ovary superior, 1-celled, with 1 or 2 sus-
pended ovules.. Fruit baccate or drupaceous. Seeds exalbu-
minous; embryo with large cotyledons, and a superior radicle.

Distribution and Numbers.—They are chiefly natives of
tropical regions, but a few occur in North America, and one
(Laurus nobilis) in Europe. Illustrative Genera :—Cinnamo-
mum, Burm.; Nectandra, Rottb.; Laurus, Towrn. There are
above 456 species.

Properties and Uses.—The plants of this order are aliens
universally characterised by the possession of aromatic pro-
perties, which are due to the presence of volatile oils; many of

them are therefore employed as aromatic

Fig. 1003. stimulants. Others are narcotic ; some have
sudorifie properties; and several are tonic,
stomachic, febrifugal, or astringent. A few
have edible fruits, and many yield valuable
‘timber.

Order 21. Proteacea, the Protea Order.
—Character.—Shrubs or small _ trees.
Leaves hard, dry, opposite or alternate, exsti-
pulate. Flowers usually hermaphrodite.
Calyx inferior, 4-partite or of 4 sepals; estz-

vation valvate. Stamens perigynous, equal in
Fig. 1003. Vertical number to the partitions of the calyx and
section of the flow-
er of a species of opposite to them; anthers bursting longi-
Daphne: tudinally. Ovary simple, superior, 1-celled,
with 1 or more ovules, ascending or sus-
pended. Fruit dehiscent or indehiscent. Seeds exalbuminous ;
embryo straight, radicle generally inferior.

Distribution and Numbers.—Natives chiefly of Australia and
the Cape of Good Hope. Illustrative Genera :—Protea, Linn. ;
Banksia, Linn. fil. There are more than 600 species.

Properties and Uses.—They are chiefly remarkable for the

beauty or singularity of their flowers and their evergreen foliage.
= But the fruits and seeds of some species are caten; and the
wood is largely employed at the Cape and in Australia for burn-
ing, and occasionally for other purposes; thus, that of Protea
grandiflora is used at the Cape of Good Hope for wagon-
wheels, hence the plant is named Wagenboom. The seeds of
Macadamia ternifolia, a native of Queensland, are edible.
Order 22. THymutaces, the Mezereon Order.—Character.

 
DICOTYLEDONES—MONOCHLAMYDEA 245

—Trees, shrubs, or very rarely herbs, with an acrid very tough
bark. Leaves entire, exstipulate. Flowers hermaphrodite
or rarely unisexual. Calyx inferior, regular, coloured, tubular,
4—5-lobed ; estivation imbricate. Stamens perigynous, twice
as many as the divisions of the calyx, or equal in number to them,
or fewer, in the two latter cases they are opposite to the lobes of
the calyx; anthers 2-celled, bursting longitudinally. Ovary
superior, simple, 1-celled, with a solitary suspended ovule.
Fruit dry and nutlike, or drupaceous. Seed suspended: albu-
men none or but small in quantity; embryo straight, with a
superior radicle.

Distribution and Numbers.—They are found more or less
abundantly in all parts of the world, but especially in Australia
and the Cape of Good Hope. Jilustrative Genera :—Daphne,
Linn.; Pimelea, Banks et Sol. There are about 300 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for the toughness and acridity of their bark. The
fruit of Dirca palustris is narcotic, and that of the plants
generally of the order poisonous or suspicious; but the seeds of
Inocarpus edulis are said to resemble Chestnuts in flavour when
roasted. Several species of Daphne, Pimelea, and other genera,
are handsome shrubby plants.

Order 23. AQUILARIACER, the Aquilaria Order.—Charac-
ter.—Trees with entire exstipulate leaves. Calyx tubular or
top-sbaped, 4—5-lobed, imbricate, persistent. Stamens perigy-
nous, 10, 8, or 5, opposite the lobes of the calyx when equal to
them in number ; anthers 2-celled, opening longitudinally. Ovary
superior, usually 2-celled; ovwles 2, suspended ; or rarely 1-celled
with parietal placentation. Frutt generally 2-valved, capsular,
sometimes succulent and indehiscent. Seeds usually 2, or rarely
1 by abortion ; exalbuminous. This order is sometimes included
in Thymelacee.

Distribution and Numbers.—Natives exclusively of tropical
Asia. Illustrative Genera :—Aquilaria, Lam.; Leucosmia,
Benth. There are about 10 species.

Properties and Uses—Some species yield a fragrant stimu-
lant resin.

Order 24. Prenmacem, the Penea Order.—Character.—
Evergreen shrubs, with opposite, exstipulate, imbricate leaves.
Flowers hermaphrodite. Calyx inferior, bracteate, 4-lobed ;
estivation valvate or imbricate. Stamens perigynous, 4 or 8,

-alternate with the divisions of the calyx when equal to them in
number. Ovary superior, 4-celled; style 1; stigmas 4, with
246 MANUAL OF BOTANY

appendages on one side. Fruit 4-celled, dehiscent or inde-
hiscent. Seeds varying in position, exalbuminous ; embryo with
very minute cotyledons.

This order is sometimes placed near Proteaceae, but it 1s espe-
ctally distinguished from that order by its 4-celled ovary and 4-
celled fruit.

Distribution and Numbers.—They are only found at the Cape
of Good Hope. Illustrative Genera :—Penea, Linn.; Geisso-
loma, Lindl. There are over 20 species.

Properties and Uses.—Unimportant.

Order 25. ELmaGNnacEa, the Oleaster Order.—C haracter.—
Small trees or shrubs, with entire exstipulate usually very scurfy
leaves. Flowers mostly unisexual or rarely perfect. Male
flowers amentaceous, bracteate. Sepals 2—4, distinct or united.
Stamens definite perigynous. Female flowers with an inferior
tubular calyx, and a fleshy disk; estivation imbricate. Ovary
superior, 1-celled, with a solitary ascending ovule. F'rutt enclosed -
in the succulent calyx, indehiscent. Seed solitary, ascending,
with thin albumen; embryo straight, with an inferior radicle.

Distribution and Numbers.—-They are generally diffused
throughout the northern hemisphere, and rare in the southern,
Illustrative Genera :—Hippophaé, Linn.; Eleagnus, Linn.
There are about 30 species.

Properties and Uses.—Unimportant. The fruits of Hl@agnus
orientalis are esteemed in Persia under the name of zinzeyd;
and those of #. arborea, EH. conferta, and others are eaten in
certain parts of India. Those also of Hippophaé rhamnoides,
the Sea-Buckthorn, which is a native of England, are also
edible, and have been employed in the preparation of a sauce
for fish, but their use requires caution from containing a narcotic
principle.

‘Series 6.—Achlamydosporee.

Order 26. LoranTHACES, the Mistletoe Order.—-Charac-
ter.—Parasitic shrubs. Leaves greenish, commonly opposite,
exstipulate. Flowers hermaphrodite, or unisexual and dicecious.
Calyx superior, with 4—8 divisions; estivation valvate ; some-
times absent. Stamens opposite to the lobes of the calyx and
equal tothem innumber. Ovary inferior, 1-celled, with 8 ovules,
suspended from a free-central placenta, or 1 erect and arising
from the base of the ovary. Ovules without integuments.
Fruit commonly succulent, 1-celled, with a solitary seed ; embryo
in fleshy albumen, with the radicle remote from the hilum.
DICOTYLEDONES—MONOCHLAMYDEA 247

Distribution and Nwmbers.—They are principally found in
the hotter parts of America and Asia. Three species are natives
of Europe, and a few occur in Africa and some other regions.
Illustrative Genera :—Myzodendron, Sol.; Viscum, Towrn.;
Loranthus, Linn. There are above 400 species.

Properties and Uses.—Unimportant. Some are astringent.

Order 27. SantTaLacres, the Sandal-wood Order.—Charac-
ter.—Herbs, shrubs, or trees. Leaves entire, alternate. Flowers
usually hermaphrodite. Calyx superior, 4—5-cleft, valvate in
estivation. Stamens perigynous opposite to the segments of the
calyx and equal to them in number. Ovary 1-celled, inferior ;
ovules 1—4, without integuments ; placentatfree-central. Fruit
indehiscent, 1-seeded. Seed with a quantity of fleshy albumen ;
embryo straight, minute ; radicle superior.

Distribution and Numbers.—Natives of various parts of the
world. The species found in North America and Europe are
inconspicuous herbs; those of India, Australia, &c., are trees
or shrubs. The genus Thesiwm is partially parasitic on the
roots of other plants. Illustrative Genera :—Thesium, Linn. ;
Santalum, Linn. There are about 120 species.

Properties and Uses.—Some of these plants, as Thesium, are
slightly astringent; others have a fragrant wood; and a few
produce edible fruits and oily seeds.

Order 28.- BALANoPHORACEx, the Balanophora Order.—
Character.—Leafless root-parasites with amorphous fungoid
stems of various colours, but never green; and underground
more or less fleshy tubers or rhizomes. Peduneles naked or
scaly, bearing spikes of flowers, which are commonly unisexual,
bracteate, and of a white colour. Male flowers very evident,
each with a tubular calyx, which is either entire or 8—5-lobed.
Stamens usually 3—5, or sometimes 1, in the former case more or
less united or distinct. Female flowers very minute, with a
tubular superior calyx, the limb either wanting or present and
bilabiate. Ovary inferior, usually 1-celled ; styles 2; ovule soli-
tary, pendulous. Fruit small, more or less compressed, in-
dehiscent. Seed solitary, albuminous, with a lateral undivided
or amorphous embryo.

Distribution and Numbers.—These plants are parasitical on
the roots of various Dicotyledonous plants, especially in the
tropical and sub-tropical mountains of Asia and South America.
Other species are found in different parts of Africa, Australia,
&e. Illustratwe Genera :—Cynomorium, Michel; Balanophora,
Forst. There are, according to Sir Joseph Hooker, 37 species.
248 MANUAL OF BOTANY

Properties and Uses.—Many are remarkable for their astrin-
gent properties; others are edible, as Ombrophytwm, a native of
Peru, and Lophophytwm of Bolivia ; and somne secrete a kind of
wax. :

Series 7.—Unisexuales.

Order 29. EupHorBiaces, the Spurge Order.—Character.
—Trees, shrubs, or herbs, usually with an acrid milky juice.
Leaves alternate or opposite, simple or rarely compound,
stipulate or exstipulate. Flowers unisexual, monececious, or
dicecious, axillary or terminal, sometimes enclosed in a calyx-
like involucre ; achlamydeous, or with a lobed inferior calyx
having on its inside glandular or scaly appendages, or even

Fie. 1004. Fie. 1005.

 

Fig. 1004. Moneecious head of flowers of a species of Luphorbia. 7. Invo-
luere, a portion of which has been removed in front. g, g. Glands on the
divisions of the involucre. 6, b. Scales or bractlets at the base of the flowers.
fm, fm. Male flowers, each consisting of a stamen supported on a pedicel,
to which it is articulated. 7. Female flower, supported ona stalk. From
Jussieu.—-Fig. 1005. Vertical section of the pericarp and seed of a carpel
(coccus) of a species of Luphorbia.

evident petals, which are either distinct or united. Male
flowers consisting of 1 or more stamens, distinct or united into
one or more bundles; anthers 2-celled. Female flowers with a
superior ovary, which is either elevated upon a stalk or sessile,
1. 2- 3- or many-celled; styles either absent or corresponding
in number to the cells of the ovary, entire or divided; stigmas
equal in number to the cells of the ovary, or, when the styles
are divided, corresponding in number to their divisions; ovules
1 or 2 in each cell, suspended from the inner angle. Fruit
either dry, and its component carpels then separating from each
other and from the axis and usually opening with elasticity ; or
succulent and indehiscent. Seeds 1 or 2 in each cell, suspended,
DICOTYLEDONES— MONOCHLAMYDEA 249

often carunculate; embryo straight, in fleshy albumen, with
flattened cotyledons, and a superior radicle.

Diagnosis.—Herbs, shrubs, or trees, commonly with an
acrid milky juice. Flowers unisexual, monecious or diccious.
Calyx absent, or present and inferior. Petals rarely present.
Male flowers with one or more stamens, distinct or united, and
2-celled anthers. Female flowers with a superior, sessile or
stalked, 1- or more-celled ovary, and with 1 or 2 suspended_
ovules in each cell. Fruit of 1, 2, 3, or many dry carpels,
which separate from the axis and from each other, and usually
open with elasticity; or fleshy and indehiscent. Seeds sus-
pended; embryo in fleshy albumen, straight, with flattened
cotyledons, and a superior radicle.

Distribution and Numbers.—They are more or less distri-
buted over the globe, and are especially abundant in equinoctial
America. Illustrative Genera :—Euphorbia, Linn. ; Mercurialis,
Linn.; Ricinus, Tourn.; Buxus, Tourn. There are above
2,500 species.

Properties and Uses.—These plants generally contain an
acrid poisonous principle or principles, which is found more or
less in all their parts. Some are very deadly poisons. But in
proper doses many are used medicinally as emetics, purgatives,
diuretics, or rubefacients. A pure starch, which is largely em-
ployed for food, may be obtained from some plants of the order,
while india-rubber may be procured from the milky juice of
others. A few are entirely devoid of any acrid or poisonous
principle, and are used medicinally as aromatic tonics. Some
have edible roots; others yield dyeing agents; and several are
valuable on account of their wood.

Order 30. Scrpaces, the Scepa Order.—Diagnosis.—This
order is closely allied to Euphorbiacee, in which it is included
by Bentham and Hooker, but from which it is readily distin-
guished by its flowers being amentaceous.

Distribution, Numbers, and Properties.—Natives of the East
Indies. There are 6 species. The wood of Scepa (Lepidostachys)
Roxburghit is called Cocus or Kokra. It is very hard, and is
chiefly employed for flutes and similar musical instruments.

Order 31. StILacinaces, the Stilago Order.—Character.
—Trees or shrubs. Leaves alternate, simple, leathery, with
deciduous stipules. Flowers minute, unisexual, in scaly spikes.
Calyx 2—5-partite. Male flowers consisting of 2 or more
stamens on an enlarged thalamus ; anthers usually 2-lobed, with
a fleshy connective, and dehiscing transversely at the apex.
250 MANUAL OF BOTANY

Female flowers with a superior 1—2-celled ovary, each cell with
2 suspended ovules. Fruit drupaceous. Seeds suspended, albu-
minous ; embryo straight, with leafy cotyledons, and a superior
radicle. This order is made a tribe of Huphorbiacee by Bentham
and Hooker. ;

Distribution and Numbers.—Natives of Madagascar and the
East Indies. Illustrative Genera :—Stilago, Linn. ; Falconeria,
Royle. There are about 20 species.

Properties and Uses.—Unimportant. The fruits of Antidesma
pubescens and Stilago Bunias are subacid and agreeable.

_ Order 32. Urticacem, the Nettle Order.—Character.—
Herbs, shrubs, or trees, with a watery juice. Leaves opposite
or alternate, usually rough or with stinging glands; stipulate

Fie. 1006. Fic. 1007.

  

Fig. 1006. Male flower of the Small Nettle (Urtica wrens). c. Calyx. e,e,
e, e. Stamens, with 2-celled anthers. pr. Rudimentary ovary.——Tiy.
1007. Vertical section of the evary of the female flower of the same.
p. Wallof the ovary. s. Stigma. o, Ovule. .

or rarely exstipulate. Flowers small, unisexual (fig. 1006) or
rarely hermaphrodite, scattered or arranged in heads or cat-
kins. Calyx inferior, lobed, persistent. Male flower with a few
distinct stamens, perigynous, opposite the divisions of the calyx,
and with a rudimentary ovary; filaments at first incurved.
Female flower with a superior 1-celled ovary ; ovule erect, ortho-
tropous. Fruit indehiscent, surrounded by the persistent calyx.
Seed solitary, erect ; embryo straight, enclosed in albumen ; and
with a superior radicle.

Bentham and Hooker, in ‘ Genera Plantarum,’ include the
four succeeding orders—Moracee, Cannabinacee, Artocar-
pacea, and Ulmacea—in Urticacea, as sub-orders.

Distribution and Numbers.—These plants are more or less
distributed over the world. Illustrative Genera :—Urtica,
DICOTYLEDONES—MONOCHLAMYDEZ 251

Tourn.; Parietaria, Tourn. The order contains more than 300
species.

Properties and Uses.—Chiefly remarkable for yielding valu-
able fibres, and for the acrid stinging juice contained in their
glands.

Order 33. Moracra, the Mulberry Order.—Character.—
Trees or shrubs with a milky juice. Leaves with large stipules.
Flowers unisexual, in heads, spikes, or catkins. Male flowers
with a 3—4-partite calyx, or achlamydeous. Stamens 3—4,
perigynous, and opposite the segments of the calyx; anthers
usually inflexed. Female flowers with 8—5 sepals. Ovary
superior 1—2-celled. F'rutt a sorosis or syconus. Seed solitary,
pendulous ; embryo hooked in fleshy albumen, and with a supe-
rior radicle.

Distribution and Numbers.—They are natives of both hemi-
spheres, and occur in temperate
and tropical climates. Illwstra- Fie. 1008. Fic. 1009.
tive Genera :—Morus, Tourn. ;
Dorstenia, Plum. There are
over 200 species.

Properties and Uses.—The
milky juice of some species pos-
sesses acrid and poisonous pro-
perties, while in others it is
bland, and may be taken as a rig. 1008. Male flower of the Black

 

1 iui Mulberry (Morus nigra).—lfvy.
beverage. From the milky jalee 1009. Vertical section of the ovary
of some caoutchouc or india- of the female flower of the same.

rubber is obtained. The inner

bark of other species supplies fibres. Some possess stimulant,
sudorific, tonic, or astringent properties. Many yield edible
fruits, while the seeds generally of the plants of this order are
wholesome.

Order 84. CANNABINACES, the Hemp Order.—-Character.
—Rough herbs, erect or twining, with a watery juice. Leaves
opposite or alternate, simple or compound, stipulate, often
glandular. Flowers small, unisexual, dicecious. Male flowers
in racemes or panicles. Calyx scaly, imbricate. Stamens 5, op-
posite the sepals; filaments filiform. Female flowers in spikes
or strobiles, each flower with 1 sepal surrounding the ovary,
which is superior and 1-celled, and containing a solitary pen-
dulous campylotropous ovule. Fruit dry, indehiscent. Seed
solitary, pendulous, without albumen ; embryo curved or spirally
coiled, with a superior radicle.
252 MANUAL OF BOTANY

Distribution and Numbers.—Natives of the temperate parts
of the northern hemisphere in Europe and Asia. Idlustrative
Genera :—Cannabis, Tourn.; Humulus, Linn. These are the
only genera, and each contains but one species.

Properties and Uses.—The plants of this order yield valuable
fibres and possess narcotic, stomachic, and tonic properties.

Order 35. ArvrovaRPacum®, the Bread-fruit Order.—Cha-
racter.—Trees or shrubs with a milky juice. Leaves alternate,
simple, with large convolute stipules. Flowers unisexual, in
dense heads on a fleshy receptacle. Male flowers achlamy-
devus, or with a 2—4-lobed or 2—4-sepaled calyx. Stamens’
: opposite the lobes of the calyx
or to the sepals; anthers
erect. Female flowers ar-
ranged on a fleshy receptacle
of varying form. Calyx in-
ferior, tubular, 2—4-cleft or
entire. Ovary superior, 1-
celled. Fruit commonly a
sorosis. Seed erect or pen-
dulous, with little or no albu-
men; embryo straight, with
a superior radicle.

Distribution and Num-
bers. — Exclusively tropical
plants. Illustrative Genera :
Antiaris, Leschen.; Artocar-
pus, Linn. There are about
Fig. 1010. Branch of the Bread-fruit tree 60 species.

(Artocarpus incisa). a,c. Heads of = Properties and Uses.—
female or pistillate flowers. 0. Head 7 i
of staminate or male flowers. The milky juice of several
species yields india-rubber.
This juice is in certain cases poisonous, while in others it forms
a nutritious beverage. A few yield valuable timber. The fruits
of gome are edible, and the seeds generally of plants of this order
are wholesome.

Order 36. ULMAcEm, the Elin Order.—Character.— Trees
or shrubs with a watery juice. Leaves alternate, simple,
scabrous, with deciduous stipules. Flowers hermaphrodite or
unisexual, in loose clusters. Calyx inferior, membranous, im-
bricate. Stamens perigynous, definite; anthers erect. Ovary
superior, 1—2-celled ; styles or stigmas 2. Fruit indehiscent,
samaroid or drupaceous, 1—2-celled. Seeds solitary, pendulous,

Fie. 1010.

 
DICOTYLEDONES—MONOCHLAMYDEA 253

with little or no albumen; embryo straight; cotyledons folia-
ceous ; radicle superior. ;

Division of the Order and Tilustrative Genera.—This

_order may be divided into two sub-orders or tribes as follows :—
Sub-order 1. Celtee@—Ovary 1-celled, with drupaceous fruit.
Illustrative Genera :—Celtis, Tourn. ; Mertensia, H. B. K.
Sub-order 2. Ulmee.—Ovary 2-celled, Fie. 1011.
with usually samaroid fruit. I1-
lustrative Genera :—Planera,
Gmel.; Ulmus, Linn.

Distribution and Numbers.—They
are chiefly natives of the northern
regions of the world. There are about
60 species.

Properties and Uses.—Some are
valuable timber trees. The bark and
fruit of others are bitter, tonic, and
astringent; and a few possess aromatic
properties.

Order 37. PLATANACES, the Plane
Order.—Character. — Trees with a
watery juice. Leaves alternate, pal-
mately lobed, with deciduous sheathing
stipules. Flowers unisexual, mone-
cious in globular amentaceous heads ;
achlamydeous. Male flowers with 1
stamen and a two-celled linear anther.
Female flowers consisting of a 1-celled
ovary and a thick style; ovules 1—2,
pendulous. Fruits arranged in a com-

. pact rounded head, consisting of clavate
achenia with persistent styles. Seeds
1 or rarely 2, pendulous; embryo
straight, in very thin albumen, with an Fig. 1011. Branch of the Plane

_ inferior radicle. ally dinenbecedus Weds

Distribution and Numbers.—They of _achlamydeous female
arenatives principally of North Ame- pe
rica and the Levant. Platanus, Linn., is the only genus, of
which there are 5 or 6 species. .

Properties and Uses.—Of no particular importance, except
that, from their being large handsome trees, and flourishing well
in large towns, they are commonly planted in our parks and
squares. The leaves closely resemble in appearance those of

 
254 MANUAL OF BOTANY

‘the Sycamore tree. The timber is sometimes used by the
cabinet-maker. /

Order 88. JUGLANDACER, the Walnut Order.—C haracter.—
Trees. Leaves alternate, pinnate, exstipulate. Flowers unisexual.
‘Male flowers in amenta; with an irregular calyx, or « simple
‘scale. Female flowers solitary, or in small terminal elusters, or

amenta, without a cupule; calyx superior, regular, 3—5-lobed ;
ovary inferior, 2—4-celled at the base, 1-celled above; ovule
solitary, erect, orthotropous. Fruit called a tryma. Seed
2—4-lobed, exalbuminous ; embryo with sinuous oily cotyledons,
and a short superior radicle.

Distribution and Numbers.—Chiefly natives of North

America, but a feware found in the East Indies, Persia, and the

Fie. 1012. ‘Fie. 1013.

 

Fig. 1012. Staminate amentum
of the Walnut tree (Juglans
regia): the flowers are se-
parated by scaly bracts.——
Fig. 1013. Seed of the Wal-
nut tree.

 

Caucasus. Juglans regia, the Walnut tree, is a native of the
countries between Greece and Cashmere. Illustrative Genera:
—Juglans, Linn.; Carya, Nutt. There are about 30 species.

Properties and Uses.—Chiefly important for their valuable

’ timber, and for their oily edible seeds.

Order 89. Myricacem, the Bog-myrtle Order—C haracter.
Shrubs or small trees, with alternate, simple, resinous-dotted
leaves, which are usually exstipulate. Flowers unisexual, amenta-
ceous, monecious or dicecious, both kinds of flowers in the
same or in different catkins. Male flowers achlamydeous;
stamens definite. Female flowers achlamydeous, with a 1-celled
sessile ovary, 2 styles, and 1 erect orthotropous ovule; fruit dru-
paceous; seed solitary, erect, without hairs; embryo without
albumen; radicle superior.
DICOTYLEDONES—MONOCHLAMYDE 255

Distribution and Numbers.—Natives of the temperate parts
‘of Europe and North America, and of the tropical regions of
South America, India, and the Cape of Good Hope. Illustra-
tive Genera :—Myrica, Linn.; Comptonia, Banks. There are
about 20 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for aromatic and astringent properties.

Order 40. CasuaRrinaces, the Beef-wood Order.—C harac-
ter.—Trees with pendulous, jointed, striated branches, without
evident leaves, but: sometimes having short toothed sheaths, re-
presenting whorls of leaves, at the nodes. Flowers in bracteate
spikes or heads, unisexual. Male flowers with 2 sepals united at

‘their points, and 2 alternating bracts; 1 stamen, and a 2-celled
“anther. Female flowers in dense spikes or heads, naked, but
each having 2 bracts; ovary 1-celled or rarely 2-celled, with 1—2
ascending ovules, and 2 styles. Fruits winged, indehiscent,

Fic. 1014. Fic. 1015. Fic. 1016.

  

Fig. 1014. Male flower of a species of Oak ( Quercus).——Fig. 1015. Female
flower of the same.— Fig. 1016. Transverse section of the female flower.
collected together into a cone-shaped body hidden under the

thickened bracts. Seeds exalbuminous; radicle superior.

Distribution and Numbers.—These plants are principally
natives of Australia. They are called Beef-wood trees from the
colour of their timber somewhat resembling that of raw beef.
In general appearance they much resemble the branched
Equisetine. Caswarina, Linn., is the only genus; it contains
about 32 species.

Properties and Uses.—The species of Casuarina yield very
hard and heavy timber, and the bark of some is said to be tonic
and astringent.

Order 41. CoRyLACE® or CUPULIFER, the Oak Order.—
Character.—Trees or shrubs. Leaves alternate, usually feather-
veined, simple, with deciduous stipules. Flowers moncecious.
Male flowers clustered or in amenta, and with or without bracts ;
stamens 5—20, inserted into the base of a membranous calyx,
or of scales or bracts. Female flowers solitary or amentaceous,
256 MANUAL OF BOTANY

and surrounded by an involucre of bracts, which ultimately
form a cupule round the ovary and fruit; ovary inferior, sur-
mounted by a rudimentary calyx, 3- or more-celled; ovules 2
in each cell or solitary, pendulous or peltate; stigmas almost
sessile. Fruit a glans or nut, 1-celled by abortion, more or less
enclosed by the cupule. Seeds large, 1 or 2, exalbuminous ;
cotyledons thick, fleshy or farinaceous ; ‘radicle superior.

Bentham and Hooker include the order Betulacex in the
Cupulifere, and divide the order as thus constituted into three
tribes as follows :—Tribe 1. Betulew. Tribe 2. Corylex. Tribe
3. Quercinex.

The Betulee are at once distinguished by their superior
ovary and the absence of a cupule from the two latter ; and the
Corylee from the Quercinee by the male flowers being achla-
mydeous, and having one ovule in each cell of the ovary; the
latter having a 3—T-lobed ovary, and 2 ovules in each cell.

Some authors, again, divide this order into two orders—
Corylacee and Cupulifere.

Distribution and Numbers.—They abound in the forests of
temperate regions, A few occur in the high lands of tropical
and hot climates. Illustrative Genera :—Carpinus, Tourn. ;
Corylus, Towrn.; Quercus, Tourn. There are nearly 300
species.

Properties and Uses.—Most important on account of their
valuable timber. Many yield edible seeds, and some have
highly astringent barks and cupules.

Order 42. Brtutaces, the Birch Order.—Character.—
Trees or shrubs. Leaves simple, alternate, with deciduous
stipules. Flowers small, unisexual, moncecious, amentaceous,
with no true calyx, but in its place small scaly bracts, which in
some cases are arranged in a whorled manner. Male flowers
with 2 or 8 stamens opposite the bracts. Female flowers witha
2-celled ovary, and 1 pendulous anatropous ovwle in each cell.
Fruit dry, thin, indehiscent, often winged, 1—2-celled, 1-seeded,
without a cupule. Seed pendulous, exalbuminous; embryo
straight ; ; radicle superior. Bentham and Hooker include this
order in Cupulifere as the tribe Betulea.

Distribution and Numbers.—They are principally natives of
the colder regions in the northern hemisphere. Illustrative
Genera :—Betula, Linn.; Alnus, Towrn. These are the only
genera : there are about 70 species.

Properties and Uses.—They are valuable for their timber,
and for their astringent, tonic, and febrifugal barks.
DICOTYLEDONES—MONOCHLAMYDEA 257

Series 8.—Ordines Anomali.

Order 42. Saticacrm, the Willow Order.— Character —
Trees or shrubs. Leaves simple, alternate, deciduous, with per-
sistent or deciduous stipules. Flowers unisexual, dicecious,
amentaceous, naked, or with a membranous or cup-like calyzx.
Male flowers with 1—30 stamens, distinct or monadelphous.
Female flowers sessile or stalked, with a superior 1-celled
ovary, and numerous erect anatropous ovules on 2 parietal pla-
centas. Fruit 1-celled, 2-valved, dehiscing loculicidally. Seeds
minute, numerous, with long silky hairs springing from a
funicle and covering the seed, ex-
albuminous; embryo erect, with an Fic. 1017. Fre. 1018,
inferior radicle.

Distribution and Numbers. —
Chiefly natives of cold and temperate
climates. Illustrative Genera :— Salix,
Tourn.; Populus, Tourn. These are
the only genera; there are about 250
species.

Properties and Uses. — Many
species are either valuable for their
timber, or for basket-work and other
economic purposes. The bark com-
monly possesses tonic, astringent, and iy. 1017. Male flower of a
febrifugal properties. The hairs which species of oS
invest the seeds have been employed single bract at their base.
for stuffing cushions, and for other Fae mens

. of the same with bract atthe
purposes. The buds of some species _ base, and a solitary stalked

: ‘ ovary and style surmounted
secrete an oleo-resinous substance of a by tivo stigmas.
stimulating nature.

Order 48. LactsteMacEa&.—The Lacistema Order.—Cha-
racter.—Shrubs. Leaves simple, alternate, dotted, stipulate.
Flowers in axillary catkins, perfect or unisexual. Calyx inferior,
with several divisions, enclosed by a bract. Stamen 1, hypogy-
nous, with a 2-lobed connective, each lobe bearing 1 cell of the
anther, which bursts transversely. Ovary superior, seated in uw
disc, 1-celled, with numerous ovules atéached to parietal pla-
centas. I*rutt capsular, 1-celled, 2—3-valved Seeds generally
2 or 3, arillate, suspended, with fleshy albumen.

Distribution, Numbers, and Properties.—Natives of woody
places in tropical America. Illustrative Genera :—There are
2 genera, namely, Lacistema, Swartz, and Synzyganthera, R.

VOL. I. s

 
258 MANUAL OF BOTANY

et P., which contain 6 species. Their properties and uses are
unknown.

-Order 44. Emprrracem, the Crowberry Order.—Cha-
racter.— Small heath-like evergreen shrubs. Leaves exstipu-
late. Flowers axillary, small, unisexual. Calyx of 4—6 persist-
ent, imbricate, hypogynous scales, the innermost occasionally
petaloid and combined. Stamens alternate with, and equal in
number to, the inner sepals or scales. Ovary superior, placed
on a disc, 2—9-celled ; ovules solitary. Frutt fleshy, composed
of from 2 to 9 nuts. Seed solitary in each nut, ascending;
embryo with an inferior radicle in fleshy-watery albumen.

Distribution and Numbers.—Mostly natives of Northern
Europe and North America. Illustrative Genera :—Empetrum,
Linn.; Corema, Don. There are 4 species.

Properties and Uses.—The leaves and fruit are generally
slightly acid. The berries of Hmpetrum nigrum, the Crowberry,
are eaten in the very cold parts of Europe, and are also em-
ployed in Greenland in the preparation of a fermented liquor.
In Portugal, the berries of Corema are used in the preparation
of a beverage which is said to be useful in febrile complaints.

Order 45. CERATOPHYLLACE®, the Hornwort Order.—Cha-
racter.—Aquatic herbs. Leaves verticillate, very finely divided.
Flowers minute, axillary, sessile, monecious. Calyx or rather
perianth inferior, 8—12-partite. Male flower consisting of
12—20 stamens ; anthers sessile, 2-celled. Female flower with
a superior 1-celled ovary, and 1 pendulous orthotropous ovule.
Fruit hard or nut-like, indehiscent. Seed exalbuminous,
pendulous ; embryo with a large many-leaved plumule, and w
very short inferior radicle.

Distribution and Properties.—-Natives of the northern hemi-
sphere. Ceratophyllum, Linn.,is the only genus. The proper-
ties and uses of the species are unknown.

Artificial Analysis of the Orders in the Sub-class.
MonocutamMyDEa or INcomPLETa.
(Modified from Lindley.)

1. Achlamydeous Flowers,
A. Leaves stipulate.
a. Flowers unisexual,

Ovary 1-celled.
Ovules numerous . Salicacce.
DICOTYLEDONES—MONOCHLAMYDEAX 259

Ovules 1—2.
Ovule erect.
Ovule pendulous

Ovary 2- or more-celled.
Seeds few, not winged

b. Flowers hermaphrodite.

Carpel solitary.

Ovule erect. Embryo with endosperm and

perisperm

Ovule suspended. Embryo with endlosnerm

Carpels several.

Ovule erect. Embryo with endosperm

B. Leaves exstipulate.
a. Flowers wnisexual.

Ovules very numerous

Ovules solitary or very few.

Flowers naked.
Ovary 1-celled

Flowers within an involucre.
Anther-valves recurved
Anther-valves slit.
Embryo on the outside of the albumen .

Embryo enclosed in the albumen

b. Flowers hermaphrodite.
Embryo with endosperm
Embryo without endosperm .

Myricacee.
Platanacee.

Euphorbiaceae.

Piperacee
Chloranthacee.

Saururacee.

Podostemacee.

Myricacee.
Atherospermacee.

Moniniacee.
Euphorbiacee.

Piperacee.
Podostemacee.

2. Monochlamydeous Flowers.

A. Ovary inferior, or partially so.

a. Leaves stipulate.

1. Flowers hermaphrodite

2. Flowers unisexual .
b. Leaves exstipulate.

1. Flowers hermaphrodite.

Ovary 3—6-celled. Ovules numerous .

Ovary 1-celled. Ovules definite.
Ovules with a naked nucellus.

posite

Leaves op-

Ovules with a alee auedling: Leaves

alternate .

Ovules with integuments

2. Flowers unisexual,
Amentaceous .

B. Ovary superior.

a. Leaves stipulate.

1. Flowers hermaphrodite.

a. Carpel solitary.
Stipules ochreate
Stipules distinct.

Aristolochiacee.
Corylacee.

Aristolochiucee.

Loranthacee.

Santalacee.
Chenopodiacee.

Juglandacee.

Polygonacee.
Petiveriacee.
$2
260

b. Carpels more than one, combined.
Seeds exalbuminous.
Calyx imbricate
Seeds albuminous.

Styles or stigmas 2. Leaves not dotted

2. Flowers unisexual.

a. Carpel solitary.
Cells of anther perpendicular to the fila-
ment :
Cells of anther parallel to ihe lament:
Embryo straight.

Sap watery. Stipules small. Seeds
albuminous . ‘
Sap milky. Stipules ee Seeds ex-
albuminous ;
Embryo hooked.

Sap watery. Seeds without albumen
Sap milky. Seeds with albumen

b. Carpels more than one, combined.
Flowers amentaceous.
Seeds arillate.
Stamen 1
Stamens more theo Ls
Seeds not arillate
Flowers not amentaceous

b. Leaves exstipulate.
1. Flowers hermaphrodite.
w. Carpel solitary.
Anther-valves recurved
Anthers slit.
Leaves covered with scales
Leaves not so covered.
Calyx long or tubular.
Hardened at base
Not hardened in any part.
Stamens in the points of the sepals
Stamens not in the cae of the
sepals
Calyx short, not (abaine or
slightly so.
Flowers in involucels
Flowers not in involucels.
Calyx dry and coloured
Calyx herbaceous or succulent.
Stamens Hupegneas or ae
x)
Stamens wedenncues . .

but

MANUAL OF BOTANY

Ulmacee.

Ulmacee.

Stilaginacee.

Urticacee.
Artocarpacee.

Cannabinacee
Moracee.

Lacistemacee
Scepacee.
Betulacee.
Euphorbiacee

Lauracee.

Eleagnacee.

Nyctaginacee.
Proteacee.

Thymelacee.

Polygonacee.

dAmarantacee.

Chenopodiaceae
Basellacee.
DICOTYLEDONES—MONOCHLAMYDEA 261

b. Carpels more than one, either distinct or
combined.
Carpels distinct . Phytolaccacee.
Carpels combined.
Seeds exalbuminous.

Calyx tubular.
Ovary 2-celled . é é ‘ . Aquilariacee.
Ovary 4-celled. ‘ , . Peneacee.
Calyx tubular, or imperfect . Podostemacee.
Seeds albuminous . x Phytolaccacee.

2. Flowers unisexual.
a. Carpels solitary, or quite distinct.

Calyx tubular.
Anthers opening by recurved valves Atherospermacee.
Anthers opening longitudinally Myristicacee.

Calyx not tubular.
Seeds exalbuminous. Embryo straight.

Leaves verticillate Ceratophyllacee
No evident leaves . Casuarinacee.
Seeds albuminous.
Embryo curled round the albumen . Chenopodiacee.
Embryo straight . ‘ Monimiacee.
b. Carpels more than one, combined.
Ovules indefinite.
Leaves with pitchers . Nepenthacee.
Ovules definite. :
Fruit fleshy. Seeds ascending . Empetracee.
Fruit dry. Seeds suspended . Euphorbiacee.

Root Parasites (Rhizogens of Lindley).

A. Ovary inferior. Ovules solitary . ‘ . Balanophoracee.
B. Ovary superior. Ovules indefinite.
Anthers opening longitudinally Cytinacee.
Anthers opening by pores . . Rafflesiacee.

Monochlamydeous or Achlamydeous flowers also occasion-
ally, or in some orders always, occur in plants belonging to
the following orders of the Sub-classes Polypetale and Gamc-
petalae :—

Sub-class 1. Polypetale :—

Series 1. Thalamiflore :—Ranunculacee, Menispermacee,
Papaveracee, Bixacee, Caryophyllacee, Scleranthacee, Paro-
nychiacee, Sterculiacee, Byttneriacee, Tiliacee.

Series 2. Disciflore :—Malpighiacee, Rutacee, Chailletiacee,
Xanthoxylacea, Geraniacee, Celastraceea, Rhamnacee, and
Anacardiacee.

Series 8. Calyciflore :—Leguminosa, Rosacea, Lythracea,
262 MANUAL OF BOTANY

Sazifragacee, Cunoniacee, Begoniacee, Datiscacee, Mesembry-

anthacee, Passifloracee, Myrtaceae, Onagracee, Samydacee,

Haloragacee, Combretacea, Hamamelidacea, and Araliacee.
Sub-class 2. Gamopetale :—Oleacee and Primulacee.

Synopsis of the British Natural Orders of the Sub-class
Monochlamydee.
A. Male flowers in catkins.
Flowers dicecious.
Male and female flowers in catkins.

Fruit dry : q Salicacee.
Fruit drupaceous Myricacea.
Flowers monecious.
Flowers all in catkins ‘ . Betulacee.
Male flowers only in catkins. : : . Cupulifere.

B. Flowers not in catkins.

Ovary inferior. Fruit indehiscent.
Stamens 4—5, epiphyllous . Santalacee.
Stamens 6—12, epigynous Aristolochiacee.

Ovary one, superior. Perianth sometimes absent.

Fruit separating into several carpels. No

perianth . . Fj i Euphorbiacee.
Fruit not separating into carpels.
Leaves stipulate.
Stipules ochreate ‘ . Polygonacee.
Stipules free deciduous. Ovary 1-celled.
Perianth 4—5-parted Urticacee.
Perianth of female flower scale-like, open Cannabinacee.
Stipules free deciduous. Ovary 2-celled Ulnacee.
Leaves exstipulate.
Flowers moneecious or dicecious.
Fruit fleshy. Stamens 2 or 8. Perianth
scaly, imbricated . Empetracee.

Fruit dry.
Stamens 3 or more. Perianth tubular Eleagnacee.
Stamens 12-20. Perianth 10-12-cleft Ceratophyllacee.
Flowers perfect or polygamous.
Perianth 8-5-cleft, herbaceous. Fruit
autricle . é Chenopodiaree.
Perianth 3-cleft, scarious Amaranthacee.
Perianth tubular. Stamens perigynous Thymelacec.
DICOTYLEDONES—THALAMIFLORA 263

Sub-Class II.—PonyperaLa.
Series I.— Thalamiflore.
Cohort 1.—Ranales.

Order 46. RanuncuLace®, the Buttercup Order.—Cha-
racter.—Herbs or rarely climbing shrubs, with a watery,
colourless, usually acrid juice. Leaves radical or alternate (or
opposite in Clematides), generally much divided, or sometimes
entire, with usually dilated and amplexicaul petioles. Stipules

Fie. 1019. Fic. 1020. Fic. 1021.

 

Fig. 1019. Diagram of the flower of a species of Ranwnculus.——Fig. 1020.
Vertical section of the flower of Ranunculus acris. e. Calyx. pe. Petals.
e, Stamens. yp. Carpels— Fig. 1021, Adnate anther of a Ranuncnlaceous

 

 

plant. Fig. 1022. Numerous follicles of @rodlius enropeeus. Fiy. 1023.
Vertical section of the seed of the Monkshood ( Aconitum), sp. Coverings
of the seed. emb. Embryo. alb. Albumen,.— Fig. 1024. Vertical section
of a carpel of Ranunculus acris. 0. Ovary. gy. Ovule. s. Stigma.

generally absent; if present, adnate. Inflorescence generally
terminal; one-flowered, or racemose, or paniculate. Flowes
regular, or rarely irregular, usually hermaphrodite; often
acyclic or hemicyclic. Calys of 3-6, usually 5 distinct sepals,
regular or irregular, sometimes petaloid; deciduous, or very
rarely persistent; «stivation imbricate (or valvate in Clema-
tide). Corolla either isomerous with the calyx, or having
numerous petals; regular or irregular. Petals distinct, hypo.
gynous, sometimes 0; sometimes modified into nectaries:
estivation imbricate. Stamens o, pluriseriate, or spirally ar-
264 MANUAL OF BOTANY

ranged; hypogynous, free; anthers innate, dehiscing longitu-
dinally. Carpels o, or rarely few or only one; usually distinct
and one-celled; rarely forming a compound ovary; when
numerous, spirally arranged. Ovary with one or many ovules.
Ovules anatropous. Frwit generally consisting of a number of
achenes; sometimes of several follicles; very rarely baccate or
capsular. Seeds solitary or numerous; when solitary, erect or
pendulous; exarillate. Embryo minute, embedded in horny or
rarely fleshy albumen.

Diagnosis.—Herbs or rarely shrubs, with a colourless, watery,
and usually acrid juice. Sepals, petals, and stamens distinct,
hypogynous. Corolla with an imbricate estivation. Stamens
usually numerous; anthers adnate, bursting longitudinally.
Carpels, except in a very few instances, more or less distinct.
Seeds with a minute embryo, and homogeneous horny albumen,
anatropous.

Ranunculacee may be distinguished from Papaveracee by
the apocarpous pistil and watery juice; from Berberidacee by
the herbaceous habit, the indefinite stamens, and the dehiscence
of the anthers; from Dilleniacee by the habit, the deciduous
sepals, and the absence of an aril to the seeds; from Magnoliacee
by the habit and by the arrangement of the perianth.

The order is divided into the following tribes :—

Tribe 1. Clematidee.—Sepals usually valvate. Petals absent.
Carpels with one ovule, which is pendulous. Fruit consisting
of a number of achenes. Stem herbaceous or climbing ;
leaves opposite.

Tribe 2. Anemonee.—Sepals imbricate. Carpels with a single
pendulous ovule. Fruit consisting of a number of achenes.
Leaves radical, or alternate; sometimes simulating an invo-
lucre.

Tribe 3. Ranunculee.—Sepalsimbricate. Carpels with a single
ascending ovule. Fruit anumber of achenes. Leaves radical
or alternate.

Tribe 4. Helleboree.—F lowers regular or irregular. Sepals im-
bricate. Petals small, or irregular, or absent. Fruit anumber
of follicles, or rarely a capsule or a berry.

Tribe 5. Paoniew.—Sepals imbricate. Fruit of 2-5 follicles,
more or less surrounded at the base by a cup-shaped disc.

Distribution.—The order includes 30 genera and about 600
species. It is widespread in its distribution, but is scantily repre-
sented in the tropics, except on mountains.
DICOTYLEDONES-—-THALAMIFLORA 265

Properties and Uses.—The plants of this order generally
abound in an acrid principle, which in some is even vesicant.
This acridity is, however, very volatile, so that in most cases it
is dissipated by drying, or by infusing them in boiling, or even
sometimes in cold water ; it varies also in different parts of the
same plant, and even in the same parts at different seasons.
Some plants contain in addition a narcotic principle; and when
these principles are in excess, they are virulent poisons. Gene-
rally the plants of this order are to be regarded with suspicion,
although some are simply bitter and tonic.

Order 47. DILLENrIAcEa, the Dillenia Order.—C haracter.—
Trees or shrubs, sometimes climbing; rarely herbs. Leaves
alternate, entire or dentate, rarely pinnatifid or trifid; generally
exstipulate. Sepals 5, rarely 3-4 or ©,persistent. Petals 5 or
fewer, hypogynous, imbricate, free. Stamens o, rarely definite,
10 or fewer, hypogynous, free, or united at their bases. Carpels
1-o, generally free. Ovules1- , anatropous. Sceds1 or few,
arillate. Lmbryo minute in fleshy albumen.

Diagnosis.—Stipules absent, except in rare cases. Sepals
and petals 5 each, hypogynous; the former persistent in two
rows, the latter with an imbricate estivation. Carpels more
or less distinct. Seeds numerous, arillate; albumen fleshy,
homogeneous.

Dilleniacesx differ from Ranunculacee in habit, and in their
having a persistent calyx and arillate seeds ; from Magnoliacee
in the latter possessing a multiseriate perianth.

Distribution and Numbers.—The plants of this order occur
chiefly in Australia, India, and equinoctial America; a few
species have been also found in equinoctial Africa; none occur
in Europe. Illustrative Genera :—Dillenia, Linn.; Candollea,
Labill. There are 17 genera and nearly 200 species belonging to
this order. .

Properties and Uses.—These plants have generally astringent
properties; they have been used as vulneraries, and for tanning
in Brazil.

Order 48. CALYCANTHACES, the Calycanthus Order.—Cha-
racter.—Shrubs with opposite entire exstipulate leaves. Sepals
and petals arranged in several series, inserted on a hollow urceo-
late receptacle. Stamens w, closing the throat of the receptacle ;
inner ones sterile. Carpels w, free; situated in the cavity of
the hollow receptacle. Ovules solitary or two together, ana-
tropous. Fruit a number ofachenes. Seeds erect, exalbuminous.
Cotyledons foliaceous, convolute.
266 MANUAL OF BOTANY

Distribution and Numbers.—They are natives of Japan and
North America. Illustrative Genera :—Calycanthus, Chimo-
nanthus. These are the only 2 genera, which include 4 species.

Properties and Uses.—The flowers generally are fragrant and
aromatic ; and the bark of Calycanthus floridus, Carolina All-
spice, is sometimes used in the United States as a substitute
for Cinnamon bark.

Order 49. Macnotiace®, the Magnolia Order.—Cha-
racter.—Trees or shrubs, frequently aromatic. Leaves alter-
nate, usually entire; often with convolute stipules, which enclose
the buds and fall off as the latter open. Flowers axillary or
terminal, rarely racemose or fascicled; sometimes unisexual.
Sepals and petals wultiseriate, usually in whorls of 3; imbricate,
deciduous. Stamens «x, arranged spirally, hypogynous, free ;
anthers adnate. Carpels », or rarely solitary or few, free or
rarely coherent; sometimes multiseriate or spirally arranged
in a head or spike. Ovules 2—a, anatropous, pendulous, or
rarely erect. Fruit capsular, or indehiscent and fleshy, or a
samara. Seeds with a tleshy or crustaceous testa ; embryo mi-
nute, in a copious oily or fleshy albumen, which is not ruminated.

Diagnosis.—Trees or shrubs. Leaves alternate, leathery.
Stipules usually present, and then large and enveloping the leaf-
bud; deciduous. Sepals and petals with « ternary arrangement
of their parts, hypogynous, the former deciduous, the latter with
an imbricate estivation. Carpels distinct or coherent at the
base. Albumen homogeneous.

The order is divided into the following tribes :—

Tribe 1. Trochodendree.-Sepals and petals 0. Flowers
polygamo-dicecious. Carpels whorled, uniseriate. Stipules 0.

Tribe 2. Winterea.—F lowers hermaphrodite or polygamous.
Carpels whorled, uniseriate, or solitary. Stipules 0.

Tribe 8. Magnoliee.—Flowers hermaphrodite. Carpels imbri-
cate, multiseriate, on an elongated thalamus. Stipules en-
closing the leaves.

Tribe 4. Schizandre@.—Flowers unisexual. Fruit baccate.
Carpels as in Tribe 3. Stipules 0.

Distribution.—The order includes 9 genera and 70 species;
it flourishes in tropical and eastern Asia and in North America;
it is sparingly represented in tropical and extra-tropical South
America, and in Australia and New Zealand. No plants of the
order occur in Europe or Africa. Magnoliacee are distinguished
from Dilleniacee by the absence of an aril from the seeds, and
from Anonacex by the non-ruminated albumen.
DICOTYLEDONES—THALAMIFLORA 267

Properties and Uses.—These plants are chiefly remarkable
for bitter, tonic, and aromatic principles. Some of the Schi-
zandree have mucilaginous edible fruits.

Order 50. ANoNAcE®, the Custard-apple Order.—Cha-
racter.—Trees or shrubs, sometimes climbing. Leaves alter-
nate, simple, exstipulate. Caly,r of three sepals, generally united
at the base, persistent. Corolla of usually six petals, in two
whorls, leathery; estivation usually valvate ; hypogynous, rarely
united. Stamens usually numerous, and inserted on a large
hypogynous thalamus; connective enlarged, 4-angled; anthers
adnate. Carpels usually numerous, distinct or united, or very
rarely solitary, with one or more anatropous ovules. Fruit com-
posed of a number of dry or succulent carpels, which are distinct,
or united so as to form a fleshy mass or rarely simple. Seeds
one or more, anatropous; embryo minute; albumen ruminated.

Diagnosis.—Trees or shrubs. Leavesalternate. No stipules.
Calyx of 3 sepals, persistent. Petals 6, in two rows, hypo-
gynous, usually valvate. Anthers adnate, with an enlarged 4-
cornered connective. Albumen ruminated.

Distribution and Numbers.—The plants of this order are
almost entirely confined to the tropical regions of Asia, Africa,
and America. None are found in Europe. Illustrative Genera :—
Xylopia, Linn.; Anona, Linn.; Monodora, Dunal. There are
47 genera and nearly 400 species in this order.

Properties and Uses.—Generally aromatic and fragrant in
all their parts. Some have edible fruits, which are much
esteemed..

Order 51. MENISPERMACER, the Moon-seed Order.—Cha-
racter.—Climbing or trailing shrubs. Leaves alternate, simple,
exstipulate, usually entire. Flowers diccious. Staminate
flower :—Calyx and corolla with a ternary arrangement of their
parts, generally in two whorls, imbricate or valvate. Stamens
usually distinct, equal and opposite to the petals, rarely more or
fewer, sometimes monadelphous. Carpels rudimentary or
wanting. Pistillate flower : —Sepals and petals usually resem-
bling those of the ¢ flower. Stamens imperfectly developed,
or wanting. Carpels usually 38, sometimes 6 or 2, commonly
supported on a gynophore, distinct, 1-celled, each containing one
curved ovule. Fruits drupaceous, curved around a central pla-
cental process, 1-celled. Seeds 1 in each cell, and curved so as
to assume the form of that cell; embryo curved; albumen co-
pious or scanty ; sometimes ruminate ; rarely 0.

Diagnosis.—Trailing or climbing shrubs. Leaves alternate,
268 MANUAL OF BOTANY

simple, exstipulate. Flowers usually diwcious. Sepals, petals,
stamens, and carpels with a ternary arrangement, hypogynous.
Carpels distinct. Fruits 1-celled, curved. Seed solitary, curved ;
embryo curved; albumen absent, or usually small in amount,
and then either homogeneous or somewhat ruminated.

Distribution and Numbers.—The plants of this order are
chiefly found in the forests of the tropical parts of Asia and
America. None occur in Europe. Illustrative Genera :—Jateo-
rhiza, Miers; Menispermum, Tourn. There are 88 genera and
fewer than 100 species included in this order.

Properties and Uses.—These plants are chiefly remarkable
for their narcotic and bitter properties. A few are mucilaginous.
‘When the narcotic principle is in excess they are very poisonous.
Some are valuable tonics.

Order 52. BrERBERIDACER, the Barberry Order.—Charac-
ter.—Herbs, undershrubs or shrubs, often climbing (in Lardiza-
balee). Leaves alternate or radical, sometimes simple, some-
times pinnate or palmate, sometimes reduced to spines, usually
exstipulate. Flowers regular, hermaphrodite, or unisexual,
solitary axillary, or in spikes, racemes, panicles, or cymes.
Sepals deciduous, in 1—aw whorls of 2 or 8 each, often petaloid ;
petals equal in number to the sepals and opposite to them, or
twice as many, hypogynous. Stamens in 1—38 series, opposite
to the petals, generally free, but monadelphous in some
Lardizabalee ; hypogynous. Anthers dehiscing longitudinally
or by recurved valves. Carpels 1 or 8, distinct ; ovules anatro-
pous, attached to a marginal placenta, or scattered over the
surface of the ovary wall. Fruit baceate, or dry and follicular ;
seeds albuminous.

The order is divided into two tribes as follows :—

Tribe 1. Lardizabalee. Flowers unisexual, anthers dehiscing
longitudinally, carpels 3.

Tribe 2. Berbere@. Flowers hermaphrodite; anthers dehis-
cing by recurved valves (except in Podophyllum and Nan-
dina), carpel solitary.

Diagnosis.—Leaves alternate, very often spiny. Sepals3, 4,
6, or © deciduous. Petals hypogynous, and >pposite to the sepals
when equal to them in number. Stamens definite, hypo-
gynous, opposite to the petals; anthers 2-celled, each opening by
a recurved valve, except in Tribe 1 and the genera Podophyllum
and Nandina, where they dehisce longitudinally. Carpel solitary ;
placenta marginal; ovules anatropous. Seeds with albumen.
DICOTYLEDONES—THALAMIFLORA 269

Distribution and Numbers.——They are found in the
temperate parts of Europe, America, and Asia, and are very
common in the mountainous parts of the North of India.
Illustrative Genera :—Berberis, Linn.; Epimedium, Linn.;
Leontice, Linn. The order includes 20 genera and about 100
species.

Properties and Uses.—These plants are generally acid,
astringent, and bitter; but some are purgative. Their acid
properties are due to the presence of oxalic acid.

Order 58. NympHmaAcEs, the Water-lily Order.—Character.
—Aquatic herbs, with generally floating leaves which are
peltate or cordate; when submerged leaves are present, they are
much divided. Flowers generally floating, sometimes emerged,

Fie. 1025.
Fie. 1026.

 

fig. 1025. Diagram of the flower
of the Barberry (Berberis).
Fig. 1026. Vertical section of the
flower of Lpimedium.—Tlvy.
1027, Vertical section of the
ovary of Berberis—— iy. 1028.
Vertical section of the seed of
Berberis, with the embryo in the
axis surrounded by albumen.

 

 

solitary, large and showy; usually acyclic, without any sharp
demarcation between the petals and stamens. Sepals 3—5,
petals 3— cw, imbricate; stamens 6~ om: outer filaments peta-
loid. The petals and stamens are sometimes all free and
hypogynous, sometimes all, or the inner ones only, inserted at
different heights on « torus which encloses the carpels. Carpels
8—8, sometimes distinct, but usually cohering in a whorl and
forming a many-celled ovary, which is free and superior in
Nuphar or adherent to the torus in Nymphea and other genera.
Sometimes the carpels are embedded singly in cavities in the
270 MANUAL OF BOTANY

flattened torus (Nelumbiwm). Stigmas either distinct or

uniting into an epigynous disc. Ovules anatropous, or in

Barclaya orthotropous, distributed over the surface of the

dissepiments of the ovary, or pendulous from the central suture

or the apex of the carpels when the latter are distinct. Seeds
albuminous, with endosperm and perisperm, or exalbuminous ;
arillate or naked.

The order is divided into the following sub-orders :—

Sub-order 1. Cabombee.—Sepals and petals 3. Carpels 3.
Ovules few. Flowers small.

Sub-order 2. Nymphee.—Sepals 4—6. Petals and stamens o.
Carpels numerous, coherent. Ovules ». Flowers generally
showy. =

Sub-order 3. Nelwmbonee.—Sepals 4—5. Petalsand stamens o.
Carpels sunk in a fleshy torus. Ovules 1—2. Seeds

exalbuminous.
Distribution.—The plants of this order are chiefly found in

Fic. 1029. Fic. 1030. Fie. 1081.

 

Lig.1029. Flower of Yellow Water-lily (Vuphar
luteum). fig. 10380. Ovary of Nuphar with
numerous radiating stigmas. fig. 1031.
Vertical section of the seed of Wymphea
alba, showing the embryo embedded in endo-
s} erm, outside which lies amass of ; erisperm.

 

 

 

quiet waters throughout the whole of the northern hemisphere
and more sparingly in the southern. Illustrative Genera :—
Victoria, Lindl.; Nympheea, Linn.;Cabomba, Awbl.; Nelumbium.
There are 8 genera and 35 species.

This order is distinguished from the others of the Ranales by
the seeds usually containing both endosperm and perisperm.
The Nymphee approach the Papaveracee in their placentation,
but differ in the contents of the seed, and in their habit. The
character of the seeds is almost the only distinction between
Cabomba and the Ranunculacee.

Properties and Uses.—These plants have bitter and
astringent properties. The flowers are said to be narcotic.
DICOTYLEDONES.~THALAMIFLORA 271

Cohort 2.—Parietales.

Order 54. SARRACENIACEH, the Side-saddle-flower Order.—
Character.—Percnnial herbs, growing in boggy places, with
radical hollow leaves, which are pitcher- or trumpet-shaped.
Sepals 4—6, usually 5, persistent, imbricate. Petals 5, hypogy-
nous, sometimes absent. Stamens numerous, hypogynous ;
anthers adnate, 2-celled. Carpels 83—5, united so as to form a
compound 8—5-celled ovary ; ovules numerous ; placentas axile ;
style simple and truncate, or expanded at its top into a large
shield-like angular process with one stigma beneath each of its
angles. Capsule 38—5-celled dehiscing loculicidally. Seeds

Fie. 1032. Fie. 1033. Fie. 1034.

 

fig. 1032. Diagram of the fower of the Poppy, with two sepals, four
crumpled petals, numerous stamens, and a compownl vne-celled
ovary with several parietal placentas projecting into its interior
so as to nearly divide it into several cells. f'tg. 1033. Flower of
Celandine (Chelidonium majus), sti. Two stigmas on the apex of a
lengthened or pod-like ovary.— Jig. 1034. Siliqueeform or pod-shaped
capsule (ceratium) of Celandine.

 

 

numerous, attached to large axile placentas; albumen abun-
dant.

Diagnosis.—Perennial boggy plants, with pitcher- or trumpet-
shaped leaves. Calyx permanent, imbricate. Carpels united
so as to form a compound ovary and a 3—5-celled dehiscing
fruit, with large axile placentas; albumen abundant.

Distribution and Numbers.—There are 8 species, of which 6
are confined to the bogs of North America: 1 occurs in Guiana,
the other species is found in California. Illustrative Genera :—
Sarracenia, Heliamphora.

Properties and Uses.—The pitchers serve to entrap any
insects that find their way into them. They contain a watery
fluid in which the insects drown and putrefy, and the solution
272 MANUAL OF BOTANY

thus formed is ultimately absorbed, and appears to be necessary
for the healthy condition of the plants.

Order 55. PapavERACEs, the Poppy Order.—Character.—
Herbs or shrubs, usually with a milky juice (white or coloured).
Leaves alternate, exstipulate. Sepals usually 2 or rarely 3,
caducous. Petals 4 (figs. 1032 and 1033), or rarely 6, or some
multiple of 4, or very rarely wanting; usually crumpled in
estivation, hypogynous. Stamens generally numerous and
hypogynous; anthers 2-celled, innate. Ovary 1-celled, with 2 or
more parietal placentas, which project more or less from the walls
into its cavity, and in Rommneya actually cohere in the axis;
styles absent or very short; stigmas 2 or many, alternate with
the placentas, and opposite the imperfect dissepiments ; when
numerous, they form a star-like process on the top of the ovary ;
ovules numerous. Fruit 1-celled, and either pod-shaped with 2
parietal placentas, or capsular with several placentas; dehiscing
by valves or pores, or sometimes indehiscent. Seeds usually
numerous ; embryo in fleshy-vily albumen.

Diagnosis.—Usually herbs with a milky juice. Leaves
alternate and exstipulate. Peduncles 1-flowered ; flowers regular
and symmetrical. Calyx and corolla with a binary or ternary
arrangement of their parts, deciduous, hypogynous. Stamens
numerous, generally hypogynous; anthers 2-celled, innate.
Ovary compound, 1-celled, with parietal placentas, stigmas
alternate to the placentas. Fruit 1-celled, except in Romneya.
Seeds numerous, albuminous.

Distribution and Numbers.—Nearly two-thirds of the plants
of this order are natives of Europe, and are mostly annuals.
They are almost unknown in tropical regions, and are but
sparingly distributed out of Europe in a wild condition. Illus-
trative Genera :—Papaver, Linn.; Chelidonium, Linn. The
order includes above 180 species.

Properties and Uses.—The plants of this order are in almost
all cases characterised by well-marked narcotic properties.
Some are acrid, while others are purgative. From a medicinal
point of view, this order must be regarded as the most important
in the Vegetable Kingdom on account of its yielding Opium,
undoubtedly the most valuable drug of the Materia Medica.

Order 56. FuMaRiace®, the Fumitory Order.—Character.
—Smooth herbs with a watery juice. Leaves alternate, much
divided, exstipulate. Sepals 2, deciduous. Petals 4, cruciate,
very irregular, in two whorls; one or both of the outer petals
being gibbous or spurred, and the two inner frequently united
DICOTYLEDONES—THALAMIFLORA 273

at the apex. Stamens hypogynous, usually 6, diadelphous, the
two bundles being opposite the outer petals, and containing an
equal number of stamens, the middle stamen of each bundle
having a 2-celled anther, the two outer with 1-celled anthers ;
in rare cases there are four stamens, which are then distinct and
opposite the petals. Ovary superior, 1-celled, with parietal
placentas ; style short, or long and filiform; stigma obtuse or
lobed ; ovules amphitropous. Fruit indehiscent and 1- or
2-seeded, or 2-valved and dehiscent, or a succulent indehiscent
pod-like fruit ; in the two latter cases containing a number of
seeds. Seeds shining, crested; embryo abaxial, minute; albu-

Fie. 1035. Fic. 1036. Fie. 1037.

Fie. 1038.

 

Fiy, 1035, Diagram of the flower of Corydalis, with two sepals, four petals, in two
whorls, six stamens in two bundles, and a one-celled ovary with two
parietal placentas. Fig. 1036. Vertical section of the flower of Hypecoum,
——Fig. 1037. Upper or posterior petal of Corydalis, spurred at the base,
and a bundle of three stamens.—VFig. 1038. Vertical section of the seed
of Fumaria,

 

men fleshy. This order is included in Papaveracee by
Bentham and Hooker.

Diagnosis.—Smooth herbs, with a watery juice, and alternate
exstipulate much-divided leaves. Flowers very irregular and
unsymmetrical, and either purple, white, or yellow. Sepals 2,
deciduous. Stamens hypogynous, usually 6, diadelphous, or 4
distinct; always opposite to the petals. Ovary superior with
parietal placentas ; ovules amphitropous. Embryo minute, ab-
axial, in fleshy albumen.

Distribution and Numbers. —The plants of this order prin-
cipally occur in thickets and waste places in the temperate
latitudes of the northern hemisphere. Illustrative Genera :—
Dicentra, Borkh.; Fumaria, Tourn. There are about 110 species.

VOL. II. T
274 MANUAL OF BOTANY

Properties and Uses.—These plants possess slightly bitter,
acrid, astringent, diaphoretic, emmenagogue, and aperient pro-
perties. The rhizomes or tubers of Dicentra (Corydalis) for-
mosa are the source of corydalin, which is used by the eclectic
practitioners in the United States of America in syphilis,
scrofula, &c.; but the properties of this and other plants of the
order appear to be unimportant. Some species are cultivated
in our gardens and greenhouses. The most important of these
is Dicentra (Dielytra) spectabilis, which has very showy flowers,
but, like all other plants of the order, it is scentless.

Order 57. CRUCIFER, the Cruciferous Order.—Character.
—Herbs, or very rarely shrubby plants. Leaves alternate,
exstipulate. Flowers usually yellow or white, rarely purple, or

Fie. 1039.. Fie. 1040.

 

ay, “
orn acca

Fig. 1039, Diagram of a Cruciferous flower.— Fig. 1040. Portion of the
flowering branch of the Wallflower.

 

iZ

some mixture of these colours; inflorescence racemose or
corymbose; usually ebracteate. Sepals 4, deciduous; estiva-
tion imbricate or rarely valvate. Petals 4, hypogynous,
arranged in the form of a Maltese cross, alternate with the
sepals, deciduous. Stamens 6, tetradynamous, hypogynous.
Thalamus furnished with small green glands placed between
the stamens. Ovary superior, with two parietal placentas,
1-celled, or more usually 2-celled from the formation of a
spurious dissepiment called the repluwim; ovules generally
numerous, arranged alternately on two parietal placentas so as
to form a single row, amphitropous or campylotropous; style
none, or very short; stigmas 2, opposite the placentas. Fruit a
siliqua or silicula, 1- or 2-celled, 1- or many-seeded. Scers
DICOTYLEDONES—THALAMIFLORZ 276

stalked, generally pendulous ; embryo with the radicle variously
folded upon the cotyledons ; albwmen none, or very scanty.

Diagnosis.—Generally ebracteate herbs. Inflorescence in-
definite; racemose or corymbose. Sepals and petals 4, de-
ciduous, regular, the latter cruciate. Stamens tetradynamous.
Ovary with two parietal placentas; stigmas 2. Fruit a siliqua
or silicula. Seeds stalked, with the radicle variously folded
upon the cotyledons. No other order is likely to be confounded
with this if ordinary care be taken, as tetradynamous stamens
only occur here, except in a very few plants belonging to the
order Capparidacea,

Division of the Order and Illustrative Genera.—This large
and truly natural order has been divided into sub orders
according to the nature of the fruit, and also as to the mode in
which the embryo is folded. The latter is the most natural
arrangement. :

The sub-orders founded on the nature of the fruit are as
follows :—

Sub-order 1. Siliquose.—Fruit a siliqua, opening by valves
longitudinally. Illustrative Genera :—Cheiranthus, Linn. ;
Brassica, Linn.

Sub-order 2. Siliculose@ latisepte.—Fruit a silicula opening by
valves; the replum in its broader diameter. Illustrative
Genus :—Cochlearia, Linn. °

Sub-order 3. Siliculose angustisepte.—Fruit a silicula opening
by valves; the replum in its narrower diameter. Illustrative
Genera :—Capsella, Manch ; Iberis, Linn.

Sub-order 4. Nucwmentacee.—Fruit an indehiscent silicula ;
often 1-celled, owing to the absence of the replum. Jilustra-
tive Genus :—Isatis, Linn.

Sub-order 5. Sepulate.—The valves of the fruit opening lon-
gitudinally and bearing transverse septa in their interior.
There are no examples among British plants.

Sub-order 6. Lomentace@.—Fruit a siliqua or silicula, dividing
transversely into 1-seeded portions, the true siliqua sometimes
barren; the beak placed above it containing one or two seeds.
Illustrative Genera :—Cakile, Gaert.; Raphanus, Linn.

The arrangement of Bentham and Hooker is essentially the
same as the above.
The sub-orders founded on the mode in which the embryo is
folded are as follows :—
if
276 MANUAL OF BOTANY

Sub-order 1. Pleurorhizee (CO = ).—Cotyledons accumbent,
flat; radicle lateral. Illustrative Genera :—Cheiranthus,
Linn.; Arabis, Linn.

Sub-order 2. Notorhizee (Q || ).—Cotyledons incumbent, flat ;

Fic. 1041. Fic. 1042. Fic. 1043.

Fie. 1044, Fie. 1045. Fic. 1046.

 

Fig. 1041. Sporophylls of the Wal'flower (Cheiranthus Cheiri), 1. Tha-
lamus. gl. Glands. ec. Tetradynamous stamens. s¢i. Stigmas.— Fig. 1042,
An unripe siliqua of the Wallflower, with one of the valves removed to
show the replum and the stalkel pendulous seeds.——/'ig. 1u43. The sili.
cula of Shepherd’s Parse (Cpsella Bursa-pastoris) in the act of dehiscing,
showing the stalked pendulous seeils. —/ig. 1044. Silicula of the Seurvy-
grass (Cochlearia officinalis) in the act of dehiscing.——/’.g. 1045. The em-
bryo of Bunias orientalis. —-Fig. 1046. The embryo of .he Cabbage plant
(Brassica oleracea). 1. Undivided. 2. Horizontal tion. +. Radicle,
ce. Cotyledons,

radicle dorsal. Illustrative Genera :—Hesperis, Linn.;
Isatis, Linn.

Sub-order 3. Orthoplocee (©  ).—Cotyledons conduplicate,
longitudinally folded in the middle; radicle dorsal, within the
fold. Illustrative Genera :—Brassica, Linn.; Raphanus, Linn.
DICOTYLEDONES—THALAMIFLORA 277

Sub-order 4. Spirolobee (© || ||)—Cotyledons twice folded,

linear, incumbent. Illustrative Genus :— Bunias, Linn.
There are no examples among British plants.
Sub-order 5.  Diplecolobee (CE || || ||)—Cotyledons thrice

folded, linear, incumbent. Illustrative Genera :—-Senebiera,
DC.; Subularia, Linn.

Distribution and Numbers.—The plants of this order chiefly
inhabit temperate climates. A large number are also found in
the frigid zone, and a few in tropical regions, chiefly on moun-
tains. The order includes about 1,600 species.

Properties and Uses.—This order is generally characterised
by antiscorbutic and pungent properties, frequently combined
with acridity ; it is one of the most natural in the Vegetable
Kingdom, and does not contain a single poisonous plant. The
seeds frequently contain a fixed oil. Many of our commonest
culinary vegetables are derived from this order.

Order 58. CAPPARIDACES, the Caper Order.—Character.—
Herbs, shrubs, or rarely trees. Leaves alternate, exstipulate, or
rarely with spiny stipulate appendages. Sepals 4, sometimes
cohering more or less; @stivation imbricate or valvate, equal or
unequal. Petals usually 4, cruciate, imbricate, generally unequal
and unguiculate. rarely 8, or sometimes none. Stamens nume-
rous or definite, if 6, very rarely tetradynamous, placed usually
upon a prolonged thalamus or stalk by which they are raised
above the calyx and corolla. Ovary placed on a gynophore or
sessile, 1-celled; placentas 2 or more, parietal; style filiform or
wanting; ovules amphitropous or campylotropous. Fruit 1-
celled, usually many-seeded, very rarely 1-seeded, either pod-
shaped and dehiscent, or baccate and indehiscent. Seeds
generally reniform, without albumen; embryo curved ; cotyledons
leafy.

Diagnosis.—Herbs, shrubs, or trees, with alternate leaves.
Sepals and petals 4 each, the latter cruciate, and generally un-
equal. Stamens usually numerous, very rarely tetradynamous,
commonly inserted ona stalk, which raises them above the calyx
and corolla. Ovary 1-celled, placentas parietal. Fruit dehis-
cent or indehiscent, 1-celled. Seeds generally reniform ; embryo
curved; no albumen.

Division of the Order and Illustrative Genera.—The order has
been divided, according to the nature of the fruit, as follows :—
Sub-order 1. Cleomee.—Fruit capsular and dehiscent. Jllus-

trative Genera :—Gynandropsis, DC.; Cleome, DC.
278 MANUAL OF BOTANY

Sub-order 2.—Capparee@.—F ruit baccateandindehiscent. Illus
trative Genera :—Cadaba, Forsk.; Capparis, Linn.

Distribution and Numbers.—The plants of the order are
found in tropical and subtropical regions of the globe. In
Africa they are especially abundant.. The common Caper (Cap-
paris spinosa), which inhabits rocky places in the south of Europe,
is the only European species, and also that one which is found
farthest north. The order contains about 360 species.

Properties and Uses.—In their properties these plants re-
semble in many respects the Crucifere, being generally pun-
gent, stimulant, and antiscorbutic. Others are aperient, diuretic,
and anthelmintic. In some plants the pungent principle is
highly concentrated, or probably is in itself deleterious, so that
those in which it is found are very poisonous.

Order 59. ResEpAcEs, the Mignonette Order—Character.
—Herbs, or rarely small shrubs. Leaves alternate, entire or
divided, exstipulate, or with minute glandular stipules. Calyx
with from 4 to 7 divisions. Petals 2—T, entire or with a deeply
lobed or fringed limb, unequal. Disc fleshy, large, hypogynous,
one-sided. Stamens definite, inserted on the disc. Ovary sessile,
l-celled; ovules amphitropous or campylotropous; placentas
parietal; stigmas 3, sessile. Fruit usually opening at the
apex long before the seeds are ripe, 1-celled. Seeds usually
numerous, reniform ; embryo curved, without albumen.

Diagnosis.— Usually herbs, with alternate leaves and unsym-
metrical flowers. Disc large, hypogynous, one-sided. Stamens
definite, not tetradynamous. Ovary sessile, 1-celled, with parie-
tal placentation; stigmas 3, sessile. Fruit usually opening
at the apex before the seeds are ripe. Seeds generally nume-
rous, reniform, exalbuminous.

Distribution and Numbers.—They are chiefly natives of
Europe and the adjoining parts of Africa and Asia. A few
occur in the north of India, Cape of Good Hope, and California.
Illustrative Genera :—Reseda, Linn.; Astrocarpus, Neck. There
are about 45 species in this order.

Properties and Uses.—But little is known of their properties.
The plants are generally somewhat acrid, and were formerly.
supposed to be sedative.

Order 60. Cistaces, the Rock-rose Order.—C haracter.—
Shrubs or herbs, often viscid. Leaves opposite or alternate, entire,
stipulate or exstipulate. Flowers showy. Sepals usually 5,
sometimes 3, persistent, unequal; estivation of the three inner
DICOTYLEDONES—THALAMIFLORA 279

twisted. Petals usually 5, very rarely 3, caducous, hypogynous,
frequently corrugated in the bud, and twisted in a reverse way
to that of the sepals. Stamens distinct, hypogynous, definite or
indefinite. Ovary 1- or many-celled from parietal septa ; ovules
orthotropous; style single; stigma simple. Fruit capsular,
usually 1-celled, with 3—5, or rarely 10 valves; or imperfectly
3—-5—10-celled; placentas parietal. Seeds definite or numerous,
albuminous; embryo curved or spiral, with the radicle remote
from the hilum.

Diagnosis.—Leaves entire. Sepals and petals with a ternary
or quinary arrangement, twisted in estivation ; the former per-
sistent, the latter caducous. Stamens hypogynous, distinct.
Ovary with parietal placentas and orthotropous ovules; style
single; stigma simple. Fruit capsular. Seeds with mealy
albumen ; embryo inverted, curved or spiral.

Distribution and Numbers.—These plants are most abundant
in the south of Europe and the north of Africa. Some few are

Fie. 1047.

Fic. 1048.

  

rig. 1047. Diagram of the flower of a species of Helianthemum.—lTvy. 1048.
Section of the seed of a species of Cistus, the pointed end being its apex.

found in other parts of the globe. Illustrative Genera :—Cistus,
Tourn. ; Helianthemum, Tourn. There are about 200 species.

Properties and Uses.—These plants have generally resinous
and balsamic properties. Some are regarded as stimulant, ex-
pectorant, and emmenagogue.

Order 61. ViotacEm, the Violet Order.—Character.—
Herbs or shrubs. Leaves simple, stipulate with an involute
vernation, alternate or sometimes opposite. Sepals 5, per-
sistent, imbricate, usually prolonged at the base. Petals 5,
hypogynous, equal or unequal, one usually spurred. Stamens
equal in number to the petals, and usually alternate with them,
280 MANUAL OF BOTANY

or rarely opposite, inserted on a hypogynous dise, often unequal ;
anthers 2-celled, sometimes united, introrse; filaments short
and broad, and elongated, so as to project beyond the anthers;
when the flowers are irregular, two of the anthers are spurred
at the base. Ovary 1-celled, with 3 parietal placentas; style
single, usually declinate; stigma capitate oblique, hooded;
ovules usually numerous. Fruit capsular, 3-valved, dehiscence
loculicidal ; placentas parietal, on the middle of the valves.
Seeds usually numerous, sometimes definite ; embryo straight,
erect, in the axis of fleshy albumen.

Diagnosis.—Herbs or shrubs. Leaves simple, stipulate,
and with involute vernation. Sepals, petals, and stamens 5
each, hypogynous. Stamens all perfect; anthers introrse with
the filaments prolonged beyond them, and sometimes having
spur-like appendages below. Ovary 1-celled, with three parietal
placentas; style and stigma single. Fruit 1-celled, dehiscing by
3 valves, each valve bearing a placenta in its middle. Seeds
having a straight erect embryo in the axis of fleshy albumen.

Fie. 1049.

Fic. 1050.

  

Fig. 1049. Sporophylls of the Pansy (Viola tricolor). st. Obliquely hooded
stigma, a. United anthers, two having long spurred appendages at the
base.——Jig. 1050, Vertical section of the seed.

Division of the Order and Illustrative Genera—-The order
has been divided as follows :—
Sub-order 1. Violee.—Having irregular flowers and appendaged
anthers. Illustrative Genera :—Viola, Linn.; Ionidium, Vent.
Sub-order 2. Alsodee.—With regular flowers, and anthers not
furnished with spurred appendages. Illustrative Genera :—
Alsodeia, Thouars; Pentaloba, Lowr.

Distribution and Numbers.—The herbaceous plants of the
sub-order Violew are chiefly natives of Europe, Siberia, and
North America; the shrubby mostly of South America. The
DICOTYLEDONES—THALAMIFLORA 281

Alsode are exclusively natives of South America, Africa, and
Malacca. There are about 300 species belonging to the order.

Properties and Uses.—The plants of this order are chiefly
remarkable for emetic and purgative properties. A few also
are mucilaginous, and others have been reputed to be anodyne.
The emetic property is due to a peculiar alkaloid named violine,
which greatly resembles, if it be not identical with, emetine, the
active principle of the true Ipecacuanha root. This principle is
more especially found in some of the shrubby South American
species, but it also occurs, to some extent at least, in many of
the herbaceous European species.

Order 62. SAUVAGESIACES, the Sauvagesia Order.—Charac-
ter.—This order is by some botanists considered as merely a
sub-order of Violacew. It is distinguished by the flowers of its
species having either 5 perfect stamens alternate with 5 sterile
ones, or numerous stamens. If there are only 5 stamens, these
are also opposite the petals; the anthers are likewise extrorse,
and have no appendages. The fruit also bursts septicidally, and
hence each valve bears the placentas at its margins.

Distribution and Numbers.—They are natives chiefly of
South America and the West Indies. Illustrative Genera :—-
Sauvagesia, Linn.; Lavradia, Velloz. There are about 15
species.

Properties and Uses.—But little is known of the properties of
the plants in this order. Sawvagesia erecta contains a good deal
of mucilaginous matter, and has been used internally as a
diuretic, and in inflammation of the bowels, and also externally
in diseases of the eye.

Order 63. CANELLACER, the Canella Order.—Diagnosis.—
By some authors this small order is placed in Clusiacee ; it is,
however, at once distinguished from the Clusiacee by its
general appearance; alternate leaves; longitudinal dehiscence
of anthers ; absence of dise ; presence of a style ; and albuminous
seeds. It is placed here in accordance with the views of
Bentham and Hooker.

Distribution and Numbers.—This order contains but 2
genera and 8 species. They are natives of the West Indies and
continent of America.

Properties and Uses.—These plants have aromatic, stimulant,
and tonic properties ; being closely allied in these respects to
the Magnoliacee.

Order 64. Brxacem, the Arnatto Order.—Character.—
Shrubs or small trees. Leaves alternate, exstipulate, usually
282 MANUAL OF BOTANY

entire and leathery, and very often dotted. Flowers polypeta-
lous or apetalous; usually hermaphrodite, but sometimes
unisexual. Sepals 4—7, somewhat united at the base. Petals
hypogynous, distinct, equal in number to the sepals and alter-
nate with them, or sometimes absent ; sometimes with scales at
the base. Stamens hypogynous, of the same number as the
petals, or some multiple of them. Ovary 1- or more-celled,
sessile or slightly stalked; placentas 2 or more, parietal, some-
times branched so as to form a network over the inner surface
of the ovary and fruit. Fruit 1-celled, dehiscent or indehiscent,
having a thir pulp in its centre. Seeds numerous, usually
enveloped in a covering formed by the withered pulp; albumen
fleshy-oily; embryo straight, axial; radicle turned to the
hilum. The Pangiacexe of some authors are included in this
order, in accordance with the views of Bentham and Hooker.

Diagnosis.—Shrubs or small trees, with alternate exstipulate
leaves. Flowers polypetalous or apetalous, rarely unisexual ;
petals hypogynous, sometimes with scales at the base. Stamens
hypogynous, equal in number to the petals or some multiple of
them. Fruit dehiscent or indehiscent; placentas parietal.
Seeds numerous, albuminous; embryo axial, straight ; radicle
towards the hilum.

Distribution and Numbers.—The plants of this order are
almost confined to the hottest parts of the East and West Indies,
and Africa. Illustrative Genera :—Bixa, Linn.; Pangium,
Rumph. There are over 100 species.

Properties and Uses-—Many plants of the order are feebly
bitter and astringent, and have been used as stomachics; others
are alterative, tonic, and emetic. The fruits of Oncoba and of
some of the Flacourtias are edible and wholesome; but those
of some other plants are poisonous. It is said, however, that by
boiling, and maceration afterwards in cold water, the poisonous
properties may, in some cases, be got rid of, as in the seeds of
Pangium edule, the kernels of which are then used as a condi-
ment, and for mixing in curries. But even these, according to
Horsfield, act as a cathartic upon those unaccustomed to their
use. The seeds of some species are employed as dyeing and
colouring agents.

Cohort 3.—Polygales.

Order 65. Pirrosporaces®, the Pittosporum Order.—-C ha-
racter.—Trees or shrubs, with simple alternate exstipulate
leaves. Flowersregular. Sepals and petals 4 or 5, hypogynous,
DICOTYLEDONES—THALAMIFLORA 283

imbricate, deciduous. Stamens 5, hypogynous, alternate with
the petals; anthers 2-celled. Ovary superior; style single ;
stigmas equal in number to the placentas, which are 2 or more,
and either axile or parietal; ovules anatropous, horizontal or
ascending. Fruit baceate, or a loculicidal capsule. Seeds
numerous, with a minute embryo in copious fleshy albumen.

Distribution and Numbers.—They are chiefly Australian
plants, but are occasionally found in Africa and some other
parts of the globe. None, however, occur in Europe or America.
Illustrative Genera :—Pittosporum, Soland.; Cheiranthera,
Cunningham. The order includes about 80 species.

Properties and Uses.—These plants are chiefly remarkable
for their resinous properties. Some have edible fruits, as cer-
tain species of Billardicra. A tew are cultivated in this
country on account of their Howers, as Sollya, Billardiecra, &e.

Order 66. TREMANDRACE, the Porewort Order.—Charac-
ter.—Heath-like shrubs, with usually glandular hairs. Leaves
exstipulate, alternate or whorled. lowers axillary, solitary,
pedicellate. Sepals 4 or 5, equal, slightly coherent, deciduous,
and with avalvate estivation. Petals corresponding in number
to the sepals, deciduous, and with an involute estivation. Sta-
mens distinct, hypogynous, 8—10, 2 being placed before each
petal; anthers 2- or 4-celled, with porous dehiscence. Ovary
2-celled; ovules 1—8 in each cell, pendulous; style 1 or 2;
stigmas 1-2. Fruit 2-celled, a capsule with loculicidal dehis-
cence. Seeds pendulous, hooked at the chalazal end; embryo
straight, in the axis of feshy albumen; radicle next the hilum.

Distribution and Numbers.— All are natives of New Holland.
Illustrative Genera :—Tetratheca, Smith; Tremandra, R. Br.
The order includes about 16 species.

Properties and Uses.—Altogether unknown.

Order 67. PotyGcaLace®, the Milkwort Order.—C haracter.
—-Shrubs or herbs. Leaves alternate or opposite, exstipulate,
and usually simple. Pedicels bracteate. Flowers irregular,
unsymmetrical, and arranged in a somewhat papilionaceous
manner ; but here the wings are derived from the calyx, where-
as in the Leguminose they belong to the corolla. Sepals 5, very
irregular, usually distinct; 38 are exterior, and of these 1 is
posterior and 2 anterior; the other 2 are interior and lateral,
usually petaloid, and form the wings to the flower. Petals
hypogynous, usually 3, more or less united, of which 1, forming
the keel, is larger than the rest, and placed at the anterior part
of the flower; the keel is either naked, crested, or 3-lobed; the
284 MANUAL OF BOTANY

other 2 petals are posterior, and alternate with the wings and
posterior sepal of the calyx, and are often united tothe keel;
sometimes there are 5 petals, and then the 2 additional ones
are of small size, and alternate with the wings and anterior
sepals. Stamens hypogynous, 8; usually combined into a tube,
unequal, the tube split on the side next to the posterior °
sepal; anthers clavate, innate, usually 1-celled, rarely 2-celled,

Fic. 1051. Fig. 1052. Fic. 1058. Fre. 1054.

 

Fic, 1056. Fic. 1055.

tig. 1051. A portion of the stem of the common
Milkwort (Polygala vulgaris), with simple alter-
nate exstipulate leaves, and irregular flowers.
— Fig. 1052. Diagram of the flower of the
same. s, Sepals. ps, ps, ps. Posterior and
anterior large petals. pr, pr. Lateral petals.
e. Stamens. c. Carpels. — Fig. 1053. Gyncecium
of the same. ov. Ovary. styl. Style. stig.
Stigma, —- /%g.1054. Fruit with one cell opened.
per. Pericarp. gr. Seed. 7. Caruncula..—— Fig.
1055. Section of seed. ¢e. Testa. ar. Caruncula.
al. Albumen. pl. Embryo. Jig. 1056. Androe-
cium of the same, with one-celled anthers
dehiscing at their apex.

 

 

opening by a pore at their apex, or rarely by valves. Ovary 2—3-
‘celled, one cell being frequently abortive ; ovules solitary or twin,
suspended ; style simple, curved, sometimes hooded at the apex ;
stigma simple. Fruit varying in its nature and texture, inde-
hiscent or opening in a loculicidal manner, occasionally winged.
Seeds pendulous, smooth or hairy, with a caruncule next the
hilum ; embryo straight or nearly so, in copious fleshy albumen,
and with the radicle towards the hilum.
DICOTYLEDONES—THALAMIFLORA 285

Diagnosis (excluding Krameria)..—Herbs or shrubs, with
simple exstipulate leaves. Flowers irregular, unsymmetrical.
Sepals and petals imbricate, not commonly corresponding in
number, and usually arranged in a somewhat papilionaceous
manner ; odd petal anterior ; odd sepal posterior. Stamens 8,
hypogynous, usually combined ; anthers generally 1-celled, with
porous dehiscence. Fruit flattened, usually 2-celled and 2-seeded.
Seeds with abundant fleshy albumen, and with a caruncule next
the hilum.

Distribution and Numbers.—Some genera of the order are
found in almost every part of the globe. The individual genera
are, however, generally confined to particular regions, with the
exception of the genus Polygala, which is very widely distributed,
being found in almost every description of station, and in both
warm and temperate regions. Illustrative Genera :—Polygala,
Linn.; Monnina, Ruiz et Pavon; Soulamea, Lam. There are
over 500 species.

Properties and Uses.—The greater part of the plants of this
order are bitter and acrid, and their roots milky; hence they
are frequently tonic, stimulant, and febrifugal. Some are
emetic, purgative, diuretic, sudorific, or expectorant. The roots
of the different species of Krameria are very astringent from
the presence of tannic acid; they are commonly known under
the name of Bhatany roots. A few species have edible fruits,
and others abound in a saponaceous principle.

Order 68. VocuystacE®, the Vochysia Order.—Character.
—Trees or shrubs, with entire usually opposite leaves, which are
furnished at the base with glands or stipules. Flowers very
irregular and unsymmetrical. Sepals 4—5, united at the base,
very unequal, the upper one spurred, @stivation imbricate.
Petals 1, 2, 8, or 5, unequal, inserted upon the calyx; @estivation
imbricate. Stanrens 1 to 5, usually opposite the petals, or rarely
alternate, arising from the bottom of the calyx, most of them
sterile. Ovary superior or partially inferior, 3-celled, or rarely
l-celled; placentas axile; style and stigma 1. Fruit usually
capsular, 8-cornered, 3-celled, with loculicidal dehiscence; or
rarely indehiscent and 1-celled. Sceds usually winged, without
albumen, erect.

This order is, on account of its Calycitloral character, fre-
quently placed near Combretacea, but it is readily distinguished
from it by its superior or nearly superior ovary. Lindley
considered it most nearly allied to the Violacee and the Poly-
galacee—hence we place it here.
286 MANUAL OF BOTANY

Distribution and Numbers.—Natives of equinoctial America.
Illustrative Genera :—Vochysia, Juss. ; Salvertia, St. Hil. There
are about 50 species.

Properties and Uses.—Generally unimportant, although some
are said to form useful timber.

Cohort 4.—Caryophyliales.

Order 8. FRANKENIACER, the Frankenia Order.—Character.
—Herbs or wndershrubs, much branched, with small opposite
exstipulate leaves, and sessile flowers. Calyz tubular, furrowed,
persistent. Petals unguiculate, 4-6, hypogynous. Stamens 4 or
more, hypogynous, distinct or connate at the base. Ovary
superior, 1-celled, with parietal placentas. Fruit capsular,
1-celled, enclosed in the calyx, and dehiscing in a septicidal
munner. Seeds numerous, minute; embryo straight, erect, in the
middle of mealy albumen.

Distribution and Numbers. —The plants of this order are
scattered over the globe, except in tropical India and North
America, but they occur chiefly in the south of Europe and
north of Africa. Illustrative Genera :—Frankenia, Linn. ;
Beatsonia, Roxb. There are about 24 species.

Properties and Uses.—Unimportant. They have been
reputed mucilaginous and slightly aromatic. The leaves of a
species of Beatsonia are used at St. Helena asa substitute for
tea.

Order 69. CARYOPHYLLACEA, the Pink Order.—Character.
—Herbs. Stems swollen at the nodes. Leaves opposite, entire,
exstipulate, or with small membranous stipules, often connate
at their base. Inflorescence cymose. IFlowers generally herma-
phrodite, or rarely unisexual. Sepals 4 or 5, distinct or united
into a tube, persistent. Petals equal in number to the sepals,
hypogynous, unguiculate, often deeply divided, sometimes ab-
sent, frequently raised above the calyx on a stalk. Stamens
equal in number to the sepals, and then either alternate or
opposite to them, or usually twice as numerous, or rarely fewer,
frequently attached with the petals on a stalk above the calyx ;
filaments generally distinct, or sometimes united at the base,
subulate ; anthers innate. Ovary sessile, or supported with the
petals and stamens on a short gynophore, generally 1-celled, and
with a free central placenta, or rarely 2—5-celled; styles 2 to 5,
papillose on their inner surface; ovules few or numerous,
amphitropous. Jruita 1-celled capsule, opening by 2—5 valves,
or by 4—10 teeth at the apex, and having a free central placenta,
DICOTYLEDONES—THALAMIFLOR/ 287

or rarely 2—5-celled with a loculicidal dehiscence, and with
the placentas slightly attached to the dissepiments. Seeds
usually numerous, rarely few; embryo curved round the
albumen, which is of a mealy character, or rarely straight.
Diagnosis.—Herbaceous plants with the stems swollen at
the nodes, and opposite entire exstipulate leaves; or rarely with
small membranous stipules. Inflorescence cymose. Flowers
usually hermaphrodite. Sepals, petals, and stamens with a
quaternary or quinary arrangement, the petals sometimes absent.
Calyx persistent. Stamens hypogynous; anthersinnate. Ovary
commonly 1-celled, styles 2—5. Capsule 1-celled, or rarely 2—5-
celled; placenta usually free central, or in the 2—5-celled
fruit slightly attached to the dissepiments. Seeds with the
embryo curved round mealy albumen; or rarely straight.
Division of the Order and Illustrative Genera.—The order
has been divided into four tribes or sub-orders as follows :—

Tribe 1. Alsinew.—sSepals distinct, and opposite the stamens
when the latter are equal to them in number. Styles free.
Stipules none, or small and membranous. T/lustrative
Genera :—Alsine, Wahlenbd.; Stellaria, Linn.; Spergula,
Linn.

Tribe 2. Silenee.—Sepals cohering into a tube, and opposite
the stamens when the latter are equal to them in number.
No stipules. Illustrative Genera:—Dianthus, Linn. ;
Lychnis, Linn.

Tribe 38. Molluginee.—Sepals distinct or nearly so, and alter-
nate with the stamens when the latter are equal to them in
number. If the stamens are fewer than the sepals, they
are then alternate with the carpels. No stipules. [l/ustrative
Genera :—Mollugo, Linn.; Cvelanthum, H. Mey.

Tribe 4. Polycarpee.—Sepals distinct. Ovary segsile. Styles
connate at the base. Stipules membranous. Illustrative
Genus :—Polycarpon, Linn.

Distribution and Numbers.—They are natives chiefly of tem-
perate and cold climates, When found in tropical regions they
are generally on the sides and summits of mountains, commonly
reaching the limits of eternal snow. The order contains nearly
1,100 species.

Properties and Uses.—The plants of this order possess no
important properties. They are almost always insipid. Some
of the wild species are eaten as food by small animals, and some
have been said to increase the lacteal secretions of cows fed upon
288 MANUAL OF BOTANY

them. This is supposed to be the case more particularly with
Vaccaria vulgaris. Saponaria officinalis has been used in
syphilis ; it contains a peculiar principle called saponin. This
principle has also been found in species of Lychnis, Silene,
Cucubalus ; and more especially in Gypsophila Struthium, to
which latter plant it communicates well-marked saponaceous
properties: hence it is commonly termed Egyptian Soap-root.
The other species in which saponin is found also possess, to

Fie. 1057. Fie. 1058.

  

Fic. 1059. Fie. 1060. Fie. 1061.

Fig. 1057. Diagram of the flower of a species of Dianthus, — Fiy.1058. Ver-
tical section of the flower of the sume. — Fig. 1059. Sporophylls of a
species of Ste/laria.—— ig. 1060. Capsule of a species of Dianthus, dehiscing
partially in a valvular manner so as to form four teeth at the apex.—
fig. 1061, Vertical seztion of the seed of Chickweed (Stellaria media).|

some extent, similar properties. Saponin is reputed to be
poisonous in its nature.

Some of the plants have showy flowers, as the species of
Dianthus, Silene, and Lychnis; but they are generally insig-
nificant weeds. Dianthus barbatus is the Sweet- William of our
gardens; D. plumarius is the parent of all the cultivated
varieties of the common Pink; and D. Caryophyllus, the Clove
Pink, is the origin of the Carnation and its cultivated varieties,
DICOTYLEDONES—THALAMIFLORA 289

which are commonly known as Picotees, Bizarres, and
Flakes.

Order 70. Paronycuraces, the Knotwort Order.—Cha-
racter.—Herbs or shrubs, with entire, simple, alternate or
opposite leaves, and membranous stipules. Flowers minute.
Sepals 5, or rarely 8 or 4, distinct or more or less united. Petals
small or absent, perigynous. Stamens perigynous or somewhat
hypogynous, either equal in number to the sepals and opposite
to them, or more numerous, or rarely fewer. Ovary superior,
1- or 3-celled; styles 2—5. Fruit dry, 1- or 3-celled, dehiscent
or indehiscent. Seeds either numerous upon a free central
placenta, or solitary on a long funiculus arising from the base of
the fruit ; albumen farinaceous; embryo curved.

In the tribe Scleranthe there are no stipules.

Distribution and Numbers.—Natives chiefly of barren places
in the south of Europe and the North of Africa, Illustrative
Genera :—Wlecebrum, Linn.; Corrigiola, Linn. There are about
100 species.

Properties and Uses.—Slightly astringent.

Order 71. PorTuLacacE# the Purslane Order.—Character.
—Sueculent herbs or shrubs, with entire exstipulate leaves.
Flowers unsymmetrical. Sepals 2, or rarely more, united at
the base. Petals usually 5, distinct or united. Stamens peri-
gynous or hypogynous, varying in number, sometimes opposite
to the petals; filaments distinct; anthers 2-celled, versatile.
Ovary superior, or rarely partially adherent. Fruit capsular,
usually dehiscing transversely, or by valves; sometimes indehis-
cent; placenta free central. Seeds numerous or solitary ;
embryo curved round farinaceous albumen.

Distribution and Numbers.—Natives of waste dry places in
various parts of the world, but chiefly at the Cape of Good
Hope andin South America. Illustrative Genera :—Portulaca,
Tourn.; Claytonia, Linn. There are about 190 species.

Properties and Uses.—The fleshy root of Claytonia tuberosa
is edible. Portulaca oleracea has been used from the earliest
times as a pot-herb, and in salads. It possesses cooling and
antiscorbutie properties. Many of the plants have large showy
flowers.

Order 72. TAMARICACEA, the Tamarisk Order.—Character.
—Shrubs or herbs, with alternate entire scale-like leaves and
spiked or racemose inflorescence. Calyx 4—5-partite, imbri-
cate, persistent. Petals distinct, and attached to the calyx,
withering, imbricate. Stamens hypogynous; anthers introrse.

VOL. IL, U
290 MANUAL OF BOTANY

Ovary superior, 1-celled, with 3 distinct styles. Fruit 1-celled,
with 8 parietal or basal placentas, and dehiscing loculicid-
ally by 3 valves. Seeds numerous, comose, without albumen,
and having a straight embryo, with the radicle towards the
hilum.

Distribution and Numbers:—The plants of this order
usually grow by the seaside, or sometimes on the margins of
rivers or lakes. They are most abundant in the basin of the
Mediterranean, and are altogether confined to the northern
hemisphere of the Old World. Illustrative Genera :—Tamarix,
Linn. ; Myricaria, Desv. ‘There are about 40 species.

Properties and Uses.—The bark of these plants is astringent,
slightly bitter and tonic. The ashes of some species of Tamarix
contain much sulphate of soda.

Order 73. REAUMURIACEA, the Reaumuria Order.—This small
order was first instituted by Ehrenberg. The plants belonging
to it do not differ greatly from Hypericacex, except that they
have a pair of appendages at the base of the petals, and shaggy
seeds with a small quantity of mealy albumen. Bentham and
Hooker refer them to Tamaricacee.

Distribution and Numbers.—Natives of the coast of the
Mediterranean and the salt plains of Northern Asia. Illustrative
Genus :-—Reaumuria, Hasselg. There are 4 species.

Cohort 5.—Guttiferales,

Order 74. WLatiInace®, the Water-pepper Order.—Charac-
ter.—Little annual marsh plants, with hollow creeping stems,
and opposite leaves with interpetiolar membranous stipules.
Flowers small and axillary. Sepals and petals 3—5, the latter,
as well as the stamens, being distinct and hypogynous. Ovary
superior ; styles 83—5; stigmas capitate. Fruit capsular, 3—5-
celled, placentation axile; dehiscence loculicidal. Seeds nume-
rous, exalbuminous; embryo straight. This order has been
variously placed, but it appears to be most nearly related to
Hypericacee, although in some respects resembling the Alsinex
of the Caryophyllacez.

Distribution and Numbers.—The plants of this small order
are scattered all over the world. Illustrative Genera :—FElatine,
Linn.; Merimea, Camb. Lindley enumerates 22 species.

Properties and Uses.—They are generally considered acrid,
hence the English name of the order.

Order 75. WHypsricacem®, the St. John’s Wort Order.—
Character.—Herbs, shrubs, or trees. Leaves opposite or very
DICOTYLEDONES—THALAMIFLORA 291

rarely alternate, exstipulate, simple, entire, often dotted; some-
times bordered with black glands. Flowers regular. Sepals 4 or
5, persistent, unequal, distinct or united at the base, imbricate.
Petals equal in number to the sepals, hypogynous, unequal-
sided, frequently bordered with black glands; estivation twisted.
Stamens usually numerous, rarely few, hypogynous, polyadel-
phous, or rarely distinct, or monadelphous, sometimes having
glands alternating with the bundles of stamens; filaments
filiform; anthers 2-celled, with longitudinal dehiscence. Ovary
1-celled, formed of from 8 to 5 carpels, which are partially
inflected so as to project into the cavity; or 83—5-celled by the
union of the dissepiments in the centre; sty/es equal in
number to the carpels; stigmas usually capitate or truncate,
rarely 2-lobed. Fruit capsular, usually 83—d-celled, sometimes

Fic. 1062. Fie. 1063. Fic. 1064.

 

Fig. 1062. Diagram of the flower of a species of St. John’s Wort (Huperi-
cum).——ig. 1063. Vertical section of the flower of the same._—ig. 1064.
Vertical section of the seed.

l-celled; placentas axile or parietal, dehiscence septicidal.
Seeds minute, numerous, exalbuminous; embryo straight or
curved.

Diagnosis.—Leaves entire, often dotted, exstipulate. Flowers
regular. Sepals and petals hypogynous, with a quaternary or
quinary distribution ; the former with an imbricate estivation ;
the latter unequal-sided, commonly marked with black glands,
and having a twisted estivation. Stamens hypogynous, usually
numerous and polyadelphous, rarely few, and then distinct or
monadelphous ; anthers 2-celled, opening longitudinally. Styles
several. Fruit 1-celled, or 3—5-celled. Seeds numerous, ex-
albuminous. .

Distribution and Numbers.—The plants are generally dis-
tributed over the globe, inhabiting both temperate and hot
regions, and almost all varieties of soil. Illustrative Genera :—
Hypericum, Linn.: Vismia, Vell. There are about 280 species,

v2
292 MANUAL OF BOTANY

Properties and Uses.—They abound usually in a resinous
yellow juice, which is frequently purgative, as in Vismia
guanensis and V. micrantha. Other plants of the order,
as Hypericum perforatum and H. Androsemum, have tonic
and astringent properties, and Cratoxylon Hornschuchti is
slightly astringent and diuretic.

Order 76. GUTTIFERE or CLusIAcEz, the Gamboge or
Mangosteen Order.—Character.— Trees or shrubs, sometimes
parasitical, with a resinous juice. Leaves coriaceous, entire,
simple, opposite, exstipulate. Flowers usually perfect, some-
times unisexual by abortion. Sepals 2, 4, 5, 6, or 8, imbricate,
usually persistent, frequently unequal and petaloid. Petals
hypogynous, equal in number to, or a multiple of, the sepals,

sometimes passing by im-
Fre. 1065. perceptible gradations into
them. Stamens usually
numerous, rarely few, hy-
pogynous, distinct, mona-
delphous, or  polyadel-
phous; anthers adnate, not
beaked, introrse or extrorse,
opening by a pore or trans-
verse slit, 2-celled or some-
times 1-celled. Disc fleshy,
or rarely with five lobes.
: ; ; Ovary superior, 1- or many-
Fig. 1065. Flowering stem and fruit of the

Mangosteen plant (Gareinia Mangostana). celled ; style absent ;
stigmas peltate or radiate ;

placentas axile. Fruit dehiscent or indehiscent, 1- or many-
celled. Seeds solitary oy numerous, frequently arillate, without
albumen ; embryo large, straight, with minute cotyledons.

Diagnosis.—Trees or shrubs with a resinous juice, and with
opposite, simple, coriaceous, exstipulate leaves. Sepals and
petals usually having a binary arrangement of their parts; the
former imbricate and frequently unequal; the latter equal and
hypogynous. Stamens almost always numerous; anthers
adnate, without a beak, opening by a pore or transversely.
Dise fleshy or lobed. Ovary superior, with sessile radiate
stigmas, and axile placentas. Seeds exalbuminous; cotyledons
minute.

Distribution and Numbers.—Exclusively tropical, and
especially occurring in moist situations. The larger proportion
are natives of South America, but a few occur in Madagascar

 
DICOTYLEDONES—THALAMIFLORA 293

‘and the African continent. Tllustrative Genera :—Clusia,
Linn. ; Garcinia, Linn. There are about 250 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for yielding a yellow gum-resin of an acrid and
purgative nature. In many cases, however, the fruits are edible,
and are held in high estimation for their delicious flavour. The
seeds of some are oily, and other plants of the order are good
timber-trees.

Order 77. TERNSTREMIACEZE or CAMELLIACES, the Tea Order.
—Character.—Trees or shrubs. Leaves leathery, alternate,
usually exstipulate, and sometimes dotted. lowers regular,
and generally very showy, rarely polygamous. Sepals 5 or 7,
coriaceous, imbricate ; often deciduous. Petals 5, 6, or 9, often
united at the base, imbricate. Stamens hypogynous, numerous,
distinct or united by their filaments into one or several bundles ;
anthers 2-celled, versatile or adnate. Ovary superior, many-
celled; styles filiform, 3—7. Fruit capsular, 2—7-celled; pla-
centas axile; dehiscence various. Seeds few, sometimes arillate ;
albwmen wanting or in very small quantity ; embryo straight or
folded; cotyledons large and oily; radicle towards the hilum.

Diagnosis.—Trees or shrubs, with alternate usually exstipu-
late leathery leaves. Sepals and petals imbricate in estiva-
tion, and having no tendency to a quaternary arrangement.
Stamens numerous, hypogynous; anthers versatile or adnate.
Ovary superior, styles filiform. Seeds solitary or very few,
attached to axile placentas; albumen wanting or in very small
quantity.

Distribution and Numbers.—These plants, which are mostly
ornamental trees or shrubs, are chiefly natives of South America,
but a few are found in the Hast Indies, China, and North
America. One species only occurs in Africa. There are no
European species, although a few are cultivated in Europe.
Illustrative Genera :—Ternstremia, Mut.; Camellia, Linn.
The order, as defined above, following Lindley, contains about
130 species.

Properties and Uses.—Generally speaking, we know but little
of the properties of the plants of this order; but some, as those
from which China tea is prepared, are moderately stimulant,
astringent, and slightly soothing and sedative.

Order 78. MarcGRAAVIACE, the Marcgraavia Order.—Dia-
gnosis.—This is a small order which is generally regarded as
allied to Clusiacee and Hypericacee. The species belonging to
it are chiefly distinguished from Clusiacee by their unsymmetri-
294 MANUAL OF BOTANY

cal flowers, versatile anthers, and very numerous minute seeds.
Some genera of the order are remarkable for their peculiar bracts,
which become hooded, pouched, or spurred. They are distin-
guished from Hypericacer chiefly by their unsymmetrical
flowers, equal-sided petals, distinct stamens, and sessile stigmas.
They are sometimes placed as a tribe of Ternstremiacee.

Distribution and Numbers.— Generally natives of equinoc-
tial America. Illustrative Genera :—Ruyschia, Jacg.; Mare-
graavia, Plum. There are 26 species.

Properties and Uses.—Scarcely anything is known of their
properties. Marcgraavia umbellata is reputed to be diuretic and
antisyphilitic.

Order 79. RuizoBoLaces, the Souari-nut Order.—Cha-
racter.—Large trees. Leaves opposite, coriaceous, digitate,
exstipulate, with an articulated stalk. Sepals 5 or 6, more or
less united, imbricate. Petals 5 to 8, unequal. Stamens very
numerous, slightly monadelphous, in two whorls, the inner
shorter and often abortive. inserted with the petals on an hypo-
gynous disc; anthers 2-celled, with longitudinal dehiscence.
Ovary 4-, 5-, or many-celled ; styles short, as many as the cells
of the ovary; stigmas sniall; ovules solitary, attached to the
axis. Fruit consisting of several combined indehiscent 1-seeded
nuts. Seeds reniform, exalbuminous, with the funiculus expanded
so as to form a spongy excrescence ; radicle very large, forming
the great bulk of the embryo; cotyledons very small. This
order is frequently incorporated with the Ternstreemiaces.

Diagnosis.—Large trees, with opposite digitate exstipulate
leaves, with an articulated stalk. Flowers regular, hypogynous.
Petals equal-sided, and inserted with the numerous stamens on
an hypogynous disk. Styles very short. Seed solitary, exalbu-
minous, with a very large radicle, and two very small coty-
ledons.

Distribution and Numbers.—The order contains but 2
genera, including 8 species, all of which are large trees, natives
of the forests in the hottest parts of South America. Itlustrative
Genus :—Caryocar, Linn.

Properties and Uses.—Some of the trees are valuable for
their timber, others yield edible nuts, and some an excellent
oil.

Order 80. DiprERAcEs, the Sumatra Camphor Order.
—Character.—Large trees with a resinous juice. Leaves
alternate, involute, feather-veined, with large convolute
deciduous stipules. Calya 5-lobed, tubular, unequal, persistent,
DICOTYLEDONES—THALAMIFLORA 295

imbricate, ultimately enlarged into winglike expansions. Petals
5, hypogynous, often'coherent at the base; estivation twisted.
Stamens numerous, hypogynous, distinct or united in an irregular
manner by their filaments so as to become somewhat poly-
adelphous ; anthers innate, 2-celled, subulate, prolonged above
or beaked. Ovary superior, 3-celled; ovules pendulous; style
and stigma simple. Fruit 1-celled, dehiscent or indehiscent,
surrounded by the enlarged permanent calyx. Seed solitary,
exalbuminous ; radicle superior.

Distribution and Nuwmbers.—Natives exclusively of the
forests of the tropical Hast Indies, with the exception of the
genus Lophira, which belongs to tropical Africa. (The latter
genus, by Endlicher and others, has been separated from the
Dipteracez, and placed in an order by itself under the name of
Lophiracee. The chief characters of distinction are its 1-celled
ovary with numerous ovules on a free central placenta, and its
inferior radicle.) Illustrative Genera :—Dipterocarpus, Gértn.;
Dryobalanops, Garin. There are about 50 species belonging to
this order.

Properties and Uses.—These plants form very large and
handsome trees, which abound in an oleo-resinous juice. To
the presence of this they owe their peculiar properties.

Order 81. CHLmNacrem, the Sarcolena Order.--Character.
—Trees or shrubs. Leaves entire, alternate, with large deciduous
convolute stipules. Flowers regular, unsymmetrical, furnished
with an involucre: the involucre surrounding 1—2 flowers, and
persistent. Sepals 8, imbricate. Petals 5, convolute, sometimes
united at the base. Stamens generally very numerous, rarely
but 10, monadelphous; anthers roundish, 2-celled. Ovary 3-
celled; style 1; stigma trifid. Fruct capsular, 3-celled or rarely
1-celled ; placentas axile. Seeds solitary or numerous, suspended ;
embryo in the axis of fleshy albumen ; cotyledons leafy ; radicle
superior.

Diagnosis.—Readily distinguished among the Thalamiflore
by ‘their alternate simple stipulate leaves and involucrate
flowers, which are regular and unsymmetrical. The calyx is
also imbricate, the stamens monadelphous, and the seed has
abundant albumen.

Distribution and Numbers.—There are but 8 species in-
cluded in this order, all of which are natives of Madagascar.
lllustrative Genus :—Sarcolena, Thouars.

Properties and Uses.—Altogether unknown.
295 MANUAL OF BOTANY

Cohort 6.—Malwvales.

Order 82. Matvacem®, the Mallow Order.—Character.—
Herbs, shrubs, or trees. Leaves alternate, often downy, more or
less divided in a palmate manner, stipulate. Flowers regular,
usually axillary, and often surrounded by an involucre or
epicalyx. Sepals usually 5, rarely 3 or 4, more or less united ;
with valvate or some form of circular estivation. Petals

Fie. 1066. Fie. 1067.

 

Fiy. 1066. Diasram of tle flower of a species of Malva. Thi three external
lines represent bracts, which together form an epicalyx or involucre.——
Fig. 1067. Vertical section of the flower of a Malow.— iy. 1068. Pistil of
the same surrounded by the inferior calyx and involucre.-—Fig. 1069.
Horizontal section of the fruit of Malva sylvestris. a. Axis, pl. Placenta,
7. An empty cell. c. Embryo with twisted cotyledons.

hypogynous, equal in number to the divisions of the calyx, with
a twisted estivation, either attached to the column formed by
the united stamens or free. Stamens hypogynous, numerous,
monadelphous; anthers 1-celled, reniform, with transverse
dehiscence. Ovary superior, consisting of several carpels,
which are either apocarpous, or united so as to form a compound
‘ovary with as many cells as there are carpels; placentas
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DICOTYLEDONES—THALAMIFLORA 279

attached to the ventral sutures when the carpels are apocarpous,
or axile when the ovary is compound; styles equalling the
carpels in number, united or distinct. Fruit either a carcerule,
that is, consisting of a number of 1-celled, indehiscent, 1- or
many-seeded carpels; or a capsule with loculicidal or septicidal
dehiscence, and numerous seeds. Seeds sometimes hairy;
albumen none or in small quantity ; embryo curved; cotyledons
much twisted.

Diagnosis.—Leaves alternate, palmately veined, simple,
stipulate. Flowers regular. Calyx with valvate or some form
of circular estivation. Petals twisted in estivation. Stamens
hypogynous, numerous; anthers 1-celled, reniform, dehiscing
transversely ; filaments united so as to form a column. Carpels
distinct or united. Seeds with very little or no albumen;
embryo curved; cotyledons twisted.

Division of the Order and Illustrative Gencra.—This order
may be divided into three tribes as follows :—

Tribe 1. Malvee.—Flowers furnished with an involucre or epi-
calyx (jig. 1066). Fruit consisting of separate carpels (apo-
carpous) (fig. 1069). Illustrative Genera :—Malva, Linn. ;
Althea, Linn.

Tribe 2. Hibiscee.—Flowers furnished with an involucre.
Fruit formed of united carpels (syncarpous). Illustrative
Genera :—Hibiscus, Linn.; Gossypium, Linz.

Tribe 3. Sidee.—Flowers without an involucre. Fruit
apocarpous or syncarpous. Illustrative Genus :—Sida,
Linn.

Distribution and Numbers.—These plants are chietly
natives of the tropics and the warmer parts of temperate regions.
They diminish gradually as we approach the north, and are
altogether absent from the frigid zone. There are more than
1,000 species.

Properties and Uses.—No plant of this order possesses any
deleterious properties. The order is generally characterised by
mucilaginous and demulcent qualities. From the bast of many
species strong and tough fibres are obtained, and the hairs cover-
ing the seeds of certain species constitute cotton.

Order 83. SteRcuLiaces, the Silk-cotton Order.—C harac-
ter.—Trees or shrubs, sometimes climbing. Leaves alternate,
simple or compound, with deciduous stipules. Flowers usually
perfect, sometimes by abortion unisexual, regular or irregular,
often surrounded by an involucre. Calyx and corolla resem-
=00 MANUAL OF BOTANY

Division of the Order and Illustrative Genera.—The order has
been divided into two tribes, as follows :—

Tribe 1. Tiliee.—Corolla with entire petals, or wanting ; anthers
dehiscing longitudinally. Illustrative Genera :—Corchorus,
Linn.; Tilia, Linn.

Tribe 2. Eleocarpee.—Petals divided, anthers opening by pores
at the apex. Illustrative Genera :—Eleocarpus, Linn. ;
Vallea, Mut.

Distribution and Numbers.—A few are found in the northern
parts of the world, where they form large trees; but the plants
of this order are chiefly tropical, and are there found as herbs,
shrubs, or trees. There are about 350 species. ;

Properties and Uses.—In their properties the Tiliacee re-
semble the Malvaceex. They are altogether innocuous, and are
generally mucilaginous, emollient, and demulcent. Many of
them also yield fibres, which are much used for manufacturing
purposes. Some are valuable timber-trees, and some have
edible fruits.

Artificial Analysis of the Orders in the Sub-class Polypetale.
Series 1. THaLAMIFLORE.

1. FLowERs with more than 20 stamens.

A. Leaves without stipules.
a. Carpels more or less distinct (at least as to
the styles), or solitary.

1. Stamens distinct.
Carpels immersed in a fleshy tabular tha- ; Nympheacee
lamus \ (Nelumbonee).
Carpels not immersed in a thalamus.

Embryo with endosperm and perisperm { ss aa

Embryo naked, very minute.

Seeds arillate . ‘ . Dilleniacee.
Seeds exarillate. Albumen fleshy and
homogeneous.
Flowers hermaphrodite Ranunculacee.
Flowers unisexual : Schizandracee.
Seeds usually exarillate. Albumen ru-
minated . Anonacee.

2. Stamens united in one or more parcels.
Calyx imbricate.
Seeds smooth . Hypericacee.
Seeds shaggy » i . Reaumuriacee.
DICOTYLEDONES—THALAMIFLORZ 301

b. Carpels wholly combined (at least as to the
ovaries), with more than one placenta ; or
with a free central placenta.

Placentas parietal, in distinct lines.

Anthers versatile. Juice watery Capparidacee.
Anthers innate. Juice milky ‘ . Papaveracee.
Placentas parietal, spread over the lining of
the fruit. : 2 Bixacee.
“ . . Nympheacee
Placentas covering the dissepiments { CM yateplicea’),
Placentas in the axis.
Stigma large, broad, and petaloid . Sarracentacee.
Stigma simple. Calyx imbricate.
Leaves compound Rhizobolacea.

Leaves simple.
Petals equal in number to the sepals.

Seeds few a : ; Guttifere.
Seeds numerous. Petals flat. Marcgraaviacee.
Seeds numerous. Petals crumpled Cistacee.
Petals not equal in number to the sepals.
Styles not perfectly combined Ternstramiacee.
Placentas free central Portulacacee.

B. Leaves with stipules.
a. Carpels more or less distinct (at least as to
the styles).
Carpels numerous ‘ Magnoliacee.

b. Carpels wholly combined (at least as to the
ovaries), with more than one placenta.
Placentas parietal . Bixacee.
Placentas in the axis.
Calyx with an imbricate sestivation.
Flowers involucrate . i Chlenacee.
Flowers not involucrate . Cistacee.
Calyx with a valvate estivation.
Stamens monadelphous. Anthers 2-celled Sterculiacee.
Stamens monadelphous. Anthers 1-celled Malvacee.
Stamens monadelphous. Calyx irregular,
and enlarged in the fruit Dipteracee.
Stamens quite distinct Tiliacee.

2. FLOWERS with less than 20 stamens.

A. Leaves without stipules.
a. Carpels more or less distinct, or solitary.
Anthers with recurved valves . Berberidacee.
Anthers with longitudinal dehiscence.
Albumen abundant, embryo minute.
Flowers unisexual. Seeds usually nu-

merous Lardizabalacee.
3( 302

Flowers perfect.
Embryo with
sperm .
Embryo without perlaper ‘m.
Albumen homogeneous.
Sepals 2
Sepals more than 2 . ;
Albumen ruminated. Shrubs
Albumen in small quantity, or alto-
gether wanting.
Flowers unisexual
Flowers perfect

er and peri-

b. Carpels wholly combined (at least as to the
ovaries).

Placenta parietal.

Stamens tetradynamous
Stamens not tetradynamous.
Large hypogynous disc.

Flowers tetramerous.
the apex . . }
Flowers not tetramerous. Unripe fruit
usually open at the apex. é
Small hypogynous disc, or none.
Albumen abundant.
Flowers irregular :
Flowers regular. Sap milky.
without central pulp
Fruit with central pulp, or fleshy,
Sap watery
Albumen in small quantity, or camitines:
Calyx tubular, furrowed

Fruit closed at

Fruit

Placentas covering the dissepiments

Placentas axile or free central.
Styles distinct to the base.
Calyx imbricate.
Seeds smooth. Petals unequal-sided,
without appendages .
Seeds shaggy. Petals nuequal-eided,
usually with appendages at the base
Calyx slightly imbricate.
Petals not twisted in estivation.
Ovary with a free central placenta
Styles more or less combined.
Calyx imbricate, in an irregular broken
whorl,
Flowers symmetrical
Flowers unsymmetrical, pauiliowseagits

MANUAL OF BOTANY

N ympheacee
(Cabombee).

Fumariacee.
Ranunculacee.
Anonacee.

Menispermacee.
Calycanthacee.

Cruciferae.

Capparidaree.

Resedacee.

PFumariacee.,
Papaveracee.
Bixacee.
Frankeniacew,

Nympheacee
(Nymphee).

Hypericacee.

Reaumuriacee.

Caryophyllacee.

Guttifere.
Polygalacee.
DICOTYLEDONES—THALAMIFLORA

Calyx slightly imbricate, in a complete
whorl.
Carpels 4 or more.

Ovary 1-celled, with a free central

placenta
Carpels less than 4.
Seeds comose
Seeds not comose.
Ovules pendulous.
in estivation
Ovules ascending or horizontal.
Petals imbricate in estivation
Calyx valvate, or but very slightly im-
bricate.
Anthers opening by pores
B. Leaves with stipules.
a. Carpels distinct, or solitary.

Anthers with recurved valves. Carpel solitary
b. Carpels wholly combined (at least as to the
ovaries), with more placentas than one.

Placentas parietal.

Petals twisted

Leaves with involute vernation. Anthers
crested, and turned inwards

Stamens opposite to the petals. Anthers
naked, and turned outwards

Placentas in the axis.
Styles distinct to the base.
Calyx imbricate, in an irregular broken
whorl.
Petals small, sessile
Calyx slightly imbricate, in a complete
whorl.
Petals minute .
Calyx valvate
Styles more or less easing,
Calyx imbricate, in an irregular broken
whorl.
Flowers surrounded by an involucre
Calyx slightly imbricate, in a complete
whorl.
Sepal spurred .
Calyx valvate.
Stamens united by their filaments into a
column
Stamens not united jets a column .

303

Portulacacee.

Tamaricacee.

Canellacee.

Pittosporacee.

Tremandracee.

Berberidacee.

Violacee.

Sauwvagesiacee.

Elatinacee.

Paronychiacee.
Tiliacee.

Chlenacee.

Vochysiacea.

Sterculiacee.
Tiliacee.

In order to prevent the student being misled, and thus referring plants
to their wrong positions in the Vegetable Kingdom, it should be particularly
noticed, that although the general character of the Thalamiflore is to have
dichlamydeous flowers and polypetalous corollas, yet exceptions do occur
304 MANUAL OF BOTANY

occasionally to both these characters. Thus, we find apetalous genera and
species in Ranunculaceae, Magnolvacee, Berberidacee, Sarraceniacee,
Menispermacee, Papaveracee, Crucifere, Canellacee, Bixacee, Vio-
lacee, Caryophyllacee, Paronychiacee, Scleranthacee, Malvaceae,
Sterculiacee, and Tiliacee.

Again, in the orders Anonacee, Pittosporacee, Polygalacee. Portu-
lacacee, Tamaricucea, Ternstremiacee, Rutacee, and Dipteracee, we
find some monopetalous species and genera.

In Dilleniaceea, Papaveracee, Capparidacee, Resedacee, Violacea,
Caryophyllacee, Portulacacee, Malvacee, and Sterculiacee, some of
the species have stamens more or less perigynous instead of hypogynous.
Again, in some orders, as in certain Ranunculaceae, Calycanthacee,
nonacea, Nympheacee, Portulacacee, Capparidacee, Polygalacee,
Bixacee, Ternstremiacee, Vochysiacer, Tiliacea, and Dipteracea, the
calyx is more or less superior.

Synopsis of the British Natural Orders of the Series Thalamiflore.

A. Corolla polypetalous, hypogynous.
1. Ovaries many, distinct or united, each with
a style, or solitary with one lateral placenta.
Corolla regular.
Sepals free. Stamens hypogynous.
Stamens x, usually many. Anthers de-

hiscing by slits Ranunculacee.
Stamens equal and opposite to petals.
Anthers dehiscing by valves , . Berberidacee.

Corolla irregular.
Leaves exstipulate. Stamens diadelphous . Fumariacee.

2. Ovary solitary, with parietal placentation.
Corolla regular.

Petals 4.
Stamens x. Sepals 2, fugacious . Papaveracee.
Stamens tetradynamous. Crucifere.
Petals 5.

Sepals distinct, 3 inner twisted in the bud,
2 outer smaller or wanting. Stamens © Cistacee.
Sepals united below. Stamens iso- or

diplostemonous inserted onadise . Tamaricacee.
Petals 4-5, clawed. Placentas 3 . . PFrankeniacee.
Petals and sepals acyclic ‘ . Nympheacee.

Corolla irregular.
Leaves stipulate. Sepals 5. Stamens 5 free Vivlacee.
Leaves exstipulate. Fruit open at the end.
Stamens 0. ‘i n ‘ s . Resedacee.
8. Ovary solitary, with axile or free central pla-
centation.
Calyx imbricate in bud.
Corolla regular.
Placentation free central.
{ Caryophyllacee

Calyx tubular . (Silenea),
DICOTYLEDONES—DISCIFLORA 805

Sepals. distinct.
Stamens opposite to the petals.
Sepals 2 ‘ Portulacacee.
Sepals 3-5.
Stamens 10 or fewer. Sti- Caryophyllacee
pules 0 5 (Alsinee).
Stamens 5. Leaves stipulate, | Caryophyllacee
Petals distinct , (Polycarpee).
Petals minute or 0 Paronychiacee.
Placentation axile.
Stamens free. Styles 3-5 Elatinacee.
Stamens polyadelphous . Hypericacee.
Calyx valvate in the bud.
Stamens columnar Malvacee.
Stamens free é : Tiliacee.
B. Corolla partly gamopetalous, or with petals
slightly united at their base . Polygalacee.

Series II.—Disciflore.
Cohort 1.—Geraniales.

Order 85. Linacrm, the Flax Order.—Character.—Herbs
or rarely shrubs. Leaves alternate, opposite, or rarely verticil-
late, simple, entire, exstipulate, or rarely stipulate. Injlores-

Fie. 1073. Fie. 1074. Fie. 1075.

 

Fig. 1073, Diagram of the flower of the Flax Plant (Linum usitatissimum).
Fig. 1074. Sporoplylis of the same, showing the monadelphous stamens
surrounding the pistil——/ig. 1075. Pistil of the same, with distinct
styles and capitate stigmas.

 

cence cymose. Flowers regular, symmetrical, generally very
showy. Calyx imbricate, with 8, 4, or 5 sepals, persistent.
Petals 4—5, unguiculate, very deciduous, twisted in estivation.
Stamens 4—5, united at the base so as to form an hypogynous
VOL. II. x

wheal
306 MANUAL OF BOTANY

ring, from which proceed 5 tooth-like processes (staminodes)
which alternate with the fertile stamens, and are opposite to
the petals. Disc none or glandular. Ovary compound, its
cells usually corresponding in number to the sepals; styles 3—
5; stigmas capitate. Fruit a septicidal capsule, each cell more
or less perfectly divided into two by a spurious dissepiment
proceeding from the dorsal suture, and having a single seed in
each division. Seed compressed, with or without albumen;
embryo straight, with the radicle towards the hilum.

Diagnosis.—Herbs or very rarely shrubs, with simple entire
leaves, which are usually exstipulate. Flowers regular, sym-
metrical. Sepals, petals, and stamens 3—5 each; the sepals
persistent and imbricate; the petals fugacious and twisted in
estivation ; the fertile stamens united at their bases, and having
little tooth-like staminodes alternating with them. Ovary 3—5-
celled, styles distinct, stigmas capitate. Fruit a septicidal
capsule, each cell more or less divided by a spurious dissepiment,
and each division containing one seed. Seeds compressed, with
or without albumen, and a straight embryo.

The plants of the order Hrythrorylacee of some botanists,
which, following Bentham and Hooker, we include in this order,
are exceptional in each petal having at its base two scales, in
their drupaceous fruit, and woody stem.

Distribution and Numbers.—Chiefly natives of the south of
Europe, Brazil, and some other parts of South America, West
Indies, and the north of Africa, but more or less distributed
over most regions of the globe. Illustrative Genera :—Linum,
Linn.; Radiola, Gmelin. There are about 160 species.

Properties and Uses.—The plants of this order are generally
remarkable for the tenacity of their bast fibres, and also for the
mucilage and oil contained in their seeds; hence the latter are
emollient and demulcent. A few of the plants are bitter and
purgative, and some are stimulant and sedative. Others are
tonic, and some are used for dyeing red.

Order 86. HumiriacEm®, the Humirium Order.—Charac-
ter.—Trees or shrubs with a balsamic juice. Leaves alternate,
simple, coriaceous, exstipulate. Calyx 5-partite, imbricate.
Petals 5, imbricate. Stamens hypogynous, 20 or more, mona-
delphous; anthers 2-celled; connective elongated beyond the
anther lobes. Ovary superior, usually surrounded by a disc, 5-
celled; ovules 1 or 2 in each cell, suspended; style simple;
stigma 5-lobed. Fruit drupaceous, 5-celled, or fewer-celled by
DICOTYLEDONES—DISCIFLORAG 307

abortion. Seeds orthotropous, with a narrow embryo lying in
fleshy albumen.

Distribution and Numbers.—Natives of tropical America.
Illustrative Genera :—Huiirium, Mart. , Vantanea, Auwbl.
There are 18 species.

Properties and Uses.—A balsamic yellow oily liquid, called
Balsam of Umiri, is obtained from the incised stem of Humiriwiit
Aoribundum ; this is reputed to resemble Copaiba in its proper-
ties. The bark is used by the Brazilians as a perfume.

Order 87. Matpiguiacrs, the Malpighia Order.—Charac-
ter.— Trees or shrubs, often climbing. Leaves usually opposite
or whorled, rarely alternate; stipules generally short and
deciduous, sometimes large and interpetiolar; the leaves are
occasionally furnished with peltate hairs. Flowers perfect or
polygamous. Calyx 5-partite, persistent, frequently with glands
at the base of one or all of the divisions; estivation imbricate
or rarely valvate. Petals 5, hypogynous, unguiculate; estivation
convolute. Stamens usually 10, monadelphous or distinct; con-
nective fleshy and elongated beyond the anther lobes. Ovary
generally consisting of 3 carpels, rarely 2 or 4, partially or wholly
combined; ovules 1 in each cell, pendulous from a long stalk;
styles 8, distinct or united; stigmas 3, simple. Fruit either
drupaceous, samaroid, or a woody nut. Secd solitary, exalbu-
minous ; embryo straight or variously curved.

Diagnosis.—Trees or shrubs, with simple stipulate leaves.
Flowers perfect or polygamous. Calyx and corolla with 5 parts ;
the sepals having usually large glands at the base, and imbricate
or very rarely valvate in estivation; the petals unguiculate,
without appendages, hypogynous, convolute. Stamens usually
10, sometimes 15, with a fleshy prolonged connective. Ovary
generally composed of 8 carpels, or in any case not corresponding
in number to, or being any power of, the three outer whorls;
ovules solitary, pendulous from long stalks. Seeds exalbuminons,
usually with a convolute embryo.

Distribution and Numbers.—They are almost exclusively
natives of tropical regions. Illustrative Genera :—Malpighia,
Plum.; Byrsonima, Rich.; Nitraria. There are about 580
species.

Properties and Uses.—An astringent property appears to be
most general in the plants of this order. Some have edible
fruits, and the seeds of others are reputed to be poisonous.

Order 88. ZycopHyLLacem, the Bean-caper or Guaiacum

Order.—C haracter.—Herbs, shrubs, or trees. Leaves opposite,
x2
308 MANUAL OF BOTANY

stipulate, without dots, usually imparipinnate, or rarely simple.
Flowers perfect, regular, and symmetrical. Caly.r 4- or 5-partite,
convolute. Petals unguiculate, 4 or 5, imbricate, hypogynous.
Stamens 8—10, hypogynous, usually arising from the back of
small scales; filaments dilated at the base. Ovary 4—5-celled,
surrounded by glands or a toothed disc; style simple; ovules 2 or
more in each cell; placentas axile. Fruit capsular, dehiscing
in a loculicidal manner, or separating into cocci, 4- or 5-celled,
and presenting externally as many angles or winged expansions
as cells; rarely indehiscent. Seeds few; albumen in small
quantity, or rarely absent; radicle superior ; cotyledons folia-
ceous.

Diagnosis.—Herbs, shrubs, or trees, with opposite stipulate
dotless leaves. Calyx and corolla with a quaternary or quinary
arrangement; the former convolute in estivation, the latter,
with unguiculate petals and imbricate. Stamens 8—10, hypo-
gynous, usually arising from the back of scales. Ovary 4—5-
celled ; style simple. Fruit 4- or 5-celled. Seeds few, with
little or no albumen; radicle superior; cotyledons foliaceous.

Distribution and Numbers.—They are generally distributed
throughout the warm regions of the globe, but chiefly beyond
the tropics. Illustrative Genera :—Zygophyllum, Linn.; Guaia-
cum, Plum. There are about 100 species. Melianthus is by
some botanists separated from the Zygophyllacex, and taken as
the type of a new order, to which the name Melianthee has
been applied.

Properties and Uses.—-Some of the plants are resinous, and
possess stimulant, alterative, and diaphoretic properties; others
are anthelmintic. The wood of the arborescent species is
remarkable for its hardness and durability.

Order 89. GERANIACER, the Crane’s-bill Order.—Charace-
ter.—Herbs or shrubs, with swollen, usually articulated nodes.
Leaves simple, opposite or alternate, with membranous stipules.
Flowers regular or irregular. Scpals 5, inferior, persistent,
more or less unequal; estivation imbricate. Petals 5, or
rarely 4 from abortion, unguiculate, hypogynous or perigynous;
estivation twisted. Stamens usually twice as many as the
petals (some are, however, frequently abortive), hypogynous,
and generally united at the base, the alternate ones shorter and
occasionally barren. Disc inconspicuous or glandular. Carpels
5, arranged around an elongated axis or carpophore ; styles
corresponding in number to the carpels, and adhering to the
carpophore. Fruit consisting of five 1-seeded carpels, which
DICOTYLEDONES— DISCIFLORA 309

ultimately separate from the carpophore from below upwards
by the curling up of the styles, which remain adherent at the
summit. Seeds without albumen; cotyledons foliaceous, con-
volute. ;

Diagnosis.—Herbs or shrubs, with simple leaves, membranous
stipules, and swollen nodes. Sepals 5, imbricate. Petals
twisted in estivation. Stamens hypogynous, generally united
at the base. Fruit consisting of 5 carpels attached by means of
their styles-to an elongated axis or carpophore, from which they
separate when ripe from below upwards by the curling up of
the styles. Seeds 1 in each carpel, exalbuminous ; embryo with
foliaceous convolute cotyledons.

Fic. 1076. ty ; Fie. 1078.

 

Fic. 1079.

Fiy. 1076. A portion of the flowering stem of Gerunium sulvaticnm.— Fiy.
1077. The andreecium and gyneecium of the same. Fig. 1078. The pistil,
partially matured, surrounded by the persistent calyx.——Fiy. 1079.
Transverse section of the seed.

 

Distribution and Numbers.—Some are distributed over
various parts of the world, but they abound at the Cape of
Good Hope. E-rumples of the Genera :—-Erodium, L’Héritier ;
Geranium, Linn.; Pelargonium, L’Héritier. There are nearly
550 species.

Properties and Uses.—Astringent, resinous, and aromatic
qualities are the more important properties of the plants of this
order. Many are remarkable for the beauty of their flowers,
and others forthe agreeable odours of their leaves and tlowers,
which render them useful in perfumery.

Order 90. BaLSaMINAcEs, the Balsam Order.--Character.
Herbaceous plants with succulent stems and a watery juice.
Leaves alternate or opposite, simple, exstipulate. Flowers
310 MANUAL OF BOTANY

hypogynous, very irregular Sepals 3—5, very irregular, decidu-
ous, with an imbricate estivation, the odd one spurred. Petals
5, or more usually 4, 1 being abortive: distinct or irregularly
united, deciduous, alternate with the sepals; @stivation con-
volute. Stamens 5, alternate with the petals, and somewhat
united. Dise none. Ovary composed of 5 carpels, united so
as to form a 5-celled compound body; style simple; stigma
more or less divided into 5 lobes. Fruit usually capsular, 5-
celled, and dehiscing in a septifragal manner by 5 elastic valves,
which become coiled up; sometimes succulent and indehiscent ;
placentas axile. Seeds solitary or numerous, suspended, ex-
albuminous; embryo straight.

Diagnosis.—Succulent herbaceous plants, with simple ex-

stipulate leaves. Stems continuous and not

Fie. 1080. separable at the nodes. Flowers hypogynous,
very irregular. Sepals 3-5; petals usually 4;
both irregular and deciduous; estivation of
sepals imbricate, that of the petals convolute.
Stamens 5. Ovary 5-celled; style simple.
Fruit 5-celled, usually bursting with elasticity,
without a beak. Seeds suspended, exalbu-
minous. This order is included by Bentham
and Hooker in Geraniacee.

Distribution and Numbers.—A few are
scattered over the globe; but they are chiefly

: natives of the Indies, growing generally in
er oueianeahe ae damp shady places and where a temperature
ee is moderate. Illustrative Genus :—Impati-
coiled-up valves. ens, Linn. There are about 110 species.
Properties and Uses.—They are said hy
De Candolle to be diuretic, but their properties are generally
unimportant.

Order 91. VivtantacEm, the Viviania Order.—Diagnosis.
These plants are readily known among the Disciflore by their
exstipulate leaves, regular flowers, valvate 10-ribbed calyx, per-
manent withering twisted petals, 10 hypogynous stamens with
distinct filaments, 2-celled anthers with longitudinal dehiscence,
superior 8-celled ovary, 3-celled capsule with loculicidal dehis-
cence, and albuminous seeds with a curved embryo and radicle
next the hilum. This order is included by Bentham and Hooker
an Geraniacee.

Distribution and Numbers.—They inhabit Chili and South

 
DICOTYLEDONES—DISCIFLORA 311

Brazil. Illustrative Genera :—Cesarea, Cambess.; Viviania,
Willd. There are 15 species.

Properties and Uses.—Unimportant.

Order 92. TropmoLacem®, the Indian Cress Order.—Cha-
racter.—Smooth twining or trailing herbaceous plants, with
an acrid juice. Leaves alternate, exstipulate. Flowers irregular.
Sepals 83—5, the upper one spurred; valvate or very slightly
imbricate in exstivation. Petals 3—5, hypogynous, more or
less unequal; estivation convolute. Stamens 6—10, somewhat
perigynous, distinct; anthers 2-celled. Disc none. Ovary of
3 or 5 carpels, each of which contains one pendulous ovule ;
style 1; stigmas 3 or 5. Fruit indehiscent, usually consisting
of 3 carpels arranged round a common axis, from which they
ultimately separate, each carpel containing one seed. Seed
large, exalbuminous; embryo large; radicle next the hilum.
This order is included in Geraniacee by Bentham and
Hooker.

Distribution and Numbers.—Chiefly natives of South Ame-
rica. Illustrative Genera :—Tropeolum, Linn.; Chymocarpus,
Don. There are about 40 species.

Properties and Uses.—Generally acrid, pungent, and anti-
scorbutic, resembling the Crucifere. The unripe fruit of Tro-
peolum majus, which is commonly known as Indian Cress, or
Garden Nasturtium, is frequently pickled, and employed by
housekeepers as a substitute for Capers. Most of the Tro-
peolums have tubercular roots, some of which are edible, as
T. tuberosum.

Order 98. LIMNANTHACE®, the Limnanthes Order.—Dia-
gnosis.—This is a small order of plants included by Lindley in
the Tropzolaceex, with which it agrees in its general characters;
but it is distinguished from that order by having regular flowers,
more evidently perigynous stamens, and erect ovules. Jé is
placed in Geraniacee by Bentham and Hooker.

Distribution and Nuwmbers.—Natives of North America.
Illustrative Genus :—Limnanthes, R. Br. There are 3 species.

Properties and Uses.—In these they resemble the Cruciferz
and Tropeolacez.

Order 94. OXALIDACES, the Wood-sorrel Order.—Charac-
ter.—Herbs, or rarely shrubs or trees, generally with an acid
juice. Leaves alternate or rarely opposite, usually compound or
occasionally simple, generally with stipules, or rarely exstipu-
late. Flowers regular and symmetrical. Sepals 5, persistent,
imbricate, occasionally somewhat united at their base. Petals 5,
312 MANUAL OF BOTANY

hypogynous, unguiculate, rarely wanting; estivation twisted.
Stamens double the number of the petals and sepals, arranged
in two rows alternating with each other, the inner row longer
than the outer and opposite to the petals, commonly somewhat
monadelphous ; anthers 2-celled, innate. Disc none. Ovary
superior, 8—5-celled, with as many distinct styles as there are
cells; stigmas capitate or somewhat bifid. Fruit usually cap-
sular and 3—5-celled and 5—10-valved, occasionally drupaceous
and indehiscent ; placentas axile. Seeds few; sometimes pro-
vided with a fleshy integument, which bursts with elasticity
when the fruit is ripe, and expels the seeds; embryo straight, in
cartilaginous fleshy albumen ; radicle long, and turned towards
the hilum; cotyledons flat.

Diagnosis.—Herbs, or rarely shrubs or trees, usually with

Fic. 1081. Fic. 1082. Fie. 1083.

 

Fig. 1081. Diagram of the flower of Oxalis.—Fig. 1082. Vertical section of
the flower oi the same.— Fig. 1083. Vertical section of the seed.

compound exstipulate leaves. Stems continuous and not sepa-
rable at the nodes. Flowers hypogynous, regular, symmetyrical.
Sepals, petals, and stamens with a quinary distribution; the
sepals persistent and imbricate; the petals twisted in westivation ;
the stamens commonly somewhat monadelphous, with 2-celled
innate anthers. Disc absent. Styles filiform, distinct. Fruit
8—5-celled, without a beak. Seeds few, with abundant albumen,
a straight embryo, long radicle turned towards the hilum, and
flat cotyledons. This order is closely allied to the Geraniacea,
to which it is referred by Bentham and Hooker.

Distribution and Numbers.—These plants are generally dis-
tributed throughout both the hot and temperate regions of the
globe; the shrubby species are, however, confined to the former.
They are most abundant at the Cape of Good Hope and in
DICOTYLEDONES—DISCIFLORA 313

tropical America. Illustrative Genera :—Oxalis, Linn.; Aver-
rhoa, Linn. There are about 330 species.

Properties and Uses.—Chiefly remarkable for their acid juice,
which is due to the presence of binoxalate of potassium. The
fruits of some are eaten by the natives in the East Indies, but
they are too acid to be generally acceptable to Europeans.

Order 95. Rutacem, the Rue Order.—Character.-—Trees,
shrubs, or rarely herbs. Leaves exstipulate, simple or compound,
dotted. Flowers perfect or polygamous, regular. Calyx having
3—5 segments, imbricate. Petals equal in number to the
divisions of the calyx or wanting, rarely combined so as to form
a gamopetalous corolla; @stivation usually twisted, rarely val-

Fic. 1084. Fie. 1085. Fie. 1086. 9 Fre. 1087.

     

iw

Fig. 1084, Diagram of the flower of the Orange ((i/rus Aurantium).—— Fis.
1085. Vertical section of the pistil, showing a portion of the disc at its
base, and a solitary hypogynous stamen.— fig. 1086. Pistil of the Orange,
with dise at its base, and the calyx: the petals and stamens have been
removed.— Fig. 1087. Vertical section of the seed of the Common Rue
(Ruta graveolens).

vate. Stamens distinct, or more or less united into one or
several bundles, equal in number to or twice as many as the
petals, or some multiple of them, or rarely fewer by abortion.
Disc annular or cup-shaped, glandular, hypogynous. Ovary
sessile, or raised on a gynophore; it is composed of from 2 to 5
carpels, which are either distinct or united so as to form a com-
pound ovary having as many cells as there are component
carpels ; style simple or divided towards the base; ovzles 2, 4,
or rarely more in each cell. Frwit capsular, its carpels either
united or more or less distinct, or succulent and indehiscent,
and in Aurantiee forming a hesperidium. Seeds solitary or in
pairs; albumen present or absent ; radicle superior.
Diagnosis.--Leaves exstipulate, dotted. Flowers perfect
314 MANUAL OF BOTANY

or polygamous. Calyx and corolla with a ternary, quaternary,
or quinary distribution of their parts; the former with an im-
bricate estivation, the latter twisted or valvate, and sometimes
wanting. Stamens equal in number to or twice as many as the
petals, or some multiple of them, or fewer. Ovary of from 2 to 5
carpels, separate or combined, either sessile and surrounded at
the base by a fleshy and glandular disc, or elevated upon a
gynophore; ovules sessile. Fruit capsular or succulent. Em-
bryo with a superior radicle. Albumen present or absent.

Division of the Order and Illustrative Genera.—The Rutacese
have been variously divided, and Bentham and Hooker have
largely extended the order by including the orders Aurantiacee
and Xanthoxylacee of former botanists, which arrangement is
here adopted. As thus extended, they have divided it into the
following tribes:—Cuspariex, Rutee, Diosmex, Boroniex,
Xanthoxylex, Toddaliew, and Aurantier. Illustratwe Genera:
Ruta, Tourn.; Barosma, Willd.; Xanthoxylon, Kunth.; Tod-
dalia, Juss.; Citrus, Linn.

The Xanthoxylee are especially distinguished by their poly-
gamous flowers ; and the Aurantiee by the blade of their leaves
being articulated to the petiole, their deciduous imbricate petals,
and their peculiar fruit (hesperidiwm).

Distribution and Numbers.—The Rutee are found chiefly
in the southern part of the temperate zone and in Northern
Asia; the genera Diosma, Barosma, &c., abound at the Cape of
Good Hope; other genera are found in Australia, and some
in equinoctial America. Xanthoxylee are mostly American,
Aurantiee usually Hast Indian. There are about 620 species.

Properties and Uses.—The Rutes are generally characterised
by a powerful penetrating odour and bitter taste. In medicine
they are employed as antispasmodics, tonics, febrifuges, diure-
tics, &. The Xanthoxylex are almost universally characterised
by pungent and aromatic properties, and sometimes by bitter-
ness. In medicine, they have been employed as stimulants,
sudorifics, febrifuges, tonics, sialogogues, and emmenagogues.
The Auranties: abound in glands containing essential oils, which
render them fragrant. These volatile oils are especially abundant
in the leaves, the petals, and the rind of the fruit. The latter
also contains a bitter tonic principle. The pulp of the fruit has
an acid or somewhat saccharine taste; and the wood is always
hard, and of a compact nature.

Order 96. SIMARUBACE®, the Quassia Order.—C haracter.—
Shrubs or trees. Leaves without dots, alternate, compound or
DICOTYLEDONES—DISCIFLORA 315

sometimes simple, exstipulate. Flowers regular and symme-
trical, axillary, or terminal, perfect, or unisexual by abortion.
Calyx imbricate, in 4 or 5 divisions. Petals equal in number
to the divisions of the calyx, with an imbricate estivation,
sometimes united into a tube. Stamens twice as many as the
petals, the filaments usually with a scale at their back; anthers
with longitudinal dehiscence. Dise conspicuous, hypogynous.
Ovary stalked, 4- or 5-lobed, 4- or 5-celled, each cell with 1
suspended ovule ; style simple; stigma with as many lobes as
there are cells to the ovary. Fruit usually consisting of 4 or 5
indehiscent, 1-seeded, drupaceous carpels, arranged around a
common axis, or capsular or samaroid. Seeds with a membranous
integument, exalbuminous; radicle superior, retracted within
thick cotyledons.

Distribution and Nuwmbers.—With the exception of one
plant, which is a native of Nepaul, they are all found in the
tropical parts of India, America, and Africa. Illustrative
Genera :—Quassia, Linn.; Simaruba, Awbl. There are about 50
species.

Properties and Uses.—A bitter principle is the most remark-
able characteristic of the order ; hence many of them are tonic
and febrifugal.

Order 97. OcunacEm, the Ochna Order.—Character.—
Under-shrubs or smooth trees, with a watery juice. Leaves simple,
stipulate, alternate.’ Pedicels jointed in the middle. Sepals 5,
persistent, imbricate. Petals hypogynous, definite, sometimes
twice as many as the sepals, deciduous, imbricate. Stamens
equal in number to the sepals and opposite to them, or twice as
many, or more numerous; filaments persistent, inserted on an
hypogynous fleshy dise ; anthers 2-celled, with longitudinal or
porous dehiscence. Carpels sessile, corresponding in number to
the petals, inserted on a large fleshy disc, which becomes larger
as the carpels grow; ovules 1 in each carpel. Fruit consisting
of several indehiscent, somewhat drupaceous, 1-seeded carpels.
Seeds exalbuminous or nearly so; embryo straight ; radicle to-
wards the hilum.

Distribution and Numbers.—Natives chiefly of the tropical
parts of India, Africa, and America. Illustrative Genera :—
Gomphia, Schreb.; Ochna, Schreb. There are about 80
species.

Properties and Uses.—The plants are generally remarkable
for their bitterness. Some have been employed as tonics and
astringents ; others, as Gomphia parviflora, yield oil, which is
316 MANUAL OF BOTANY

used in Brazil for salads. In their properties generally, the
Ochnacee much resemble the Simarubacee.

Order 98. BursERACEZ or Amyripacts, the Myrrh Order.
Character.—Trees or shrubs, abounding in a fragrant gum-
resinous or resinous juice. Leaves compound, alternate or oppo-
site, frequently dotted and stipulate. Flowers perfect, or rarely
unisexual. Calyx persistent, with 2—5 divisions. Petals 3—5,
arising from the calyx below the disc; @stivation valvate, or
occasionally imbricate. Stamens twice as many as the petals,
perigynous. Disc perigynous. Ovary 1—5-celled, superior,
sessile, placed in or upon the dise ; ovules in pairs, attached to a
placenta at the apex of the cell, anatropous. Fruit dry, 1—5-
celled; epicarp often splitting in a valvular manner. Seeds
exalbuminous; radicle superior, turned towards the hilum.

Distribution and Numbers.—They have been found only in
the tropical regions of America, Africa, and India. Illustrative
Genera :—Boswellia, Rowb.; Balsamodendron, Kunti. There
are about 60 species.

Properties and Uses.—The plants of the order appear to be
almost universally characterised by an abundance of fragrant
resinous or gum-resinous juice. Some are considered poisonous;
others bitter, purgative, or anthelmintic; and a few furnish
useful timber.

Order 99. MEuiacem, the Melia Order.--Character.—- Trees
or shrubs. Leaves alternate or rarely somewhat opposite, sim-
ple or pinnate, exstipulate. lowers occasionally unisexual by
abortion. Calyx 8- 4- or 5-partite. Petals equal in number to
the divisions of the calyx, hypogynous, sometimes united at the
base; imbricate or valvate. Stamens twice as many as the
petals, monadelphous; anthers sessile, placed within the orifice
of the tube formed by the united filaments. Dise hypogynous,
sometimes large and cup-like. Ovary compound, usually 2- 3-
4- or 5-celled, rarely 10- or 12-celled; style 1; stigmas separate
or combined; ovules 1, 2, or rarely 4, in each cell. Frwit
baceate, drupaceous, or capsular, in the latter case opening
loculicidally ; many-celled, or by abortion 1-celled. Seeds few,
not winged, arillate or exarillate; albumen fleshy or usually
absent ; embryo generally with leafy cotyledons.

Diagnosis.—This order is very nearly allied to Cedrelacex,
and by some botanists the latter order is included in it. It is
chiefly distinguished from Cedrelacee by having more com-
pletely monadelphous stamens ; by the possession of fewer seeds ;
and in those seeds being without wings.
DICOTYLEDONES—DISCIFLORZ 317

Distribution and Numbers.—They are found more or less
in all the tropical parts of the globe, but are said to be more
common in Anierica and Asia than in Africa. A few are extra-
tropical. Illustrative Genera :---Melia, Linn.; Aglaia, Louwr.
There are about 150 species.

Properties and Uses.—These plants are generally remarkable
for bitter, tonic, and astringent properties. Others are power-
ful purgatives and emetics, as Guarca Aubletit, G. trichilioles,
G. purgans, G. spiciflora, and some species of Trichtlia ; these
all require much caution in their adininistration, and in some
cases are reputed poisonous. A few species have edible fruits.
The seeds of some yield fixed oils by expression.

Order 100. CEDRELACES, the Mahogany Order.—Charac-
ter—Trees. Leaves alternate, pinnate, exstipulate. Calyx
4—5-cleft, imbricate. Petals hypogynous, of the same number
as the divisions of the calyx, imbricate Stamens twice as
many as the petals and divisions of the calyx, either united
below into a tube, or distinct and inserted into an annular
hypogynous disc; anthers 2-celled, with longitudinal dehis-
cence. Ovary usually with as many cells as there are divisions
to the calyx and corolla, or rarely only 3; ovules 4 or more, in
two rows, anatropous ; style and stigma simple. Fruit capsular,
dehiscence usually septifragal. Seeds flat, winged, attached to
axile placentas; a/bunven thin or none; embryo straight, erect,
with the radicle next the hilum. This order is now frequently
incorporated with Meliacea.

Distribution and Numbers.—Chiefly natives of the tropical
parts of America and India ; they are very rare in Africa. Illus-
trative Genera :—Swietenia, Linn.; Soymida, <Adr. Juss.
There are about 25 species.

Properties and Uses.—The plants of this order have fra-
grant, aromatic, tonic, astringent, and febrifugal properties,
and many of them are valuable timber-trees.

Order 101. CHAILLETIACES, the Chailletia Order—C harac-
ter.—Trees or shrubs. Leaves alternate, entire, stipulate.
Calyx inferior, with 5 sepals; @stivation induplicate. Stamens
10, perigynous, in two alternate whorls, the outer petaloid and
sterile ; but the latter whorl more resembles a corolla. Ovary
superior, 2--8-celled, with twin suspended ovules. Fruit dry,
1—38-celled. Seeds exalbuminous. This order has been variously
placed, but is more commonly referred here.

Distribution and Numbers.—-Natives of tropical regions.
318 MANUAL OF BOTANY

Illustrative Genera :—Chailletia, DC. ; Stephanopodium, Popp.
There are about 10 species.

Properties and Uses.—Unimportant. The fruit of Chail-
letia toxicaria, a native of Sierra Leone, is commonly called
Ratsbane on account of its poisonous nature.

Cohort 2.— Olacales.

Order 102. OtacacEm®, the Olax Order.—Character.—
Trees or shrubs, with alternate simple entire exstipulate leaves.
Flowers small, regular, axillary. Calyx minute, gamosepalous,
generally enlarging so as to cover the fruit; cestivation imbri-
cate. Petals hypogynous, valvate in estivation. Stamens
definite, partly sterile and partly fertile ; the latter opposite to
the petals, inserted upon or outside of a conspicuous disc;
anthers 2-celled, bursting longitudinally. Ovary free, often
imbedded in the disc; ovwles suspended from a free central
placenta. Fruit drupaceous. Seed without integuments, soli-
tary ; embryo minute ; albwmen fleshy.

Distribution and Numbers.—Natives of tropical or sub-
tropical regions. Illustrative Genera :—Olax, Linn. ; Liriosma,
Pépp. The number of species is doubtful.

Properties and Uses.—Some have fragrant flowers. The
fruit of Ximenia americana is eaten in Senegal. The leaves of
Olax zeylanica are used by the Cingalese in their curries, &c.,
and the wood in putrid fevers. The wood of Heisteria coccinea
is considered by some to furnish the Partridge-wood of cabinet-
makers.

Order 103. Icactnacu®, the Icacina Order.—Diagnosis.—
This is an order of plants consisting of evergreen trees and shrubs,
and formerly included in the order Olacacee ; but, as shown
by Miers, they are clearly distinguished from that order, as
follows: ‘They differ most essentially in the calyx being
always small, persistent, and unchanged, and never increasing
with the growth of the fruit; the stamens being always alternate
with the petals, not opposite; the petals and stamens are never
fixed on the margin of the conspicuous cup-shaped disc; the
ovary is normally plurilocular with axile placentation, and when
unilocular, this happens only from the abortion of the other
cells, the traces of which are always discernible, never com-
pletely unilocular at the summit, and plurilocular at base, with
free central placentation. In Icacinacee the ovules are sus-
pended below the summit of the cell in pairs superimposed by
DICOTYLEDONES—DISCIFLOR® 319

cup-shaped podosperms; only one of these becomes perfected,
and the seed is furnished with the usual integuments.’

Distribution and Numbers.‘ They are natives of tropical
or sub-tropical countries; chiefly the East Indies, Africa, and
South America, a single species being found each in New
Holland, Norfolk Island, and New Zealand.’ Tillustrative
Genera :—Icacina, Adi. Juss.; Sarcostigma, W. et A. There
are about 70 species.

Properties and Uses.— Unknown.

Order 104. Cyrinnacsm, the Cyrilla Order.—Diagnosis.—
Evergreen shrubs, with alternate exstipulate leaves, nearly
related to Olacacee, but chiefly distinguished by their imbricate
petals, which are altogether free from any hairiness on their
inside ; and by the stamens being all fertile, and, if equal in
number to the petals, alternate with them.

Distribution and Numbers.—They are all natives of North
or Tropical America. Illustrative Genera :—Cyrilla, Mylo-
caryum. There are 6 species.

Properties and Uses.—Unknown.

Order 105. Paytocrenacem, the Phytocrene Order.-—Dia-
gnosis.—This order has been variously placed by botanists, bat
is referred here by Bentham and Hooker. Formerly it was in-
corporated with the Artocarpace, but their seeds have a large
quantity of albumen, which at once distinguishes them from
that order. The plants comprised in it, all of which belong to
the genus Phytocrene, Wall., are climbing shrubs, natives of the
East Indies, with dichlamydeous unisexual flowers, and seeds
with a large quantity of albumen. Their wood has also a very
peculiar structure. They yield a large quantity of watery juice
when wounded ; hence they are termed Water-vines, or ‘ Plant-
fountains.’ In Martaban this juice is drunk by the natives.

Order 106. AquirotiacEz# or Inicacrm, the Holly Order.—
Character.—Evergreen trees or shrubs. Leaves coriaceous,
simple, exstipulate or with minute stipules. Flowers small,
axillary, sometimes unisexual. Sepals distinct, 4—6, imbricate.
Corolla 4—6-partite, imbricate. Stamens equal in number to
the divisions of the corolla and alternate with its segments;
anthers 2-celled, adnate, opening longitudinally. Disc none.
Ovary superior, 2—6- or more-celled, with one suspended ovule
in each cell; placentas axile. Fruit fleshy, indehiscent. Seed
suspended; embryo small, at the base of a large quantity of
fleshy albumen ; radicle superior.

Distribution and Numbers.—They are widely although
320 MANUAL OF BOTANY

sparingly scattered over the globe. Only one species, the
common Holly, is foundin Europe. Illustrative Genera :—Ilex,
Linn.; Prinos, Linn. There are about 115 species.

Properties. and Uses.—Bitter, tonic, and astringent properties
are those chiefly found in the plants of this order. Some are
emetic and purgative, while others are largely used as a kind of
Tea.

Cohort 3.—Celastrales.

Order 107. CeLastRAcEs, the Spindle-tree Order.—C harac-
ter.—Shrubs or small trees, Leaves simple, generally alter-
nate, or rarely opposite, with small deciduous stipules. Sepals.
4—5, imbricate. Petals with imbricate estivation, equal in
number to the sepals, inserted on a large disc; sometimes
wanting. Stamens as many as the petals and alternate with
them, inserted on the disc; anthers innate. Disc large, flat,
expanded. Ovary sessile, superior, surrounded by the disc, 2—
5-celled, each cell with 2 ovules; ovules erect, with a short
stalk. Fruit superior, 2—5-celled, either drupaceous and inde-
hiscent, or capsular with loculicidal dehiscence. Seeds with or
without an aril; albumen fleshy; embryo straight; radicle
short, inferior ; cotyledons flat.

Diagnosis.—Shrubby plants, with simple leaves and small
deciduous stipules. Flowers small, regular, and perfect; or
rarely unisexual by abortion. Sepals and petals 4—5, imbricate
in estivation. Stamens equal in number to, and alternate with,
the petals, and inserted with them on a large flat expanded
disc. Ovary superior, sessile, surrounded by the disc. Fruit
superior, 2—5-celled. Seeds albuminous ; embryo straight ;
radicle inferior.

Distribution and Numbers.—Chietly natives of the warmer
parts of Asia, North America, and Europe; they are also plenti-
ful at the Cape of Good Hope. Generally speaking, the plants
of the order are far more abundant out of the tropics than
inthem. Illustratiwe Genera :—Kuonymus, Linn.; Celastrus,
Kunth. There are about 280 species.

Properties and Uses.—Chiefly remarkable for the presence of
an acrid principle. The seeds of some contain oil.

Order 108. HippocratEacr, the Hippocratea Order.—C ha-
racter.—Shrubs, with opposite simple leaves, and small deci--
duous stipules. Flowers small, regular, and unsymmetrical.
Sepals and petals 5, hypogynous, imbricate, the former per-
sistent. Stamens 3, hypogynous, monadelphous; anthers with
DICOTYLEDONES—DISCIFLORE 321

transverse dehiscence. Disc conspicuous. Ovary 8-celled;
placentas axile; style 1. Fruit baccate, or consisting of 3
samaroid carpels. Seeds definite, exalbuminous; embryo
straight ; radicle inferior. This order is referred to Celastracee
by Bentham and Hooker.

Distribution and Numbers—They abound principally in
South America; some are found also in Africa and the East
Indies. Illustrative Genera :—Hippocratea, Linn.; Tontelea,
Aubl. There are about 86 species.

Properties and Uses.—Very little is known generally of the
plants of this order. The fruit of several Brazilian species of
Tontelea is edible, and in Sierra Leone that of T. pyriformis is
described as very pleasant. Hippocratea comosa yields nuts of-
an oily and sweet nature. The inner yellow bark of Kokoona
zeylanica is employed in Ceylon asa febrifuge and sternutatory,
and as a dye.

Order 109. StackHOUSIACEA, the Stackhousia Order.— Cha-
racter.— Herbs or rarely shrubs, with simple, entire, alternate,
minutely stipulate leaves. Calyx 5-cleft, with its tube inflated.
Petals 5, united below into a tube, arising from the top of the
tube of the calyx, and haying a narrow stellate limb. Stamens
5, distinct, of unequal length, perigynous. Ovary superior, 8-
or 5-celled, each cell containing one erect ovule; styles 3 or 5.
distinct or united at the base. Fruit consisting of from 3 to 5
indehiscent carpels, attached to a central persistent column.
Seeds with fleshy albumen ; embryo erect ; radicile inferior.

Distribution and Numbers.—Natives of Australia. Illus-
trative Genera :—Stackhousia, Smith; Tripterococcus, Lindl.
There are about 20 species.

Properties and Uses.—Unknown.

Order 110. Ruamnacra, the Buckthorn Order.—Character.
Shrubs or small trees, which are often spiny. Leaves simple,
alternate or rarely opposite; stipwlessmallor wanting. Flowers
small, usually perfect or sometimes unisexual. Calyx 4—-5-cleft,
with a valvate estivation. Dzisc fleshy, lining the tube of the
calyx. Petals equalin number to the divisions of the calyx, and
inserted into its throat, hooded or convolute, sometimes wanting.
Stamens perigynous, equal in number to the petals and opposite
to them, or alternate with the divisions of the calyx when the
petals are wanting. -Ovaiy superior or half superior, immersed
in the disc, 2- 3- or 4-celled; ovules one in each cell, erect.
Fruit dry and capsular, or fleshy and indehiscent. Seeds one
in each cell, erect, usually with fleshy albumen, but this is

VOL. I, Y
322 MANUAL OF BOTANY

sometimes wanting, exarillate; embryo long, with a short in-
ferior radicle, and large flat cotyledons.

Diagnosis.—Small trees or shrubs, with simple leaves and
small regular usually perfect flowers; rarely unisexual. Calyx
4—5-parted, valvate, with the tube coated with a disc. Petals
and stamens distinct, perigynous, and equal in number to the
divisions of the calyx; the petals sometimes wanting, but, when
present, opposite to the stamens. Ovary more or less superior,
surrounded by a fleshy disc. Fruit 2- 3- or 4-celled, with one
erect seed in each cell. Seed usually albuminous, without an
aril.

Distribution and Numbers.— Generally distributed over the
globe except in the very coldest regions. Illustrative Genera :—
—Zizyphus, Tourn.; Rhamnus, Juss. There are about 400
species.

Properties and Uses.—Some of the plants have acrid and
purgative properties; others are bitter, febrifugal, and tonic.
A few are used in the preparation of dyeing materials, and some
few others have edible fruits.

Order 111. Viract2, the Vine Order. --Character.— Usually
shrubs, with a watery juice, climbing by tendrils, the young
nodes swollen. Leaves simple or compound, opposite below,
alternate above, stipulate or exstipulate. lowers regular,
small, green, stalked. Calyx minute, with the limb generally
obsolete. Petals 4 or 5, sometimes united at the base ; inserted
on a dise which surrounds the ovary, caducous; e@stivation
induplicate. Stamens corresponding in number to the petals
and opposite to them, also inserted on the disc ; filaments dis-
tinct or somewhat united at the base; anthers versatile, burst-
ing longitudinally. Ovary superior, surrounded by a disc;
usually 2-celled; style very short, simple; stigma _ simple.
Fruit succulent, sometimes termed a nuculanium, usually 2-
celled. Seeds erect, few, usually 2 in each cell; testa bony ;
albumen hard ; embryo erect, with an inferior radicle.

Diagnosis.— Shrubby plants, climbing by tendrils, with sim-
ple or compound leaves, which are opposite below and alternate
above. Flowers sinall, green, regular. Petals and stamens
corresponding in number, 4 or 5, the latter opposite to the
petals, both inserted on an hypogynous disc; estivation of
petals induplicate; anthers versatile, opening longitudinally.
Ovary superior, surrounded by a disc, with a very short simple
style and stigma. Fruit baccate. Seeds few; testa bony ;
embryo erect in horny albumen ; radicle inferior.
DICOTYLEDONES—DISCIFLORA 823

Distribution and Numbers.—The plants of this order are
found in warm and tropical regions of the globe. None are
natives of Europe. The common Grape Vine, which is now
completely naturalised in the South of Europe, and is cultivated
nearly all over the globe where the temperature does not rise
too high or fall too low, is supposed to be a native of the shores
of the Caspian. Illustrative Genera :—Vitis, Linn. ; Ampelopsis,
L. C. Rich. There are about 260 species.

Properties and Uses.—The leaves, stems, and especially the
unripe fruits of the plants of this order, abound more or less
in an acid juice, the acidity being chiefly due to the presence of
tartaric and malic acids and acid tartrate of potash. As the
fruit ripens, it generally loses its acidity, and becomes sweet,
owing to the formation of sugar.

Cohort 4.—-Sapindales.

Order 112. SaprnpacEem, the Soapwort Order.—Character.
Usually large trees or twining shrubs, or rarely climbing herbs.
Leaves generally compound, or rarely simple, alternate or some-
times opposite, often dotted, stipulate or exstipulate. Flowers
mostly perfect and unsymmetrical, sometimes polygamous.
Sepals 4—5, either distinct or united at the base, imbricate.

Fie. 1088. Fic. 1089.

Fie. 1090.

  

Fig. 1088. Diagram of the flower of the Horsechestint (.#sculus Hippo-
castanum).——Fig. 1089. Vertical section of the flower.—-—Ly. 1090, Ver-
tical section of the seed.

Petals 4—5, rarely 0, hypogynous, alternate with the sepals,
imbricate, naked or furnished with an appendage on the inside.
Stamens 8—10, rarely 5—6—1, or very rarely 20, inserted into
the dise or into the thalamus; filaments distinct or slightly
monadelphous; anthers introrse, bursting longitudinally. Dzse

fleshy or glandular, hypogynous or perigynous. Ovary usually
: ae
324 MANUAL OF BOTANY

3-celled, rarely 2- or 4-celled, each cell containing 1, 2, 8, or
rarely more ovules; style undivided or 2—8-cleft. Frwét either
fleshy and indehiscent; or capsular, with 2—3 valves. Seeds
usually arillate, exalbuminous; embryo rarely straight, usually
curved or twisted in a spiral direction; cotyledons sometimes
very large; radicle next the hilum.

Diagnosis.——F lowers unsymmetrical, hypogynous. Sepals
and petals 4—5, imbricate, the latter commonly with an appen-
dage. Stamens never agreeing in number with the sepals and
petals, inserted on a fleshy or glandular disc, or upon the thala-
mus; anthers bursting longitudinally. Fruit usually consisting
of 8 carpels. Seeds commonly 2, sometimes 1 or 8, or very
rarely more, exalbuminous, usually arillate and without wings;
embryo almost always curved or spirally twisted.

Division of the Order and Illustrative Genera :—This
order has been divided by Lindley into 4 sub-orders as fol-
lows :—

Sub-order 1. Sapindee.—Leaves alternate. Ovules usually
solitary. Embryo generally curved or sometimes straight.
Illustrative Genera :—Sapindus, Linn.; Nephelium, Linn.

Sub-order 2. Hippocastanee.—Leaves opposite. Ovules 2 in
a cell, of which one is ascending, and the other suspended.
Embryo curved, with a small radicle and large fleshy con-
solidated cotyledons. Illustrative Genus :—Aisculus, Linn.

Sub-order 8. Dodonea.—Leaves alternate. Ovules 2 or 3 ina
cell. Embryo spiral. Illustrative ‘tenera :—Dodonea, Linn. ;
Ophiocaryon, Schomb.

Sub-order 4. Meliosmee.—Leaves alternate. Flowers very irre-
gular. Stamens 5, 3 of which are abortive, and only 2, there-
fore, fertile. Ovules 2 in each cell, suspended. Fruit drupa-
ceous. Embryo folded up. Illustrative Genus :—Meliosma,
Blume. Bentham and Hooker include the Meliosmee in the
order Sabiacee.

Distribution and Numbers.—Chiefly found in tropical
regions, especially those of South America and India; some
occur in temperate climates, but none inhabit the cold northern
parts of the globe. There are no native plants of this order in
Europe. The Horsechestnut, now so well known in this
country, is only naturalised among us. There are nearly 400
species.

Properties and Uses.—One of the most prominent character-
istics of the plants of this order is the presence of a saponaceous
DICOTYLEDONES—DISCIFLORZ 325

principle, from which its common name is derived. Many are
poisonous in all their parts; but it is more frequently the case
that, while the root, leaves, and branches are dangerous, the
fruits are innocuous, or even palatable. It sometimes happens,
as in the Litchi and Longan fruits, that while the pericarp is
wholesome, the seeds are dangerous. Some plants of the order
are astringent and aromatic; others are diaphoretic, diuretic,
and aperient; and some are valuable timber trees.

Order 118. AcERAcE&, the Maple Order.—Character.—
Trees. Leaves opposite, simple, without stipules; venation
usually radiate, rarely pinnate. Flowers often polygamous,
racemose or corymbose, regular. Calyx with an imbricate
estivation, usually 5-partite, occasionally 4- or 9-partite. Petals
imbricate, without appendages at their base; corresponding in
number to the divisions of the calyx, or altogether absent.
Stamens usually 8, inserted on a fleshy hypogynous disc, or
rarely the disc is absent. Ovary superior, 2-lobed, 2-celled ;
stigmas 2; ovules in pairs. Fruit a samara, 2-celled. Seeds
1 or 2 in each cell, ascending, without an aril, exalbuminous ;
embryo curved, with leafy wrinkled cotyledons, and an inferior
radicle. This order is placed by Bentham and Hooker in
Sapindacee, tribe Acerinea.

Diagnosis.—Trees with opposite simple exstipulate leaves.
Flowers often polygamous, and usually regular. Sepals and
petals imbricate, the latter without any appendages on their in-
side. Stamens hypogynous, usually on a fleshy disc; anthers
bursting longitudinally; ovary superior, 2-celled. Fruit a
samara, 2-celled, each cell containing 1 or 2 seeds. Seeds as-
cending, without an aril, exalbuminous; embryo curved, with
an inferior radicle.

Distribution and Numbers.—The plants of this order are
natives of the temperate parts of Europe, Asia, and North
America. None have been found in Africa and the southern
hemisphere. Illustrative Genera:—Acer, Linn.; Negundo,
Ménch. There are about 50 species.

Properties and Uses.—These plants are chiefly remarkable
for their saccharine sap. Their light and handsome timber is
also much used for certain parts of musical instruments ; their
barkis astringent, and is employed in different districts by the dyer
in the production of yellow, reddish-brown, and blue colours.

Order 114.—STAPHYLEACER, the Bladder-nut Order.—Cha-
racter.—Shrubs, with opposite or rarely alternate pinnate
leaves, which are furnished with deciduous stipules and stipels.
326 MANUAL OF BOTANY

Flowers symmetrical. Calyx 5-partite, coloured, imbricate.
Petals 5, alternate with the divisions of the calyx, imbricate.
Stamens 5, alternate with the petals, and inserted with them on
a large disc. Ovary superior, composed of 2 or 3 carpels,
which are more or less distinct ; ovules numerous; styles 2 or 8,
united at the base. Fruit fleshy or membranous. Seeds as-
cending, with a bony testa; embryo straight ; albwmen little or
none. This order is now frequently placed in Sapindacee.

Distribution and Numbers.—They are scattered irregularly
over the globe. Illustrative Genus :—Staphylea, Linn. There
are about 14 species.

Properties and Uses.—The bark of some species is bitter and
astringent, as that of Huscaphis staphyleoides. Others have
oily and somewhat purgative seeds, as Staphylea pinnata, &c.

Order 115. Sastaceas, the Sabia Order.—Diagnosis.—This is
a small order of plants, containing only 9 species, forming 2
genera which were formerly placed as doubtful genera of the
Anacardiacez ; but the Sabiacee differ essentially from the
Anarcardiacez, in their stamens being opposite to the petals ;
in their distinct carpels; and in their solitary ovules being
directly attached to the ventral suture. Miers and Blume
regard the Sabiaces as related to Menispermacee and Lardiza-
balacex. Bentham and Hooker include the Meliosmee of the
Sapindacee in this order.

Distribution, Properties, and Uses.—Natives of the East
Indies. Their properties are altogether unknown.

Order 116. ANAcARDIACE®, the Cashew-nut Order.—Cha-
racter.—Trees or shrubs, with
alternate, simple or compound,
dotless, exstipulate leaves, and a
milky acrid or resinous juice.
Flowers regular, small, and fre-
quently unisexual. Calyaz per-

& sistent, with usually 5, or some-
times 3, 4, or 7 lobes. -Petals
equal in number to the divisions
of the calyx, perigynous, imbricate ;
UN sometimes absent. Stamens alter-
ee (Dn en Bite teh nate with the petals, and of the
one branch bearing fruit, and the same number, or twice as many,
Se ie. hair-like ap- oy even more numerous; peri-
gynous, and united at the base if

there is no dise, but if this is present then distinct and inserted

Fie. 1091.

 
DICOTYLEDONES—DISCIFLORA 827

upon it. Disc annular and hypogynous, or wanting. Ovary
usually single, 1-celled, generally superior, or very rarely inferior ;
styles 1, 8, 4, or none; stigmas the same number as the styles;
ovules solitary, attached to a long funiculus which arises from
the base of the cell. Fruit indehiscent, drupaceous, or nut-like.
Seeds without albumen.

Distribution and Numbers.—-The plants of this order are
chiefly found in the tropical regions of the globe, although « few
are found in the South of Europe and in other extra-tropical
warm districts. Illustrative Gencra:—Pistacia, Linn.; Ana-
cardium, Rottb. There are about 110 species.

Properties and Uses.—They abound in a resinous, somewhat
gummy, acrid, or milky juice, which is occasionally very poison-
ous; they sometimes become black in drying. The fruits and
seeds of some species are, however, held in high estimation, and
are largely eaten in different parts of the world. Many plants
of this order furnish varnishes.

Anomalous Orders.

Order 117. CorIARIAce®, the Coriaria Order.—Diaynosis.—
Its atiinities are by no means understood; but it appears to be
most nearly related to Ochnacew, with which it agrees in having
its carpels distinct and placed on an enlarged disc; but it is
distinguished from that order by having opposite leaves; some-
times polygamous flowers; persistent fleshy petals; no style ;
and long linear distinct stigmas.

Distribution.—This order includes but 1 genus and 8 species.
They are natives of the South of Europe, Chili, Peru, New Zea-
land, and Nepaul.

Properties and Uses.—The plants of this order are generally
to be regarded with suspicion, as they have sometimes produced
poisonous effects. The fruits of some, however, are edible, as
Coriaria nepalensis, a native of the north of India, and those of
C. sarmentosa, a native of New Zealand; in the latter case the
pericarp is alone eaten, the seeds being poisonous. The fruits
of C. myrtifolia and C’. ruscifolia are very poisonous; these
plants have been employed by dyers in the production of a black
dye.

Order 118. Morincace#, the Ben-nut Order.— Character.
Trees with bi- or tri-pinnate leaves, and thin deciduous stipules.
Flowers white, irregular. Sepals and petals 5 each; the former
deciduous and petaloid, the calyx lined by a fleshy disc; estiva-
tion imbricate. Stamens 8 or 10, placed on the disc lining the
328 MANUAL OF BOTANY

tube of the calyx in two whorls, the outer of which is sometimes
sterile; anthers 1-celled. Ovary stalked, superior, 1-celled, with
3 parietal placentas. Fruit long, pod-shaped, capsular, 1-celled,
3-valved, with loculicidal dehiscence. Seeds numerous, without
albumen.

Distribution and Numbers.—Natives of the East Indies and
Arabia. There is only one genus (Moringa, Burm.) and 4
species.

Properties and Uses.—Pungent and slightly aromatic pro-
perties more or less prevail in plants of the order ; hence they
have been employed as stimulants.

Artificial Analysis of the Orders in the Sub-class
Polypetale.
Series 2. DiscirFLone.
1. FLowers with more than 20 stamens.
Carpels more or less distinct (at least as to the
styles), or solitary, superior or partially
inferior. Stamens perigynous . Anacardiacee.
Carpels wholly combined (at least as to the
ovaries), superior. Stamens hypogynous . Hwmiriacee.
2. FLowERs with less than 20 stamens.
A. Leaves generally without stipules.
a. Carpels more or less distinct, or solitary.
Leaves without dots. ,

Albumen abundant Zygophyllacece.
Albumen absent Anacardiacee.

Leaves dotted . Burseracee.

b. Carpels wholly combined (at least as to their

ovaries).

Styles distinct to the base.
Calyx valvate. ; % Vivianiacec.
Calyx imbricate Linacee.

Styles more or less combined.
Calyx valvate or united, or but very slightly
imbricate.
Stamens hypogynous.
Calyx generally enlarging with the fruit Olacacee.
Calyx not enlarging with the fruit.
Stamens opposite to the petals, iso-

merous . \ ‘i ‘i 4 . Rhamnacee.
Stamens alternate with the petals,
isomerous.
Leaves compound Burseracee.

Leaves simple . Icacinacee.
DICOTYLEDONES—DISCIFLORA 329

Stamens more or less perigynous.
Flowers irregular, ovules suspended

Flowers

regular, ovules erect

Calyx imbricate.
Style gynobasic.
Stamens arising from scales

Stamens not arising from scales.

Styles

wholly combined.

Flowers perfect

Flowers polygamous

Styles

divided at the apex.

elastic valves

Style not gynobasic.

Calyx much imbricate, in an irregular

broken whorl.

Petals with appendages at their base.

Leaves alternate .

Petals without appendages at “thee
base.
Calyx but little imbricate, in a complete

Leaves opposite

whorl.

Carpels 4 or more.
Seeds winged
Seeds wingless.

Stamens united into a long tube .
Stamens distinct, or nearly so.

Leaves dotted.

Seeds amygdaloid .

Leaves without dots.
Seeds erect

Carpels less than 4.
Petals imbricate.
Ovules suspended

Ovules erect

B. Leaves generally with stipules.

a. Carpels distinct, or solitary.

Carpels several .

b. Carpels wholly imbibed (at least as to their
ovaries), with more placentas than one.

Placentas parietal
Placentas in the axis.
Styles distinct to the base.
Petals conspicuous, stalked

Styles more or less combined, gynobasic.

Gynobase fleshy .

{

Flowers irregular, fruit usually with

Tropeolacee.
Limnanthacee.

Simarubacee.

Rutacee.
Xanthoaylee of
Rutacee.

Balsaminacece.

Sapindacce.

Aceracee.

Cedrelacee.

Meliacee.

Aurantiee of

Rutacee.

Celastracee.

Cyrillacee.

Celastracec.

Coriariacce.

Moringacee.

Malpighiacee.

Ochnacee.
330 MANUAL OF BOTANY

Gynobase dry.
Leaves regularly opposite
Leaves more or less alternate.
Fruit beaked
Fruit not beaked .
Styles more or less combined, not gyno-
basic.
Calyx much imbricate, in an irregular
broken whorl.

Flowers not surrounded by an involucre

Calyx but little imbricate, in a complete
whorl.

Stamens 8, sepals and petals penta-
merous .

Stamens more than 3.

Calyx glandular.
Petals without appendages
Calyx not glandular.
Leaves simple.
Petals united by their claws into
a tube
Leaves compound.
Petals distinct
Calyx valvate.

Stamens opposite to the petals, iso-
merous.

Seeds one in each cell.

Stamens opposite to the petals if iso-
merous, anthers versatile, seeds two
in each cell ‘ ‘

Stamens twice as many as the petals

Zygophyllacee.

Geraniacec.
Oxalidacee.

Sapindacee.

Hippocrateacee.

Malpighiacee.

Stackhousiacee.

Staphyleacee.

Rhamnacee.

Vitacee.
Burseracee.

The following exceptions may be noted to the characters usually dis-
tinctive of the Discifloree. We have apetalous species in Zygophyllacee,
Geraniacea, Bualsaminacee, Rutacee, Simarubacee, Burseracee,
Olacacee, Celastracee, Rhamnacee, Sapindacee, Anacardiacee, and
some others.

Gamopetalous corollas are sometimes found in Humiriacee, Rutacea,
Balsaminacee, Meliacee, and Stackhousiacee.

In Geraniacee, Balsaminacee, Tropeolacee, Oxalidacee, Aceracee,
wlnacardiacee, Malpighiacee, Linacee, &c., the disc is small, or entirely
or partially absent. The ovary is more or less inferior in some Olacacee
and Rhamnacee ; and the placentation is parietal instead of axile in some
Ochnacee and Moringacee.
DICOTYLEDONES—-CALYCIFLORA 331

Synopsis of the British Natural Orders of the Series Disciflore.

A. Corolla completely polypetalous, inferior.
Calyx imbricate in the bud.

Corolla irregular Balsaminacee.
Corolla regular.
Stamens in an hypogynous ring.
Stamens 4-—5. Stipules absent Linacee.

Stamens 10. Ovary 5-celled, many- sandal, Oxalidacee.
Stamens 10. Leaves stipulate. Ovary
5-celled, with one seed in each cell Geraniacee.
Stamens free.
Style solitary. Stamens and petals 4—5,

inserted on an hypogynous disc . Celastracee.
Calyx valvate in the bud.
Stamens perigynous, opposite to the petals Rhamnacee.
B. Corolla gamopetalous, or with petals connate at
the base.
Fruit fleshy . ‘ ‘ Aquifoliacee.

Series 8.—Calyciflore.
Cohort 1.—-Rosales.

Order 119. ConNARACES, the Connarus Order.—Character.
Trees or shrubs. Leaves alternate, without dots, compound,
and generally exstipulate. Flowers usually perfect, or rarely
unisexual. Calyx 5-partite, inferior, imbricate or valvate in
estivation. Petals 5, inserted on the calyx, imbricate or valvate.
Stamens 10, usually monadelphous, nearly or quite hypogynous.
Carpels 1 or more; ovules 2, sessile, collateral, ascending, ortho-
tropous. Fruit follicular. Seeds with or without albumen,
arillate or exarillate; radicle superior, at the extremity most
remote from the hilum.

Distribution and Numbers.—Natives of the tropics, and most
common in tropical America. Illustrative Genera :—Connarus,
Omphalobium. There are about 42 species.

Properties and Uses.—Some have oily seeds; others, as cer-
tain species of Omphalobium, have edible arils. The zebra-wood
of the cabinetmakers is said by Schomburgk to be furnished by
Omphalobium Lamberti, a very large Guiana tree.

Order 120. Lecuminos®, the Pea and Bean Order.—Cha-
racter.—Herbs, shrubs, or trees. Leaves alternate, stipulate,
usually compound. Calyx gamosepalous, inferior, more or less
deeply divided into five parts, the odd division being anterior.
Petals usually five, or sometimes by abortion 4, 3, 2,1, or rarely
332 MANUAL OF BOTANY

none, inserted into the base of the calyx ; equal or unequal ; often
papilionaceous, the odd petal, if any, posterior. Stamens definite
or indefinite, usually perigynous, or rarely hypogynous, distinct
or united into 1, 2, or rarely 3 bundles. If in two bundles these
contain respectively 9 and 1. Ovary superior, usually formed of
1 carpel, although rarely of 2 or 5; 1-celled with 1, 2, or many
ovules; style and stigma simple. Fruit usually a legume, or
sometimes a lomentum, or rarely a drupe. Seeds 1 or more,
sometimes arillate, attached to the upper or ventral suture;
albumen usually absent; embryo straight, or with the radicle
folded upon the cotyledons; cotyledons leafy or fleshy, and
either hypogeal or epigeal.

Diagnosis.—Herbs, shrubs, or trees. Leaves nearly always
alternate and stipulate, and usually compound. Flowers regular
or irregular. Calyx inferior, 5-partite; odd division anterior.
Petals 5, and then unequal or equal; or fewer by abortion, or

Fie. 1092. Fic. 1093. Fie. 1094.

   

ig. 1092, The flower of the Pea (Pisum). et. Standard or vexillum. ai. Wings
or ale. car. Carina or keel enclosing the sporophylls. ¢. Calyx.—
ig. 1093. The sporophylls of the same surrounded by the calyx c.
es. Bundle of nine stamens. el. Solitary stamen. st. Style and stigma.—
’ Fig. 1094. Legume of the same, with one valve removed.

none; perigynous ; odd one, when present, posterior. Stamens
distinct, or united into one or more bundles. Ovary superior,
simple, 1-celled; style simple, proceeding from the ventral
suture. Fruit usually a legume, sometimes a lomentum, or
rarely a drupe. Seeds 1 or more, usually without albumen.
This order may be generally distinguished by having legumi-
nous fruit.

Division of the Order and Illustrative Genera.—The order
has been divided into three sub-orders as follows :—--

Sub-order 1. PapinionAcem.—Petals arranged so as to form a
papilionaceous corolla, imbricate in estivation, and the upper
or odd petal exterior to the lateral petals. Illustrative
Genera :—Ulex, Linn.; Trifolium, Linn.; Vicia, Linn.;
Ornithopus, Linn.

Sub-order 2. CasaLpiniex.—Petals not arranged in a papi-
lionaceous manner, imbricate in estivation, and the upper
DICOTYLEDONES—CALYCIFLORA 333

or odd petal with its margins inside the lateral petals. IUlus-
trative Genera :—Cesalpinia, Linn.; Cassia, Linn. There are
no British plants in this sub-order.

Sub-order 38. MimosEs.—Petals equal, valvate in estivation.
Stamens often ©. Pollen slightly coherent. Leaves some-
times replaced by phyllodes. Illustrative Genera :—Mimosa,
Linn.; Acacia, Willd. There are no British plants in this
sub-order.

Distribution and Numbers.—This is a very extensive order,
and has some representatives in almost every part of the world.
A considerable number of the genera are, however, confined
within certain geographical limits, while others have a very wide
range. As a general rule, the Papilionacee are universally dis-
tributed, although most abundant in warm regions; while the
Cesalpiniee and Mimosee are most common in the tropics; but
many of the latter are also to be found in Australia. There are
about 7,000 species in this order.

Properties and Uses.—The properties and uses of the plants
of this order are exceedingly variable. Many are valuable fodder
plants, others yield timber, gums, drugs, and dyes. Some species
are poisonous.

Order 121. RosacE#, the Rose Order.—Character.—Trees,
shrubs, or herbs. Leaves simple or compound, alternate, usually
stipulate. Flowers regular, generally hermaphrodite, or rarely
unisexual. Thalamus more or less convex, elongated, or con-
cave, or tubular; the tube sometimes becoming fleshy as the
fruit develops, and often so enclosing the carpels as to make the
fruit spuriously synearpous and inferior. Calyx gamosepalous,
sometimes partly adherent to the tube of the thalamus; 4. or 5-
lobed ; when 5, the odd lobe posterior; sometimes surrounded
by a whorl of bracts forming an involucre or epicalyx. These
are by some botanists considered to represent stipules of the
sepals. Petals 5, distinct, perigynous; or rarely none. Sta-
mens definite or », perigynous. Carpels 1, 2, 5, or numerous,
with 1-celled ovaries; usually apocarpous and superior; some-
times becoming spuriously syncarpous and inferior during the
development of the fruit, as in the Pomee ; styles basilar, lateral,
or terminal ; ovules 1 or few. Fruit various: either a drupe, an
achenium, a follicle, a dry or succulent eterio, a cynarrhodon,
ora pome. Seeds 1 or few, exalbuminous; embryo straight.

Diagnosis.—Trees, shrubs, or herbs, with alternate leaves.
Flowers regular. Calyx 4—-5-lobed ; when 5, the odd lobe pos-
334 MANUAL OF BOTANY

terior. Petals 5, perigynous, or rarely none. Stamens perigynous,

distinct ; anthers 2-celled. Carpels one or more, usually distinct

or sometimes ultimately united ; generally superior or occasion-

ally becoming more or less inferior during development of the

fruit. Seeds 1 or few, exalbuminous ; embryo straight.
Division of the Order and Illustrative Genera.—The order

Rosacez, as above defined, may be divided into five sub-orders,

which are by some botanists considered ‘as distinct orders. They

are characterised as follows :—

Sub-order 1. CHRYSOBALANEH.—Trees or shrubs, with simple
leaves and free stipules. Carpel solitary, cohering more or
less on one side with the tube of the thalamus ; ovules 2; style
basilar. Fruit a drupe. Seed erect; radicle inferior. Illustra-

Fic. 1095. Fic. 1096.

 

Fig. 1095. Diagram of the flower 0, a species of Rose, with five sepals, five
petals, numerous stamens, and many distinct carpels——/ig. 1096. Ver-
tical section of the flower.

tive Genus :—Chrysobalanus, Linn. There are no British
plants in this sub-order.

Sub-order 2. Drupacem.—Trees or shrubs, with simple leaves
and free stipules. Calyx deciduous. Carpel solitary, free ;
style terminal. Fruit a drupe. Seed suspended. Ilustra-
tive Genus :—Prunus, Linn.

Sub-order 3. Rosk#.--Shrubs or herbs, with simple or compound
leaves and adherent stipules. Carpels 1 or more, superior,
not united to the tube of the thalamus, distinct or sometimes
more or less coherent; styles lateral or nearly terminal.
Fruit either an etrio, a cynarrhodon, or several follicles.
Seed usually suspended, or rarely ascending ; radicle superior.
Illustrative Genera :—Rosa, Linn.; Rubus, Linn.
DICOTYLEDONES—CALYCIFLORA 835

Sub-order 4. SaneuisorBem or Porrerine.—Herbs or under-
shrubs. Flowers often unisexual. Petals frequently absent.
Carpels 1—8; style terminal or basilar. Fruit an achenium
enclosed in the tube of the thalamus, which is often indurated.

Fic. 1097. Fria. 1098.

 

aM

Fie. 1099. Fic. 1100. Fic. 1101. Fie. 1102. Fie. 1103.

i . Vertical section of the flower of the Peach (Prunus (Amygdalus)

re, 1098. Vertical section of the flower of the Quince (Pyrus
Cydonia).—F'ig. 1099. Two-cellel anther with part of the filament of a
species of Rubus. ——Fig. 1100. Vertical section of the flower of a species of
Alchemilla——F'iy. 1101. Vertical section of the fruit (drupe) of the Cherry
(Prunus Cerasus). ep. Epicarp. me. Mesocarp. en. Endocarp, within
which is the seed with embryo.—/"ig. 1102. Vertical section of an achee-
nium of a species of Rose. ——/iq. 1103. Vertical section of the ovary, 0, of
a species of Rubus, with the ovule, or.

Seed solitary, suspended, erect, or ascending. Illustrative
Genera :—-Alchemilla, Linn.; Poterium, Linn.

Sub-order 5. Pome#.—Trees or shrubs, with simple or compound
leaves and free stipules. Carpels 1 to 5, cohering more or
less with each other and united to the sides of the tube of
the thalamus, thus becoming inferior ; styles terminal. Fruit
336 MANUAL OF BOTANY

a pome, 1—5-celled or rarely spuriously 10-celled. Seeds
erect or ascending. Illustrative Genera :—Pyrus, Linn.;
Crategus, Linn.

Distribution and Numbers.—The Chrysobalane@ are princi-
pally natives of the tropical parts of America and Africa. The
Drupacee are almost exclusively found in the cold and tem-
perate regions of the northern hemisphere. The Rose@ and
Sanguisorbee are also chiefly natives of cold and temperate
climates, although a few are found within the tropics. The Pomee
occur only in the cold and temperate regions of the northern
hemisphere. The order Rosacesw comprises about 1,000 species,
of which about one-half belong to the sub-order Rosew.

Properties and Uses.—The plants of the order are principally
remarkable for their astringency, and for their succulent edible
fruits. The seeds, flowers, leaves, and young shoots of many
of the Drupacee and Pome, when moistened with water, yield
hydrocyanic acid; hence parts of such plants are sometimes
poisonous. All other Rosacex are entirely devoid of poisonous
properties.

Order 122. Saxirracacks&, the Saxifrage Order.—Charac-
ter.—Herbs with alternate leaves, which are entire or lobed,
stipulate or exstipulate. Calyx of 4 or 5 sepals, which are more
or less united at the base, inferior or more or less superior.
Petals 4 or 5, perigynous, imbricate, alternate with the lobes
of the calyx, sometimes wanting. Stamens 5—10, perigynous
or epigynous; anthers 2-celled, with longitudinal dehiscence.
Dise usually evident, either existing in the form of 5 scaly
processes, or annular and notched, epigynous or perigynous.
Ovary superior or more or less inferior, usually composed of two
carpels, united below, but more or less distinct towards the
apex; 1- or 2-celled; styles equal in number to the carpels, dis-
tinct, diverging. Fruit capsular, 1—2-celled, usually mem-
branous. Seeds small, numerous; embryo in the axis of fleshy
albumen, and with the radicle towards the hilum.

Diagnosis.—Herbs with alternate leaves. Calyx inferior
or generally more or less superior, 4—5-partite. Stamens
perigynous or epigynous. Ovary superior or more or less
inferior, composed of 2 carpels united at the base, and diverging
at the apex; styles distinct, equal in number to the carpels.
Fruit capsular, 1—2-celled. Seeds numerous, small, with
fleshy albumen.

Bentham and Hooker include the succeeding orders, Fran-
coacee, Escalloniacee, Philadelphacea, Hydrangeacea, Hen-
DICOTYLEDONES—CALYCIFLORA 337

sloviacee, Cunoniacee, and Ribesiacee, in the order Saaifra-
gacee, and arrange the whole in the following sub-orders :—
1. Saxifragee. 2. Francoee. 3. Escalloniee. 4. Philadelphee
or Hydrangea. 5. Cunoniee. 6. Ribesiee.

Distribution and Numbers.—They are exclusively natives of
the northern parts of the world, where they chiefly inhabit
mountainous districts, and sometimes grow as high as 16,000
feet above the level of the sea. Illustrative Genera :—Saxifraga,
Linn.; Heuchera, Linn. There are about 320 species.

Fic. 1104. Fic. 1105.

 

Fic. 1106

     

Fis. 1104. Saxifraga tridactulites. The leaves are trifid and wedge-shaped,
and the flowers arranged in a cyme.—/'ig. 1105. Vertical section of the
flower.——Fig. 1106. Vertical section of the seed.

Properties and Uses.—The plants of the order are all more
or less astringent. This is remarkably the case with the root of
Heuchera americana, which is much employed for its astringent
properties in the United States under the name of Alwm-root.

Order 123. Francoaces®, the Francoa Order.—Character.
Stemless herbs. Leaves exstipulate. Calyx 4-partite. Petals 4,
persistent. Stamens hypogynous or nearly 80, four times as
many as the petals, the alternate ones sterile, and commonly
termed scales. Ovary superior, 4-celled; ovules numerous ;

VOL. II. Zz
338 MANUAL OF BOTANY

stigma sessile, 4-lobed. Fruzt a membranous 4-celled, 4-valved
capsule, with loculicidal or septicidal dehiscence. Seeds small,
indefinite ; embryo very minute, at the base of a large quantity
of fleshy albumen.

Distribution and Numbers.—Natives of Chili. Illustrative
Genera :—Francoa, Cavan.; Tetilla, DC. These are the only
genera; they include about 6 species.

Properties and Uses.—The Francoas are reputed to be cooling
and sedative. Tetilla is astringent, and is employed as a remedy
in dysentery.

Order 124. EscALLONIACEA, the Escallonia Order.—Charac-
ter.—Evergreen shrubs, with alternate exstipulate glandular
leaves and axillary showy flowers. Calyx superior, 5-toothed,
imbricate in estivation. Petals 5, alternate with the divisions
of the calyx, perigynous, or rarely hypogynous. Stamens 5,
alternate with the petals, perigynous, or rarely hypogynous.
Ovary inferior, 2—5-celled, crowned by a cone-shaped disc ;
placentas axile ; style simple; stigmas 2—5-lobed. Fruit cap-
sular or baccate, crowned by the persistent style and calyx.
Seeds very numerous, minute ; embryo small, in a mass of oily
albumen.

Distribution and Numbers.—They are chiefly natives of the
mountains of South America. Illustrative Genera :—Escallonia,
Mutis ; Itea, Linn.; Brexia, Thouars. There are more than
66 species.

Properties and Uses.—Unknown.

Brexia.—This genus has been made the type of a distinct
order, named Brexiacee ; but Bentham and Hooker place it
near the genus Lscallonia.

Order 125. PHILADELPHACES, the Syringa Order.—Charac-
ter.—Shrubs. Leaves opposite, simple, deciduous, exstipulate.
Calyx superior, persistent, 4——10-lobed, with a valvate westiva-
tion. Petals equal in number to the divisions of the calyx,
and alternate with them. Stamens numerous, epigynous. *
Ovary inferior ; styles united or distinct ; stigmas several. Cap-
sule half-inferior, 4-—10-celled, placentas axile. Seeds nume-
rous, with fleshy albumen.

Distribution and Numbcrs.—Natives of the South of Europe,
North America, Japan, and India. Illustrative Genera :—
Philadelphus, Linn.; Deutzia, Thunb. There are about
25 species.

Properties and Uses.—Of little importance.

Order 126. Hypranceacem®, the Hydrangea Order.—Dia-
DICOTYLEDONES—CALYCIFLORAi 389

gnosis.—This order is frequently regarded as a sub-order of
Saxifragacee, with which it agrees in many important particu-
lars ; but it differs in its plants being of a shrubby nature ; in
their having opposite leaves, which are always exstipulate ; in
their valvate calyx ; in their tendency to a polygamous structure,
as exhibited.in the possession of radiant staminal flowers; and
in having frequently more than 2 carpels, with a corresponding
increase in the number of styles and cells to the ovary.

' Distribution and Numbers.—Natives chiefly of the temperate
regions of Asia and America. About one-half of the species
are natives of China and Japan. Illustrative Genera :—
Hydrangea, DC.; Bauera, Sm. There are about 45 species.

Properties and Uses.—Unimportant.

Order 127. Henstoviacem, the Henslovia Order.—Dia-
gnosis.—This is a small order of tropical plants, containing but 1
genus and 3 or 4 species, which was considered by Lindley to be
nearly allied to Hydrangeacee ; but distinguished by their tree-
like habit, their styles being united into a cylinder, and the
total absence of albumen. Illustrative Genus :—Henslovia,
Wall.

Properties and Uses.—Unknown.

Order 128. Cunontaces, the Cunonia Order.—Dtagnosis.—
Nearly allied to Saxifragacee, but differing from them in being
trees or shrubs, with opposite or whorled leaves, and large in-
terpetiolar stipules. The latter character will also distinguish
them readily from Hydrangeacez, which are exstipulate. They
are also known from the latter order by their calyx not being
valvate. :

Distribution and Numbers.—Natives of South America, the
Cape, the East Indies, and Australia. Illustrative Genera :—
Weinmannia, Linn.; Cunonia, Linn. There are about 100
species.

Properties and Uscs.—-Astringent. Some have been used
for tanning; others exude a gummy secretion.

Order 129. Ripestaces, the Currant Order.—Character.—
Shrubs with or without spines or prickles. Leaves alternate,
simple, lobed, radiate-veined. Injlorescence axillary, racemose.
Flowers perfect or rarely unisexual. Calyx superior, 4—5-lobed.
Petals 4—5, minute, inserted on the calyx. Stamens 4—5,
perigynous, alternate with the petals: Ovary inferior, 1-celled,
with 2 parietal placentas. Fruit: a berry. Seeds numerous ;
embryo minute, in horny albumen.

Distribution and Numbers.— Natives of the temperate regions
“2
340 MANUAL OF BOTANY

of Europe, Asia, and North America. Illustrative Genera :—
Ribes, Linn.; Polyosma, Br. These are the only genera;
they include about 100 species.

Properties and Uses.—Some are showy garden plants, as
Ribes fuchsioides, R. sanguinewm, R. aureum, R. coccineum ;
but they are chiefly remarkable for their agreeable acid fruits.
Thus the fruit of Ribes Grossularia is the Gooseberry; R.
rubrum and its varieties yield both Red and White Currants ;
and R. nigrum is the Black Currant. ;

Order 1380. CrassuLacem, the Houseleek Order.—Charac-
ter.— Succulent herbs or shrubs. Leaves entire or pinnatifid,
exstipulate. Flowers symmetrical. Calyx generally composed
of 5 sepals, but varying in number from 3 to 20, more or less
united at the base, inferior, persistent. Petals equal in number
to the divisions of the calyx, with which they are alternate ;
either distinct or united, and inserted into the bottom of the
calyx; estivation imbricate. Stamens inserted with the petals,
either equal to them in number and alternate with them; or
twice as many, and then forming 2 whorls, one of which is
composed of longer stamens than the other, the longer stamens
being placed alternate to the petals, and the shorter stamens
opposite to them; anthers adnate, 2-celled, with longitudinal
dehiscence. Carpels equal in number to the petals and opposite
to them, each having frequently a scale on the outside at the
base; distinct or more or less united; styles distinct. Frutt
either consisting of a whorl of follicles, or a capsule with loculi-
cidal dehiscence. Seeds very small, variable in number; em-
bryo in the axis of fleshy albumen, with the radicle towards the
hilum.

Diagnosis.—Succulent herbs or low shrubs. Leaves exstipu-
late. Flowers perfectly symmetrical, the sepals, petals, and
carpels being equal in number and the stamens being also
equal to them, or twice as many. Petals and stamens almost
hypogynous. Corolla gamopetalous or polypetalous. Carpels
opposite the petals. Fruit either apocarpous and follicular, or a
many-celled capsule with loculicidal dehiscence. Seeds small ;
embryo in the axis of fleshy albumen.

Division of the Order and Illustrative Genera :—The order
may be divided as follows :—

Sub-order 1. CrassuLea#.—Fruit consisting of a whorl of fol-
licles. Crassula, Haw.; Sedum, Linn.

Sub-order 2. DramorpHes.—Fruit a many-celled capsule with
loculicidal dehiscence. Diamorpha, Nutt.; Penthorum, Linn.
DICOTYLEDONES—CALYCIFLORA 341

Distribution and Numbers.—They are found in very dry
situations in all parts of the world; a large number occur at the
Cape of Good Hope. There are about 450 species.

Properties and Uses.—Astringent, refrigerant, and acrid pro-
perties are found in the plants of this order, but none are of
much importance.

Order 181. DRosERACEm, the Sundew Order.—Character.
Herbaceous plants growing in boggy or marshy places, fre-
quently glandular. Leaves alternate, fringed at their margins
and with a circinate vernation. Inflorescence helicoid. Sepals
and petals 5, hypogynous, equal, imbricate, persistent. Stamens
as many as the petals and alternate with them, or twice, thrice,
or four times as many, distinct, withering, hypogynous ; anthers
innate or versatile, extrorse. Ovary superior, 1-celled, with
parietal placentation ; styles 8—5, distinct or connected at the
base; ovules numerous, anatropous. Fut capsular, 1-celled,
bursting by 3 or 5 valves, which bear the placentas in their
middle or at their base ; hence the dehiscence is loculicidal.
Seeds numerous, with or without an aril; embryo minute at the
base of abundant fleshy albumen.

Diagnosis.—Bog or marsh herbs, with alternate exstipu-
late leaves and aw circinate vernation. Inflorescence helicoid.
Flowers regular and symmetrical, hypogynous, with a quinary
arrangement of their parts, which are also persistent and im-
bricate. Anthersextrorse. Placentas parietal. Fruit capsular,
1-celled, with loculicidal dehiscence. Seeds numerous; embryo
small, at the base of copious fleshy albumen.

Distribution and Numbcrs.—These plants are found in
almost all parts of the world with the exception of the Arctic
regions. Illustrative Genera :—Drosera, Linn, ; Dionea, Ellis.
There are about 110 species in this order.

Properties and Uses.—They possess slightly acid and acrid
properties. The plants of the order are chiefly interesting from
the peculiar irritability of the glands on their leaves. Thus, the
leaves of the Droseras are fringed with stalked glands, which
curve over and imprison any insects that alight upon the leaf-
blade; while the plant known as Venus’s Flytrap (Dionea
muscipula), « native of North America, has two-lobed leaves,
each lobe furnished on its upper surface with three stiff hairs ;
these, when touched, cause the two lobes of the leaf to shut
together face to face and enclose the object touching them.
The glands in these plants secrete w viscid acid digestive fluid,
342 MANUAL OF BOTANY

so that insects which are imprisoned by them become ulti-
inately dissolved and absorbed for their nourishment.

Order 132. HamamELipace#, the Witch-hazel Order.—
Character.—Small trees or shrubs, with alternate simple
leaves and deciduous stipules. Flowers in globular heads or
spicate, perfect or unisexual, polygamous or monecious. Calyx
superior, 4- or 5-lobed. Petals 4 or 5, with an involute or
circinate estivation, or altogether wanting. Stamens 8, half of
which are scale-like, sterile, and placed opposite to the petals,
and half fertile and alternate with them; or numerous. Ovary
inferior, 2-celled ; ovules solitary or numerous; styles 2. Fruit
capsular, 2-celled, with 1 seed in each cell; seeds albuminous.

Distribution and Numbecrs.—Natives of North America,
Asia, and Africa. Illustrative Genera :—Hamamelis, Linn. ;
Liquidambar, Linn. There are about 25 species.

Properties and Uses.—-Chiefly remarkable for their fragrant
balsamic properties. Some have acrid bitter barks; and the
leaves and bark of others are astringent.

Order 133. Bruntace®, the Brunia Order.—Character.—
Heath-like shrubs, with small imbricate, rigid, entire, exstipulate
leaves. Calyx usually superior, or sometimes nearly inferior,
imbricate. Petals and, stamens 5, inserted on the calyx, the
petals alternate with the divisions of the calyx and valvate ;
anthers 2-celled, extrorse, bursting longitudinally. Ovary
superior or half inferior, 1—-3-celled, with 1 or 2 suspended
anatropous ovules in each cell; style simple or bifid. Fruit
crowned by the remains of the calyx and a disc; 1—2-celled, in
the first case indehiscent, in the latter dehiscent. Seeds with
a minute embryo, in fleshy albumen.

Distribution and Numbers.—Natives of the Cape of Good
Hope, except one Madagascar species. Illustrative Genera :—
Brunia, Linn.; Ophiria, Linn. There are about 60 species.

Properties and Uses.—Unknown.

Order 134. HaLoracaceg, the Mare’s-tail order.— Diagnosis.
Herbs or shrubs, generally aquatic. Flowers small, frequently
incomplete and unisexual. They are nearly allied to Onagracer,
and, in fact, have been considered a degenerate form of that
order. They are distinguished from it by their minute calyx, the
limb of which is frequently obsolete; and by having solitary
pendulous seeds, with fleshy albumen.

Distribution and Numbers.—They are found in all parts of
the world. Illustrative Genera .—Hippuris, Linn.; Trapa,
Linn. There are about 70 species.
DICOTYLEDONES—CALYCIFLORA 343

Properties and Uses.—Of little importance except for their
edible seeds.

Ordcr 185. CaLLITRICHACE®, the Starwort Order.—Charac-
ter.—Small aquatic herbs. Leaves simple, opposite, entire.
Flowers minute, axillary, solitary, unisexual, achlamydeous.
Male flower of 1—2 stamens ; anthers reniform. Female flower
with a 4-cornered, 4-celled ovary, with 1 pendulous ovule in
each cell. Fruit indehiscent, 4-celled. Seeds 4, pendulous, with
fleshy albumen; embryo inverted, with w very long superior
radicle.

Distribution.—Natives of freshwater pools in Europe and
North America. Caillitriche is the only genus; it includes
several species or varieties.

Properties and Uses——Unknown.

Cohort 2.—Myrtales.

Order 186. RuizopHorace®, the Mangrove Order.—
Character.—Trees or shrubs. Leaves simple, opposite, dotless
or rarely dotted, with deciduous interpetiolar stipules. Calyx
superior, 4—12-lobed, with a valvate estivation, the lobes
sometimes united so as to form a calyptra. Petals arising from
the calyx, alternate with its lobes and equal to them in number.
Stamens on the calyx, twice or thrice as many as its lobes, or
still more numerous. Ovary inferior, 2- 8- or 4-celled, each cell
with 2 or more ovules. Fruit indehiscent, 1-celled, 1-seeded,
crowned by the calyx. Seeds pendulous, exalbuminous, usually
germinating while the fruit is still attached to the tree.

Distribution and Numbers.—Natives of muddy seashores
in tropical regions. Illustrative Genera :—Rhizophora, Lam. ;
Bruguiera, Lam. There are about 20 species.

Properties and Uses.—Generally remarkable for their astrin-
gent properties, whence they are used for dyeing and tanning;
they are also used medicinally for their febrifugal and tonic
properties.

Order 187. CoMBRETACES, the Myrobalans Order.—Charac-
ter.—Trees or shrubs. Leaves alternate or opposite, exstipu-
late, entire, without dots, Flowers perfect or unisexual. Calyx
superior, with a 4—5-lobed deciduous limb. Petals equal in
number to, and alternate with, the lobes of the calyx ; often
absent. Stamens inserted with the petals on the calyx, gene-
rally twice as numerous as its lobes, or thrice as many, or
sometimes equal to them in number; anthers 2-celled, with
longitudinal or valvular dehiscence. Ovary inferior, 1-celled,
344 MANUAL OF BOTANY

with 2—4 ovules; style and stigma simple. Frwit indehiscent,
1-seeded. Seeds pendulous, exalbuminous; cotyledons leafy,
convolute or plaited.

Distribution and Nuwmbers.—Exclusively natives of the
tropical parts of America, Africa, and Asia. Illustrative Genera:
Terminalia, Linn.; Combretum, Léfl. There are about 200
species.

Properties and Uses.—The order is chiefly remarkable for
the presence of an astringent principle; hence the bark of some
species, and the fruits and flowers of others, are employed in

tanning and dyeing. Some yield
Fie. 1107. excellent timber.

Order 188. Myrtacra, the
Myrtle Order..— Character. —
Trees or shrubs. Leaves opposite
or alternate, entire, exstipulate, usu-
ally dotted, and having a vein run-
ning just within their margins.
Calyx superior, 4- or 5-cleft, valvate,
sometimes separating in the form
of a cap. Petals 4—5, imbricate,
rarely absent. Stamens usually 8—
10, or numerous, or rarely 4—5_

filaments distinct or polyadelphous,
Ovary inferior, 1—6-celled; style
and stigma simple; placentas axile,
or very rarely parietal. Fruit dry
he bee ace ices aie or succulent, dehiscent or inde-
common Myrtle (Ayrtus com. hiscent. Seeds without albumen,

munis). usually numerous.
Division of the Order and

Illustrative Genera.—The order may be divided into two tribes
as follows : —

 

Tribel. Leptosperme.—Fruit capsular. Illustrative Genera :
Melaleuca, Leptospermum.

Tribe 2. Myrtee.—Fruit baccate.

: Illustrative Genera :—
Punica, Linn. ; Myrtus, Tourn.

Distribution and Numbers.—Natives of the tropics and of
the warmer parts of the temperate zones. Myrtus communis,
the common Myrtle, is the most northern species of the order.
This plant, although now naturalised in the South of Europe,
DICOTYLEDONES— CALYCIFLORE 345

was originally a native of Persia. There are about 1,320 species
belonging to this order.

Properties and Uses.—These plants are generally remarkable
for aromatic and pungent properties, which are due to the
presence of volatile oils. Many of these oils have been used in
medicine as stimulants, aromatics, carminatives, diaphoretics,
or antispasmodics; and also in perfumery. The dried flower-
buds and unripe fruits of some species are in common use as
spices. Other plants of the order are astringent, and a few secrete
a saccharine matter. The fruits of some having a sweetish
acidulous taste are edible. Many are valuable timber-trees.

Order 139. LecyTHiIpAace®, the Brazil-nut Order.—C harac-
ter.—Large trees, with alternate dotless leaves, and small
deciduous stipules. Flowers large andshowy. Calyx superior.
Petals 6, imbricate, distinct, or sometimes united at the base.
Stamens numerous, epigynous ; some of them cohering so as to
form a unilateral petaloid hooded body. Ovary inferior, 2—6-
celled; placentas axile. Fruit woody, either indehiscent or
opening in a circumscissile inanner. Seeds several, large, and
without albumen. This order is referred to Myrtaceae by
Bentham and Hooker.

Distribution and Numbers.— Principally natives of Guiana
and Brazil, and also occasionally of other hot regions of South
America. Illustrative Genera :—Lecythis, Léfi. ; Bertholletia,
Humb. et Bonpl. There are about 40 species.

Properties and Uses.—These plants are chiefly remarkable
for their large woody fruits, the pericarps of which are used as
dvinking-vessels and for other purposes. Their seeds are
frequently edible. : :

Order 140. BarrineTontaces, the Barringtonia Order.—
Diagnosis.—This is a small order of plants frequently placed
among the Myrtacezx, but differing from that order in the pre-
sence of a large quantity of albumen in their seeds, in their
having alternate dotless and often serrated leaves, and in the
estivation of the calyx, which in Myrtaceex is valvate, while in
Barringtoniacee it is imbricate.

Distribution and Numbers.—Natives of tropical regions in
all parts of the world. Illustrative Genera :—Barringtonia,
Forsk.; Gustavia, Linn.

Properties and Uses.—The bark of Stravadium racemosum
is reputed to be febrifugal, and the root bitter, aperient, and
acrid. The fruit of Careya arborea is eaten, while that of
Gustavia brasiliana is emetic, and produces an intoxicating
346 MANUAL OF BOTANY

effect upon fish. Generally the plants of the order should be
regarded as somewhat dangerous.

Order 141. CHaMmuauctacem, the Fringe-myrtle Order.—
Diagnosis.—This is a small order of shrubby plants with ever-
green dotted leaves, and nearly allied to Myrtacex, but distin-
guished from them by their heath-like aspect, their more
or less fringed scaly or bristly calyx-tube, and their 1-celled
ovary. From Lecythidacee they are known by their habit,
their dotted exstipulate leaves, and 1-celled ovary.

Distribution and Numbers.—Exclusively natives of Aus-
tralia. Illustrative Genera :—Chamelaucium, Desf.; Darwinia,
Rudg. There are more than 50 species.

Properties and Uses.—Unknown.

Order 142. Benvistacem, the Belvisia Order.—Charac-
ter.—Shrubs. Leavesalternate, exstipulate, witha leathery tex-
ture. Calyx superior, coriaceous, 5-partite, with a valvate
estivation. Corolla consisting of three distinct whorls of
united petals. Stamens 20, somewhat polyadelphous. Disc
fleshy, and forming a cup-shaped expansion over the ovary.
Ovary 5-celled, with two ovules in each cell; placentas axile ;
style 5-angled or 5-winged; stigma flat, pentagonal. Fruit
a soft rounded berry crowned by the calyx. Seeds large,
kidney-shaped, exalbuminous.

Distribution and Numbers.—Natives of tropical Africa and
Brazil. Illustrative Genera :—Asteranthos, Desf.; Napoleona,
Palis. These are the only genera; they include 4 species.

Properties and Uses.—Nothing is known of the uses of
these plants, except that the pulp of their fruits is edible, and
the pericarp contains much tannic acid.

Order 143. Mrtastomaces, the Melastoma Order.—Cha-
racter.—Trees, shrubs, or herbs. Leaves opposite, and almost
always with several large curved ribs, and dotless. Flowers
showy. Calyx 4-5- or 6-lobed, more or less adherent to the
ovary, imbricate. Petals equal in number to the divisions of the.
calyx, twisted in estivation. Stamens equal in number to, or
twice as many as, the petals; filaments curved downwards in
zstivation ; anthers long, 2-celled, curiously beaked, usually
dehiscing by two pores at the apex, or sometimes longitudinally ;
in estivation lying in spaces between the ovary and sides of the
calyx. Ovary more or less adherent, many-celled ; placentation
axile. Fruit either dry, distinct from the calyx, and indehiscent ;
or succulent, united to the calyx, and indehiscent. Seeds very
numerous, minute, exalbuminous. :
DICOTYLEDONES-—CALYCIFLORA 347

Distribution and Numbers.—They are principally natives of
tropical regions, but a few are also extra-tropical, being found in
North America, China, Australia, and also in the northern
provinces of India. Illustrative Genera :—Melastoma, Juss. ;
Medinilla, Gaud. There are about 2,000 species.

Properties and Uses.—The prevailing character of these
plants is a slight degree of astringency. Many produce edible
fruits, and some are used for dyeing. Generally speaking, the
plants of this order possess but little interest from a medicinal or
economic point of view, but none are unwholesome. A number
of species are cultivated in this country on account of the beauty
of their flowers.

Order 144. Lyruracre®, the Loosestrife Order.—Character.

Fic. 1108.

Fie. 1109.

  

Fig. 1108. Vertical section of the flower of the Purple Loosestrife (Lythrum
Salicaria).- —Fig. 1109. Calyx of the same.

Herbs or rarely shrubs, frequently 4-sided. Leaves opposite or
rarely alternate, entire, and exstipulate. lowers regular or
irregular. Calyx persistent, ribbed, tubular below, the lobes with
a valvate estivation, sometimes with intermediate teeth. Petals
inserted between the lobes of the calyx and alternate with
them, occasionally wanting; deciduous. Stamens perigynous,
inserted below the petals, to which they are equal in number,
or twice as many, or even more numerous; anthers adnate, 2-
celled, opening longitudinally. Ovary superior, 1- 2- or 6-celled ;
ovules numerous or rarely few; style 1, filiform; stigma
capitate or rarely 2-lobed. Fruit capsular, membranous, dehis-
cent, surrounded by the non-adherent calyx-tube. Seeds
348 MANUAL OF BOTANY

numerous, with or without wings, exalbuminous; placentation
axile; embryo straight, with flat leafy cotyledons, and the radicle
towards the hilum.

Diagnosis.—Herbs or shrubs, with entire exstipulate usually
opposite leaves. Calyx tubular, ribbed, persistent, bearing the
deciduous petals and stamens; the latter being inserted below
the petals. Anthers 2-celled, adnate, bursting longitudinally.
Ovary superior, with axile placentation; style 1. Fruit mem-
branous, dehiscent, surrounded by the non-adherent calyx-tube.
Seeds numerous, exalbuminous.

Distribution and Numbers.—The greater
number are tropical plants, but some are also
found in temperate regions, as, for instance, in
Europe and North' America. One species only,
Lythrum Salicaria, hitherto has{been found in
Australia. Illustrative Genera: — Lythrum,
Linn.; Lawsonia, Linn. There are about 250
species.

Properties and Uses.—These plants are
chiefly remarkable for the possession of an
astringent principle,"and,for their value in dye-
ing

Fie. 1110.

    
 
  

    

SEE Fo)
LESS KS)

OOO
SSS

     
     

Order 145. Onacracrea, the Evening Prim-
rose Order.—Character.—Herbs or shrubs.
Leaves alternate or opposite, simple, exstipulate,
without dots. Calyx superior, tubular, with the
limb usually 4-lobed, or sometimes 2-lobed ; in
estivation valvate; or rarely the limb is absent.
Fig. 110, verti. Petals usually large and showy, generally regular
cal section of and equal in number to the divisions of the
the flower of a : : = f * 3
species of Wil. Calyx, twisted in estivation, and inserted into
at (Zvi- the throat of the calyx; rarely absent. Stamens
; definite, 2, 4, or 8, or rarely by ‘abortion 1, in-
serted with the petals into the throat of the calyx; filaments
distinct ; pollen trigonal. Ovary inferior, 2—4-celled ; placentas
axile; style 1, filiform; stigma lobed or capitate. Fruit cap-
sular, or succulent and indehiscent, 2—4-celled. Seeds nume-
rous, without albumen ; embryo straight.

Diagnosis.—Herbs or shrubs, with simple exstipulate dotless
leaves. Calyx superior, 2—4-lobed, valvate in estivation. Petals
usually equal in number to the lobes of the calyx, with a twisted
estivation, or rarely absent. Stamens few, inserted into the
throat of the calyx with the petals. Ovary inferior, 2—4-celled;

SSS
SSS

  
   
     

 

—

   
DICOTYLEDONES—CALYCIFLORA 349

style simple; stigma lobed or capitate. Fruit dehiscent or in-
dehiscent. Seeds numerous, without albumen.

Distribution and Numbers.—Chiefly natives of the temperate
parts of North America and Europe; many are also found in
India, but they are rare in Africa, except at the Cape. Tllus-
trative Gencra :—(CEnothera, Linn.; Circera, Tourn. There are
about 300 species.

Properties and Uses.—Generally the plants are harmless
and possess mucilaginous properties. The roots of @nothera
biennis and other species of the same genus are edible. The
fruits of many Fuchsias are somewhat acid and good to eat.
Some species of Jussiea are astringent.

Cohort 3.—Passijflorales.

Order 146. SamypacEx, the Samyda Order.—Character.
Trees or shrubs. Leaves alternate, simple, evergreen, stipu-
late, usually with round or linear transparent glands. Calyx
inferior, 4—5-partite. Petals absent. Stamens perigynous, 2,
3, or 4 times as many as the divisions of the calyx; filaments
united, some of them frequently without anthers; anthers 2-
celled. Ovary superior, 1-celled; style 1, filiform; placentas
parietal, bearing numerous ovules. Fruit capsular, leathery, 1-
celled. Seeds numerous, arillate, with oily or fleshy albumen ;
embryo large.

Distribution and Numbers.—Exclusively tropical, and prin-
cipally American. Illustrative Genera :—Samyda, Linn. ;
Casearia, Jacy. There are more than 100 species.

Properties and Uses.—Of little importance. They are com-
monly bitter and astringent.

Order 147. Homauiacea, the Homalium Order.—C harac-
ter.— Trees or shrubs, with alternate leaves. Calyx superior,
funnel-shaped, with from 5 to 15 divisions. Petals equal in
number to, and alternate with, the divisions of the calyx. Sta-
mens opposite to the petals and inserted on them, either distinct
or in bundles of 8 or 6. Ovary inferior, 1-celled; placentas
parietal; ovules numerous; styles 3—5. Fruit a capsule or
berry. Seeds small; embryo in the axis of a little fleshy albu-
men. This order is included in Samydacee by Bentham and
Hooker.

Distribution and Numbers.—They are natives of the tropi-
cal parts of India, Africa,and America. Illustrative Genera :—
Homalium, Jacq.; Trimeria, Harv. There are about 36 spe-

cies.
850 MANUAL OF BOTANY

Properties and Uses.—Some species of Homaliwm are astrin-
gent, but nothing is known of the properties of the other
genera.

Order 148. Loasacra, the Chili Nettle Order.—C haracter.
Herbaceous plants, with stiff hairs or stinging glands. Leaves
exstipulate.: Calyx superior, 4- or 5-parted, persistent. Petals
5 or 10, in 2 whorls, often hooded. Stamens numerous, in
several whorls, either distinct or united in bundles. Ovary
inferior, 1-celled, with several parietal placentas, or 1 axile pla-
centa; style 1; ovules anatropous. Fruit capsular or succulent.
Seeds with a loose testa, and having an embryo lying in the
axis of fleshy albumen.

Distribution and Numbers.—They are all natives of North
and South America. Illustrative Genera :—Bartonia, Muehl. ;
Loasa, Adans. There are about 70 species.

Properties and Uses.—Some of the species are remarkable
for their stinging glands; hence their common name of Chili
Nettles. Several species are cultivated on account of the beauty
of their flowers. A Mexican species, Mentzelia hispida, is re-
puted to possess a purgative root.

Order 149. TuRNERACE®, the Turnera Order.—Charac-
ter.—Herbaceous or somewhat shrubby plants. Leaves alter-
nate, exstipulate, hairy. Flowers axillary. Calyx inferior, 5-
lobed, imbricate in estivation. Petals 5, equal, twisted in esti-
vation, without a corona, perigynous, deciduous. Stamens 5,
alternate with the petals, perigynous ; filaments distinct. Ovary
1-celled, superior, with 3 parietal placentas; styles 8, more or
less united at the base, forked or branched above. Fruit cap-
sular, 1-celled, 3-valved, partially dehiscing in a loculicidal
manner. Seeds with a caruncle on one side, and a slightly
curved embryo in the midst of fleshy albumen.

Distribution and Numbers.—Natives exelusively of South
America and the West Indies. Illustrative Genera :—Turnera,
Plum.; Piriqueta, Avb/l. There are about 60 species.

Properties and Uses.—Some are said to be astringent, others
tonic and expectorant, and a few aromatic.

Order 150. PasstrLoracE&, the Passion-flower Order.—C ha-
racter.—Herbs or shrubs, usually climbing by tendrils, or
rarely trees. Leaves alternate, with foliaceous or rarely minute
stipules. Flowers perfect or very rarely unisexual. Sepals 5,
united below into a tube, the throat of which bears a number
of filamentous processes, thus forming a kind of corona;
petals 5, inserted into the throat of the calyx on the outside
DICOTYLEDONES— CALYCIFLORZ 351

of the filamentous processes, with an imbricate exstivation;
sometimes wanting. Stamens usually 5, monadelphous or
rarely numerous, attached to the stalk of the ovary, and thus
raised above the calyx. Ovary stalked, superior, 1-celled;
styles, 3, clavate; placentas parietal. Fruit 1-celled, stalked,
generally succulent. Seeds numerous, arillate ; embryo in thin
fleshy albumen.

Distribution and Numbers.—They are chiefly found in tro-
pical America, but a few also occur in North America and the
East Indies, and several in Africa. Illustrative Genera :—Passi-
flora, Juss.; Tacsonia, Juss. There are about 214 species.

Properties and Uses.— Several have edible fruits, and others
are said to be bitter and astringent, narcotic, emmenagogue, or
diaphoretic.

Order 151. MALESHERBIACES, the Crownwort Order.—Dia-
gnosis.—This is a small order of herbaceous or somewhat shrubby
plants, resembling Passifloracex, in which it is included by
Bentham and Hooker, but they differ in never being climbers; in
the want of stipules ; in the filamentous processes of the flowers
of that order being reduced to a short membranous ring or
coronet in this; in the insertion of the styles at the back in-
stead of the apex of the ovary; and in the seeds not being
arillate. \

Distribution and Numbers.—They are all natives of Chili
and Peru. Illustrative Genera :—Malesherbia, R. et P.; Gyno-
pleura, Cav. These are the only genera; they include 5
species.

Properties and Uses.—Altogether unknown.

Order 152. Papayaces, the Papaw Order.—Character.—
Trees or shrubs, sometimes with an acrid milky juice. Leaves
alternate, on long stalks, lobed. lowers unisexual, or rarely
perfect. Calyx inferior, minute, 5-toothed. Corolla gamope-
talous, and usually without scales or filamentous corona in the
female flowers; 5-lobed. The male flower has a few stamens
inserted onthe corolla. The female flower has a 1-celled superior
ovary, with 3—5 parietal placentas. JF ruit succulent or dehis-
cent. Sceds numerous, albuminous, with the radicle towards
the hilum. This order is included in Passifloracee by Bentham
and Hooker.

Distribution and Numbers.—Natives of South America and
the warmer parts of the Old World. Illustrative Genera :—-
Carica, Linn.; Modecea, Linn. There are about 26 species.

Properties and Uses.— Generally unimportant ; but the acrid
352 MANUAL OF BOTANY

milky juice is said to be poisonous in some species, and emmena-
gogue in others. The seeds of some species are also emmena-
gogue.

Order 153. CUcURBITACE, the Gourd Order.—Character.—
Herbs, generally of a succulent nature, and either prostrate, or
climbing by means of tendrils. Leaves succulent, alternate, with
a radiate venation, more or less scabrous, exstipulate. Flowers
unisexual, monecious or diwcious. Calyx gamosepalous, 5-
toothed, the limb sometimes obsolete, superior in the female
flowers. Corolla gamopetalous, 4—5-parted, or of distinct valvate
or induplicate petals, sometimes fringed, perigynous. Male
flower :—Stamens usually 5, epipetalous, and alternate with the

Fie. 1111. Fie. 1112.

  

Fig. WALL. Female or pistillate flower of the Cucumber (Cucumis sativus), co.
Calyx adherent to the ovary ; the limb is seen above, with five divisions.
p. Corolla. s. Stigmas.—Jig. 1112. Male or staminate flower of the same,
the floral envelopes of which have been divided in a longitudinal manner,
From Jussieu. c. Calyx. p. Corolla, st, Stamens.

segments of the corolla, either distinct or monadelphous, or
more frequently triadelphous in such a way that two of the
bundles contain each 2 stamens, and the other but 1 stamen;
rarely there are but 2 or 3 stamens present; anthers 2-celled,
usually long and sinuous, or sometimes straight. Memale
flower :—Ovary inferior, 1-celled, or generally spuriously 3-
celled from the projection inwards of the placentas; placentas
parietal, usually 3, or rarely 2; ovules indefinite or sometimes
solitary; style short; stigmas thickened, papillose, lobed or’
fringed. Fruit « pepo, or rarely a berry. Seeds more or less
flattened, usually with a leathery or horny testa, which is en-
veloped in a succulent or membranous covering; generally
DICOTYLEDONES-—-CALYCIFLORA 353

numerous, or rarely solitary; embryo flat, without albumen ;
cotyledons leafy ; radicle towards the hilum.

Diagnosis.—Herbs, usually of a succulent nature, prostrate
or climbing. Leaves rough, alternate, radiate-veined, exstipu-
late. Flowers unisexual. Calyx 5-toothed or obsolete, superior
in the female flowers. Corolla perigynous. Male flower with
usually 5 stamens, which are distinct, monadelphous, or tria-
delphous, and epipetalous; rarely there are but 2 or 3 stamens ;
anthers long and usually sinuous or sometimes straight. Female
flower :—Ovary inferior, with parietal placentas; style short;
stigmas more or less dilated. Fruit succulent. Seeds flat,
generally numerous, exalbuminous, cotyledons leafy.

Division of the Order and Illustrative Genera.—The Cucur-
bitaceze have been divided by Bentham and Hooker as follows :—

Series 1. PxaciosPpeRME#.—Ovules horizontal. Illustrative
Genus :—Bryonia, Linn.

Series 2. ORTHOSPERMEH.—Ovules erect or ascending. Illwstra-
tive Genus :—Trianosperma, Torr. et Gr.

Series 8. CREMOSPERMEH.—Ovules pendulous. TIilustrative
Genera :—Sicyos, Linn. ; Sechium, P. Br.

Distribution and Numbers.—Natives principally of hot
climates in almost every part of the world, but especially abun-
dant in the East Indies. One species only, Bryonia dioica,
occurs in the British Islands. There are about 360 species.

Properties and Uses.—An acrid bitter purgative property is
the chief characteristic of the plants of this order; this is
possessed more or less by all parts of the plant, but it is
especially evident in the pulp surrounding the seeds; the seeds
themselves are, however, usually harmless. In some plants
this acridity is so concentrated that they become poisonous;
while in other cases, and especially from cultivation, it is so
diffused that their fruit is edible.

Order 154, BEGoNIACEe, the Begonia Order.—C haracter.—
Herbs, or low succulent shrubs. Leaves alternate, very unequal-
sided at the base, with large membranous stipules. Flowers uni-
sexual. Perianth coloured. Male flower with 4 perianth-leaves,
2 of which are smaller than the others, and decussating with
them, are placed internally to them. Stamens numerous, distinct
or united by their filaments into a column; anthers 2-celled,
clavate, with longitudinal dehiscence, clustered. Female flower
with 5 or 8 perianth-leaves. Ovary inferior, winged, 3-celled,
with three large projecting placentas, meeting in the axis;

VoL. Il. AA
354 MANUAL OF BOTANY

stigmas 3, sessile, 2-lobed. Fruit winged, capsular. Seeds
numerous, with a thin reticulated testa, and without albumen.
Distribution and Numbers.—Natives chiefly of India, South
America, andthe West Indies. Illustrative Genera :—Begonia,
Linn.; Diploclinium, Lindl. There are more than 160 species.
Properties and Uses.—They are generally reputed to possess
astringent and bitter properties, and occasionally to be purgative.
Order 155. Datiscacra, the Datisca Order.—Character.—
Herbs, or in the case of Tetrameles a large tree. Leaves alter-
nate, exstipulate. Flowers diclinous, apetalous. Male flower
with a 8—4-cleft calyx. Stamens 83—1 ; anthers 2-celled, linear,
bursting longitudinally. Female flower with a superior 3—4-

Fie. 1113. Fie. 1114..

 

Fig. 1118. Vertical section of
the flower of the Prickly
Pear (Opuntia vulgaris).
——Fig. 1114. Diagram of
the flower of the same.

 

toothed calyx, and a 1-celled ovary, with 3—4 polyspermous
parietal placentas. Fruit dry, opening at the apex. Seeds
without albumen, minute, numerous.

Distribution and Numbers.—They are widely distributed
over the globe. Illustrative Genera :—Datisca, Linn. ; Tetra-
meles, R. Br. The above are the only genera: there are 4
species.

Properties and Uses.—Of little importance.

Cohort 4.—Ficotdales.

Order 156. Cacracem, the Cactus Order.—Character.—
Succulent plants, which are usually spiny and leafless. Stems
fleshy, globular, columnar, flattened, or 3- or more-angled, and
DICOTYLEDONES—CALYCIFLORA 355

altogether presenting a peculiar and irregular appearance.
Flowers solitary, sessile. Sepals and petals imbricate, usually
numerous, in several whorls, and scarcely distinguishable from
each other, or rarely 4-merous ; adherent to the ovary (fig. 1118).
Stamens numerous, with long filaments and versatile anthers.
Ovary inferior, fleshy, 1-celled, with parietal placentas; style 1;
stigmas several. Fruit succulent. Seeds numerous, without
albumen.

Distribution and Numbers.—Natives almost exclusively of
the tropical regions of America. Illustrative Genera :—Melo-
cactus, C. Bauhin; Mammillaria, Haw. There are about 800
supposed species.

Properties and Uses.—The fruit of many species is some-
what acid and agreeable, and is useful in febrile complaints.
The fleshy stems of the Melon Cactus (Melocactus) are eaten by
cattle in the dry districts of South America on account of their
juice. Many species of Cereus, Epiphyllum, &c., are culti-
vated on account of their showy flowers. Some species of Cereus,
as C. grandiflorus and C. nycticallus, open their flowers at
night; they are remarkable for their size, some being as much
as 1 foot in diameter.

Order 157, MrsEMBRYANTHACEA or FICOIDACEs, the Ice-
plant Order.—Character.—Succulent herbs or shrubs, with
opposite or alternate, simple, exstipulate leaves. Calyx 3—8-
partite, either free or partially adherent to the ovary. Petals
either numerous and showy, or altogether absent. Stamens
perigynous or epigynous, distinct, numerous or definite. Ovary
inferior or nearly superior, usually many-celled, rarely 1-celled ;
placentas axile, free central, or parietal; styles and stigmas as
many as the cells of the ovary, distinct; ovules usually nume-
rous or rarely solitary, amphitropous or anatropous. Fruit
usually capsular and many-celled, or rarely 1-celled, dehiscing
in a stellate or circumscissile manner at the apex, or splitting at
the base; or woody and indehiscent. Seeds few or numerous,
or rarely solitary; embryo curved or spiral, on the outside of
mealy albumen.

Diagnosis.—Succulent herbs or shrubs, with simple exstipu-
late leaves. Sepals definite, generally more or less adherent to
the ovary. Petals very numerous or absent. Stamens perigy-
nous or nearly epigynous. Ovary inferior or nearly superior ;
styles distinct; placentas axile, free central, or parietal. Fruit
capsular or indehiscent. Seeds with a curved or spiral embryo
on the outside of mealy albumen.

AA
356 MANUAL OF BOTANY

Division of the Order and Illustrative Genera.—The Mesem-
bryanthacee may be divided into three sub-orders as follows :—

Sub-order 1. MesEMBRYANTHEH.—Leaves opposite. Petals nu-
merous, conspicuous. Stamens numerous. Fruit capsular,
dehiscent. — Illustrative Genera: — Mesembryanthemum,
Linn.; Lewisia, Pursh.

Sub-order 2. TeTRaconir#.—Leaves alternate. Petals absent.
Stamens definite. Fruit woody and indehiscent.—Illustrative
Genera :—Tetragonia, Linn. ; Aizoon, Linn.

Sub-order 3. Szsuvir=.—Leaves alternate. Petalsabsent. Sta-
mens definite. Fruit capsular, with transverse dehiscence.—
Illustrative Genera :—Sesuvium, Linn.; Cypselea, Turp.

The last two sub-orders are sometimes placed in an order by
themselves, called Tetragoniacee, which is distinguished from
the Mesembryanthacee by having alternate leaves, no petals,
and definite stamens. The plants comprehended in the above
three sub-orders are, however, so nearly allied, that we have,
following Bentham and Hooker, placed them in one order as
above. The tribe Molluginee of Caryophyllacee is also
placed in this order by Bentham and Hooker.

Distribution and Numbers.—Natives exclusively of warm
and tropical regions. A large number are found at the Cape of
Good Hope. There are about 450 species.

Properties and Uses.—Several are edible; others yield an
abundance of soda when burned ; but generally the plants of the
order are of little importance.

Cohort 5.—Umebellales.

Order 158. UMBELLIFER&, the Umbelliferous Order.—Cha-
racter.—Herbs, shrubs, or very rarely small trees, with usually
hollow or rarely solid stems. Leaves alternate, generally amplexi-
caul, usually compound, or sometimes simple, and always exstipu-
late. Flowers generally in umbels, which are usually compound,
or sometimes simple; rarely the flowers are in capitula, with
or without an involucre ; the partial umbels or umbellules also
with or without an involucel. Calyx superior, the limb entire,
annular, or 5-toothed, or obsolete. Petals 5, usually inflexed at
the point, often unequal in size, inserted on the calyx outside
the dise which crowns the ovary; @stivation imbricate, or rarely
valvate or induplicate. Stamens 5, inserted with the petals and
DICOTYLEDONES—CALYCIFLORA 357

alternate with them; incurved in exstivation. Ovary inferior,
crowned by a double fleshy disc (stylopod), 2-celled, with a
solitary pendulous ovule in each cell; styles 2, stigmas simple.
Fruit (figs. 1116-1118) a cremocarp consisting of 2 carpels
(mericarps) adhering by their face (commissure) to a common
axis (carpophore), which is undivided or forked, from which they

Fie. 1115. Fie. 1116.

 

Fig. 1115. a. General umbel of Fool’s Parsley (thusa Cynapium) in fruit.
b. One of the umbellules, showing the 3-leaved unilateral pendulous in-
volucel.—V"ig. 1116. A side view of the ripe fruit of Hemlock (Conium
maculatum).— Fig. 1117. Transverse section of the fruit of the same.——
Fig. 1118. Vertical section of one of the halves (mericarps) of the same
fruit. The letters refer to the same parts in the last three figures.
a. Ridges. b., Channels. d. Albumen. f. Embryo. g. Remains of the
styles. A. Axis. i. Prolonged axis or carpophore.

ultimately separate and become pendulous; each mericarp is an
indehiscent 1-seeded body, traversed on its dorsal surface by
ridges, a, of which there are usually 5; but sometimes there
are 4 others, alternating with them, in which case the former
are termed primary, and the latter secondary ridges; sometimes
the primary ridges are absent; the spaces between the ridges are
358 MANUAL OF BOTANY

called channels (vallecul@), b; in the pericarp are frequently oil-
receptacles called vitte. Seed pendulous; embryo minute, f, at
the base of abundant horny albumen, d; radicle pointing to-
wards the hilum.

Diagnosis.—Herbs or shrubs. Stems generally hollow;
leaves alternate, usually compound and amplexicaul, or some-
times simple, and always exstipulate. Flowers arranged in
umbels, or rarely in capitula. Calyx superior, inconspicuous.
Petals and stamens 5, inserted on the outside of a double
fleshy epigynous disc. Ovary Inferior, 2-celled, with a solitary
pendulous ovule in each cell; styles 2. Fruit consisting of two
indehiscent carpels, which separate when ripe from a common
axis or carpophore. Each carpel bearing primary or secondary
ridges, or both. Seeds pendulous, one in each carpel, with a
minute embryo at the base of abundant horny albumen.

Division of the Order and Illustrative Genera :—The order
has been divided into three sub-orders from the appearance of
the albumen, but these are by no means well defined. They
are as follows :—

Sub-order 1. Orrnosperme®.—Albumen not curved. Iilus-
trative Genera:—Hydrocotyle, Linn.; Cinanthe, Linn. ;
Heracleum, Linn.

Sub-order 2. CampyLospErME#.—Albumen rolled inwards at the
margins, and presenting a vertical furrow on its face. Illus-
trative Genera :—Anthriscus, Hoffm.; Cherophyllum, Linn. ;
Conium, Linn.

Sub-order 3. CaLospeRMEz.—Albumen with the base and apex
curved inwards towards the axis. Illustrative Genera :—
Ormosciadium, Boiss.; Coriandrum, Linn.

By Bentham and Hooker this order has been divided as
follows :—

Series 1. HererosctapIgEm.—Umbels generally simple or very
irregularly compound, or the inflorescence is a capitulum.
Vittz absent or obscure. Illustrative Genera :—Hydrocotyle,
Linn.; Astrantia, Linn.; Eryngium, Linn.

Series 2. Hartozycizm.—Umbels compound. Primary ridges
of fruit alone conspicuous. Vitte usually, but not always,
obvious. Illustrative Genera:—Conium, Linn.; Myrrhis,
Scop.; Foeniculum, Adanson.

Series 3. DreLozycir%.—Umbels usually compound. Fruit
with both primary and secondary ridges generally well marked.
lllustrative Genera :— Caucalis, Linn.; Daucus, Linn.
DICOTYLEDON ES—CALYCIFLORA 359

Distribution and Numbers.—Chietly natives of the northern
parts of Europe, Asia, and America. Many occur, however, in
the southern hemisphere. They are rare
in tropical regions except upon the moun- Fie. 1119.
tains, where they are by no means un-
common. There are about 1,400 species.

Properties and Uses.—Extremely
variable: thus, some are edible; others
aromatic and carminative, and, in some
cases, stimulant and tonic, from the
presence of a volatile oil; some, again,
contain a narcotico-acrid juice, which
renders them more or less poisonous;
while others are antispasmodic and
stimulant from the presence of « more /“-1119. Flower of the com-

3 i : * mon Ivy (Hedera Helix).
or less foetid gum-resin, which is essen-
tially composed of gum, resin, and volatile oil. This oil in the
case of Asafcetida contains sulphur.

Order 159. ARALIACEs, the Ivy Order.—Character.—Trees.
shrubs, or herbs. Leaves alternate, exstipulate. Flowers
generally in umbels or capitula, usually perfect or rarely uni-
sexual. Calyx more or less superior, entire or toothed. Petals
2, 4,5, 10, deciduous, almost always valvate in estivation or
rarely imbricate, generally distinct or rarely gamopetalous ;
occasionally wanting. Stamens corresponding in number to
the petals and alternate with them, or twice as many, inserted
on the outside of a dise which crowns the ovary; anthers
introrse, versatile, with longitudinal dehiscence. Ovary more or
‘less inferior, usually with more than 2 cells, or very rarely
1-celled, crowned by a disc ; each cell with a solitary pendulous
anatropous ovule; styles as many as the cells, sometimes
united ; stigmas simple. Fruit usually 3- or more-celled, succu-
lent or dry, each cell with 1 pendulous seed, with fleshy albumen.

Diagnosis.—Closely allied to Umbellifere, from which it may
be distinguished by the valvate estivation of the corolla; and
by the fruit being usually 3- or more-celled, the carpels of which
do not separate when ripe from a carpophore. There is also a
greater tendency among Araliacee to form a woody stem than
in Umbellifere.

Distribution and Numbers.—These plants are universally
distributed, being found in tropical, subtropical, temperate,
and the coldest regions. Illustrative Genera :—Panax, Linn.;
Hedera, Linn. The order includes about 300 species.

 
360 MANUAL OF BOTANY

Properties and Uses.—Generally stimulant, aromatic, dia-
phoretic, and somewhat tonic.

Order 160. Cornacem, the Dogwood Order.—Character.—
Shrubs, trees, or rarely herbs. Leaves simple, opposite or very
rarely alternate, exstipulate. Flowers perfect or rarely uni-
sexual, arranged in heads, or in a corymbose or umbellate
manner, with or without aninvolucre. Calyx superior, 4-lobed.
Petals 4, broad at the base, inserted at the top of the calyx-
tube; estivation valvate. Stamens 4, inserted with the petals
and alternate to them. Ovary inferior, surmounted by a disc ;
usually 2-celled; ovule pendulous, solitary, anatropous; style
and stigma simple. Fruit drupaceous, crowned with the
remains of the calyx. Seed pendulous; embryo in the axis of
fleshy albumen.

Diagnosis.—Trees, shrubs, or rarely herbs, with simple ex-
stipulate, and (with but one exception) opposite leaves. Flowers
perfect, or sometimes unisexual. Calyx superior, 4-lobed. Co-
rolla with 4 petals, and a valvate estivation. Stamens 4, alternate
with the petals. Ovary inferior, surmounted by a disc; usually
2-celled, with a single pendulous anatropous ovule in each cell ;
style and stigma simple. Fruit drupaceous. Embryo in the
axis of fleshy albumen.

Distribution and Numbers.—Natives of the temperate parts
of Europe, Asia, and America. Illustrative Genera :—Cornus,
Linn.; Aucuba, Thunb. There are more than 70 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for tonic, febrifugal, and astringent properties.

Order 161. Garryace®, the Garrya Order.—Character.
Evergreen shrubs. Leaves opposite, exstipulate. Flowers uni-
sexual, apetalous, amentaceous. Male flower with 4 sepals, and
stamens alternating with them. Female flower with a superior
-2-toothed calyx, and 1—3-celled ovary with 2 styles, and 2
pendulous stalked ovules. /’ruit indehiscent, baccate, 2-seeded.
Seeds with a very minute embryo in abundant albumen. By
Bentham and Hooker this order is included in Cornacee.

Distribution and Numbers.—Natives of the temperate parts
of North America, or of the West Indies, Illustrative Genera :—
Garrya, Dougl.; Fadgenia, Endl. These are the only genera;
they include 6 species.

Properties and Uses.—But little is known of the properties
of these plants; but Garrya Fremontit, a native of California,
is known as the Quinine Bush from its leaves being used in
fevers and ague.
DICOTYLEDONES—CALYCIFLORA 361

Order 162, AuanarIace, the Alangium Order.—Character.
Trees or shrubs. Leaves alternate, entire, exstipulate, without
dots. Calyx superior, 5—10-toothed. Petals 5—10, linear, re-
flexed. Stamens equal in number to, or twice or four times as
numerous as, the petals; anthers adnate. Ovary inferior, 1—2-
celled; style simple, ovwle solitary, pendulous. Fruit drupa-
ceous, more or less united to the calyx, 1-celled. Seed solitary,
pendulous, with fleshy albumen, and large flat leafy cotyle-
dons.

Distribution and Numbers.—Natives of various parts of the
East Indies and the United States. Illustrative Genera :—
Alangium, Lam.; Nyssa, Linn. There are about 8 species.
By Bentham and Hooker they are included in Cornacee.

Properties and Uses.—Of little importance. Some species
of Alangiwm are said to be purgative and aromatic; and their
succulent fruits are also edible. The fruit of Nyssa capitata or
N. candicans is used occasionally as a substitute for Lime fruit,
whence it is called the Ogechee Lime.

Artificial Analysis of the Orders in the Sub-class
Polypetale.

Series 8. CALYCIFLOBA,
1. FLowerrs with more than 20 stamens.

A. Ovary wholly superior.
a. Leaves without stipules.
1. Carpels more or less distinct (at least as
to the styles) ; or solitary.
Stamens distinctly perigynous. Ovules sus-
pended, erect, or ascending . . Rosacee (part).
2. Carpels wholly combined (at least as to
the ovaries).
Sepals more than 2, united into a tube.
Ovary with axile placentas X Lythracee (part).

b. Leaves with stipules.
1. Carpels more or less distinct (at least as to
the styles) ; or solitary.
Calyx with the odd lobe inferior. Stamens | Leguminose

somewhat hypogynous . é * .? (Mimose),.
Calyx with the odd lobe superior. Stamens
distinctly perigynous . . Rosacee.

2. Carpels wholly combined (at leaks as to
the ovaries).
Leaves with circinate vernation. Placentas
parietal . : e : . .« Droseracee.
362

B. Ovary inferior, or partially so.
a. Leaves without stipules.
1. Placentas parietal.
Petals definite in number, distinct from the
calyx x
Petals indefinite in gues gradually pa
ing into the sepals .
2. Placentas in the awis.
Leaves with transparent dots.
Ovary 1-celled
Ovary with more than one ell
Leaves without dots.
Petals very numerous
Petals definite in number.
Petals narrow and strap-shaped
Petals roundish and concave.
Styles united
Styles distinct

b. Leaves with stipules,
1. Carpels more or less distinct, or solitary .
2. Carpels wholly combined (at least as to the
ovaries).
Leaves opposite .
Leaves alternate.
Placentas axile
Placentas parietal

MANUAL OF BOTANY

Loasacee.
Cactacee.
Chamelauciacee.
Myrtaceae.
Mesembryanthacee.
Alangiacee.

Barringtoniacee.
Philadelphacea.

Rosacee (part).

Rhizophoracee.

Lecythidacee.
Homaliacee.

2. FLowErs with fewer than 20 stamens.

A. Ovary wholly superior.
a. Leaves without stipules.
1. Carpels more or less distinct, or solitary.

Carpels with hypogynous scales.
Each carpel having one scale
Each carpel having two scales

Carpels without hypogynous scales.
Carpels solitary, or all but one imperfect.

Leaves without dots.
Ovules collateral, ascending, sessile

2. Carpels more or less combined (at least by
their ovaries).
Placentas parietal.
Flowers with a ring or crown.
Flowers unisexual . -
Flowers hermaphrodite .
Flowers without a ring or crown
Placentas in the axis.
Styles distinct to the base.

Crassulacee.
Francoacee.

Connaracee.

Papayacee.
Malesherbiacee.
Turneracee.
DICOTYLEDONES—CALYCIFLORA 363

Carpels each with one hypogynous scale
Carpels without hypogynous scales
Styles more or less combined.
Calyx imbricate. Ovules suspended
Calyx valvate.
Leaves simple. Calyx tubular

b. Leaves with stipules.
1. Carpels distinct, or solitary.

Fruit leguminous; odd lobe of the calyx in-
ferior

Fruit not leguminous: oda lobe of the pale
superior .

2. Carpels more or less combined (at least by
their ovaries).
Placentas parietal.
Flowers with a ring of appendages
Placentas in the axis.
Styles distinct to the base.
Petals conspicuous.
Leaves opposite
Leaves alternate .

B. Ovary inferior, or partially so.

au. Leaves without stipules, or with cirrhose ap-
pendages.
Placentas parietal.
Flowers completely unisexual. Gamopeta-
lous .
Flowers hermaphrodite or polygamous.
Petals distinct ‘ ;
Placentas in the axis.
Flowers in umbels, or capitula.
Styles two .
Styles three or more
Flowers not in umbels.
Carpel solitary.
Petals strap-shaped, reflexed .
Petals oblong.
Cotyledons convolute .
Cotyledons flat
Carpels two or more, diverienting at the
apex.
Leaves alternate. Herbs

Leaves opposite. Shrubs

Crassulacee.

Saxifragacee
(part).

Bruniacee.

Lythracee.

Leguminose.

Rosacee.

Passifloracee.

Cunomacee.
Saxifragacee
(part).

Cucurbitacee.
Ribesiacee.
Umbellifere.
Araliacee.
Alangiacee.
Combretacee.

Haloragacee.

Saxtifragacee

(part).
Hydrangeacee
364 MANUAL OF BOTANY

Carpels two or more, not divaricating,
combined.
Calyx valvate, or the limb obsolete.
Stamens alternate with the petals if
isomerous.
Albumen none. Ovules horizontal

or ascending i ‘i Onagracee.
Albumen present. Ovules pendu-

lous . a ‘ ; ‘ . Haloragacee.
Albumen abundant. Flowers con-

spicuous . 4 4 . Cornacee.

Calyx not valvate.
Stamens doubled downwards. Anthers
with appendages. Leaves ribbed Melastomacee.
Stamens only curved. Anthers short.

Leaves dotted . : ; ‘ Myrtacee.
Leaves not dotted.
Seeds very numerous, minute . Escalloniacee.
Seeds few . ; ‘ : . Bruniacee.

b. Leaves with stipules.

Placentas parietal.
Stipules cirrhose. Gamopetalous. 3 . Cucurbitacea,
Stipules deciduous. Petals distinct . . Homaliacee
Placentas in the axis.
Stamens, if equal to the petals, alternate with

them,
Leaves opposite . ‘ > ; ‘ . Rhizophoracee.
Leaves alternate ‘ . Hamamelidacee.

Although it generally happens that the Calycifloree have dichlamydeous
flowers, polypetalous corollas, and perigynous or epigynous stamens, yet
many exceptions occur, which should be particularly noted by the student.
Thus, we find apetalous plants in the Leguminosae, Rosacee, Saxifra-
gacee, Cunoniacee, Crassulacee, Hamamelidacee, Haloragacee, Cal-
litrichacee, Rhizophoracee, Combretacee, Samydacee, Loasacea,
Datiscacee, Mesembryanthacee, Araliacee, Garryacee, Myrtaceae,
Lythracee, Onagracee, Passifioracee. Gamopetalous corollas occur in
some Papayacee, Cucurbitacee, Belvisiacee, Crassulacee, Droseracea,
Bruniacee, Melastomacee, Turneracee, Cactacee, Lecythidacee, Ara-
liacee. In some Calyciflore, again, the stamens are wholly or in part
hypogynous or nearly so, as in some Connaracee, Leguminosae, Saxifra-
gacee, Crassulacee, Francoacee.

Unisexual flowers occur as a rule in Callitrichacea, Papayacea,
Garryacee, and Cucurbitacee, and sometimes in Rosacee, Hydran-
geacee, Passifloracee, Ribesiacee, Haloragacee, Combretacee, Cor-
nacee, Hamamelidacee, and Araliacee.
DICOTYLEDONES—CALYCIFLORA

Synopsis of the British Natural Orders in the
A. Corolla polypetalous.

Ovary superior.

1. Ovaries many, distinct or united, each with a
style ; or solitary with one lateral placenta.

Corolla regular.

Sepals combined below.
Stamens equal to or double the number of

the petals ;
Stamens 20 or more, perigynous.

stipulate
Corolla irregular.

no stipules
Leaves

Leaves with stipules. Stamens mono- or dia-

delphous .

2. Ovary solitary, with natiebil sstousenatiioiie:

Corolla regular.
Stamens 5

Sepals ae free, imbricate.

8. Ovary solitary, with omubeel siatantud
Calyx valvate in the bud.
Stamens inserted in the calyx tube below the

petals

B. Corolla polypetalo
inferior.

1. Ovary 1-celled. Placentas 2, ae

numerous
2. Ovary 2—many-c

us, ovary partly or wholly
Ovules

elled. Placsntas centr i

Stamens as many as the petals, or twice as

many.

Petals imbricate in the bud.

Petals 5.

Stamens 5. Flowers in umbels

Petals 4—5. Ovary only partially inferior.
Capsule 2-valved .

Petals 4.

Stamens 4—8, Fruit, 4 nuts :

Petals valvate in the bud.

Fruit a berry:
alternate

Styles more than 2; leaves

Fruit a drupe.
Fruit a cremocarp

Petals twisted in the bud.

Sepals valvate

Style 1; eaves opposite

C. Corolla gamopetalous.

Flowers unisexual
D. Corolla wanting.

Flowers moneecious.

4-celled

Stamens solitary. Ovary

365

Series Calyciflore.

Crassulacee.

Rosacee.

Leguminose.

Droseracee.

Lythracee.

Ribesiacee.

Umbellifere.
Saxifragacee

Haloragacee.

Araliacee.
Cornacee.
Umbellifere.

Onagracee.

Cucurbitacec.

Callitrichacee.
366 MANUAL OF BOTANY

Sub-Class III.—GamoPetTaL= oR CoROLLIFLORE.

Series 1.—Infer@ or Epigyne.

Cohort 1.—Rubiales.

Order 163. CaPRIFoLIACE®, the Honeysuckle Order.—Cha-
racter.—Small trees, shrubs, or rarely herbs. Leaves opposite,
usually exstipulate. Calyx superior, 4—5-cleft. Corolla gamo-
petalous, 4—5-cleft, tubular or rotate, regular or irregular,
rarely polypetalous. Stamens 4—5, inserted on the corolla,
and alternate with its lobes. Ovary inferior, 1—6-celled, often
with 1 ovule in one cell, and several in the others, pendulous, or
suspended; style filiform or absent; stigmas 1—3 or 5. Fruit
indehiscent, 1- or more-celled, dry or succulent, and crowned by

Fic, 1121. Fie. 1122. Fie. 1123.

 

Fig. 1121. Pistil of the common Elder (Sambucus nigra) surrounded by a
superior 5-lobed calyx.—-Fig. 1122. Entire flower of the same.— Fig.
1123. Vertical section of the seed.

the persistent calyx lobes. Seeds solitary or numerous; embryo
small, in fleshy albumen.

Diagnosis.—Small trees, shrubs, or rarely herbs, with oppo-
site usually exstipulate leaves. Calyx superior, 4—-5-cleft, per-
sistent. Corolla gamopetalous, and bearing commonly as many
stamens as it has lobes, to which they are alternate; regular
or irregular. Ovary inferior, 1—6-celled. Fruit indehiscent.
Seeds with fleshy albumen.

Distribution and Numbers.—Chiefly natives of the northern
parts of Europe, Asia, and America. They are rare in the
southern hemisphere. Illustrative Genera :—-Lonicera, Linn. ;
Viburnum, Linn.; Sambucus, Linn. There are about 220
species.

Properties and Uses.—The plants of this order have fre-
DICOTYLEDONES—COROLLIFLORZ 367

quently showy flowers, which are also commonly sweet-scented ;
hence many are cultivated in our gardens and shrubberies, as
Honeysuckles, which are species of Caprifoliwm and Lonicera ;
Guelder Roses (Viburnum Opulus), Laurustinus (Viburnum
Tinus), Snowberry (Symphoricarpus racemosus), &e. Some are
emetic and purgative; others astringent, sudorific, or diuretic;
and some are acrid.

Order 164. Rusiacem, the Madder Order.—Character.—
Trees, shrubs, or herbs. Stems rounded or angular. Leaves
simple, entire, and either opposite and with interpetiolar stipules,
or whorled and exstipulate. (The view is commonly held that
the whorls of apparent leaves are in reality partly formed of
leaves and partly of stipules, which resemble the true leaves in

Fie. 1124. Fie. 1125. Fie. 1126. Fic. 1127.

    

Fig. 1124. Diagram of the flower of the Madder (Rubia tinctorum).——Fig.

1125. Pistil of the Madder, with its ovary adherent to the calyx, cal.

st. Styles and stigmas.— Fig. 1126. Pistil of the Goose-grass or Cleavers

(Galium Aparine) adherent to the calyx, b, by its ovary. st, Styles——

fig. 1127. Vertical section of the fruit and seeds of the same. a. Albumen.

ec. Embryo. pl. Placenta.
appearance.) Inflorescence cymose. Calyx superior, with the
limb 4—-6-toothed or entire, or obsolete. Corolla epigynous,
gamopetalous, regular, tubular or rotate, with its lobes corre-
sponding in number to the teeth of the calyx when the latter is
divided ; estwation valvate. Stamens inserted upon the corolla
and equal in number to, and alternate with, its lobes. Ovary
inferior, crowned by a disc, usually 2-celled or sometimes more;
style 1 or 2, stigma simple or divided. Fruit inferior, 2-celled
or rarely more, dry or succulent, indehiscent or separating into
two or more dry cocci. Seeds 1, 2, or more, in each cell; when .
few they are erect or ascending, or when numerous, then at-
tached to axile placentas; embryo small, in horny albumen
(fig. 1127, a).

Diagnosis.—Trees, shrubs, or herbs, with opposite simple

entire leaves, interpetiolar stipules, and rounded stems; or with
whorled exstipulate leaves, and angular stems. Calyx superior.
368 “MANUAL OF BOTANY

Corolla regular, epigynous, with its lobes valvate. Stamens
equal in number to the teeth of the calyx and segments of the
corolla, with the latter of which they are alternate, epipetalous.
Ovary inferior, 2- 6r more-celled, with an epigynous disc; ovules
anatropous. Fruit inferior. Seeds 1 or more in each cell, with
horny albumen.

Division of the Order and Illustrative Genera.—This order
was separated by Lindley into two orders, the Cinchonacee and
the Galiacee or Stellate. The Galiacee of Lindley were more
especially distinguished from the Cinchonacex by their whorled
exstipulate leaves and angular stems. The order Rubiacez is

Fic. 1128. Fic. 1129. Fic. 1130.

 

Fig. 1128, Vertical section of the ovary, &c., of the Red Valerian (Centran-
thus ruber). ca. Calyx. co. Corolla. sty. Style. ov. Ovule-—/ig. 1129.
Fruit of Scabiosa purpurea (Dipsacee), surmounted by the pappose calyx.
— Fig. 1130. One of the central florets of the capitulum of Scabiosa
purpurea, With the ovary, &c., cut vertically.

now divided by Hooker and Bentham into three series, each of
which is again divided into sub-series and tribes. The Galiacex
of Lindley are natives of the northern parts of the northern
hemisphere and the mountains of the southern; while the
Cinchonaceze are almost exclusively natives of tropical and
warm regions. There are about 8,000 species in the Rubiacew
as defined above. Illustrative Genera :—Galium, Linn.;
Cinchona, Linn. ; Ixora, Linn.

Properties and Uses.--The properties of the plants of this
extensive order are very important. Many possess tonic, febri-
fugal, astringent, emetic, or purgative properties; some are
DICOTYLEDONES—COROLLIFLORZ 369

diuretic and emmenagogue; a few are valuable dyeing and
tanning agents; and others have edible fruits and seeds. Some
are reputed to possess intoxicating, and in rare cases even
poisonous, properties.

Cohort 2.—Asterales.

Order 165. VALERIANACES, the Valerian Order.—Charace-
ter.—Herbs. Leaves opposite, exstipulate. Flowers cymose,
hermaphrodite or rarely unisexual. Calyx superior, with the
limb obsolete, membranous, or pappose. Corolla epigynous,
gamopetalous, tubular, imbricate, 3—6-lobed, regular or irregular,
sometimes spurred at the base. Stamens 1—5, distinct, fewer
than the lobes of the corolla, and inserted in its tube. Ovary
inferior, with 1 fertile cell, and usually 2 abortive or empty ones.
Fruit dry and indehiscent, frequently crowned by a pappus.
Seed solitary, suspended, exalbuminous ; radicle superior.

Distribution and Numbers.—Chiefly natives of the temperate
parts of Europe, Asia, and America; they are rare in Africa.
Illustrative Genera :—Centranthus, DC.; Valeriana, Linn.
There are about 190 species.

Properties and Uses.—They are chiefly remarkable for the
presence of u strong-scented volatile oil, which renders them
stimulant, antispasmodic, and tonic. Some are highly esteemed
in the East as perfumes, but they are not generally considered
agreeable by Europeans.

Order 166. DrpsacE#, the Teazel Order.—Character.—
Herbs or undershrubs. Leaves opposite or verticillate, exstipu-
late. Flowers in dense heads (capitula), surrounded by an
involucre. Calyx superior, with a membranous or pappose
limb, and surrounded by an involucel. Corolla tubular, epigy-
nous, gamopetalous, the limb 4—5-lobed, generally irregular, and
with an imbricate estivation. Stamens 4, epipetalous ; anthers
distinct. Ovary inferior, 1-celled; ovwle solitary, pendulous ;
style and stigma simple. Fruit dry, indehiscent, and sur-
mounted by the pappose calyx. Seed with fleshy albumen;
embryo straight ; radicle superior.

Distribution and Numbers.—Chiefly natives of the South of
Europe, and of North and South Africa. A few species are
found in this country. Illustrative Genera :—Dipsacus, Towrn. ;
Scabiosa, Linn. There are about 170 species.

Properties and Uses.—Some are reputed to possess astringent
and febrifugal properties, but as remedial agents they are alto-

VOL. Il. BB
370 MANUAL OF BOTANY

gether unimportant. Dipsacus Fullonwm is, however, an
important economical species.

Order 167. CatycERscrm, the Calycera Order.—Charac-
ter.—Herbs.— Leaves alternate, exstipulate. Flowers in capitula,
surrounded by an involucre. Calyx superior, irregular, 5-lobed.
Corolla epigynous, gamopetalous; regular, valvate, 5-lobed.
Stamens 5, epipetalous ; filaments monadelphous; anthers par-
tially united. Ovary inferior, 1-celled; ovwle solitary, pendulous.
Fruit indehiscent. Seed solitary, pendulous, with fleshy albu-
men; radicle superior.

Diagnosis.—These plants hold an intermediate position be-
tween Dipsacee and Composite, being distinguished from the
former by their alternate leaves, absence of involucel to their
individual florets, valvate estivation of corolla, monadelphous
filaments, and partially united anthers; and from the Composit
in their anthers being only partially united, and in their pendu-
lous albuminous seed, and superior radicle.

Distribution and Numbers.—Exclusively natives of South
America, especially the cooler parts. Illustrative Genera :—
Calycera, Cavan.; Leucocarpus, Don. There are about 20
species.

Properties and Uses.—Unknown.

Order 168. Composit#, the Composite Order.—Charac ter.
Herbs or shrubs. Leaves alternate or opposite, exstipulate.
Flowers (florets) hermaphrodite, unisexual, or neuter, arranged
in capitula, which are commonly surrounded by an involucre
formed of a number of imbricate bracts (phyllaries); the
separate florets are also frequently furnished with membranous
or seale-like bractlets (pale). Capitula developing sucessively
in a centrifugal order. Calyx superior, its limb either entirely
abortive or membranous; in the latter case it is entire, toothed,
or pappose—that is, divided into bristles, or simple, branched,
or feathery hair-like processes. Corolla epigynous, gamo-
petalous, tubular, ligulate, or bilabiate, 4—5-toothed, with a
valvate estivation. Stamens 5 or rarely 4, inserted on the
corolla, and alternate with its divisions; filaments distinct or
monadelphous ; anthers united into a tube (syngenesious),
which is perforated by the style and stigmas. Ovary inferior,
bicarpellary, 1-celled, with 1 erect ovule; style 1, undivided
below, and commonly bifid above; stigmas 2, one being
usually placed on the inner surface or margin of each division
of the style. Fruit w cypsela, dry, indehiscent, 1-celled,
DICOTYLEDONES—COROLLIFLORA& 371

crowned by the limb of the calyx, which is often pappose.
Seed solitary, erect, exalbuminous ; radicle inferior.
Diagnosis.—Herbs or shrubs, with exstipulate leaves.
Flowers (called florets) arranged in capitula, which are
commonly surrounded by an involucre. Capitula developed
successively in a centrifugal manner. Calyx superior, its limb
abortive, or membranous, or pappose. Corolla epigynous, gamo-
petalous, 4--5-toothed, with a valvate estivation. Stamens

Fie. 1131. Fic. 1132. Fre. 1133; Fie. 1134.
ls

/

   

 

Fig. 1131. Labiate floret of Chielanthera linearis. 0. Ovary with adherent
calyx. ¢. Tube of the corolla. Zs. Upper lip of the corolla. 7 4. Lower lip.
e. Tube formed by tie united anthers. s. Stigmas.——Vig. 1132. Vertical
section of the floret of Aster rubricavlis. 0. Ovary containing one
erect ovule. a. Pappose limb of the calyx. p. Corolla. s. Style. ¢. Tube
formed by the united anthers.—~/ig. 1133. Floret of the chicory ((icho-
rium Intybus). 0. Ovary with adherent calyx. e. Tube formed by the
united anthers. s. Stigmas.——/ig. 1134. Vertical section of the ripe fruit
of the Groundsel (Senecio), surmounted by a portion of the style, s; and
the pappose limb of the calyx. p. Pericarp. ¢. Testa. e. Seed. The above
figures are from Jussieu,

epipetalous, equal in number to the divisions of the corolla
(generally 5), and alternate with them; anthers syngenesious.
Ovary inferior, 1-celled, with 1 erect ovule; style simple, bifid
above, with stigmatic branches. Fruit 1-celled, dry, inde-
hiscent. Seed solitary, erect, exalbuminous ; radicle inferior.
Division of the Order and Illustrative Genera.—This order
has been variously divided by authors. By Linneus, the

plants of his class Syngenesia, division Polygamia (which
‘ BB2
372 MANUAL OF BOTANY

corresponded to the Natural Order Composite as above defined),
were arranged in five orders, under the names of Polygamia
equalis, P. superflua, P. frustranea, P. necessaria, and P.
segregata. Jussieu separated the Composite into three sub-
orders as follows :—1. Corymbifere, the plants of which have
either all tubular and perfect florets; or those of the disc tubular
and perfect, and those of the ray tubular or ligulate and pistilli-
ferous (radiant). 2. Cynarocephale, the florets of which are all
tubular and perfect; or those of the disc perfect, and those of
the ray neuter. And 3. Cichoracee, having all the florets ligu-
late and perfect. A fourth sub-order was afterwards added,

Fie. 1135.

   

Fig. 1138. Styles and stigmas of composite flowers to illustrate De Candolle’s
tribes, after Heyland and Lindley. 1. Albertinia erythropappa (Vernonier),.
2. Anisocheta mikanioides (Kupatoriee). 3. Blumea senecioides (Aste-
roidex). 4. MUenderia bicolor (Senecioidere). 5. Lipochela umbellata
(Senecioidez). 6. Aplotaxis nepalensis (Cynaree). 7. Leucomeris specta-
bilis (Mutisiew). 8. Leuceria tenuis (Nassauvies).

called Labiatiflore, which includes those plants the florets of
which were bilabiate, and which were unknown to Jussieu. The
arrangement most frequently adopted at the present day is that
of De Candolle ; this was founded on that of Lessing. It is as
follows :—

Sub-order 1. TusuLirLor”.—Florets all tubular and perfect;
or those of the centre (disc) are tubular, and alone perfect,
while those of the circumference (ray) are tubular or ligulate,
and pistillate or neuter; juice watery. This sub-order in-
cludes the Corymbiferee and Cynarocephale of Jussieu. It
has been divided into five tribes as follows :—
DICOTYLEDONES—COROLLIFLORA 3873

Tribe 1. Vernonieew.—Style cylindrical; its arms generally long
and subulate, sometimes short and blunt, always covered
all over with bristles. Illustrative Genera :—Vernonia,
Schreb.; Elephantopus, Linn.

Tribe 2. Hupatoriee.—Style cylindrical; its arms long and
somewhat clavate, with a papillcse surface on the outside
near the end. Illustrative Genera :—Eupatorium, Tourn. ;
Tussilago, Tourn.

Tribe 8. Asteroidee.—Style cylindrical; its arms linear, flat
on the outside, equally and finely downy on the inside.
Illustrative Genera :—Erigeron, Linn. ; Bellis, Linn.

Tribe 4. Senecioidee.—Style cylindrical, its arms linear,
fringed at the point, generally truncate, but sometimes
extended beyond the fringe into a short cone or appendage
of some kind. Illustrative Genera:—Anthemis, Linn. ;
Senecio, Linn.

The above four tribes correspond to the  sub-order
Corymbifere of Jussieu; the next or fifth tribe to the
Cynarocephale of the same author.

Tribe 5. Cynaree.—Style thickened above, and often with a
bunch or fringe of hairs at the enlarged portion; its
branches united or free. Illustrative Genera :—Arctium,
Linn.; Centaurea, Linn.

Sub-order 2. LaBIaATIFLORe.—Florets with bilabiate corollas,
perfect or unisexual. Juice watery. Of this sub-order we
have two tribes :-—

Tribe 6. Mutisiee.—Style cylindrical or somewhat swollen;
its arms usually blunt or truncate, very convex on the
outside, and either covered at the upper part by a fine uni-
form hairiness, or absolutely free from hairs. Illustrative
Genera :—Mutisia, Linn. fil. ; Printzia, Cass.

Tribe 7. Nassauviee.—Style never swollen; its arms long,
linear, truncate, and fringed only at the point. Illustrative
Genera :—Nassauvia, Juss.; Trixis, R. Br.

Sub-order 8. LicutirLor=.—Florets all ligulate and perfect.
Juice milky. This corresponds to the Cichoracex of
Jussieu.

Tribe 8. Cichoree.—Style cylindrical at the upper part; its
arms somewhat obtuse, and equally pubescent. Illustrative
Genera :—Cichorium, Linn.; Taraxacum, Haller.
374 MANUAL OF BOTANY

Of these sub-orders the Liguliflore is the best defined.

By Bentham and Hooker the Composite are divided into
thirteen tribes.

Distribution and Numbers.—Universally distributed ; but
the Tubuliflore are most abundant in hot climates, and the
Liguliflore in cold. The Labiatiflore are almost entirely con-
fined to the extra-tropical regions of South America. In the
northern parts of the world the plants of this order are
universally herbaceous; but in South America, and some other
parts of the southern hemisphere, they occasionally become
shrubby, or even in some cases arborescent. Lindley calculated
the order to contain about 9,000 species; but Bentham and
Hooker have reduced it to about 1,000 genera and 8,000 species.

Properties and Uses.—The properties of the Compositi
are very variable. A bitter principle pervades the greater
number of the species in a more or less evident degree,
by which they are rendered tonic. Some are laxative and
anthelmintic. Many contain a volatile oil, which communicates
aromatic, carminative, and diaphoretic properties. Others are
acrid stimulants, and the Liguliflore commonly abound in a
bitter-tasting milky juice, which is sometimes narcotic.

Cohort 8.—Campanales.

Order 169, StyLip1acEs, the Stylewort Order.—Character
Herbs or undershrubs, not milky. Leaves  exstipulate.
Calyx superior, with from 2 to 6 divisions, persistent. Corolla
with from 5 to 6 divisions; estivation imbricate. Stamens 2,
gynandrous. Ovary 2-celled, or rarely 1-celled; style forming a
column with the filaments ; st¢gma without anindusium. Fruzt
capsular. Seeds albuminous.

Distribution and Numbers.—They are chiefly found in the
swamps of Australia. Illustrative Genera :—Stylidium, Swartz ;
Forstera, Linn. fil. There are about 120 species.

Properties and Uses.—Unknown.

Order 170. Goopmntacrm, the Goodenia Order.—Charac-
ter.—Herbs, or rarely shrubs, not milky. Leaves exstipulate.
Flowers never collected into heads. Calyx generally superior,
with from 3 to 5 divisions, occasionally inferior. Corolla irre-
gular, 5-parted; @stivation induplicate. Stamens 5; filaments
distinct ; anthers distinct or united. Ovary 1, 2, or rarely
4-celled; placenta free central; style 1; stigma surrounded by
a bairy ring or somewhat cup-shaped expansion of the upper

 
DICOTYLEDONES--COROLLIFLORA 875

part of the style termed an indusiwm. Fruit capsular, drupa-
ceous, or nut-like. Seeds with fleshy albumen.

Distribution and’ Numbers.—These plants are principally
natives of Australia and the islands of the Southern Ocean ; rarely
of India, Africa, and South America. Illustrative Genera :-—
Goodenia, Sm.; Leschenaultia, R. Br. There are about 200
species.

Properties and Uses.—Unimportant. Many are cultivated
for the beauty of their flowers.

Order 171. CampanuLAcEd, the Harebell Order.—Character.
Herbaceous plants or undershrubs, with a milky juice. Leaves
nearly always alternate, exstipulate. Flowers scattered, or
rarely in capitula. Calyx superior, persistent. Corolla gamo-

Fic. 1136. Fic. 1137. Fie. 1138.

nN

    

Fig. 1136. Diagram of the flower of Rampions (Campanula Rapunculus),—
Fig. 1137, Vertical section of the seed. Fig. 1138. Vertical section of the
flower.

petalous, regular, marcescent; cestivation valvate. Stamens
equal in number to, and alternate with, the lobes of the corolla ;
anthers 2-celled, distinct or partly united. Ovary inferior, 2- or
more-celled ; style undivided, hairy; stigma naked. Fruit dry,
capsular, dehiscing by lateral orifices or by valves at the apex ;
placentas axile. Seeds numerous, with fleshy albumen.

Distribution and Numbers.—Chiefly natives of the temperate
parts of the northern hemisphere; « good many are, however,
found in the southern hemisphere, especially at the Cape of
Good Hope. A few species only are tropical. Illustrative
Genera :—Phyteuma, Linn.; Campanula, Linn. There are
about 550 species. :

Properties and Uses.—The order does not contain any
plants of particular importance from either « medicinal or
an economic point of view.

Order 172. LoBeLtacE®, the Lobelia Order.—Character.—
376 MANUAL OF BOTANY

Herbs or shrubs with a milky juice. Leaves alternate, exstipu-
late. Calyx superior. Corolla gamopetalous, irregular, valvate.
Stamens 5; anthers syngenesious. Ovary inferior, 1—3-celled ;
placentas axile or parietal; style 1; stigma surrounded by a
fringe of hairs (fig. 1139). Fruit capsular, dehiscing at the apex.
Seeds numerous, albuminous. This order is especially distin-
guished from the Campanulacee by its irregular corollas and
syngenesious anthers. Itis made a tribe of the Campanulacee
by Bentham and Hooker.

Distribution and Numbers.—They are chiefly natives of
tropical and sub-tropical regions; but a few occur in temperate
and cold climates. Illustrative
Genera : — Clintonia, Doug. ;
Lobelia, Linn. There are about
400 species.

Properties and Uses.—The
milky juice with which these
plants abound is commonly of
a very acrid nature; hence the
species of this order should be
regarded with suspicion. Indeed,
some, as Lobelia inflata, Tupa
Feuillai, &e., act as narcotico-
acrid poisons; and that of Isotoma
longiflora is vesicant, and when
Fig. 1139. Stigma of Lobelia syphititica. taken internally it causes such

—Fig. 1140. The sporophylls of the yj E = ult in
abene withthe ele. violent purgation as to res

death.

Fre. 1140.

 

Series 2.—Supere, or Heteromere.
Cohort 1.—Ericales.

Order 173. Vacctniacrm, the Cranberry Order.—Charac-
ter.—Shrubs or small trees. Leaves alternate, undivided,
exstipulate-—Calyz superior. Corolla 4—6-lobed; estivation
imbricate. Stamens distinct, epigynous, twice as many as the
lobes of the corolla; anthers appendiculate, with porous de-
hiscence. Ovary 4—10-celled ; style and stigma simple. Frustt
succulent. Seeds with fleshy albumen.

Distribution and Numbers.—Chiefly natives of the tem-
perate regions of the globe. Illustrative Genera :—Vaccinium,
Thibaudia. There are about 200 species.

Propertics and Uses—They are chiefly remarkable for
DICOTYLEDONES—COROLLIFLORAi B77

their astringent leaves and bark, and for their edible sub-acid
fruits.

Order 174. Ericacem, the Heath Order.—Character.—
Shrubs or small trees. Leaves entire, evergreen, opposite,
whorled or alternate, exstipulate. Calyx 4—5-cleft, inferior,
persistent. Corolla hypogynous, gamopetalous, 4—5-cleft, or
rarely distinct; estivation imbricate. Stamens hypogynous,
as many, or twice as many, as the divisions of the corolla;
anthers 2-celled, opening by pores or slits, appendiculate.
Ovary 4—5-celled, with numerous ovules, surrounded by a disc
or scales; placentas axile; style 1; stigma simple or lobed.
Fruit capsular or rarely baccate. Seeds numerous, small,
anatropous; embryo minute in the axis of fleshy albumen.

Diagnosis.—Shrubs or small
trees. Leaves entire, evergreen, Fig. 1141. Fie. 1142.
exstipulate. Calyx and corolla a
4—5-merous. Calyx inferior.
Corolla hypogynous, gamopeta-
lous, or rarely polypetalous.
Stamens hypogynous; anthers
2-celled, appendiculate, dehise-
ing by pores or slits. Ovary 4—
5-celled; style 1; placentas
axile. Fruit capsular, or very
rarely baccate. Seeds small,
anatropous, numerous, with
fleshy albumen.

Division of the Order and
Illustrative Genera.—The order Fig. 1141. Vertical section of the

may be divided into five tribes flower of a species of Heath (Erica).

1 : —Fig. 1142. Sporophylls of the
as follows :— same. The stamens are seen to be
hypogynous.

 

Tribe 1. Arbutee.—Corolla de-
ciduous. Fruit baccate. Illustrative Genus :—Arbutus, Linn.

Tribe 2. Andromedee.—Buds usually clothed with scales.
Corolla deciduous. Fruit capsular, loculicidal. Illustrative
Genus :—Andromeda, Linn.

Tribe 3. Ericee.—Buds naked. Corolla persistent. Fruit
capsular, usually loculicidal, or rarely septicidal. Illustrative
Genera :—Erica, Linn.; Calluna, Salisb.

Tribe 4. Rhodoree.—Buds scaly, cone-like. Corolla deciduous.
Fruit capsular, septicidal. Illustrative Genera: —Azalea,
Linn.; Phyllodoce, Salisb.
378 MANUAL OF BOTANY

Tribe 5. Pyrolee—Herbs or somewhat shrubby plants. Corolla
polypetalous, or the petals united at the base, deciduous.
Fruit capsular, loculicidal. Illustrative Genera :—Pyrola,
Tourn.; Chimaphila, Pursh.

Distribution and Numbers.—They are very abundant at the
Cape of Good Hope, and are also more or less generally dis-
tributed in Europe, North and South America, and Asia. There
are more than 900 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for astringent properties; some are tonic and diu-
retic, and others are narcotic, or even poisonous. This is
especially the case with Kalmia latifolia, Rhododendron chry-
santhum, Andromeda floribunda, and Azalea pontica. The
fruits of many are edible.

‘Order 175. Monorropaces, the Fir-rape Order.—Cha-
racter.—Saprophytes with scale-like leaves. Sepals more or
less distinct, 4—5, inferior. Petals 4—5, distinct or united. Sta-
mens twice as many as the petals, hypogynous; anthers 2-celled,
with longitudinal dehiscence. Ovary superior, 4—5-celled at the
base, 1-celled with 5 parietal placentas at the apex. Fruit cap-
sular, with loculicidal dehiscence. Seeds numerous, with a loose
testa; embryo minute, at the apex of fleshy albumen. This
order is referred to Ericacee by Bentham and Hooker, It 1s
closely allied to the Pyrolea.

Distribution and Numbers.—They are found growing on Firs
chiefly, in the cool parts of Europe, Asia, and North America.
Illustrative Genus :—Monotropa, Nutt. There are about 10
species.

Properties and Uses.—Unimportant.

Order 176. Hpacripacn#, the Epacris Order.—Character.
Shrubs, or small trees. Leaves alternate or rarely opposite, simple,
with parallel or radiating veins. Calyx and corolla inferior, usu-
ally 5-partite, or rarely 4-partite. Stamens equal in number to the
divisions of the corolla, or rarely fewer, hypogynous or adherent to
the corolla; anthers 1-celled, without appendages, opening longi-
tudinally. Ovary superior, many- or 1-celled; style simple,
I’ruit fleshy or capsular. Seeds with a firm skin, albuminous.

Distribution and Numbers.—Natives of Australia, the Indian
Archipelago, and the South Sea Islands, where they are very
abundant. Illustrative Genera :—Astroloma, R. Br.; Epacris,
Snuth. There are about 350 species.

Properties and Uses.—Of little importance, exzept for the
beauty of their flowers, on which account they are much culti-
DICOTYLEDONES—COROLLIFLORZ 379

vated. The fruits of many species are edible, as those of Astro-
loma humifusum, the Tasmanian Cranberry; Lewcopogon Riche,
the Native Currant of Australia; Lissanthe sapida, and others.

Orders 177 and178. Diapensiacez and StitBacem.—These
are two small orders of shrubby plants, which are placed by
Lindley in his Gentianal alliance, and regarded by him as nearly
allied to Loganiacee. The Diapensiacexe are better regarded,
however, as being near to the Ericacew; some botanists refer
them to Convolvulacee. They have also affinities with both
Polemoniacee and Hydrophyllacee. They are but 2 genera
and 2 species, the uses of which areunknown. They are natives
of North America and Northern Europe.—The Stilbacex, of
which there are 8 genera and 7 species, without any known uses,
are natives of the Cape of Good Hope.

Fig. 1143. Fie, 1144.

 

ig. 1143. Diagram of the flower of a
species of Plumbago.—Fig. 1144.
Sporophylls of the same.

 

Cohort II.—Primulales.

Order179. PLrumMBAcinacEs, the Thrift Order—Character.
Herbs or undershrubs. Leaves entire, alternate or radical, ex-
stipulate. Flowers regular. Calyx tubular, plaited, persistent,
5-partite. Corolla membranous, 5-partite or of 5 petals, or
rarely absent. Stamens 5, opposite the petals, to which they
are attached when the corolla is polypetalous and hypogynous,
and opposite to the divisions of the corolla when this is gamo-
petalous. Ovary 1-celled; ovule solitary, suspended from a long
funiculus arising from the base of the cell; styles usually 5, some-
380 MANUAL OF BOTANY

times 3 or 4. Fruit utricular, or dehiscing by valves at the
apex. Seed solitary; embryo straight; albumen mealy, and
small in quantity.

Distribution and Numbers.—Chiefly found growing on the
seashore and in salt marshes in various parts of the globe, but
by far the greater number inhabit temperate regions. Illustra-
tie Genera:—Armeria, Willd.; Plumbago, Tourn. There are
about 250 species.

Properties and Uses.—Of little importance, but acridity and
astringency appear to be the most remarkable properties of the
plants of this order.

Order 180. PrimuLace#, the Primrose Order.—Character.
Herbs. Leaves cauline, and then simple, opposite, whorled, or

Fie. 1145. Fic. 1146.

 

Fig. 1145. Flower of the Pimpernel (Anagallts arvensis).
c. Calyx. p. Petals. s. Stamens. Fig. 1146. Vertical
section of the flower of the same. pl. Free central
placenta. s. Style and capitate stigma.——J/'ig. 1147.
Vertical section of the seed of Primula elatior. t. In-
teguments, p. Albumen. e. Embryo. #. Hilum.

 

 

rarely alternate, exstipulate; or radical. Flowers regular, perfect.
Calyx generally 4-cleft, or rarely 4—-5-cleft, persistent, inferior, or
semi-superior in Samolus. Corolla usually 5- or rarely 4—9-cleft,
very rarely absent, or rarely of distinct petals. Stamens equal
in number to the segments of the corolla or separate petals, and
opposite to them, or in apetalous flowers hypogynous and alter-
nating with the divisions of the calyx. Ovary superior, or rarely
partly inferior, 1-celled; placenta free central; style 1; stigma
capitate. Fruit a capsule, dehiscing transversely, and forming
a pyxis, or opening by valves. Seeds numerous, with fleshy or
horny albumen ; embryo placed transversely to the hilum.
Diagnosis.—Herbs with simple, exstipulate, cauline or radical
DICOTYLEDONES—COROLLIFLORA 381

leaves, and regular perfect flowers. Stamens equal in number
to the lobes of the corolla or separate petals and‘ opposite to
them. Ovary superior, 1-celled, with a free central placenta;
style 1; stigma capitate. Fruit capsular, with transverse or
longitudinal dehiscence. Seeds numerous, with albumen, and
the embryo parallel to the hilum.

Distribution and Numbers.—These plants principally in-
habit cold and temperate regions in the northern parts of the

lobe. They are rare in the tropics, where they are found only

on the seashore or in mountainous districts. Illustrative
Genera :—Primula, Linn.; Anagallis, Towrn.; Glaux, Tourn. ;
Samolus, Tourn. There are about 250 species.

Properties and Uses.—Of no particular importance except
for the beauty of their flowers. The flowers of the Cowslip
(Primula veris) are sedative and diaphoretic, and are sometimes
einployed in the manufacture of a soporific wine. The roots of
Cyclamens are acrid, especially those of Cyclamen hederefolium,
which have been used as a drastic purgative and emmenagogue.

Order 181. Myrsinacem, the Myrsine Order.—Charac-
ter.—Trees or shrubby plants. Leaves coriaceous, smooth,
exstipulate. I lowers small, perfect or unisexual. Calyx and
corolla 4—5-partite. Stamens usually corresponding in number
to the divisions of the corolla and opposite to them, but some-
times there are also 5 sterile petaloid alternate ones; anthers
dehiscing longitudinally. Ovary superior or nearly so, 1-celled;
with a free central placenta, in which the ovules are imbedded.
Fruit fleshy. Seeds 1, 2, or many ; albumen abundant, horny.

Distribution and Numbers.—Chiefly natives of the islands
of the southern hemisphere. Illustrative Genera :—Myrsine,
Linn.; Theophrasta, Linn. There are more than 300 species.

Properties and Uses.—Of little importance. The fruits and
seeds of some species are pungent, and the seeds of others are
said to be purgative.

Cohort 3.—Ebenales.

Order 182. Saroraces, the Sapota Order.—Character.—
Trees or shrubs, often having a milky juice. Leaves alternate,
simple, entire, coriaceous, exstipulate. Flowers small, herma-
phrodite. Calyx inferior, usually with 5, or sometimes with
4—8 divisions, persistent. Corolla with as many divisions as
the calyx, or twice or thrice as many. Stamens definite, in a
single row, half of them sterile and alternating with the fertile
ones, the latter being opposite to the segments of the corolla;
382 MANUAL OF BOTANY

anthers commonly extrorse. Ovary 4—12-celled, with a solitary
anatropous evule in each cell ; style 1. Fruct fleshy. Seeds
large, with a shining bony testa; embryo large, usually in albu-
men, and with a short radicle.

Distribution and Numbers.—Natives chiefly of the tropical
parts of Asia, Africa, and America. Illustrative Genera :—
‘Chrysophyllum, Linn.; Isonandra, Wight; Bassia, Konig.
There are about 220 species.

Properties and Uses——Many species yield edible fruits;
others are valuable timber trees. The seeds of several contain
a fatty oil. Some have bitter astringent febrifugal barks, and
the milky juices of others yield a substance resembling in its
general characters caoutchouc or india-rubber.

Order 188. Eprnace®, the Ebony Order.—Character.—
Trees or shrubs without milky juice. Leaves alternate, entire,
coriaceous, exstipulate. lowers polygamous. Calyx 3—7-
partite, inferior, persistent. Corolla 8—1-partite. Stamens
equal in number to the lobes of the corolla, or twice or four
times as many, epipetalous or hypogynous; anthers 2-celled,
introrse, opening longitudinally. Ovary 3—12-celled, each cell
with 1 or 2 ovules suspended from the apex ; style usually having
as many divisions as there are cells to the ovary. Frwit fleshy.
Seeds large, albuminous; radicle superior.

Distribution and Numbers.—They are mostly natives of
tropical India, but a few occur in colder regions, IWVustratine
Genera :—Rovena, Linn.; Diospyros, Linn. There are nearly
200 species.

Properties and Uscs._-Many of the trees of this order are
remarkable for the hardness of their wood, which is commonly
known under the names of Ebony and Ironwood. Many species
have edible fruits, and some have astringent barks.

Order 184. Styraczm, the Storax Order.—Character.—
Trees or shrubs. Leaves simple, alternate, exstipulate. Flowers
axillary, hermaphrodite. Calyx inferior or partially superior,
4—5-partite or almost entire, persistent. Corolla of from 5 to 10
petals, either united at the base or distinct ; estivation imbricate
or somewhat valvate. Stamens equal in number to the petals,
or twice or thrice as many, more or less united at the base;
anthers 2-celled, roundish or linear. Ovary superior or par-
tially inferior; sty/e simple. Fruit drupaceous, always more
or less fleshy. Seeds usually 1 in each cell, sometimes more ;
embryo in the midst of abundant fleshy albumen, with a long

radicle.
DICOTYLEDONES—COROLLIFLORA 383

Miers divides the Styracee@ into two orders, called Symplo-
cacee@ and Styracacee, the former of which is distinguished by
its partially inferior ovary, imbricate exstivation of corolla, and
roundish anthers ; and the latter having a superior ovary, valvate
zstivation of corolla, and linear anthers.

Distribution and Numbers.—These plants are sparingly dis-
tributed in warm and tropical regions; but a few are found in
cold climates. Illustrative Genera :—Symplocos, Jacq.; Styrax,
Tourn. Miers enumerates about 120 species.

Properties and Uses.—These plants are principally remark-
able for yielding stimulant balsamic resins. Some yield dyeing
agents, but these are of little importance.

Series 3.— Dicarpie or Bicarpellate.
Cohort 1.— Gentianales.

Order 185. OLEACE#, the Olive Order.—Character.— Trees
or shrubs. Leaves opposite, simple or pinnate, exstipulate.

Fie. 1148. Fie. 1149. Fie. 1150.

 

Fiy. 1148. Diagram of the flower of the Lilac (Suringa eulgares).
1149. Flower of the Manna Ash (fruciuus Ornus), with 4-cleft calyx ;
corolla with 4 distinct petals; 2 stamens; and 2 carpels———/%ig. 1150.
Vertical section of the calyx and pistil of the Privet (Ligustrum onlyare).

 

Fig.

Flowers usually perfect, or rarely unisexual. Calyx persistent,
4—8-cleft, sometimes obsolete, inferior. Corolla regular, 4—8-
cleft, or of 4 distinct petals, or absent; e@stivation valvate or
imbricate. Stamens usually 2, rarely 4. Ovary superior, 2-
celled, with 1—-4 erect, or 2suspended ovulesin each cell. Fruct
dehiscent or indehiscent, often 1-seeded. Seeds with abundant
fleshy albumen, or the albumen is small in quantity; embryo
straight.

The order Jasminacee of many botanists is here included
in the Oleacee. The tribe or sub-order Jasnumew ws more
384 MANUAL OF BOTANY

especially distinguished from other Oleacee by the imbricate
astivation of the corolla, erect ovules, and the small quantity
of albumen in the seed.

Distribution and Numbers.—The plants of this order are
principally natives of temperate and warm regions, but some
also occur within the tropics. Illustrative Genera :—Olea, Linn. ;
Ligustrum, Tourn.; Fraxinus, Towrn.; Jasminum, Linn.
There are about 250 species.

Properties and Uses.—The barks of many plants of this order
are tonic and febrifugal. The mild purgative called Manna is
obtained from a species of Ash. The pericarp of the common
Olive yields the well-known Olive Oil. Other species are re-
markable for the hardness of their wood. The plants of the
Jasmine have generally fragrant flowers. The volatile oil of
Jasmine, which is used in perfumery, is chiefly obtained by
distillation from the flowers of Jasminum officinale and J.
grandifiorum. The fragrant flowers of J. Sambac are used as
votive offerings in India; they are also said to have much
power in arresting the secretion of milk. The leaves and
roots of some species of Jasminum are reputed bitter, and have
been employed for various purposes, but generally speaking this
tribe contains no active medicinal plants. The flowers of
Nyctanthes Arbor tristis are employed in India for dyeing yellow.

Order 186. SaLvADORACES, the Salvadora Order.—C harac-
ter.—Shrubs or small trees. Leaves opposite, entire, leathery,
exstipulate. Flowers small, panicled. Calyx of 4 sepals. Corolla
4-partite, membranous. Stamens 4. Ovary 1—2-celled ; stigma
sessile. Fruit fleshy, 1-celled, with a solitary erect seed. Seeds
exalbuminous.

Distribution and Numbers.—Natives of India, Syria, and
North Africa. Illustrative Genera :—Salvadora, Linn.; Monetia,
DL’ Hérit.

Properties and Uses.—Some are acrid and stimulant. The
fruit of Salvadora persica is edible, and resembles the garden
Cress in taste. The bark of the root is acrid, and is employed
as a blistering agent in India. The leaves are reputed to be
purgative.

Order 187. APocyNACES, the Dogbane Order.—C haracter.—
Trees or shrubs, juice usually milky and acrid. Leaves entire,
commonly opposite, but occasionally whorled ot scattered,*
exstipulate. Calyx inferior, 5-partite, persistent. Corolla
5-lobed; estivation contorted. Stamens 5, alternate with the
lobes of the corolla; filaments distinct; anthers united to the
DICOTYLEDONES—COROLLIFLORA 385

stigma, 2-celled ; pollen granular. Ovary composed of 2 carpels,
which are generally merely in contact, but sometimes united so
as to form a 2-celled or more rarely a 1-celled ovary; styles 2
or 1; stigma 1, expanded at the base and apex, and contracted
in the middle, so as to resemble in form an hour-glass or dumb-
bell; ovules numerous. Fruit consisting of 1 or 2 follicles, or
a capsule, drupe, or berry. Seeds usually with albumen, or
rarely exalbuminous, often comose.

Distribution and Numbers.—Natives principally of the
tropics, but a few occur in northern regions. Vinca is the
only British genus. Illustratwe Genera :—Allamanda, Linn. ;
Urceola, Roxb.; Apocynum, Tourn. There are about 600
species.

Properties and Uses.—-The plants of this order are generally

Fie. 1151. Fie. 1152.

 

Fig. 1151. Vertical section of the
flower of Periwinkle (Vinca).
—Fig, 1152. Diagram of the
flower of the same.

 

to be suspected, as many of them are intensely poisonous,
although the fruits of a few species are edible. Some are
drastic purgatives, and of others the bark is tonic and febri-
fagal. India-rubber or Caoutchouc, now commonly known in
commerce as Rubber, is obtained from the milky juice of several
species.

Order 188. AscLEPIADACcES, the Asclepias Order.—Charac-
ter.—Shrubs or herbs, commonly milky, frequently twining
and sometimes succulent. Leaves entire, opposite or whorled,
or rarely scattered, exstipulate. Flowers regular. Calyx and
corolla 5-partite; estivation of the latter imbricate or rarely
valvate ; the calyx persistent, the corolla deciduous. Stamens 5,
alternate with the lobes of the corolla; filaments usually
combined so as to form a tube round the pistil, or sometimes
distinct; anthers frequently having pouch-shaped and hornlike

VOL. IL. ce
386 MANUAL OF BOTANY

appendages (fig. 1156, »), the pollen of each anther-lobe
forming a pollinium ; the right-hand pollinium of each anther
united to the left-hand one of the contiguous anther by a
gummy process formed by the stigma (fig. 1153, 6). Ovary
superior, of 2 carpels, which are more or less adherent below,
but distinct above; styles 2; stigmas united and expanded into
w fleshy 5-cornered head, the processes joining the pollinia
arising from its angles. F'rwit consisting of 2 follicles, or 1 by
abortion. Seeds numerous, generally comose, with thin albumen.
Diagnosis—This order is distinguished amongst the Di-
carpiz by its curiously formed stigma and adhering pollinia.
Distribution and Numbers.—They are chiefly tropical plants,
Fig. 1153.
Fie. 1154. Fie. 1155. Fic. 1156.

  

Fig. 1153. Pistil of a species of Asclepias, with the pollinia, p, adhering to
the stigma, s. 6. Pollen-masses as detached from contiguous anthers.— -—
Fig. 1154. Diagram of the flower of Asclepias nivea.—Fig. 1155. Flower
of a species of Asclepias, with the stamens united and forming a tube
round the pistil. y. Corolla. a. Appendages of the stamens,—TJig.
1156, One of the stamens of the same removed. /f. Filament. a. Anther.
p. Hornlike appendage of the filament.

abounding in southern Africa, India, and equinoctial America.
A few occur in Southern Europe. Illustrative Genera:—
Hemidesmus, R. Br.; Asclepias, Linn.; Hoya, R. Br.; Stapelia,
Linn. There are about 1,000 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for their bitter acrid juice, which renders them
stimulant, emetic, purgative, and diaphoretic. Several species
are reputed to be antidotes to snake-bites. Some species yield
Caoutchouc; but no important commercial kind of Rubber is
obtained from them. Parts of some are edible, as the roots
of Gomphocarpus pedunculatus, and the tubers of Ceropegia
Vignaldiana, &e.
DICOTYLEDONES—COROLLIFLORA 387

Order 189. Locantacr%®, the Strychnos Order.—Character.
Shrubs, herbs, or trees. Leaves opposite, entire, stipulate ; the -
stipules, however, sometimes exist only in the form of a raised
line or ridge. Calyw inferior, 4—5-partite. Corolla regular,
4—5- or 10-cleft; cestivation valvate, contorted, or imbricate.
Stamens epipetalous, usually equal in number, but sometimes
unequal, to the lobes of the corolla; anthers 2-celled. Ovary
2- 3- or 4-celled ; style simple below, and with as many divisions
above as there are cells to the ovary; stigma simple. Frutt
capsular or drupaceous; placentas axile, ultimately detached.
Seeds usually peltate, sometimes winged, with fleshy or carti-
laginous albumen. This order is by no means well defined.

Distribution and Numbers.—Nearly all natives of tropical
regions. Illustrative Genera :—Spigelia, Linn.; Strychnos,
Linn. There are about 200 species.

Properties and Uses.—These plants are almost universally
poisonous, acting on the nervous system and producing frightful
convulsions. Several have been used in medicine in torpid
or paralytic conditions of the muscular system, and for their
valuable tonic, anthelmintic, and other properties; but they
require much caution in their employment, and can generally
be only given in very small doses.

Order 190. GENTIANACES, the Gentian Order.—C haracter.—
Herbs, or rarely shrubs, usually smooth. Leaves generally
simple, entire, opposite, sessile, and strongly ribbed; rarely
alternate, or stalked, or compound; always exstipulate. Flowers
regular, solitary and terminal, or in di—tri-chotomous cymes.
Calyx inferior, persistent, usually with 5 divisions, or occasion-
ally with 4, 6, 8, or 10. Corolla marcescent, its divisions
corresponding in number to those of the calyx; estivation
imbricate-twisted or induplicate. Stamens as many as the
segments of the corolla and alternate with them. Ovary 1-celled,
or rarely partially 2-celled from the projection inwards of the
placentas; ovules numerous ; placentas 2, parietal, anterior and
posterior to the axis, and frequently turned inwards; style 1;
stigmas 2, right and left of the axis. Fruit capsular, 1—2-celled,
2-valved, with septicidal dehiscence; or rarely fleshy and inde-
hiscent. Seeds numerous, small; embryo minute, in the axis
of fleshy albumen.

Diagnosis.—Usually smooth herbs. Leaves exstipulate.
Inflorescence definite. Flowers regular, solitary and terminal,
orineymes. Calyx and corolla persistent, with an equal number

of lobes. Stamens alternate to the lobes of the corolla, and
cod
388 MANUAL OF BOTANY

equal to them in number. Ovary superior, 1-celled, with 2

anterior and posterior parietal placentas, very rarely meeting

in the centre and forming a 2-celled ovary; style 1; stigmas 2.

Seeds small, numerous, with a minute embryo in the axis of

fleshy albumen.

Division of the Order and Illustrative Genera.—The order
may be divided into two sub-orders as follows :—

Sub-order 1. GuntTianra.—-Leaves opposite, corolla imbricate-
twisted. Illustrative Genera :—Gentiana, Linn.; Chlora,
Linn.

Sub-order 2. MrnyantaHes.—Leaves alternate, corolla indupli-
cate. Illustr. Genera :—Menyanthes, Tourn.; Villarsia,
Vent.

Distribution and Numbers.—They are found in nearly all
parts of the world, inhabiting both the coldest and the hottest
regions. There are upwards of 500 species.

Properties ond Uses.—A bitter principle almost universally
pervades the plants of this order; hence many of them are tonic,
stomachiec, and febrifugal.

Cohort 2.—Polemoniales.

Order 191. PoLemontacre®, the Phlox Order.—C haract er.—
Herbs. Leaves opposite or alternate, simple or compound,
exstipulate. Calyx inferior, 5-partite, persistent, generally
regular. Corolla 5-lobed with contorted or occasionally im-
bricate estivation. Stamens 5, alternate with the segments of
the corolla; pollen usually of a blue colour. Ovary 3-celled ;
style 1; stigma trifid. Fruit capsular, 3-celled, 3-valved ; pla-
centas axile. Seedsfew or many; embryo straight, in the axis
of copious horny albumen; cotyledons elliptical, foliaceous.

Distribution and Numbers. They abound most in the tem-
perate parts of North and South America; but are far less
abundant in Europe and Asia, and altogether unknown in
tropical countries. Illustrative Genera :—Phlox, Linn.; Pole-
monium, Tourn. ; Cobea, Cav. There are more than 100 species.

Properties and Uses.—Of no importance.

Order 192. HypropHyLLace®, the Hydrophyllum Order.—
Character.—Herbs, bushes, or small trees. Leaves usually
alternate, hairy, and lobed. Jlowers either solitary, stalked,
and axillary; or numerous and arranged in a helicoid cyme.
Calyx persistent, 5-partite. Corolla regular, 5-cleft. Stamens
equal in number to, and alternate with, the segments of the
DICOTYLEDONES—COROLLIFLORA 389

corolla. Ovary 1—2-celled, with two parietal placentas ; styles
and shgmas 2; ovules 2 or many. Fruit capsular, 2-valved,
2- or 1-celled. Seeds netted; albwmen hard, abundant.

Distribution and Numbers.—Chiefly natives of the northern
and most southern parts of the American continent. Illustrative
Genera :—Hydrophyllum, Tourn.; Nemophila, Bart. There
are about 80 species.

Properties and Uses.—Unimportant.

Order 193. Boracinacna, the Borage Order.—Character.—
Herbs or rarely shrubs, with more or less rounded, usually rough
and hairy stems. Leaves alternate, entire, or rarely sinuated,
usually rough, exstipulate. Inflorescence a helicoid cyme or a
unilateral raceme. Flowers regular, symmetrical. Calyx per-
sistent, inferior, 4—5-partite, or -lobed. Corolla regular or
nearly so, 4—5-partite, usually with scales in its throat; @sti-

Fie. 1157. Fic. 1158.

Fig. 1157, Vertical sec-
tion of the fruit of a
species of Myosotis. Two
acheenia are seen, and
two have been removed.
——Fig. 1158. Diagram
of the flower of the
Comfrey (Symphytum
officinale).

  

vation imbricate. Stamens equal in number to the lobes of the
corolla and alternate with them. Ovary superior, and composed
of two carpels, each of which is 2-lobed and 2-celled, with a
solitary pendulous ovule in each cell; style 1, basilar ; stigma
simple or bifid. Frutt consisting of from 2 to 4 distinct achenia,
placed at the bottom of the persistent calyx. Seeds exalbumi-
nous ; embryo straight, with a superior radicle.
Diagnosis.—Herbs with rounded, usually rough stems, and
alternate exstipulate leaves. Inflorescence helicoid or unilateral.
Flowers regular and perfect. Sepals, petals, and stamens equal
in number, the latter being alternate with the divisions of the
corolla. Ovary superior, deeply 4-lobed, with one ovule in each
lobe: style 1, basilar. Fruit composed of 2—-4 achenia placed
at the bottom of the persistent calyx. Seeds exalbuminous.
Distribution and Numbers.—Chietly natives of temperate
regions in the northern hemisphere. Illustrative Genera :—
390 MANUAL OF BOTANY

Echium, Linn.; Borago, Tourn.; Cynoglossum, Linn. There
are nearly 700 species.

Properties and Uses.—The plants of this order are chiefly
remarkable for their mucilaginous properties.

Order 194. Enretiace®, the Ehretia Order.—Diagnosis.—
These plants resemble the Boraginacee in most of their cha-
racters, but they differ in having their carpels so completely
united as to form a 2- or more-celled ovary; in their terminal
style; and drupaceous fruit. They are usually characterised also
by the presence of a small quantity of albumen in their seeds,
but this is sometimes absent. By Bentham and Hooker the
Ehretiacee are made a sub-order of the Boraginacea.

Distribution and Numbers.—Chiefly tropical plants. Jilus-
trative Genera :—Ehretia, Linn.; Heliotropium, Linn. There
are about 300 species.

Properties and Uses.—Unimportant.

Order 195. CorpiacEa, the Cordia Order.—Character.—
Trees with alternate scabrous leaves, exstipulate. Calyx and
corolla 5-merous; @stivation of the corolla imbricate-twisted.
Stamens 5, alternate with the segments of the corolla; anthers
versatile. Ovary superior, 4—8-celled, with 1 pendulous ovule
in each cell; stigma 4—8-cleft. Fruit drupaceous, 4—8-celled ;
frequently some of the cells are abortive; placentas axile,
Seeds 1 in each cell, pendulous by a long cord; albumen none;
cotyledons plaited longitudinally. This order is combined by
Bentham and Hooker with Boraginacee.

Distribution and Numbers.—Natives almost exclusively of
tropical regions. Illustrative Genera :—Cordia, Plum.; Var-
ronia, DC. There are more than 180 species.

Properties and Uses.—The fruits of many species are edible ;
the bark of C. Myzxa is reputed to be a mild tonic and astrin-
gent; some species yield timber.

Order 196. CoNVOLVULACE, the Convolvulus Order.—Cha.-
racter.—Herbs or shrubs, generally twining or trailing, or some-
times erect ; sometimes leafless and parasitic; juice frequently
milky. Leaves or scales alternate, exstipulate. Calyx inferior,
with deep divisions, much imbricate, persistent. Corolla
5-partite or 5-plaited, regular, deciduous, sometimes with scales
in its tube; estivation twisted, plaited or imbricate. Stamens
5, alternate with the lobes of the corolla. Dzse annular, hypo-
gynous. Ovary 2- 3- or 4-celled, or the carpels are more or less
distinct ; styles 1 or 2, usually 2-fid; ovwles 1—2 in each cell
or carpel, erect. Fruit capsular, 1—4-celled, with septifragal
DICOTYLEDONES—COROLLIFLORAG 391

dehiscence, or bursting tranversely at the base. Embryo large,
curved or coiled in a small quantity of mucilaginous albumen,
with foliaceous crumpled cotyledons ; in Cuscuta the embryo is
filiform, spiral, and the cotyledons scarcely perceptible ; radicle
inferior.

Diagnosis.—Generally twining or trailing milky herbs, with
alternate exstipulate leaves; or parasitic and leafless. Calyx

Fie. 1159.

Fie. 1160,

  

Fic. 1161.
f ( Fie. 1163.
|

  

Fig. 1159. Flower of Great Bindweed (Convoloulus sepium), Fig. 1160. Dia-
gram of the same flower, showing two bracts on the outside of the calyx.
Fig. 1161. Vertical section of the seed of the same.—-J’ig. 1162. Corolla of
Dodder (Cuscuta) laid open to show five epipetalous stamens and the scales
in its tube.——/Jig. 1163. Spiral embryo of a species of Cuscula.

of 5 imbricate sepals, inferior. Corolla regular, 5-plaited or 5-
lobed. Stamens 5, alternate with the lobes of the corolla.
Ovary 2—4-celled. Fruits 2—4-celled, capsular, septifragal.
Embryo curved, coiled, or spiral, in albumen ; radicle inferior.
Distribution and Numbers.—They are found chiefly in the
plains and valleys of hot and tropical regions. A few occur in
temperate climates, but they are altogether absent in the coldest
392 MANUAL OF BOTANY

latitudes. Illustrative Genera :—Convolvulus, Linn. ; Ipomvea,
Linn.; Cuscuta, Linn. There are about 750 species.

Properties and Uses.—They are chiefly remarkable for the
presence of an acrid milky purgative juice in their roots; hence
the order includes some important medicinal plants. In the
roots of some species this purgative principle is either absent or
in but small quantity. The seeds also of some species are
purgative. The Cuscutee are. leafless parasites.

Order 197. Nowanaces, the Nolana Order.—C haracter.—
Herbs or shrubs. Leaves alternate, exstipulate. Calyx 5-partite,
persistent, with a valvate estivation. Corolla regular, with a
plaited wstivation. Stamens 5, opposite to the lobes of the calyx.
Ovary composed of from 5 to 20 carpels, either distinct or more
or less combined into several bundles; style on a fleshy disc,
simple; stigma simple. Fruit composed of 5 or more separate
or more or less combined achenia, which are enclosed in the
persistent calyx. Seed with a little albumen; embryo curved ;
radicle inferior. This order is combined by Bentham and
Hooker with Convolvulacee ; and by others it has been referred
to Boraginacee.

Distribution and Numbers.—Natives exclusively of South
America, especially of Chili. Illustrative Genera :—Nolana,
Linn.; Alona, Lindl. Thete are about 36 species.

Properties and Uses.—Unknown.

Order 198. SoLanacEas, the Solanum Order.—C haracter.—
Herbs, or rarely shrubs, or trees, with a colourless juice. Leaves
alternate, often in pairs. Inflorescence axillary, or frequently
extra-axillary. Flowers isomerous. Calyx with 5 or rarely 4
divisions, usually persistent, often growing during the ripening
of the fruit (accrescent). Corolla regular or somewhat irregular,
5- or rarely 4-partite ; estivation valvate, induplicate, plaited, or
imbricate. Stamens equal in number to the lobes of the corolla,
with which they are alternate; anthers 2-celled, sometimes
connate above, with longitudinal or porous dehiscence. Ovary
superior, usually 2-celled, rarely 3—5-celled; style undivided,
stigma simple or 2-lobed. Fruit capsular or baccate, 2- or more-
celled. Seeds numerous, albuminous; embryo straight, or usually
curved in a more or less annular or spiral form.

Diagnosis——Herbs or rarely shrubs or trees, with alternate
leaves, and a colourless juice. Flowers isomerous. Calyx and
corolla with 5, or rarely 4 divisions. Corolla regular or very
slightly irregular; estivation valvate, imbricate, plaited, or
induplicate. Stamens equal in number to the lobes of the
DICOTYLEDONES—COROLLIFLORA 393

corolla, with which they are alternate; anthers 2-celled, with
porous or longitudinal dehiscence. Ovary superior, with axile
placentation, usually 2-celled, or rarely more-celled. Fruit de-

Fie. 1165.

Fre. 1164.
Te

(oe

Fie. 1166.

  

fy. 1164. Diagram of the flower of the Potato (Solanum tuberosum). Fig.
1165. Vertical section of the same. ¢. Calyx. p,p. Corolla. 0, Ovary.
e. Stamens. s. Style and stigma, Fig. 1166. Vertical section of the seed
of Solanum Duleamara. te. Testa. ch. Chalaza. alb. Albumen, enclosing
the curved embryo.

Fie. 1167.

 

Fie. 1168.

 

Fuy. 1167. Vertical section of
the flower of Tobacco (Nico-

hand Tabacum),———-Fiy.
1168. Diagram of the flower
of the same.

 

hiscent or indehiscent, 2- or more-celled. Seeds numerous,

albuminous.
The Solanacezw may be divided as follows :—

Sub-order 1. Sonanrm.—Aistivation of the corolla valvate or
394 MANUAL OF BOTANY

induplicate. Stamens equal in number to the lobes of the
corolla. Illustrative Genera :—Cestrum, Linn.; Solanum,
Linn.

Sub-order 2. ATropEx.—Aistivation of the corolla imbricate,
or some modification of imbricate. Stamens equal in number
to the lobes of the corolla, one occasionally sterile. I7lus-
trative Genera :—Atropa, Linn.; Lycium, Linn.

Distribution and Numbers.—They are scattered over most
parts of the globe except the polar circles, but are most abun-
dant in tropical regions. This order, as defined above, contains
about 1,120 species. ;

Properties and Uses.—The plants of this order frequently
possess narcotic properties. Some are pungent and stimulant
owing to the presence of an acrid oleo-resin; others contain a
bitter tonic principle; and a few have edible fruits, leaves, or
tubers.

Cohort 3.—Personales.

Order 199. ScROPHULARIACEM, the Figwort Order.—C harac-
ter.—Herbs, or rarely shrubby plants, with alternate, opposite,

Fie. 1170.

Fie. 1169.

  

Fig. 1169. Flower of a species of Speedwell ( Veronica).—— /’ig. 1170. Diagram
of whe: Dower of the Great Snapdragon (Antirrhinum majus), with one
bract below.

or whorled leaves; generally without, or very rarely with,
stipules; sometimes parasitic on roots. Inflorescence axillary.
Flowers anisomerous, irregular. Calyx inferior, ‘persistent,
4—5-partite. Corolla more or less irregular, sometimes gibbous
or spurred, 4—5-partite ; estivation imbricate. Stamens gene-
DICOTYLEDONES—COROLLIFLORA 395

rally 4, and didynamous, or sometimes 2, or rarely 5 or with a
rudimentary fifth; anthers 1—2-celled. Ovary usually 2-celled
with axile placentation ; style 1; stigma undivided or 2-lobed.
Fruit usually capsular, with variable dehiscence, or rarely
baccate, usually 2-celled. Seeds generally numerous, small,
albuminous ; embryo straight or slightly curved.

Diagnosis.—Herbs, or rarely shrubs. Flowers irregular,
anisomerous. Inflorescence axillary. Calyx and corolla with
4 or 5 divisions. Corolla more or less irregular, estivation im-
bricate. Stamens 4, didynamous, or sometimes 2, or rarely 5,
or with a rudimentary fifth or staminode; anthers 1—2-celled.
Ovary usually 2-celled, with axile placentation; style 1. Fruit
capsular, or rarely baccate. Seeds generally numerous, albu-
minous.

Distribution and Numbers.—The plants of this order are
found in all parts of the globe. Illustrative Genera :—
Scrophularia, Linn.; Antirrhinum, Tourn.; Verbascum, Linn. ;
Veronica, Tourn. As above defined, there are about 1,700
species.

Properties and Uses.—The plants of this order must be
regarded with suspicion, as some are powerful poisons. Many
are bitter, others astringent, some purgative, emetic, or diuretic,
and a few possess narcotic properties. A great many species
are cultivated in our gardens, &c., on account of the beauty of
their flowers.

Order 200. OroBANCHACE®, the Broom-rape Order.—Cha-
racter.—Herbs of a more or less fleshy character, growing
parasitically on the roots of other plants. Stems with scalelike
leaves. Calyx persistent, toothed. Corolla irregular, persis-
tent; estivation imbricate. Stamens 4, didynamous; anthers
1—2-celled. Ovary 1-celled; its 2 component carpels being
placed right and left of the axis; placentas 2—4, parietal ;
style 1; stigma 2-lobed. Fruit acapsule. Seeds very nume-
rous, minute, with fleshy albumenand a very small rudimentary
embryo.

Distribution and Numbers.—Principally natives of Europe,
Northern Asia, North America, and the Cape of Good Hope.
Illustrative Genera:—Orobanche, Linn.; Lathrea, Linn.
There are about 120 species.

Properties and Uses.—Unimportant.

Order 201. LEenTIBULARIACEA, the Butterwort Order.—C ha-
racter.—Herbs, growing in water, marshes, or wet places.
Leaves radical, entire or divided into threadlike filaments
396 MANUAL OF BOTANY

bearing little pouches or air-receptacles. Flowers irregular,
bracteate. Calyx persistent, bilabiate. Corolla personate or
bilabiate, spurred. Stamens 2, included; anthers 1-celled.
Ovary 1-celled; style 1, short; stigma bilabiate; placenta free
central. Fruit a capsule, 1-celled. Seeds minute, numerous,
anatropous, exalbuminous; embryo thick, straight, sometimes
undivided.

Distribution and Numbers.—Natives of all parts of the
globe, but more particularly of tropical regions. Illustrative
Genera :—Utricularia, Linn.; Pinguicula, Towrn. There are
about 180 species.

Properties and Uses.—Of little importance. The leaves of
Pinguwicula and the pitchers of Utricularia have the property
of capturing insects.

Order 202. CoLUMELLIACE®, the Columellia Order.—-Cha-
racter.—Evergreen shrubs or trees. Leaves opposite, ex-
stipulate. Flowers unsymmetrical, yellow, terminal. Calyx
superior, 5-parted. Corolla epigynous, rotate, 5—8-partite,
imbricate. Stamens 2, epipetalous; anthers sinuous, with
longitudinal dehiscence. Ovary inferior, 2-celled, surmounted
by a fleshy disc. Fruit capsular, 2-celled, many-seeded. Seeds
with fleshy albumen; embryo minute.

Distribution and Numbers.—Natives of Mexico and Peru.
It contains only the genus Colwmellia, Lour., which includes 3
species.

Properties and Uses.—Unknown.

Order 203.—GESNERACER, the Gesnera Order.—Character.
Herbs, or soft-wooded shrubs. Leaves wrinkled, exstipulate,
generally opposite or whorled. Flowers irregular, showy.
Calyx 5-partite. Corolla 5-lobed, perigynous or hypogynous.
Stamens diandrous or didynamous with the rudiment of a
fifth ; anthers 2-celled, frequently united. Ovary of 2 carpels,
antero-posterior, superior or half-inferior, 1-celled, surrounded
by an annular fleshy disc or by glands; style 1. Frutt
capsular or succulent, 1-celled, with 2-lobed parietal placentas.
Sceds numerous, with or without albumen; embryo with
minute cotyledons and a long radicle.

Division of the Order and Illustrative Genera.—The order
has been divided into two sub-orders or tribes as follows :—
Sub-order 1. GrsNEREm®.—Ovary partially adherent to the

calyx. Seeds albuminous. Illustrative Genera :—Gesnera,

Mart.; Gloxinia, L’ Hérit.

Sub-order 2. CyRTANDREEZ.—Ovary not adherent to the calyx.
DICOTYLEDONES—COROLLIFLORA 397

Seeds exalbuminous. Illustrative Genera :—Aischynanthus,
Jack. ; Cyrtandra, Forst.

Distribution and Numbers.—Chiefly natives of warm or
tropical regions. The Gesnerez are all American; the Cyrt-
andrex are more scattered. There are about 300 species.

Properties and Uses.—Of little importance.

Order 204. BiGNoniace2%, the Bignonia Order.—C haracter.
Trees or shrubs, which are often twining or climbing, or rarely
herbs. Leaves exstipulate, usually opposite. Inflorescence ter-
minal. Flowers irregular. Calyx entire or divided. Corolla
4—5-lobed. Stamens 2 or 43 anthers 2-celled. Ovary seated
on a disc, usually 2-celled; placentas axile; style 1. Fruct 2-
valved, capsular. Seeds numerous, sessile, large, winged, ex-
albuminous ; embryo with large leafy cotyledons.

Distribution and Numbers.—Chiefly tropical plants. Illus-
trate Genera :—Bignonia, Linn.; Tecoma, Juss.; Jacaranda,
Juss. There are about 450 species.

Properties and Uses.—Unimportant.

Order 205. CRESCENTIACE, the Crescentia Order.—C harac-
ter.—Small trees. Leaves simple, alternate or clustered, ex-
stipulate. Flowers irregular. Calyx free, entire at first,
afterwards splitting irregularly. Corolla somewhat bilabiate.
Stamens 4, didynamous, with a rudimentary fifth; anthers
2-celled. Ovary surrounded by an annular disc, 1-celled; pla-
centas 2—A, parietal; style 1. Fruit indehiscent, woody. Seeds
large, numerous, wingless, exalbuminous; cotyledons large,
amygdaloid; radicle short. This order is made a tribe of
Bignoniacee by Bentham and Hooker.

Distribution and Numbers.—Natives exclusively of tropical
regions. Illustrative Genera :—Crescentia, Linn.; Parmentiera,
DC. There are about 36 species.

Properties and Uses.—Unimportant.

Order 206. PrpauiacEa, the Pedalium order.—Charac-
ter.—Glandular herbs. Leaves entire, exstipulate. Flowers
axillary, usually large and irregular. Calywx 5-partite. Corolla
bilabiate. Stamens didynamous with the rudiment of a fifth,
included; anthers 2-celled. Ovary on a fleshy or glandular
dise, 1-celled, with two parietal placentas ; sometimes spuriously
4—6-celled; style 1; stigma divided. Fruit bony or capsular.
Seeds wingless, without albumen ; embryo with large cotyledons
and a short radicle.

Distribution and Numbers.—Chiefly tropical plants. IUlus-
398 MANUAL OF BOTANY

trative Genera :—Pedalium, Linn.; Sesamum, Linn. There
are about 25 species.

Properties and Uses.—Chiefly remarkable for their oily
seeds.

Order 207. ACANTHACE®, the Acanthus Order.—C haracter.
Herbs or shrubs. Leaves opposite or whorled, simple, exstipu-
late. Flowers irregular, bracteate. Calyx 4—5s-partite, or
consisting of 4—5 sepals, persistent, much imbricate; sometimes
obsolete. Corolla more or less 2-lipped. Stamens 2 or 4, in
the latter case didynamous. Ovary seated on a disc, 2-celled;
placentas parietal, although extended to the axis; style 1.
Fruit capsular, 2-celled, with a variable number of seeds in
each cell. Seeds hanging by hard cup-shaped or hooked pro-
jections of the placenta, without wings; albwmen none;
cotyledons large and fleshy ; radicle inferior.

Distribution and Numbers.—Chiefly tropical. Illustrative
Genera :—Acanthus, Tourn.; Justicia, Nees. There are nearly
1,500 species.

Properties and Uses.—Generally unimportant; but several
species are mucilaginous and bitter.

Cohort 4.—Lamiales.

Order 208. SELAGINACEs, the Selago Order.—Character.
Herbs or shrubs, with alternate exstipulate leaves. Flowers
irregular, unsymmetrical, sessile, bracteate. Calyw persistent,
usually gamosepalous with a definite number of divisions, or
rarely consisting of two distinct sepals. Corolla tubular, 5-
partite. Stamens 4, didynamous, or rarely 2; anthers 1-celled.
Ovary superior; style 1, filiform; ovwle solitary, pendulous.
Fruit 2-celled, with 1 pendulous seed in each cell. Seeds with
a little fleshy albumen; embryo with a superior radicle. In
Globularia there is but one carpel.

Distribution and Numbers.—Chiefly natives of the Cape of
Good Hope. The species of Globularia are, however, European
plants. Illustrative Genera :—Selago, Linn.; Globularia, Linn.
There are about 120 species.

Properties and Uses.—Of little importance.

Order 209. VERBENACE®, the Vervain Order.—Character.—
Herbs, shrubs, or trees. Leaves opposite or alternate, exsti-
pulate. Calyx inferior, persistent, tubular. Corolla irregular,
usually more or less 2-lipped. Stamens 4, usually didynamous,
or rarely equal; or sometimes there are but 2 stamens; anthers
DICOTYLEDONES—COROLLIFLORA 399

2-celled. Ovary 2—4-celled; style 1, terminal; stigma undi-
vided or bifid. Fruit dry or drupaceous, composed of from 2 to 4
carpels, which when ripe usually separate into as many 1-seeded
achenia. Seed erect or ascending, with little or no albumen,
and an inferior radicle.

Diagnosis.—Known at once from the Labiate by their more
united carpels and terminal style.

Distribution and Numbers.—They are found both in tempe-
rate and tropical regions. Illustrative Genera :—Verbena, Linn.;
Clerodendron, Linn. There are more than 660 species.

Properties and Uses.—Many of the plants are slightly
aromatic and bitter, but there are no important medicinal plants
included in this order. Some are valuable timber trees; other
species have fleshy fruits, which are edible; and the leaves of a
few are used as substitutes for China Tea. Many are cultivated

in our gardens for the beauty of their flowers or

Fic. 1171. for their fragrance, as the different species and

varieties of Verbena, the Aloysia citriodora, the
Lemon-plant, &c.

Order 210. Myoporacex, the Myopora order.
Diagnosis.—This order is sometimes regarded
as a sub-order of the Verbenacee, from which
it only differs essentially in having two seeds in

: __. each cell of the fruit, and by the embryo having
Fig. 1171. Pistil : ?
of the Vervain @ Superior radicle.
(Verbena). Distribution and Numbers.—Chiefly natives
of the southern hemisphere. Illustrative
Genera :—Myoporum, Banks et Sol.; Avicennia, Linn. There
are about 40 species.

Properties and Uses.—Unimportant. The bark of Avicennia
tomentosa, White Mangrove, and other species, is much used in
Brazil for tanning.

Order 211. Lapiatm, the Labiate Order.—Character.—
Herbs or shrubby plants, with usually square stems. Leaves
opposite or whorled, commonly strong-scented, entire or divided,
exstipulate. Flowers generally in axillary cymes, which are
arranged in a somewhat whorled manner so as to form what
are called verticillasters. Calyx inferior, persistent, either
tubular, 5- or 10-toothed, and regular or nearly so, or irregular
and somewhat bilabiate; with 8—10 divisions; the odd tooth
or division always posterior. Corolla usually more or less
bilabiate, with the upper lip undivided or bifid, and commonly
more or less arched over. the lower lip, or sometimes nearly

 
400 MANUAL OF BOTANY

suppressed ; the lower lip 38-lobed, with the odd lobe anterior;
or rarely the corolla is nearly regular. Stamens usually 4, and

Fic. 1172. Fie. 11738.

 

Fig. 1172. Diagram of the flower of the White Dead-nettle (Laminm album).
Fig. 1173. Flower of the common Bugle (Ajuga reptans).

then commonly didynamous, or very rarely of nearly equal
length, or only two by abortion; anthers 2-celled, or 1-celled by
abortion; the filament or connective sometimes forked, each

Fie. 1174. Fie. 1176. Fie. 1177.

  
 

Fig. 1174, Front view of the flower
of a species of Lamium.—-Fig.
1175. The corolla of the Garden
Sage (Salvia officinalis) cut
open.— Fig. 1176. The corolla
of the Horehound (.Merrubium
vulgare) cub open.—_—ig. 1177.
Lobed ovary, style, and bifid
stigma of the Garden Sage (Sal-
via officinalis).

branch then bearing a perfect cell, or the cell on one side
obsolete or sterile. Ovary imbedded in the dise or thalamus,
DICOTYLEDONES—COROLLIFLORZ 401

and formed of two carpels, each of which has 2 deep lobes, with
1 erect ovule in each lobe; style 1, basilar; stegma bifid. Fruit
composed of from 1 to 4 achznia, enclosed by the persistent
calyx. Seed erect, with little or no albumen; embryo erect,
with flat cotyledons ; radicle inferior. :

Diagnosis.—Herbs or shrubby plants, with opposite exstipu-
late leaves. Flowers irregular, unsymmetrical. Calyx persis-
tent. Corolla usually more or less bilabiate, with the odd lobe
anterior. Stamens usually 4 and then commonly didynamous,
cr rarely of equal length ; or only 2 by abortion. Ovary deeply
4-lobed ; style 1, basilar ; stigma bifid. Fruit consisting of from
1 to 4 achenia, enclosed by the persistent calyx. Seed erect, with
little or no albumen ; radicle inferior.

Distribution and Numbers.—Chiefly natives of temperate
regions. Illustrative Genera :—Mentha, Linn. ; Salvia, Linn. ;
Origanum, Linn.; Lamium, Linn. There are nearly 2,600
species.

Properties and Uses.—The plants of this large order are
entirely free from any deleterious qualities. They abound in
volatile oil, and are therefore conmonly aromatic, carminative.
and stimulant. All labiate plants also contain more or less of a
bitter extractive matter, and many of them possess an astrin-
gent principle, hence they are frequently tonic and stomachic.
Several are used in perfumery on account of their agreeable
odours; and many are employed by the cook for flavouring,
such as Thymus vulgaris (Garden Thyme), Thymus citriodorus
(Lemon Thyme), Salvia officinalis (Sage), Origanum vulgare
(Marjoram), Majorana hortensis (Sweet Marjoram), Satureia
montana (Winter Savory), Satureta hortensis (Summer Savory),
&e. The fleshy underground stems of Stachys palustris and of
a species of Ocymum are edible.

Anomalous Order.

Order 212. Puantacinace®, the Ribwort Order.—Cha-
racter.—Herbs, generally without aerial stems. Leaves com-
monly ribbed and radical. Flowers usually in spikes and perfect,
or rarely solitary, and sometimes unisexual. Calyx persistent,
4-partite, imbricate. Corolla dry and membranous, persistent,
4-partite. Stamens equal in number to the divisions of the
corolla, and alternate with them; filaments long and slender ;
anthers versatile. Ovary simple, but sometimes spuriously 2- or
A-celled from the prolongation of processes from the placenta;
style and stigma entire, or the latter is rarely cleft. Capsule

VOL, I. DD
402 MANUAL OF BOTANY

membranous, with transverse dehiscence ; placenta free central.
Seeds 1, 2, or more, with a mucilaginous testa; embryo trans-
verse, in fleshy albumen.

_ Distribution and Numbers.—They abound in cold or -tem-

Fie. 1178.

Fre, 1179.

 

Fig. 1178, Plant of a species of
Rib-grass (Plantago), with
radical leaves.——Jig. 1179,
Flower of the same.

 

perate climates, but are more or less diffused over the globe.
Illustrative Genera :—Littorella, Linn.; Plantago, Linn. There
are more than 100 species.

Properties and Uses.—Generally of little importance; but
some are demulcent, and others astringent.

Artificial Analysis of the Orders in the Sub-class Gamopetala
or Corolliflore.

*,* A few orders belonging to the Sub-class Polypetale, the flowers of

which are sometimes gamopetalous, are also included in this analysis.

: Ovary inferior.

A. Ovary usually 1-celled.
a. Anthers united.

Ovule solitary, pendulous . ; . . Calyceracee.

Ovule solitary, erect . y . Composite.
b, Anthers distinct.

Fruit with 1 perfect cell and 2 rudimentary

ones.
Seed exalbuminous Valerianacee.
Fruit 1-celled, and without any widntaatany
ones. Seed albuminous ; . Dipsacee.

B. Ovary with more than 1 cell.
a. Anthers united.
Leaves alternate i : . Lobeliacee.
DICOTYLEDONES—COROLLIFLORZ

b. Anthers distinct.

1. Stamens 2.
Filaments not united to the style.
Filaments united to the style

2. Stamens more than 2.

Anthers opening by pores or slits
Anthers opening longitudinally.
Stigma with an indusium
Stigma without an indusium.
Leaves without stipules.
Stamens definite.
Leaves alternate. Corolla persistent
Leaves opposite. Stem round
Leaves verticillate. Stem square .
Stamens numerous
Leaves with stipules.
Stipules interpetiolar. Flowers herma-
phrodite

Stipules cirrhose. Flowers unisexual

Ovary superior.
Carpels more than one.
uw. Anthers opening by pores or slits

b. Anthers opening longitudinally.
1. Anthers 1-celled . i
2. Anthers 2-celled.
Plants with dotted leaves ‘
Plants parasitic, leaves brown, scaly

A. Flowers regular.

a. Ovary lobed.
Inflorescence helicoid. Aéstivation of corolla

imbricate i
Inflorescence straight. Corolla with a valvate
eestivation. Leaves exstipulate

b. Ovary not lobed.
1. Carpels more than three, distinct or com-
bined.
Stamens equal in number to the petals and
opposite to them.

Stems herbaceous. Style 1. Fruit a cap-

sule f i
Stem woody Style 1. Fruit fleshy, inde-
hiscent ~

Stem herbaceous or woody. Styles 5
(rarely 3 or 4). Fruit membranous
Stamens not opposite the petals if of the
same number,

403

Columelliacee.
Stylidiacee.

Vaccintacee.

Goodeniacee.

Campanulacee.
Caprifoliacee.
Rubiacee.
Belvisiacee.

Rubiaceae.
Cucurbitacce.

Ericacee.

Epacridacee.

Rutacee.
Monotropacee.

Boraginacee.

Nolanacee.

Primulacee.
Myrsinacee.

Plumbaginacec.

ppn2
4044

Carpels distinct.
Seeds numerous
Seeds few

Carpels combined.-Ovary 2- or more-celled.

Ovules erect or ascending.

ZEstivation of the corolla plaited.
Fruit dry

Aistivation of the corolla iniintenke,
Fruit fleshy .

Ovules pendulous or stiependad, or rar ily
partly ascending.

Stamens twice or four times as many
as the lobes of the corolla, distinct

Stamens equal in number to the lobes
of the corolla, Filaments distinct.
Anthers adnate

Stamens equal in number to the Tobes
of the corolla. Filaments distinct.
Anthers versatile .

Some of the ovules potecioualte as-
cending. Filaments more or less
cohering

2. Curpels three, combined so as to form a 3-
celled ovary.
Stem herbaceous. Dise hypogynous
Stem woody. No dise
3. Carpels two, combined or more or less dis-
tinct.
Stamens 2

Stamens 4 or more. Inflorescence heli-
coid,
Fruit a capsule, 1-celled or imperfectly
2-celled

Fruit drupaceous, 2- or more- edie’ 5
Stamens 4 or more. Inflorescence straight.
Leaves alternate.
Calyx in a broken whorl
Calyx in a complete whorl.
Anthers united to the stigma
Anthers free from the stigma.
Placentas parietal
Placentas axile.

Estivation of corolla valvate, in-
duplicate-valvate, or imbri-
cate

Leaves opposite, whorled, or clustered.
Anthers united to the stigma.
Anthers free from the stigma.

Leaves with stipules
Leaves without stipules,

MANUAL OF BOTANY

Crassulacee.
Anonacee.

Convolvulacee.

Sapotacee.

Ebenacee.

Aquifoliacee.

Cordiacee.

Styracee.

Polemoniacee.
Diapensiacee.

Oleacee.

Hydrophyllacee.
Ehretiacee.
Convolvulacee.
Asclepiadacee.

Gentianacee.

Solanaceae.
Asclepiadacee.

DLogantacee.
DICOTYLEDONES--COROLLIFLORZ

Stigma shaped like an hour-glass.
AAstivation of corolla contorted
Stigma not contracted in the middle
like an hour-glass.
AXstivation of corolla imbricate,
placentas parietal
AKstivation of corolla valvate,
placentas axile . :
4. Carpel solitary.

Stamens opposite the lobes of the corolla or

petals. ;

Stamens alternate to the lobes of the corolla.
Fruit 1-celled. Stigma sessile . ‘
Fruit spuriously 2-celled or rarely 4- palled,

Style capillary i ‘ , ‘

B. Flowers irregular.
a. Ovary 4-lobed .

b. Ovary not lobed.
1. Carpel solitary
2. Carpels two.
Fruit hard or nut-like.
Anthers 1-celled .
Anthers 2-celled. Ovules erect.
Corolla imbricate in estivation
Corolla valvate in estivation .
Anthers 2-celled. Ovules pendulous
Fruit capsular or succulent.
Placentas parietal.
Leafless scaly, brown, root-parasites
Leafy plants. Seeds with wings
Leafy plants. Seeds without wings.
Fruit a capsule or baccate. Cotyledons
minute, radicle long
Fruit bony or a capsule.
large, radicle short ‘
Fruit woody with a pulpy ‘nfedion
Cotyledons large, radicle short
Placentas axile.
Seeds without wings.
Albuminous. ‘
Exalbuminous. Seeds attached , to
hard placental processes
Seeds winged. Exalbuminous .
Placentas free central

Cotyledons

405

Apocynacee.

Gentianacee.

Stilbacee.

Plumbaginacee.
Salvadoracee.

Plantaginacee.

Labiate.

Selaginacee.

Selaginacee.
Verbenacee.

Stilbacee.
Myoporacea.

Orobanchaceeé.
Bignoniacee.
Gesneracee.
Pedaliacee.

Crescentiacea,

Scrophulariacee.

Acanthacee.
Bignoniacee.
Lentibulariacee.

There are many exceptions to the characters above given of the Gamo-
petalee or Corolliflore. Thus, among the Infere or Epigyne we sometimes
find polypetalous corollasin Caprifoliacee and Lobeliacee, und the ovary
406 MANUAL OF BOTANY

is sometimes superior in Goodeniacee. In the Supere and Dicarpie,
polypetalous species are sometimes found in Ericacee, Monotropacee,
Epacridacee, Styracee, Oleacee, Primulacee, Myrsinacee, and Plum-
baginacee.

Again, among the Supere and Dicarpie we occasionally find the ovary
inferior, or partly so, asin Hbenacee, Styracee, Myrsinacea, Primulacee,
and always in Gesneracee and Vacciniacee.

In Oleacee and Primulacea, apetalous species sometimes occur; and
unisexual species are also occasionally found in Valerianacee, Composite,
Ebenacee, Myrsinacee, and Plantaginacee, and other exceptions have

been already noted.

Synopsis of the British Natural Orders of the Sub-class

Gamopetale.

A. Corolla gamopetalous, superior.

Stamens inserted beneath epigynous dise Vacciniacee.
Stamens inserted with the corolla and free from it.
Filaments free Campanulacee.
Stamens epipetalous, alternate with lobes el
corolla.
Anthers united, flowers in capitula . Conwposite.
Anthers free.
Inflorescence a la as with in-
volucel Dipsacee.
Flowers corymbose or ees
Fruit with a double indehiscent pericarp,
2-celled, 2-seeded Rubiacee.
Fruit dry, with 1 perfect and often 2 ‘aber:
tive cells é . Valerianacee.
Fruit fleshy, with 1 or several ese * Caprifoliacee.
B. Corolla gamopetalous, inferior.
Ovary and fruit 4-lobed. Style gynobasic.
Stamens 5. Corolla regular. Leaves alternate Boraginacee.
Stamens 4 or 2, corolla irregular, leaves opposite Labiate.
Ovary and fruit simple. Style terminal.
Ovary 1-celled, 1-seeded. Stamens besa
ous. Styles 5 Plumbaginacee.
Ovary 1-celled, many sented.
Corolla scarious, regular. Stamens 4 Plantaginacee.
Corolla coloured.
Corolla irregular.
Stamens 2 . . . : . Lentibulariacee.
Stamens 4, didynamous ‘ Orobanchacee.
Corolla regular. Stamens antipetalous Primulacee.
Ovary 2- or more-celled (fruit sometimes
1-celled).
Stamens hypogynous, distinct . i Ericacee.
Stamens epipetalous.
Stamens 2. Corolla regular * Oleacee.
DICOTYLEDONES—COROLLIFLORA 407

Stamens 2 or 4, didynamous. Corolla ir-
regular.
Ovary 2-celled, not lobed. Placentas
axile . ‘
Ovary 2—4- aalled, lobed.
Stamens 4 or 5, not didynamous.
Cells of ovary each with 1 or 2 ovules.
Fruit a capsule
Cells of ovary each with many evleas
Fruit a double follicle :
Fruit 2- or imperfectly 4-celled.
Leaves alternate .

Fruit 1- or imperfectly dediled,

Leaves opposite .
Fruit 3-celled

Scrophulariacee.
Verbenacee.
Convolvulacee
Apocynacee.
Solanacee.

Gentianacee.
Polemoniacee.
BOOK IV.
PHYSIOLOGY OF PLANTS.

CHAPTER I.

THE RELATION OF WATER TO THE PROTOPLASM OF THE CELL.

WE have already seen in considering the structure of. both
simple and complex plants, that they are all composed originally
of a variable number of protoplasts, which are in close relation-
ship with each other, being partially separated in most cases by
septa, or partitions, known as cell-walls. The latter show a
great deal of variety in the way they are arranged, their
thickness, the material of which they are composed, &c. The
protoplasts, on the other hand, resemble each other in all essential
particulars, though in complex plants one or other function or
property of each is often developed to a greater extent than the
remainder which it possesses.

The essential difference between the protoplasm of the plant
and the walls by which it is supported lies in the fact that the
former is the living substance, by whose activity all the
remainder is constructed. In dealing with the physiology of
the plant, we have therefore to turn our attention to the proto-
plasm. We have seen that in the simplest forms of plant this
may exist without any cell membrane, and may be freely motile,
swimming in water by means of cilia, or creeping in a semi-
animal fashion by pseudopodia. In other unicellular plants it
may be surrounded by a cell-wall, and may either entirely fill
the space afforded inside the latter, or may have inside itself a
vacuole. Inthe multicellular plants, each cell while living shows
its own protoplast or aggregation of the protoplasm, which is
probably connected always with that of the adjoining cells. The
protoplasm generally lies as a peripheral layer round the outside
of the cell, though in many cases the central cavity is crossed
by a number of bridles passing generally from a somewhat central
410 MANUAL OF BOTANY

spot to the periphery. A nucleus is a constituent of all cells
when they are young, though in some few cases it disappears
later. It is always embedded in the protoplasm, of which it is
a specially differentiated portion.

Not only does the living substance construct the substance
of the plant originally, but it is the part by which the organism
is able to place itself in harmony with its environment. It
assimilates the food the plant requires and carries out the
chemical processes incident to its life; it receives impressions
from without and regulates the response the plant makes to
these impressions, both by internal and external movements
or changes of position; finally it carries out the reproductive
processes.

Looking at the arrangement of protoplasm in the cell, or at
its environment in the free condition, we notice especially its
very close relation to water. The free-swimming zoospore is
naturally saturated with the latter, being in the fullest contact
with it. The young cell enclosed in its cell-membrane speedily
shows a tendency to accumulate water in its interior, and gradu-
ally drops appear, which lead ultimately to the formation of a
vacuole always full of liquid. The healthy protoplasm is thus
always in contact with water. Indeed the molecular constitution
of protoplasm, as far as we know it, lends itself to this relation,
for the apparently structureless substance is always saturated
with it. It is only while in such a condition that the cell can
live ; with very rare exceptions, if a cell is once completely dried,
even at a low temperature, its life is gone, and restoration of
water fails to enable it to recover.

The constancy of the occurrence of the vacuole in the cells of
the vegetable organism is itself an evidence that such cells mani-
fest their dependence upon water for the maintenance of life.
The cell-wall, though usually permeable, yet presents a certain
obstacle to the absorption of water, and so even those cells which
are living in streams or ponds usually possess a vacuole. Cells
without a membrane, such as the zoospores already many times
mentioned, can more readily absorb water from without, and
hence they are not vacuolated to the same extent as the former
ones; indeed, many of them have no vacuole. This cavity being
always filled with liquid, the protoplasm of the cell has ready
access to water, as much so indeed as the cell which possesses
no wall. The vacuole contains a store which is always available.

We have seen that the presence of water is necessary to the
life of the cell, and that a store of it is usually contained in its
OSMOSIS 411

interior. As this must be absorbed from without, it becomes
necessary to inquire into the way in which it effects its entry.
This is based upon a purely physical process which is known as
osmosis. If two fluids of different densities, for example water
and syrup, be separated from each other by a homogeneous
permeable membrane, they will tend to pass through the latter
till there is a mixture of the two of equal density on each side
of it. We shall thus have a stream of water passing through
the membrane to the syrup, and a stream of syrup similarly
passing to the water. The rate of flow of

the two streams will not be the same, Fic. 1180.
however, and the first result will be a
considerable increase in quantity of the
fluid upon the side of the membrane in
contact with the syrup, owing to the
greater amount of water that will have
passed through.

A convenient form of apparatus to
exhibit this process of osmosis is shown in
Jig. 1180. It consists of a bladder fastened
to the end of «a narrow tube, which is
immersed, as shown, in a vessel of water.
The bladder and part of the tube are filled
with syrup, and the height at which the
latter stands in the tube is noted. After
some time the contents of the tube will
be increased, and the liquid will stand in
it at a higher level, in consequence of the
osmotic action that has taken place. Ifthe rig. 1180. Apparatus to
positions of the water and the syrup were Show osmotic action. Tt
reversed, the liquid would fall in the tube, filled with syrup to the
showing that under these conditions also fPre Ee aka.
there is a greater stream of water towards the whole placed in a
the syrup than of the latter in the opposite ERS a
direction.

Though the process thus stated is far simpler than what we
have reason to believe takes place in the vegetable cell, we can
apply it to explain the original formation of the vacuole.
Consider the case of a cell of the dermatogen of a plant which is
immersed in water. It is full of protoplasm, and limited or
clothed by a cell-membrane, which is permeable more or less
readily by water. The protoplasm is saturated with water, but
there is no separate accumulation of thelatter. Part at least of

 
412 MANUAL OF BOTANY

the cell-wall is in contact with water on the outside. The
protoplasm is actively living, and in the course of the chemical
changes which are incident to vital action, certain substances are
produced by it, which, like the syrup in the experiment detailed,
havean affinity for water, or, to use a more technical phrase, have
a fairly high osmotic equivalent. Water consequently passes
into the cell, at first only in such quantities as to somewhat
distend it. As the process goes on, more liquid is present than
can be stored in the molecular interstices of the protoplasm.
Drops consequently appear, and these gradually run together
until a distinct though small vacuole, or a number of such
vacuoles, is apparent in the protoplasm. By a continuation of
the process the protoplasm ultimately forms a layer round the
cell-wall, enclosing the large cavity in which the surplus liquid
is held.

But, as has already been said, the process is not a simple
physical one. Though the conditions of the first experiment are
approximated to, they are not altogether realised. The syrup in
the bladder finds its representative in the osmotic substances”
formed by the protoplasm and dissolved in the water in its
meshes ; the water outside the cell is the same as the water in
the outer vessel. But there isa great difference in the membrane.
The bladder of the experiment is replaced by a film of cellulose
lined by the protoplasm itself. The former is readily permeable,
but the latter is not. A further experiment will show a very
important modification of the process, brought about by the
protoplasm, and demonstrating that the entry of water into the
cell is very largely under the regulation of the latter.

Take a cell of the cortex of the plant and put it in contact
with a liquid of higher osmotic power than its own contents;
for instance with a solution of common salt, containing 5—10
per cent. of the crystals, Watch its action on a slide under the
microscope, and let the salt solution be coloured with some
vegetable dye which will not injure the living substance. As the
salt solution reaches the cell, the protoplasm of the latter
gradually retreats from the walls, at first at the corners and then
all round the sides, till it appears as a rounded mass in the centre.
The salt solution has abstracted the water from the vacuole, and
the protoplasm, relieved of the outward pressure caused by the
liquid in the latter, has shrunk away from the walls. The outward
stream has been accompanied by an incoming one as in the first
experiment. The coloured salt solution will be seen inside the
cell-wall, between it and the protoplasm. But here is a great
OSMOSIS—TU RGESCENCE 413

difference between the two experiments ; the salt solution does
not pass through the protoplasm, though it does go through the
cell-wall. If, now, the salt solution be replaced by water, the
latter is gradually attracted again, of course osmotically, into
the cell. It passes through the protoplasm ; the vacuole is re-
established, and the protoplasm again comes to line the cell-
wall, pressed against it by the water.

The protoplasm thus allows water to pass through its sub-
stance, but can oppose the passage either way of the various
osmotic bodies with which it may be brought into contact. In
the last narrated experiment it prevented the salt solution from
entering the vacuole, and, as shown by the return of the water
into the latter, it prevented the osmotic substances originally in
no the cell from leaving it.

That this is due to the vital power of the protoplasm can be
shown by repeating the experiment after killing the living sub-
stance by a short immersion of the cell in alcohol. Then the
process of osmosis goes on exactly as in the first experiment
quoted. The salt solution penetrates into the vacuole as if only
a cellulose septum were present, the dead protoplasm exerting
no regulating influence.

The modified osmosis, which is thus the mode of entry of
water into a cell containing no vacuole, continues after the vacuole
is formed, and is the cause of the transfusion of water from cell to
cell. We can see that this must be the case, for if two cells are
considered which are separated from each other by a common cell-
wall, it is evident that, unless the proportion of water to osmotic
substances in the vacuoles of both is the same, osmotic currents
will flow from one to the other till this equilibrium is reached.

The quantity of osmotic substances present in any cell will
depend upon the behaviour of the protoplasm from time to time.
Such substances are usually being continually produced in all
growing cells and in most others in which chemical changes are
proceeding. Hence such cells are continually absorbing water,
and are consequently so full that a certain stretching force is
exerted on the cell-wall which bounds them. Cells in such a
condition are called turgid, and the condition itself is known
as turgescence. The equilibrium, which is attained by such a
cell, is reached when the distension caused by the osmotic sub-
stances is balanced by the elastic recoil of the extensible cellulose
wall. In some cases the tension set up in a tissue by the
turgescence of the cells is sufficient to force the water, by a pro-
cess of filtration, through the walls of the outermost ones, so
414 MANUAL OF BOTANY

that it escapes in drops or in a slow stream. This may often be
seen on the edges or apices of blades of grasses in the early
morning. It is of great use also in forcing water into the axial
woody cylinder of roots, as will appear later. Occasionally the
turgescence becomes so great as to lead to rupture of the cell-
walls, as is the case sometimes in fleshy fruits.

That the condition of turgidity in cells is attended by a
stretching of the cell-walls can be seen by taking a piece of a
plant which is turgid, such as the stalk of a rhubarb leaf, and, after
carefully measuring its dimensions, steeping it for some time in
a 10 per cent. solution of salt. On removing it, it will have
become flaccid, and « remeasurement will show that both its
length and thickness have diminished. Turgescence is not,
however, solely due to physical causes; the protoplasm which
lines the cells has a regulating influence over the passage of the
water in and out of the cell. Ifa turgid pulvinus of such a
plant as Robinia, or Mimosa, be stimulated by rough handling
of the leaf, the latter falls from its expanded position towards
the stem, and the fall is found to be due to the escape of water
from the cells of the lower side of the pulvinus. The original
state of equilibrium has been disturbed by the shock to the
protoplasm administered by the stimulation, and the latter allows
water to pass outwards.

The active influence of the protoplasm is seen also in
another class of phenomena. Certain structures known as
nectaries have been described as occurring in many flowers.
These are aggregations of cells of a particular kind which exude
a sugary fluid upon their surfaces. If the petals of certain
flowers bearing these nectaries be cut off and their cut ends
immersed in water, the glands continue for some time to exude
the nectar. There can be no question here of any filtration of
water through the tissue, as there is no pressure acting on
the base of the petal. The protoplasm causes the stream to
continue to flow by producing osmotic substances, in this case
chiefly sugar. It differs still more in its behaviour in that it
pours out not only the water thus absorbed, but a certain
amount of the sugar in addition. If the gland be killed by
alcohol, the sugar already there is retained in the cells, and no
exudation of nectar or even of water takes place.

The vital activity of the protoplasm is thus seen to be
intimately connected with the presence of water in its substance.
The importance of the ready access of the latter is seen further
from other considerations. In the foregoing pages we have
-

IMPORTANCE OF THE WATER-SUPPLY 415

spoken of it as if it were pure water only; this is, however, not
the case, for the water, when absorbed, contains small quanti-
ties of various substances in solution. Though the protoplasm
opposes the entry of anything like a strong solution of inorganic
salts, say 5 to 10 per cent., it allows very dilute ones to enter
much as it does pure water. In this way the slowly diffusing
stream brings to the protoplasm of each cell the inorganic
materials which are absorbed from the earth. and enables the
matters elaborated or formed from them by the protoplasm to
pass from cell to cell. The feeding or nutrition of the various
cells is thus dependent on the transit of fluid about the plant
in the way described. The access of various gases is similarly
made possible, for these are dissolved in the liquid stream.
Thus the oxygen, upon the presence of which life depends, is
transported to each cell, and the carbon dioxide of respiration
is removed from the seats of its liberation. The condition
of turgescence is necessary also for growth and for various
movements of different parts, enabling them to adapt them-
selves to varying conditions of their environment. Some
plants, particularly those which are aquatic in habit, and such
parts of terrestrial plants as have but little woody tissue, are
dependent upon the turgidity of their cells for the rigidity which
enables them to retain their positions in the medium in which
they live.

The importance of the water supply, and, indeed, its necessity
to the plant, explains the presence of the aqueous tissue which
we have seen to occur in various parts. The cells of this tissue
contain little else than water, and may be regarded as an addi-
tional reservoir, supplementing the vacuoles of the ordinary
cells. In plants that inhabit dry arid soils, such as sandy deserts,
there are often other adaptations relating to water storage.
Such plants are often covered with large bladder-like hairs,
which hold a considerable quantity of liquid. In many plants
the epidermal cells form a further reservoir. Plants exposed to
conditions threatening too copious evaporation are generally
furnished with a very prominent cuticle, tending.to check undue
escape.
416 MANUAL OF BOTANY

CHAPTER II.

THE TRANSPORT OF WATER IN THE PLANT.

We have seen that it is necessary for the life of the plant that
all its living cells shall be freely supplied with water. According
to the habit of life of plants the mode of supply must necessarily
vary. Those which are so constituted that water finds free-
access to all the cells, such as the unicellular or filamentous alge,
which live in streams, pools, &c., present no difficulty, as osmosis
can go on freely in each cell. Sturdier plants of aquatie habit
are almost equally easily supplied; the water enters by osmosis
into the epidermal cells, which we have already seen are pro-
vided with membranes that are not cuticularised, and it can
pass readily from cell to cell all over the plant body. Plants of
terrestrial habit, from the nature of their environment, require
a more elaborate mechanism, which is found in the large de-
velopment of woody tissue they exhibit. Throughout all such
plants a stream of water passes. entering in at the roots, passing
along the woody axis of the root, up the stem into the leaves,
where a very large part of it is evaporated. This stream of
water is often known as the ascending sap. In addition to this
comparatively rapid stream, slow currents of diffusion from
cell to cell are also maintained as in the plants of humbler
development.

Except in some special cases, the water which passes through
the body of an ordinary land plant is obtained from the soil in
which its roots are embedded. The soil itself is composed of
minute particles of inorganic matter, derived originally from
the breaking down of rocks, and of decaying animal or vegetable
matter mixed with the inorganic constituents. This organic
matter is known as humus and is of very varied composition.
The soil thus consists of a loose matrix of granular character,
the interstices of which are normally filled with air, but which
can contain varying quantities of water. When these spaces are
filled with water, the plants growing in the soil are very un-
favourably placed for absorbing it. When air is present in them,
each particle of soil is surrounded by a delicate film of water,
which adheres closely to it. This water, often spoken of as hygro-
scopic water, is the source of the plant’s supply. It adheres so
firmly to the soil particles that it escapes ordinary observation ;
if, however, soil which has been allowed to dry at any ordinary
ACTION OF ROOT-HAIRS 417

temperature till its interstices are apparently empty be exposed
to a heat approaching that of boiling water, a considerable
quantity of vapour will be given off, due to the volatilising of the
hygroscopic films.

We have seen that the youngest roots and rootlets are
furnished near their apices with a number of delicate hairs (jig.
1181) or outgrowths of their epidermal cells (fig. 1182), which
make their way into the interstices of the soil. Not only do
these play a very important part in anchoring the plant to the
substratum, but they are the means by which the water is
absorbed. The delicate walls of these root-hairs come into the
closest relationship to the particles of soil, pressing in some cases

Fic. 1181. Fig. 1182.

 

Fig. 1181. Ultimate branches of a root, show-
ing position of root-hairs. Fig. 1182.
Root-hairs on the surface of a young root.

 

 

so closely upon them, that the particles are embedded in the
membrane. The hygroscopic film of water is so separated from
the interior of the root-hair by a most delicate pellicle of almést
pure cellulose. The cell-sap in the hair contains a certain
amount of acid in solution, and by virtue of this osmosis is set
up. The root-hairs, which are very numerous, become turgid,
and by continued osmosis the water is passed inwards to the
cortex of the root, all 'the cells of which soon exhibit considerable
turgescence, thus causing a great deal of hydrostatic pressure
in the cortex. At the places where the latter abuts upon the
xylem elements of the stele a filtration under this pressure takes
place, so that the water is forced into the axial woody tissue.
VOL. IL. ER
418 MANUAL OF BOTANY

The filtration when set up tends to relieve the pressure in the
cortex, and additional water can then be absorbed as before.
The water is thus made to rise gradually in the axial stele, for
the root-hairs and the cortical tissue exert together in this way
a kind of pumping action, forcing it along the axis. This force,
due to the turgescence set up as described, is known as root-
pressure, and is one main factor in the transport of water
through the plant. The turgescence not only leads to the rise
of sap in the axial stele, but spreads throughout the whole of
the cortical tissue of the plant, reaching indeed every cell into
which osmotic diffusion can take place.

The stele of the root we have seen to be directly continuous
with that of the stem, the woody elements being in contact
throughout. The stream of water consequently passes up the
woody tissue of the stem so long as the cells are living. The
hard dead wood of the duramen takes no part in the conduction,
which is confined to the alburnum. Some discussion has taken
place as to the exact path followed, but that the one indicated is
that which is taken has been proved by cutting incisions round
the trunks of trees to various depths. So long as the alburnum
is not cut the stream is not interrupted, but if the wound passes
through that region it stops, and all parts of the tree above the~
incision droop and die.

The water has been said by some observers to pass along the
cell-walls of the woody vessels and tracheids, and not through
their interior. Other writers hold that the main stream travels
along the interior of the cells. To this point we shall return
later. In either case the water ascends through the trunk,
branches, and twigs of the tree till it reaches the points at which
the foliar meristeles leave the central axis. It passes along the
woody elements of these, entering the leaves thus by the fibro-
vascular bundles or veins. From these it makes its way to the
parenchymatous mesophyll of the leaves, the cells of which are
thus made turgid. Osmotic diffusion, interrupted in the axis of
the plant, is resumed in the leaves, and a general equilibrium of
turgescence is reached in them.

We have seen that the parenchyma of the leaves, and par-
ticularly that of the lower half of each is abundantly supplied
with intercellular spaces (fig. 1183). The cells which abut upon
these spaces are furnished with very delicate walls and readily
allow a process of evaporation to take place, watery vapour
passing into these passages. The surface of the leaf we have
seen to be furnished with a number of openings or stomata,
EVAPORATION OF WATER 419

each communicating with the system of intercellular spaces,
and having two guard-cells surrounding it. Through these
stomata the watery vapour evaporated into the intercellular
spaces passes to the external air, the quantity escaping being
regulated by the degree to which the guard-cells are approxi-
mated. We have thus a copious evaporation taking place from
the surface of the leaves, which plays an important part in
causing the flow of water through the plant. This evaporation
is known as transpiration and must be discussed more fully
later.

Little or no evaporation takes place from the surface of the
epidermis of the leaves, the cells of which have their outer
walls generally strongly or weakly cuticularised, the cuticle
offering considerable resistance to the passage of water, or
watery vapour, in either direction.

The escape of water is thus Fie. 1183.
mainly brought about by evapo-
ration into the intercellular spaces
of the leaves. It is not con-
fined, however, to these, but takes
place generally into all the inter-
cellular spaces, which form a system
of minute channels permeating the
whole plant. The actual escape
from the plant takes place wherever ig. 1183. Section of leaf of Beta.
there are stomata, as well, that is, eo Goce i on
from the young green twigs as large intercellular spaces.
from the leaves themselves. It is
supplemented in some cases by an actual excretion of water as
such, carried out by means of the water glands we have seen to
occur in some plants at the ends of some of the veins of the
leaves. When the hydrostatic pressure is very high at times in
herbaceous plants, water may be forced out of the tips of the
leaves without the intervention of glands.

The stream of water thus passing through the plant has a
very important influence upon its development. This is evident
from the consideration that a large part of the food of the plant
is absorbed by means of this stream, the water containing
minute proportions of the various nutritive salts which exist in the
soil. The quantity passing is further correlated with the amount
of leaf surface which the plant presents ; where there is a large
leaf area there is copious transpiration ; this necessitates a larger
path for the ascending stream and a consequent development of

EE2

 

 
420 MANUAL OF BOTANY

the axial portions of the plant. Where there is a large flow of
water, as in a tree, there is a continuous formation of material ;
where the transpiration is but slight, as in a Cactus, there is but
little formation of new plant substance.

CHAPTER III.

THE SKELETON OF THE PLANT.

We have seen that the protoplasm of the plant is a soft almost
jelly-like substance, incapable of resisting any considerable
disturbing force or pressure, such as almost all plants are
inevitably exposed to, whatever be the nature of their environ-
ment. To enable them to cope with the difficulties presented
by the latter, plants must possess a certain rigidity, which varies
with the nature of their situation. The soft protoplasm must
consequently be supported by something which will secure this
rigidity. The several protoplasts are in most cases surrounded
by a cell-wall or membrane which subserves this purpose.
According to the habitat of each plant the development of its
cell-membranes shows various degrees of complexity, and many
modifications of the original structure are found. We have
already seen that such modifications take the forms of alteration of
the shape of the cell, of aggregations of cells in various ways, and
of differences of chemical constitution brought about as the age of
the cell increases. These differences are not merely connected
with the maintenance of rigidity, but subserve also various
functions which the different tissues of complex plants perform.
In the simplest plants, consisting of single cells, or rows or
plates of cells, and living in water, but little rigidity is needed.
The unthickened cell-wall is here sufficient, when combined
with the turgescence of the cells, to prevent their being destroyed
by the ordinary antagonistic influences which they have to
encounter. The form of the plant is also modified to enable it
to survive such difficulties. Plants growing in rapidly flowing
water usually have flexible stems and much divided leaves,
which consequently give way to the current and escape damage.
Those of terrestrial habit, on the other hand, exposed to winds
and storms, are furnished with considerable development of
woody roots which anchor them securely to the earth, and with
sturdy trunks consisting of masses of wood, which secure
stability even when atmospheric disturbances are severe. The
THE SKELETON OF THE PLANT 421

subdivisions of the trunk, ending in finely divided twigs, while
exposing considerable surface to the air, present on the whole
a fairly yielding plant body, through which the currents of air
can make their way without meeting such a resistance as to
cause the uprooting of the tree. In other forms a weak stem
of considerable length exists, which obtains support by clinging
in various ways and holding by various mechanisms to some
other structure, such as the trunks of trees, rocks, walls, &c. In
these the woody development, though considerable, is much
less than in ordinary trees.

The leaves show similar adaptations of structure to environ-
ment. The venation of the leaves, though mainly subserving
the purpose of transport of liquids, is yet often such as to afford
considerable resistance to damage from strong winds. Often
the veins are so arranged as to form a series of arches on the
external margins, preventing lateral tearing. The epidermal
cells of many leaves frequently exposed to intense cold are
strongly cuticularised, and the rigidity thus afforded is sometimes
supplemented by a development of hypodermal sclerenchyma.

All these arrangements may be regarded as affording a
supporting skeleton to the plant, the nature of which and the
degree of its development can only be understood by a considera-
tion of the habit of life of the plant under examination and the
dangers to which its environment exposes it.

The ordinary cell-wall of the cell as it is first formed is a
clear, transparent, extensible and elastic membrane, which is
secreted by the protoplasm and which remains in contact with
it so long as the cell is living. It is capable under certain con-
ditions of absorbing considerable quantities of water, and in
consequence swelling considerably. It is usually said to be
composed of a substance named cellulose, whose chemical com-
position is represented by the formula n (C,H,,0,), the value of 1
not yet having been exactly determined. This substance is related
to such bodies as starch, sugar, &c., being a member of the group
of carbohydrates. It is capable, under the action of certain
reagents, of being converted into a form of sugar, and under
certain circumstances it can yield nutritive material for the use
of the living substance.

Probably, however, the cell-wall is in very few cases alto-
gether composed of pure cellulose, but mixed with the latter,
certain bodies occur which are compounds of pectic acid with
lime. There are. many such bodies, but our knowledge of
them is very imperfect, nor is their respective distribution at
422 MANUAL OF BOTANY

all well understood. Certain solvents will extract them from
ordinary cell-walls, leaving cellulose as the basis of the latter.

The reactions of cellulose have been already described in
an earlier section in dealing with the composition of the cell-
wall. The most characteristic one is the assumption of a blue
colour when treated with iodine and some hydrating agent, such
as strong sulphuric acid or chloride of zine.

Cellulose itself is capable of existing in more than one con-
dition. We find some kinds of it which will stain blue on
treatment with iodine alone. Examples are found in the cell-
walls of the bast of the stele of Lycopodium, the endosperm of
the Peony, the cotyledons of some of the Leguminose, ke.
The walls of the hyphex of the Fungi differ again, in that they
will not give the blue colour with iodine even after treatment
with hydrating agents. Recent observations suggest that this
variety of cell-wall approaches in composition the chitin of the
animal kingdom.

It is probable that cellulose is chemically combined with a
certain amount of water, and that the degree of hydration differs
in the different varieties described.

Where considerable rigidity of structure is needed it is
obtained by the conversion of the cellulose into lignin, the
material found conspicuously in the walls of wood cells. This is
formed in the substance of the cell-walls, and in partially lignified
membranes the lignin can be dissolved out, leaving a cellulose
basis. In its chemical characters lignin differs materially from
cellulose; it has no extensibility, nor can it absorb water and
swell as can the latter ; on the other hand it allows water to pass
through it with great rapidity and ease. It can be recognised
micro-chemically by staining red when treated with phloroglucin
and a mineral acid, or yellow with aniline chloride under the
same conditions.

Lignin is probably not a definite chemical compound, but a
mixture of substances successively formed from the cellulose.
Its physical properties render it particularly adapted to serve
as the material of which the tissues conducting the stream of
water are composed. Its Jack of flexibility or extensibility makes
it suitable for the securing of rigidity in tissues or structures
needing strong power of resistance to winds or storms.

The modification of the tegumentary tissue of the higher
plants takes the form primarily of the transformation of the
cell-wall into cutin or suberin, the former being characteristic
of the outer layers of the epidermal cell-walls, and Jeading
THE SKELETON OF THE PLANT 423

to the peculiar properties of the cuticle. Suberin is the sub-
stance found in great proportion in the walls of corky cells.
Both of these are formed like lignin by modification of cellulose.
They serve rather to prevent undue evaporation than to act as
a true skeleton. In old trees, however, the complex barks, into
the composition of which cork enters to a very considerable
extent, often subserve scmewhat the purpose of aiding in the
mechanical support of the tree, especially in cases where the
woody centre decays and the tree becomes hollow.

In many cases the cell-walls, while remaining chemically
unchanged, become impregnated with silica or other mineral
matter. The cereal grasses and the Equisetaceew accumulate
copious quantities of silica in the walls of their epidermal cells.
Though this appears not to be altogether essential to their power
of reinaining upright, it no doubt materially assists it.

Other modifications of cellulose are found in various cell-
walls, but they are comparatively unimportant from the point of
view now under discussion.

Where the ordinary unmodified cell-walls of the plant are
not sufficient to secure rigidity, as in most terrestrial plants, there
is a very varied distribution of tissues for that purpose. The
forms which are found are collenchyma, sclerenchyma, and
vascular tissue, the former two appearing to subserve mechanical
purposes only, while the latter also takes part in the transport of
water. In delicate stems but little development of either is seen ;
thus most moss plants show in their axis only the hypodermal
cells thickened, while this is supplemented in the Polytrichacce
by a central core of somewhat lignified cells. In succulent
petioles there is a hypodermal development of collenchyma, in
addition to the meristeles, which contain a certain amount of
wood. In many herbaceous stems, particularly those with
angles, strands of sclerenchyma are found underlying part or
the whole of the margins. In many Monocotyledons of humble
growth the centre of the stem is hollow or is oceupied by thin-
walled fundamental tissue, sometimes made of stellate cells, and
the margin is strengthened by strands of sclerenchymatous
fibres placed behind or between the fibro-vascular bundles.

Plants of larger growth depend very largely on the fibro-
vascular part of the stele for their supporting tissue. This is
seen most easily in the trees belonging to the Gymnosperms and
Dicotyledons, which increase regularly in thickness. Large
monocotyledonous trees depend upon the same class of elements,
though the distribution of the individual bundles is different.
424 MANUAL OF BOTANY

In many members of these groups, and in many of the Pteri-
dophytes the fibro-vascular system is not so well developed, and
we find in such plants the stereome is supplemented by the
appearance of bands or sheaths of sclerenchyma very variously
disposed. There is usually a considerable hypodermal develop-
ment, besides masses occurring more deeply in the axis. Some-
times the cortical ground tissue contains isolated sclerenchyma-
tous bands, often of large size; frequently the pericycle has
similar developments. Sometimes, again, the sclerenchyma,
instead of being in isolated strands, forms a continuous ring or
sheath. Many stems contain developments in all three regions
which are variously connected together.

The arrangements of stereome tissue in the leaves are
similarly varied. The meristele of the petiole is frequently
found to have a large amount of sclerenchyma in its pericycle,
and this is continued upwards along the chief axis or axes of the
epipodium, gradually thinning out as the margin is approached.
In the large flattened leaves of some Monocotyledons, bands of
sclerenchyma frequently extend completely across the interior.
In some leathery leaves large idioblasts of various form act
as struts or trabecule, reaching from one epidermis to the
other. The arrangement of the veins in many leaves has
already been alluded to.

The root usually depends for its rigidity upon the great
development of fibro-vascular tissue in the stele. As we have
seen, the tissues external to the endodermis are not as a rule
long-lived, and hence the bulk of an adult root is stelar in origin.
Aquatic roots, like the stems of the same plants, have but little
development of specially supporting tissue, but owe their rigidity
to the turgescence of their cortex.

CHAPTER IV.
THE TRANSPIRATION CURRENT—ROOT PRESSURE—TRANSPIRATION.

WE have seen in Chapter II. that in terrestrial plants, so long as
circumstances are favourable to the vital activity of the organ-
ism, w stream of water is passing from the roots through the
axis to the green twigs and leaves, where the greater part of it
is evaporated. This current has been called the transpiration
current, and its rate has been ascertained to be on an average
about 100 centimetres per hour. The path by which it passes
THE TRANSPIRATION CURRENT 425

has been shown to be the young wood of the axial stele, into
which it is forced by a kind of filtration from the over-turgid
cortical tissue of the root. The wood vessels and tracheids
form a closed system, quite separated from the atmosphere, con-
taining air and a certain quantity of water. Sometimes they
are filled with the latter, often they contain a much larger
quantity of air. In no case probably are they during life free
from either, though the proportions of the two vary very greatly.
Much controversy has arisen as to whether the transport of the
water takes place through the substance of the cell-walls or
through the cavity of the vessels and tracheids. The character
of the former suggests that very possibly water may be carried
through them; that indeed the structure may be regarded as a
column of water held together by the molecules of the lignified
walls. This view is supported by the behaviour of lignin,
which while refusing to absorb much liquid and swell, as
cellulose does, yet can contain a certain quantity which it will
part with very easily. On the other hand compression of the
vessels by a vice, if carried so far as partially or entirely to
obliterate their cavities, materially interferes with the rate of
flow.

Two main causes appear to co-operate in maintaining this
upward stream. We have the constant pumping action of the
cortex of the root, giving us the force known as root-pressure.
We have also the modified evaporation from the surface of the
green parts of the plant, which we have spoken of as transpira-
tion. Both these may now be discussed in greater detail.
Besides these two, other factors have been held to co-operate,
though much less certainly than they. The walls of the vessels
having extremely narrow calibre, capillarity has been suggested
as playing a part. This cannot, however, have much effect
in a system of closed tracheids, like those of the secondary
wood of the Conifers, which nevertheless conduct the water.
It has been thought that the living cells of the parenchyma which
abut upon the woody tissue of the stele may play a part similar
to the pumping action of the root. Against this theory we have
the fact that if the transpiration current be made to contain sub-
stances that are poisonous to the living cells, and the latter
are consequently killed, the current still goes on. Nor do
differences of gaseous pressure within and without the plant,
or at different portions of the axis, explain the matter more
satisfactorily.

RootT-PRESSURE.— We have shown how the absorption of water
426 MANUAL OF BOTANY

osmotically from the soil by the root-hairs leads to a great
turgescence of the tissue of the cortex of the root, which tur-
gescence exerts considerable pressure on the sides of the vessels
and tracheids of the xylem of the stele. By this means water
with various salts and other constituents in extremely small
quantity, is forced into the fibro-vascular tissue. The process
is not a purely physical one of filtration under pressure, but is
regulated to some extent by the protoplasm of the most internal
cortical cells. When these are distended to their greatest
capacity the protoplasm appears to be stimulated, perhaps by
the very distension, and in consequence to allow water to
transude through its substance. This mode of response to
stimulation is not infrequent in vegetable tissues; indeed, it
appears to correspond to the response of a muscle to stimulation
by the process of contraction. The protoplasm thus relieves
itself of the over-distension, and we get an intermittent pumping
action set up, which has a certain rhythm. By it large quanti-
ties of liquid are continually being forced into the axial stele.

This water, under particular conditions, may accumulate in
the vessels, and its presence can then very readily be demon-
strated and the force of the root-pressure measured. If a vine
stem be cut through in the early spring, before its leaves have
unfolded, a continuous escape of water takes place from the cut
surface, and the vine is said to bleed. This phenomenon is not
peculiar to the vine, but is shared in by all other terrestrial
plants. In many herbaceous forms this forcing out of water by
root-pressure may be seen without cutting the plant at all.
Many grasses and other herbaceous plants show in the early
morning a certain exudation of water from the tips of their
leaves, which is due to the same over-turgescence.

To measure the root-pressure in a plant the apparatus shown
in fig. 1184 may be used. It consists of a T-piece of glass tubing
which is fastened by indiarubber rings to the top of a cut stem,
such as that of Helianthus. To the side arm of the tube a bent
tube of capillary bore is attached by a tightly fitting cork, and
the T-piece is filled with water. Mercury is poured into the
bent tube till it stands ata level a little below the cork. As
the root continues to take up water it forces it into the tube R,
whence it overflows into the capillary tube, causing the mercury
in its two limbs to be at unequal levels. By the displacement
of the mercury the force of the root-pressure can be esti-
mated.

The root-pressure of various plants has been measured by
ROOT-PRESSURE 427

different observers; an idea of its amount may be gathered
from the fact that a medium-sized Fuchsia in a pot has been
found able to send a column of water up a tube of the same
diameter as its stem to a height of twenty-five feet.

This force is continually at work while the transmission of
water is going on, but it is not easily seen later in the year. If
the stem of the vine be cut in July instead of April, no bleeding
follows the wound. This is not, however, due to the absence of
activity by the roots, but to the fact that a copious evaporation
is taking place from the leaves. In the
experiment in April the conditions were
different, there were no expanded leaves, n
and the water absorbed and sent upwards
by the root consequently accumulated in
the vessels of the stem, escaping at once
when the latter was cut; in July the
vessels had been emptied by the transpi-
ration, and there was no accumulation of 9g’ K
water there to overflow. The apparatus
just described will show, however, that
the root-pressure is still at work if it be
used in July.

The root-pressure, though always con-
siderable, is not constant in amount; it
is lowest in the early morning, when it
begins to increase ; it continues to rise till
about midday or a little later, then gradu-
ally sinks. A second rise takes place ih
towards evening, and then it sinks con- i ‘i r i
tinuously all night. The causes of this “
rhythmic daily period are at present ' Hl Hi
unknown ; it does not appear to depend AM
upon variations of its surroundings, but to fy. 1184. Apparatus for the
arise from some cause inherent in the con- ae ee ee
stitution of the plant.

Transpiration.—The modified evaporation taking place from
the surfaces of the succulent parts of plants, and regulated
in amount by the protoplasm of the cells, is known as tran-
spiration. It is easy to demonstrate the fact of its continuous
existence by enclosing a plant, or part of one, in a dry glass
vessel, which can be closed so as to admit no air. Very soon
the surface of the glass is covered by a fine dew, which is the
condensed vapour escaping from the plant. The same thing

Fie. 1184.

 

   
  

    
  

 
       
  
     
 

i i

SSS

    
428 MANUAL OF BOTANY

may be seen if a vigorous plant be covered over by a bell-jar,
the water condensing copiously upon the sides of the latter.

The evaporation takes place to a certain extent through all
the epidermal cells of the transpiring organ, but not to a very
great one, the degree of development of the cuticle having
considerable influence upon the amount. It is carried out much
more freely through the thin walls of the cells abutting upon the
intercellular spaces, which, as we have seen, communicate with
the external air by means of the stomata and the lenticels.
The transpiration is most copious in the leaf, the structure of
the lower side of which, in dorsiventral leaves, is especially
favourable to it. Ifa leaf be taken which has stonfata upon
its under side only, and the rate of transpiration from its two
surfaces be compared, it will be found that the stomatal gives
off considerably more vapour than the other surface.

The amount of moisture given off in transpiration varies in
different plants. In the sunflower (Helianthus) the amount has
been stated to be z$3 cubic inch of water per square inch of
surface in twelve hours. Doubtless individual plants show a
considerable variety, however, in the amount. This copious
evaporation readily explains why bleeding of plants from wounds
cannot be observed when the leaves are expanded and active.

The removal of the water accumulated by root-pressure in
the closed system of vessels leads to a diminution of the pressure
of the air they contain, so that while transpiration is active there
is a negative gaseous pressure existing in them. This is of con-
siderable importance in assisting in the movements of gases in
the plant, and it further helps the pumping action of the root
in pressing forward the water by exerting a suction upon the
parenchymatous cortex.

Transpiration is not a process of simple evaporation. Asin the
other phenomena we have examined, the protoplasm exercises a
regulating influence upon the escape of watery vapour from the
cell, If the amount given off from a measured area of leaf
surface be compared with the amount evaporated from an equal
area of free water, the latter is found to be much the greater.
That this is due to the life of the leaf, and therefore to the
protoplasm, is seen from the fact that a dead leaf gives off its
water and dries up more rapidly than a surface of freely exposed
water. The cuticle of the living leaf and its cell-walls are con-
sequently not the causes of the differences observed.

If the protoplasm of the cells of the turgid leaves of a branch
be stimulated by violently shaking it, the leaves become flaccid.
TRANSPIRATION 429

The protoplasm under the stimulus allows more vapour to pass
through it, as that of the cortex of the root permitted water to
pass out of its cells under the stimulus of over-turgescence.

The ultimate exudation of watery vapour is thus seen to be
chiefly carried out through the stomata of the green parts, at
any rate in those plants which possess them. The mechanism of
the stomata has already been alluded to. The guard-cells which
surround the aperture are capable of varying turgescence, the
water entering and leaving them from the other cells of the
epidermis, which abut upon them. Those walls of the guard-
cells, which abut upon the air space underlying them, are, as a
rule, thickened and cuticularised ( fig. 1185), so that vapour can-
not enter them. The wall between them and the next epidermal
cell is thin and readily allows of osmosis. The guard-cells
themselves differ from the rest of the
epidermis in the higher plants by con-
taining chloroplasts, which suggests the
presence in them of more osmotic sub-
stances than the other epidermal cells
contain. The guard-cells are so attached
to each other that turgescence causes them
to separate, opening the aperture. Loss of
water induces in them a flaccid condition,
and their edges fall together and partly or
wholly close the slit. Hence, when the * anise oF aun
cells of the epidermis are turgid, the sto- cells. / Opening of the

. stoma. yp. Parenchyma
mata open ; when they lose their turges- of the leaf.
cence these organs are closed. Thus the
escape of watery vapour is accelerated or retarded by their
‘action.

Transpiration is markedly increased by light, rising to many
times its original amount when a plant is transported from
darkness into sunshine. This is not due to the rise of temperature
accompanying the illumination, though the greater warmth may
have some influence uponit. The effect of light upon the stomata
is to cause them to open; hence they are open during the day and
closed during the night. It is probable, however, that this is
not directly due to the light. If coloured light be en:ployed, it
is found that the rays which influence the opening or closing are
those which are absorbed by chlorophyll—a fact which has some
significance when it is remembered that the guard-cells contain
that pigment.

Other external conditions which have an n faflitenes upon this

Fie. 1185.

 
430 MANUAL OF BOTANY

function are the hygrometric condition of the air, the tempera-
ture of the soil in which the roots of the plant are embedded,
and the mechanical disturbances to which the plant is subjected.
If the air be dry, transpiration is vigorous; if moist, then it is
checked. If a plant be exposed to a warm, dry atmosphere till
the leaves droop from too great a loss of water and then be trans-
ferred to one saturated with moisture, after a short time they
again become turgid. This is not due to an absorption of water
in the form of vapour by the leaves, but to a diminished loss by
the checking of transpiration. The return of turgidity is caused
by the accumulation of the store drawn from the earth by the
roots. Warming the soil increases the amount of vapour given
off by the leaves. The mechanical disturbance of shaking has
already been alluded to, and it has been seen that when thus
stimulated, the protoplasm allows transpiration to increase.
This helps to explain the flaccid condition observable in some
trees after the prevalence of a high wind. The continued
renewal of the air around the transpiring organs may also have
the effect of increasing the removal of vapour.

When transpiration is excessive, the leaves and branches
lose their turgescence, become flaccid and droop. A branch
which has reached this condition may be revived by forcing
water into it, which can be done by fastening it in one arm of a
U-tube containing water and pouring mercury into the other.
The restoration of the water restores the turgidity of the tissues.

Transpiration is of the greatest importance to the plant in
many ways. By maintaining a copious flow of liquid to the cells
of the leaves, it brings to the metabolic cells of their mesophyll a
supply of the materials needed by the plant for the construction
of its nutritive substances, and it assists in the transportation of
the stored material laid up in various parts of the stem and root to
the growing parts and other seats of consumption. Its influence
in maintaining the turgidity of the tissues is also very consider-
able, and this turgescence is of the highest importance to the
growing cells, growth itself and many adaptations to changes in
the plant’s environment being dependent upon it. The negative
gaseous pressure in the vessels, already alluded to, is dependent
upon transpiration. The importance of the presence of the
water to the lite of the protoplasm has already been shown.
431

CHAPTER V.

THE FOOD OF PLANTS. INTRODUCTORY.

A coop deal of misconception exists as to the nature of the food
of plants. The character of their environment and the absence of
any means provided in their structure for taking in material of
a nature in any way approaching the composition of living sub-
stance, has led to a not unnatural idea that they feed upon simple
inorganic compounds of comparatively very great simplicity.
The idea has found considerable support in the fact, which is
easily ascertained, that such bodies are those which are absorbed
in the first instance. By their roots when they live fastened in
the soil, or by their general surface when they are inhabitants of
water, comparatively simple inorganic salts are found to enter
them with the water that they take up. By their green parts,
and especially by their leaves, carbon dioxide is absorbed, either
from air or water, according to their habit. A study of the
whole vegetable kingdom, however, throws considerable doubt
upon the theory that these substances are, in the strict sense, to
be called their food. Fungi and phanerogamic parasites can
make no use of such bodies as CO,, but draw elaborated products
from the bodies of their hosts. Those fungi which are sapro-
phytic, in the same way can only live when furnished with
organic compounds of some complexity, which they derive from
decaying animal or vegetable matter. We have no reason to
suppose that the living substance of these non-chlorophyllaceous
plants is so radically different from that of their green relations
that it has a totally distinct mode of nutrition.

In the higher plants we find a stage of their life in which
the nutritive processes approximate very closely to those of the
group last mentioned. When the young sporophyte first begins
its independent life—when, that is, it exists in the form of the
embryo in the seed—its living substance has no power to utilise
the simple inorganic bodies spoken of. The shoot which a
potato puts out derives its food from the interior of the tuber.
Fleshy roots, corms, bulbs, and all bodies which are capable of
renewed life after a period of quiescence, show us the same
thing ; the young shoot emerging from any of them is not fed
upon simple inorganic bodies, but upon substances of consider-
able complexity, which it derives from the tissues of the struc-
ture from which it springs.
432 MANUAL OF BOTANY

Even in adult plants of the most considerable complexity we
find instances of the same thing; the living substance is nou-
rished by materials which have been constructed by it and stored
at various places in its substance till their consumption has been
called for.

What, then, are these substances which, in the strict sense,
constitute the food of plants? We can ascertain what are
necessary by inquiring what are the materials which are de-
posited in the seed for the nutrition of the embryo when the seed
germinates. We find there examples of great classes of food
stuffs which are similar to those on which animal protoplasm is
supported, and are led again and again to the idea that vegetable
protoplasm is essentially identical with the latter. Proteids, carbo-
hydrates, fats or oils are the materials which, in varied forms,
are met with. If we study the protoplasm of a living active
vegetable cell and treat it with appropriate solvents, we can
extract representatives of these, or of some of them, from its
substance, the meshes of which are the places in which it is
deposited. The nutrition of the protoplasm can only take place
when these substances are brought into the most intimate rela-
tions with it; from them, no doubt, in ways not yet discovered,
it builds itself up, and by its own decomposition it reproduces
them. The interchange of matter between the living substance
and its food, the way in which the latter is transformed into the
former, are points about which yet almost everything essential
remains to be discovered.

But while we recognise that the ultimate nutrition of proto-
plasm is dependent upon a supply to it of such materials, we
are face to face with the fact that such materials are not furnished
from the environment to the ordinary green plant. On the
other hand we find the latter taking in by ordinary physical
processes CO, from the air and a variety of salts from the soil, and
we ascertain that if these are supplied under suitable conditions,
the plant can flourish and develop. In one sense, then, these
substances constitute its food, but we must carefully consider
what we mean by the term. In the nutrition of such plants
there are clearly two very different processes combined, which
should be kept carefully distinct. We have the absorption of
food materials rather than of food in the true sense, and we
have, following such absorption, the expenditure of a consider-
able amount of energy upon these food materials, with the
result that they are worked up into the complex compounds
which we find protoplasm can assimilate, and which are those
THE FOOD OF PLANTS 433

which are stored away in the substance of the plant for the
nutrition of embryo, bud, or growing point.

This may be made clearer by examining whether these
simple inorganic materials are capable of nourishing protoplasm
when freely supplied to it. If they are the true food, plants
everywhere should be able to make use of them. But if we
consider only one of them, the CO, of the air, we find this is not
the case. The plants which are not green, that is, which con-
tain no chloroplasts, can do nothing with this gas. So long as
a seed is in the early stages of its germination it is surrounded
by CO, which is given off by its own protoplasm. Put it can
make no use of it, and if the store of nourishment provided for
it in the endosperm or cotyledons is cut off, it inevitably dies
of starvation.

If a green plant, which is in good health and endowed with
ample vigour, is removed from light to darkness, though CO,
be supplied in appropriate quantity, it can make no use of it.

So with other constituents of the materials from which the
true food of the living substance is elaborated. They are
-absorbed in quantity, but they are not food until a con-
siderable amount of work has been done upon them by the
plant itself.

In connection with the nutrition of plants we have thus to
deal with the absorption of the crude food materials and to study
the changes which they undergo after such absorption. But
this is not all; the food which is laid up in seeds, tubers, bulbs,
&c., is not deposited there in exactly the condition in which the
living substance requires it, so that there remains for us to con-
sider the processes which these materials also undergo for the
purpose of feeding the living protoplasin. The first process is
one of building up complex bodies from simple materials; the
second is comparable with the digestion which is so marked a
feature of animal alimentation, and is one of breaking down
very complex bodies into simpler ones. The nutrition of the
protoplasm shows two similar phases; the absorption of the
ultimate coustituents of the food, or its assimilation, is a con-
structive process; it is in turn associated with a destructive

- one, by which, from the protoplasm itself and by its own activity,
simpler bodies are produced. The whole round of changes
which embraces all these operations is called metabolism, the
constructive processes being grouped together under the name
of anabolism, the destructive ones under that of catabolism.

The absence of well-differentiated organs set apart for the

VOL. II. FF
434 MANUAL OF BOTANY

-discharge of these functions makes it rather difficult at first to
appreciate their independence. In the animal body such a
differentiation is easily seen, but in plants the cellular structure
is so prominent, and the life of the protoplasm is so closely
related to its condition in the cell, that attention needs to be
specially directed to the point. Each protoplast is dependent
upon the contents of its own vacuole, and the early constructive
processes in the metabolism may take place in it side by side with
the digestive ones and at almost the same time. True, a certain
division of labour can be noted, but it is not very clearly as-
sociated with particular structures. Thus the leaf is especially
concerned in the processes of anabolism, but it is mainly so by
virtue of the chloroplasts which its cells contain. These pro-
cesses can go on perfectly well in other parts than leaves;
indeed, wherever there are chloroplasts we know they do. Thus,
though we associate the leaf with anabolisin, it would be wrong to
say that it is the organ to which this process is referred. We can
say with greater accuracy that the chloroplast is the organ con-
ducting these preliminary anabolic processes, and that they take
place wherever the chloroplasts are found. Their wide distribu-
tion, however, shows us that there is not a specially differentiated
member of the plant set apart to be an organ for this function.
In the same way, a catabolic process, the digestion of stored
products, goes on wherever there are reservoirs of such bodies,
and there, and there only, unorganised ferments or enzymes are
found, instead of being located in particular glands, as in the
animal body. These reservoirs, we have already seen, and shall
see again later, are found in the most varied regions of the
plant’s substance—regions, moreover, which vary considerably
in different plants.

Starting, then, with the intricacy of the metabolic processes
placed before us, and with their relations to each other, we may
begin the consideration of them in detail with an inquiry into
the introductory absorption of the materials from which the
food is ultimately made. Even here we meet with some com-
plexity, as the ordinary green plant shows marked differences in
behaviour from its parasitic relation, and from the great class
of fungi, which possess no chlorophyll. It will be best to con-
sider first the ordinary terrestrial green plant, noticing in passing
differences in behaviour shown by aquatic and epiphytic forms.
435

CHAPTER VI.

THE ABSORPTION OF FOOD MATERIALS BY A GREEN PLANT.

WE have seen that the materials which protoplasm is eventually
able to assimilate, and which, therefore, constitute its food, are of
asimilar nature to those deposited in seeds and other storehouses
of nutriment which are variously disposed in its substance. We
know, further, that these are not the materials which an ordinary
green plant takes into itself from the environment in which it
lives. On the contrary, we know that its structure prevents its
taking in anything solid, but that it is continually absorbing
liquid by means of its roots. Between the raw materials that
can be so absorbed and the complex products which are needful
for the nutrition of its substance there is a great difference, and
the manufacture of these latter from the raw materials taken in
constitutes a very important part of the metabolic processes.

To ascertain what this work of construction consists of, we
must find out what elements the substance of the plant and the
true nutritive matter contain, how these are supplied to the plant,
and what work is done upon them in its cells.

As already noticed, the structure of the plant demands that all
the materials of a solid character shall be in such a form of
solution that they can enter its substance by means of the
physical process of osmosis, modified as we have described.
This is equally true of gases, of which there is considerable
absorption by all plants, whatever be the nature of their habitat.

The details of absorption vary to some extent, however,
according to the environment of the plant. Aquatic plants can
absorb water and whatever is dissolved in it, whether of gaseous
or solid character, by all parts of their surface. Those which
grow with their roots embedded in soil and their shoots exposed
to the air show a certain division of labour in this respect. The
mineral constituents obtained from the soil are taken in by the
roots with the stream of water; those of a gaseous nature mainly
find entry through the leaves and other green parts.

If we examine the food stuffs described as being essential, we
find that proteids contain carbon, hydrogen, oxygen, nitrogen,
sulphur, and perhaps phosphorus. Carbohydrates and fats con-
tain only the first three of these elements. A destructive analysis
of the plant, made by burning it, shows that it contains others

also; for after all the volatile products of combustion have been
rR
436 MANUAL OF BOTANY

driven off, a certain inorganic residue is left, which is composed
of several metals and some other elements. An analysis of this
residue, which is spoken of as the ash, will not, however, tell us
in what condition these different constituents exist in the living
plant, on account of the various chemical changes which go on
during the combustion.

The ash of plants is found, when analysed, to contain always
the four metals—potassium, magnesium, calcium, and iron.
These are not present in the metallic condition, but in combina-
tion with various acids, forming nitrates, sulphates, chlorides,
carbonates, phosphates, &e.

Besides these, various plants may individually contain greater
or less quantities of many other elements variously combined.
We find sodium very generally present; less frequently so
aluminium, copper, zinc, manganese, silicon, bromine, iodine,
and others. Indeed, the composition of the soil in which a
plant grows determines to a very great extent what minerals
enter it. If a substance is soluble in the liquid which the root-
hairs absorb, a certain quantity will, by ordinary physical pro-
cesses, be taken up by them.

The quantity of each substance a given plant will absorb
will depend upon whether the plant makes use of it in any way.
If so, it will be quickly removed from the absorbing cell and
more will enter. If not, the cell-sap of the absorbing root-hair
will soon have taken up as much of it as it can contain, and the
absorption of that particular substance will cease.

Some of the materials found in the soil are readily soluble in
the water which the soil contains. Such can enter the plant
without difficulty. Others are soluble only in water containing
CO,, and as considerable quantities of this gas are continually
being generated in the soil, the water there is charged with it,
and bodies, otherwise intractable, are thereby brought into solu-
tion and absorbed. A third factor in the process of absorption is
the acid sap which the root-hairs contain. Not only does this
acid cause water to enter osmotically, but a little of it exudes in
the same way, and this has a certain solvent action upon the
particles to which the root-hairs cling. Thus certain salts can
be absorbed, though soluble neither in pure water nor in water
containing CO,.

The solutions taken in are excessively dilute. There is,
however, a certain relation necessary between the substance and
the water, for we have already noticed that strong solutions
cannot pass the lining layer of protoplasm. Every salt is taken
ABSORPTION OF FOOD MATERIALS 437

up in a certain strength of solution, or, in other words, with
each molecule of salt there is a certain invariable quantity of
water absorbed. The quantity is not the same, however, for
each salt.

The salts which different plants absorb, in like manner vary
as to amount. If two different species are growing in the same
soil, side by side, under exactly the same conditions, the amounts
of the several salts present in the soil which are absorbed by the
two plants will not be the same. In each case the quantity will
vary according to the use which the plant can make of it.

Conversely, if the same soil contains several different salts,
a plant will not absorb them in equal proportions, nor in those in
which they exist in the soil. This fact admits of a similar
explanation. Again, the absorption of a salt will cease as soon
as the cell-sap contains the same amount of it as the fluid out-
side the root-hair. In this case there will be no osmotic action
so far as the salt is concerned, though there may be a continuous
amount of water entering the hair.

We have seen that the continuous absorption of water by
the root-hair will depend upon certain external conditions, such
as the temperature of the soil, the activity of transpiration at
the time, &. These conditions affect also the absorption of the
substances in solution.

The substances which are absorbed in this way by the roots
are naturally very varied. The most important of them in
the metabolism of the plant are the compounds of nitrogen. In
the soil these exist in the form of nitrates or nitrites of the
metals mentioned, and as compounds of ammonia. Green
plants take in little or none of the latter, which are, however,
made available for their use by the action of certain bacteria
which the soil contains, which have the power of converting the
ammonia compounds into nitrites and the latter into nitrates, in
which form they are taken up. This process of nitrification
is the special property of two of these organisms, one of which
forms nitrites from the ammonia compound, and the other forms
nitrates from nitrites.

It is in this way that a normal green plant absorbs all the
nitrogen which it uses for the construction of food substances.
The nitrogen of the air is made use only of in very exceptional
cases. Certain lowly Alge seem to have the power of using it,
but the process is not fully understood. A few plants belonging
to the Leguminose can also use atmospheric nitrogen, but their
power depends upon the association with their roots of certain
438 MANUAL OF BOTANY

fungi which infest the cortical tissues and develop peculiar
tubercular structures upon the roots. The actual mode of absorp-
tion in this case also is obscure; the parts played by the root
and the fungus respectively are not at all determined.

The water taken up is the main source of the hydrogen and
oxygen which are used in the anabolic processes. A little of
both these gases is taken in in the several combinations of the
metals; sulphates and phosphates contain both, nitrates and
carbonates contain oxygen. The amount of them absorbed in
these forms is, however, relatively small. The other elements
mentioned enter the plant in various combinations in the water
stream.

The gases present in solution in the water of the soil also
make their way into the root-hairs with the stream, but the
quantity is very slight compared with what is absorbed by the
aerial parts. The gas CO,, which we have seen to be present in
the earth in considerable amount, is, however, not made use cf
in the anabolic processes. All of this particular food material is
taken in from the air. A little carbon is absorbed in the form
of carbonates. More complex organic compounds of carbon are
taken in by those roots with which fungi are living symbiotically,
such as the mycorhiza of some trees, but this is exceptional.

The absorption of gases from the air takes place in the
leaves and other green parts. They enter freely through the
stomata and find their way thus into the intercellular spaces,
which are very numerous. These intercellular spaces contain
a mixture of gases which, though approximating to the com-
position of atmospheric air, yet differs from it in the relative
quantities of the constituents. This can be readily understood
from the consideration that considerable gaseous interchange
goes on in these spaces between the air they contain and the
living cells which abut upon the spaces. The cell-walls here
are very delicate and thin, and are saturated with water. In
this water the different gases present dissolve according to their
degree of solubility. The quantity of each taken up depends, as
in the case of the metallic salts just discussed, upon the ability
of the cells to make use of the gas. If it can be combined in
any way with other bodies in the cell, it is withdrawn thus from
the sap and room made for more to enter. If not, the limit of
saturation of the sap is soon reached.

Probably little or no absorption of gas takes place through
the cells of the epidermis, though they are freely in contact with
the air. Sections show us that they are provided usually with a
ABSORPTION OF CO, 439

cuticle, which resists any such solution as is necessary for
absorption.

The only gas which is absorbed as a food material from the
air is carbon dioxide, CO,. This exists to a very slight extent in
the atmosphere, only about four parts in ten thousand being
normally present. The very large green surface which an
ordinary terrestrial plant possesses renders, however, a consider-
able amount of absorption possible. If the general conditions
are favourable, the absorption is continuous, for CO, is at once
decomposed in the cells of the green tissue, and so a stream is
always entering.

Both nitrogen and oxygen are soluble in water, though to a
different extent. It has been already stated that the nitrogen so
taken in is not used in the constructive processes, and accord-
ingly but little is absorbed in this way. The oxygen which
enters is larger in amount; experiments have proved, however,
that it is not a food material, but is used for other purposes.

The absorption of CO, takes place usually at the ordinary
atmospheric pressure or at one a little greater. Plants can,
however, absorb this gas when it is present in much larger
proportion than it is in air. Too much is, however, possible,
and then the cells are unable to take it in at all. The absorption
of CO, is possible only under certain conditions; the cells which
contain chloroplasts are the only ones which can take it in in any
quantity, and they only when they are exposed to sunlight, prefer-
ably a bright light, and when the plant is maintained at an
appropriate temperature. Its absorption is accompanied by the
evolution of a volume of oxygen, which is equal to the volume
of CO, absorbed, and it is attended by a continuous increase
in the weight of the plant.

We have seen that the water absorbed by the roots is trans-
ported regularly through the axis of the plant until it reaches
the leaves, in which after traversing the cells of the mesophyll
it is evaporated into the intercellular spaces. Into these cells
of the interior of the leaf all the food materials are thus at
once transported, both those entering from the soil and those
absorbed from the air. These mesophyll cells have generally a
different arrangement on the two sides of the leaf, but they all
agree in containing chloroplasts. In these cells takes place the
work of construction of organic substance, such as the plant can
live upon, work which is carried out mainly through the instru-
mentality of the chloroplasts.

As already noticed, various elements are constantly found in
440 MANUAL OF BOTANY

plants which do not enter into the composition of the actual
nutritive substances. The part that many of them play is
obscure ; indeed some of them, as sodium, seem to be quite
useless. Some play a secondary part in protecting the plant
tissues in various ways from destructive influences, some
euter possibly only as the medium by which the combined
nitrogen, sulphur, and phosphorus are absorbed. Others,
especially potassium, calcium, magnesium, and iron, have a part
to play in enabling the more important elements to be worked
up into nutritive material.

In the cases of some green plants these processes of absorption
are supplemented by others. In several Natural Orders there
are species which are semi-parasitic in their mode of life.
Though they possess leaves, stems, and roots, they do not live
entirely at thelr own expense, but certain of their roots pene-
trate the tissues of the roots of other plants near which they
grow. The degree of this root-parasttism varies a good deal
in the different groups. These plants supplement the processes
we have just described by drawing elaborated food material
from the host which they have attacked.

The pitcher plants, Nepenthes, Sarracenia, &c., and the fly-
catching plants, Drosera, Dionea, and others, can also absorb
nitrogenous material by the special mechanisms which they
possess. In the pitchers of Nepenthes, &c., there is an accumu-
lation of water in which insects are from time to time drowned.
Their bodies decay or are digested, and the products of the
decomposition are absorbed by the tissue of the pitchers. The
flies and other insects captured by Drosera and its allies are
similarly disposed of.

CHAPTER VII.
THE CHLOROPLASTIDS AND THEIR FUNCTION.

WE have seen that the different materials out of which the food
of the plant is constructed are carried by various means to the
cells of the parenchyma of the mesophyll in which chloroplastids
are present. The chloroplastid is a small differentiated body
consisting of protoplasm in the meshes of whose substance a
green colouring matter, chlorophyll, is contained in some form
of solution. Alcohol, chloroform, ether, benzol, and other liquids
can disgolve the chlorophyll and leave the plastid colourless.
ACTION OF CHLOROPHYLL 441

Chlorophyll is not soluble in water, nor can it be extracted with
acids or alkalies without alteration.

A solution of chlorophyll in any of the liquids mentioned
shows the curious property of flworescence; if regarded by
transmitted light it appears green, but if a strong solution is
looked at by reflected light it has a blood-red coloration.

If a solution of chlorophyll is placed in the path of a beam
of light which is then allowed to fall upon a prism, the
resulting spectrum is found to be modified. Instead of showing
a continuous band in which all the colours are represented, it
is interrupted by seven vertical dark spaces. The rays which
in the absence of the solution of chlorophyll would have occupied
those spaces have no power to pass through it, or, in other words,
chlorophyll absorbs those particular rays of light which are
missing.

In fig. 1186 is a representation of the spectrum, called from
the facts just narrated the absorption spectrum. The first band
on the left is the darkest, and is found to be in the red part of
the spectrum. The three bands on the right are broader, but
not so well defined. They cover nearly all the blue end. The
three thinner and lighter bands are in the green and yellow
parts of the spectrum. Chlorophyll therefore has the power of
absorbing a large amount of red rays, a good many blue and
violet ones, and a few of the green and yellow. The distinctness
with which the absorbtion bands are seen will depend upon the
strength of the solution, the red and blue being, however, always
prominent. :

Careful chemical experiments have proved that chlorophyll
is a single pigment, and not a mixture of two as has often been
stated. It is, however, very easily decomposed, and the products
of its decomposition are generally found with it in the chloro-
plastid. One of these, Xanthophyll, which is of a bright yellow
colour, is always extracted with the chlorophyll by alcohol. It
‘can be separated by appropriate treatment.

Chlorophyll is formed in the chloroplastids only when they
are exposed to light, except in one or two rare cases. When a
plant is grown from a seed or a tuber in the dark, the resulting
stem and leaves are not green, but of a peculiar yellowish-white
appearance. Nor can it be developed in the absence of a suit-
able temperature. Its formation has been found to depend
upon the presence of iron in the plant, but the exact relation of
the iron to the pigment is not known; it does not appear to enter
into the composition of the latter.
442 MANUAL OF BOTANY

The construction of organic substance proceeds in the cells
of the mesophyll containing the chloroplastids and supplied with
the raw materials in the way described in the last chapter. It
can, however, take place only under the influence of light, and
while the cells are at an adequate temperature. The complex pro-
ducts of the anabolic process are at first mainly, if not entirely,
confined to two classes, carbohydrates, and some nitrogen-
containing compound, probably proteid. Many other forms of
organic substance appear in plants, such as fats or oils, gluco-

Fie. 1186.

19

-

G
60 !
1

q

ia

!
i

 

Vv

fig. 1186. Absorption spectra of chlorophyll and xanthophyll. (After Kraus.)
The upper spectrum is given by an alcoholic extract of leaves, the middle
one by dissolving chlorophyll in benzol, and the lowest by xanthophyll.
The bands in the least refrangible portion, B-5, are figured as obtained
with a concentrated solution ; those in the most refrangible part of the
spectrum, F-G, are given as obtained with a weak solution, The letters
B-G indicate the principal rays, the numbers J-vu the absorption bands
of chlorophyll from red to violet, and the figures 0-100 divide the length
of the spectrum into 100 equal parts. (After Sachs.)

 

sides, &c., but these are probably all produced by processes of
catabolism, and are not directly constructed from the simple
bodies absorbed.

We will examine first the process of formation of carbohy-
drates. These consist of the elements carbon, hydrogen, and
oxygen, the latter two existing in the combination in the same
proportion as they do in water. The source of the carbon and the
oxygen is the CO, absorbed from the air, while the hydrogen is
derived from the water of the cell-sap.
ACTION OF CHLOROPHYLL 443

When carbon dioxide is exposed to the influence of the chloro-
plastid in the presence of light and moderate warmth, it under-
goes a decomposition which may probably be expressed by the
equation 2C0,=2C0+0.,, splitting up into carbon monoxide
and oxygen. At the same time, water is decomposed, probably
in the way denoted by the equation 2H,O =2H,+0,. The two
molecules of oxygen unite and are evolved, the quantity being
the same as the quantity of CO, undergoing decomposition. The
two residues, 2CO and 2H., are then thought to unite to form
2CH,0, a body known as formic aldehyde. It is a property of
the aldehydes to undergo readily what is known as polymer isa-
tion or condensation of several molecules together. Such a
condensation of formic aldehyde would lead to the formation
of sugar thus,—6CH,0 =C,,H,,0,; and it is probable that this
process takes place. At any rate, sugar is present in the meso-
phyll cells very speedily after the absorption of the CO, and
the beginning of the exhalation of oxygen.

These processes are carried out by the chloroplastid under
the conditions set forth. It is evident that such changes as the
decomposition of CO, and water cannot be accomplished without
a good deal of energy being expended upon them. In this need
we have the explanation of the composite nature of the plastid.
The chlorophyll absorb. certain of the rays of light that fall upon
it, and the energy so acquired is applied by the protoplasm of
the plastid to effect the decompositions that take place. Sugar
is the result, though what kind of sugar is first formed is still
open to experiment. There is a fairly copious and continuous
production of it, indicating, as in the case of the raw materials
and the cells which absorb them, that there must be a removal
of itas itis formed. Otherwise the cell-sap would be saturated
with sugar and its formation would cease. The quantity which
is in excess of the immediate needs of the cell may either be
transported away from it by diffusion, or some of it may be con-
verted into an insoluble form and be temporarily deposited in
the cell. The latter operation is carried out by the plastid,
which quickly forms small granules of starch in its own sub-
stance, at the expense of some of this surplus sugar. The starch
can readily be detected in sttw by treating the leaf with iodine,
after bleaching it by soaking it in aleohol. This appearance of
starch was formerly held to be the last stage in the ordinary
anabolic processes, but as starch must be re-converted into sugar
before protoplasm can use it as food, its occurrence is now held
to be a case of what we shall see is a very usual thing in plants,
444 MANUAL OF BOTANY

the accumulation of food material in various parts, to be there
held in reserve till the plant requires them.

It is not certain that the process of construction of carbo-
hydrate is so simple as what has been said would imply. There
are many other chemical compounds in the cell while it is pro-
ceeding, and to what extent they take part in the matter is not
known. It is held that some compound of potassium, at any
rate, is concerned in the process, for in the absence of this metal
sugar. does not appear to be formed.

The formation of the proteid bodies in the cells is not at all
well understood ; indeed, but little is known certainly about it.
The nitrates are absorbed and taken to the mesophyll cells. In
these cells and in others about the plant, bodies occur of com-
paratively simple composition, though much more complex
than nitrates. These, which are known as amides, include as-
paragin, leucin, and several others. Probably they are the first
bodies constructed from the nitrates, though in many cases they
arise from the decomposition of proteid and not from anabolic
processes. It is in the form of these bodies generally that
organic nitrogenous matter travels about the plant. From them
most likely proteid is constructed, compounds of sulphur and of
phosphorus in the cells supplying those elements, which, as we
have seen, are probably both in the molecule of proteid. Cer-
tainly sulphur enters into its composition.

Again there is reason to think that the carbohydrate manu-
facture is associated with the nitrogenous one. Proteid can
apparently only be formed under the same conditions as carbo-
hydrate, though we cannot say that chlorophyll is directly con-
cerned. If a shoot is not exposed to light, there will be an
accumulation of asparagin in its tissues; the same thing will be
observed if CO, is excluded from access to it. Indeed, if carbon
assimilation is prevented, nitrogenous material cannot be formed.

The proteids, if formed in the leaves, as is probably the case,
are affected just as we have seen the carbohydrates to be. They
undergo a partial decomposition, and their nitrogenous residues
leave the cells in the form of amides. Their further fate will be
examined later.

The proteid, which is the most complex body known to exist
in the plant with the exception of the living substance itself,
cannot at present be represented by any chemical formula.
Analyses of the purest forms of it point to its percentage compo-
sition lying within the following limits :—
THE VARIOUS KINDS OF PROTEIDS 445

Carbon 50°0 to 55:0
Oxygen 22°38 ,, B41
Nitrogen 15:0 18°2
Hydrogen . se,
Sulphur. ‘ O4 4, 05

There are several classes of these bodies known, the differ-
ences which they show depending chiefly on their solubilities in
different liquids. The best known groups are the following :—

1. Albumins. These are soluble in distilled water, and if the
solution be heated the proteid is converted into a peculiarly
insoluble form, known as coagulated proteid, and deposited.
Albumins can be precipitated unchanged by saturating their
solutions with sodio-magnesic sulphate. Their coagulation
temperature ranges from 70° to 80° C. They are not of
common occurrence in plants, but may be extracted from
certain roots.

2. Globulins. These differ from albumins in not being soluble
in distilled water. They can be dissolved by adding a little
neutral salt, such as sodium chloride. Their solutions are
coagulated on heating, and they can be precipitated by satu-
rating them with magnesic sulphate. There are many
members of this class, which differ from each other by
varying solubility in different strengths of the salt solution.
Their coagulation temperatures vary a good deal, some
being changed at about 55° C. and others not till about
75°—80° C.

The proteids found in plants chietly belong to this
group. They can readily be extracted from most seeds.
Probably this form is the one which occurs in the meso-
phyll cells.

8. Albuminates, or derived albumins. These are soluble in
weak acids and alkalies, but their solutions do not coagu-
late on boiling. They can be precipitated by carefully
neutralising the solution.

4. Albumoses. These are soluble in water, and do not
coagulate on heating. Their characteristic reaction is that
they give with nitric acid w precipitate which dissolves on
warming the liquid, and reappears as it cools.

5. Peptones. These are much like albumoses, but do not
give a precipitate with nitric acid.

The members of the last two groups are capable of dialysing
through membranes, which those of the first three cannot do.
446 MANUAL OF BOTANY

The peptones dialyse with far greater ease than the albumoses.
They do not occur very plentifully in plants, and are probably
formed in them only from the decomposition of the more stable
forms of globulin and albumin. Some of the albumoses occur in
certain seeds in association with some of the globulins.

By the action of peculiar secretions of the protoplasm, be-
longing to the bodies known as enzymes or unorganised ferments,
the globulins and albumins can be decomposed, with formation
successively of albumoses, peptones, and amides such as
asparagin and leucin.

It has been considered by some botanists that the sieve-tubes
or their companion cells are the places where the construction
of proteid is completed, only the amides being formed in the
leaves. It is, however, possible that this construction is, like
that of the deposition of starch in the chloroplastid, rather the
expression of the temporary deposit of proteid in those cells at
the expense of the surplus formation, which, not being needed
in the cells of the mesophyll, is converted into aniides and so
transported from the leaf. A certain amount of proteid can be
extracted from the living cells which are the seat of the original
anabolic processes.

The importance of the inorganic salts which do not enter
into the composition of the living plant-substance is very im-
perfectly understood. Potassium is apparently necessary for
the construction of carbohydrate matter by the chloroplastids.
It is generally absorbed in combination with sulphuric, nitric,
and hydrochloric acids, and can be found in the plant in com-
bination with organic acids such as tartaric, oxalic, and malic.
It is generally found in quantity in places where starch and sugar
are stored.

Calcium and magnesium are absorbed in similar combina-
tions, but their function has not been ascertained. The former
appears to be concerned in the transport of carbohydrates from
place to place. Both are of service in neutralising such acids
as oxalic, the presence of which in quantity is deleterious. We
frequently find in cells, and in some cell-walls, crystals of oxalate
of calcium.

The importance of iron has been pointed out in connection
with the action of the chlorophyll.

Most of the other elements absorbed seem to be without
effect on the metabolic processes.
447

CHAPTER VIII.

RESERVE MATERIALS, AND THEIR DEPOSITION.

WE have seen that the amount of food constructed in the
mesophyll cells from the crude materials absorbed is often con-
siderably in excess of their immediate need. A certain amount
is, no doubt, used up at once by the living substance of each
cell, the assimilation of the food being the culmination of the
anabolic processes, as protoplasm is the most complex material
existing in the plant. The remainder is otherwise disposed of;
no doubt a certain quantity is always retained in the cell to
supply the needs of the protoplasm when actual construction is
intermitted. Evidence of the temporary accumulation of a local
reserve store is afforded by the occurrence of the starch grains
which the chloroplastid forms inside its own substance. A
great deal of the manufactured organic matter is, however, con-
stantly leaving the cells in which it is formed, and passing to
other parts of the plant. Even the temporary accumulation of
starch soon disappears; if a plant, which has been vigorously
forming it in its chloroplastids during a summer's day, so that
at evening there is a great amount deposited there, is examined
early next morning, the leaves are found to be devoid of
starch. This is not brought about by its having been used
during the night, for if the path of removal is obliterated, as it
may be by severing the petiole, the leaf is found as full as on
the previous evening.

Evidently, then, the surplus food manufactured in the
mesophyll is transferred from the seat of its elaboration to other
parts of the plant. To bring about this removal of the starch and
interentially that of the proteids, a certain alteration of them
must be effected, the mechanism of which will be discussed
later. The starch is converted again into sugar, and possibly
some of the sugar may be further changed, though, no doubt,
sugar is the general form of the travelling carbohydrate. The
sugar which has not been transformed into starch may travel
as it is, or some modification of it, still a sugar, though of
another description, may be formed. That sugar is readily re-
moved from the leaf may be inferred from several considerations.
We can find but little of it in the mesophyll of the leaf, though
we know it is constantly being produced. We do find it, however,
fairly easily in the bast of the fibro-vascular bundles of the leaf,
448 MANUAL OF BOTANY

and if a leaf is cut off from the stem while construction is
going on, it can very soon be detected in the mesophyll cells as
well.

Proteids are probably gradually broken down into amides,
such as asparagin, which, being a readily diffusible body, can
pass through the cell-walls.

These elaborated materials, in their passage from the leaves,
travel by the bast and not by the wood. The carbohydrates
and the amides probably go by the parenchyma. The sieve-
tubes differ from the latter in containing « quantity of proteid
material, and it is at least possible that proteid as such may
travel by them. If so, it is probably reconstructed in the sieve-
tube from the amides, &c., which are being transported from the
mesophyll. A certain amount of carbohydrate also may go this
way.

That the stream of elaborated food is transported by tissues
external to the wood appears clear from the fact that if an
incision is made round a branch or trunk of a tree and a small
ring be removed, extending inwards as far as the wood, the
growing parts below the wound dwindle and die, while those
which leave the axis above the incision become more luxu-
riant.

Even along the path of the stream we find the same ten-
dency to temporary deposition which we noticed in the chloro-
plastids. If the progress of the stream is checked from any
cause, we find a temporary accumulation of starch near the
point of stoppage, which disappears when the flow again asserts
itself.

The direction which the food substances take is dependent
upon many circumstances. When growth is active in any
part, whether an apical meristem or a cambium layer, the stream
is directed towards such seat of consumption. This is due to
a process of diffusion set up in consequence of the removal of
constructive material from the stream by the growing cells, and
the consequent weakening of the solution there. When there is
more produced than is sufficient to supply an immediate demand,
the surplus is deposited in some part or other of the plant, to
supply future needs. There is thus continually going on during
active life a storage of surplus food substances in places which
we may call reservoirs of reserve materials. In some cases
they are again very speedily removed, but in others they remain
there for a considerable time.

The nature of these reservoirs is very varied. Seeds, tubers,
FORMATION OF STARCH-GRAINS 449

bulbs, corms, fleshy roots, and other similar structures are pev-
haps the most easily examined. In seeds the reserve materials
are deposited for the support of the young embryo, which will
need them at the onset of germination. Tubers will require
them for the support of the young shoots to which they give
rise. Fleshy roots have to support a vigorous outgrowth after
the expiration of winter. In the axes of woody plants we find
stores laid up in sheaths of celis, such as the endodermis or
pericycle, or in the medullary rays existing in the secondary wood.

In these reservoirs the stored substances are deposited
in an insoluble form, or at any rate in a shape which is not
suitable for rapid transport. In most plants the reserve carbo-
hydrates are stored in the form of starch grains, which gene-
rally differ from those in the chloroplastids by their larger size
and apparent complexity of composition. They are formed at
the expense of the sugar of transport, usually by special bodies
known as lewcoplasts from their white colour. These bodies
are very much like chloroplasts, except that they contain no
chlorophyll. The leucoplast appears to absorb the sugar and
pour out starch from some part of its surface. Layer after
layer is so excreted, till « recognisable starch grain is produced,
which shows the manner of its growth by faint striation of its
surface, the strie showing the limits of the successive lamelle
laid down. In some cases the lamelle are strictly concentric ;
in others, as in the potato, the end next the leucoplast gradually
becomes broader and broader, so that the shape somewhat
resembles that of an oyster-shell. Fig. 1187 shows a group of
leucoplasts actively forming starch grains. ig. 1188 shows the
striations of the complete grain.

Some grains often found in the potato are not so simple in
their structure. These are represented in figs. 1189 a and B. The
former usually arise by two or more originating in the interior of
the leucoplast; as they grow they become closely pressed to-
gether and constitute a compound grain. Fig. 1189 B. shows what
is often called a semi-compound grain. In such a formation the
leucoplast produces two grains on opposite sides, and as they
increase they come into contact. The leucoplast is so reduced
to a ring surrounding them at their point of union, and its con-
tinued activity then forms new layers surrounding the whole.
The leucoplast is gradually used up in its activity and disappears,
leaving the grains of starch free. Many variations of its
behaviour have been noticed in different cases

Besides this formation of large starch grains by leucoplasts

VOL. II. GG
450 MANUAL OF BOTANY

we have many cases in which the deposition of starch is effected
by the protoplasm of the cell. Such grains are generally very
small, and show no structure. Instances of their occurrence have
been already given. They are generally seen in the interior of
the plant in reservoirs which are only temporary. ;
Carbohydrate materials are deposited in other forms in
many plants. The root of the beet (Beta vulgaris) contains
large quantities of cane sugar, as do the stems of the sugar-
cane. The bulb-leaves of the onion abound in grape sugar.
Many fruits contain different kinds of sugar. Inulin is stored
in the tubers and tuberous or fleshy roots of many of the Com-
posite. Glycogen occurs in the hyphe of many of the Fungi.

Fie. 1187. Fie. 1188.

   

fig. 1187. Group of rod-like leuco-
plastids, 7, each bearing a starch-
grain, s, collected round the nu-
cleus, 7, of a cell of the pseudo-
bulb of an Orchid (Phajus grandi-
folius). x 600. (After Schimper.)
fig. 1188. Potato - starch
(x 250), —— Fig. 1189. a. Com-
pound; 3B. Semi-compound gra-
nule of starch.

 

  

In many Palms the carbohydrate is stored in the shape of cellu-
lose, the walls of the endosperm of the seeds being enormously
thickened. The cellulose is here formed by the protoplasm
of the cells, in the same way as is that which constitutes the
thickening layers of the cell-walls of the vegetative part of the
plant.

The mechanism of the storage of sugar is not accurately
known, but we may argue from analogy that it is brought about
by the living substance of the cells, by which also, though
diffusible, it is no doubt retained within them.

Proteids are stored similarly; in the meshes of the proto-
plasm of all cells there is a certain accumulation in amorphous
COMPOSITION OF ALEURONE GRAINS 451

form. In many seeds they are deposited in the form of grains of
complex nature, and sometimes of elaborate structure. Grains of
proteid material are known as alewrone grains. Sometimes they
are small, rounded and structureless, as in the Pea (jig. 1190).
In other seeds, as in the castor-oil plant, they are much larger,
of rounded or ovoid form, and contain a crystal of proteid matter,
which often occupies nearly their whole substance (fig. 1191).
This has been called a crystalloid. There is in such cases also a
small aggregation of mineral matter which lies close to the
crystal. This is known as a globoid, and consists of a double
phosphate of calcium and magnesium.

The proteids of the aleurone grain are generally mixtures of

Fie. 1191.

  

fig. 1190. Cells of a very thin section through a cotyledon of the embryo in
a ripe seed of the common Pea (Pisum sativum). a,a. Aleurone grains.
st. Starch granules. ?, 7. Intercellular spaces. (After Sachs.) —— F7y, 1191.
Cell from the endosperm or albumen of the seed of the Castor-oil plant
(Ricinus communis) in dilute glycerine, showing large transparent proteid
or aleurone grains, with crystalloids and globoids embedded in them.
(After Sachs.)

globulins and albumoses, the latter being least in quantity. If
a section of a castor-oil seed from which the oil has been
removed, be irrigated with water, a part of the outer substance
of the grain is dissolved, leaving still an ovoid body, in which
the crystal, or crystalloid, can be seen. The part dissolved
consists of the albumose, which is soluble in water. If the
section be then irrigated with a ten per cent. solution of common
salt, the body of the grain dissolves. This is composed of a
particular globulin. The crystalloid will dissolve if it be
treated with a saturated solution of the same salt, showing it to
be made up of another globulin.

Other aleurone grains show other peculiarities of solubility,

G@Ga2
452 MANUAL OF BOTANY

but probably no other kind of proteid is usually present. Some,
however, are thought to be composed of albuminates, as they
dissolve only in potassic or sodic hydrate, or other alkalies.

The aleurone grains are frequently associated in the cells of
the seed with either starch or oil. Occasionally both these
compounds are present.

In other cases the reserves of proteid are crystalline in
structure. Crystals of this character are easily found in the
tuber of the potato, lying in the cells very near the epidermis.
They are also, met with in the thallus of certain seaweeds.
Many of them can be made to crystallise from the solvents
which are used to extract them.

The mode of formation of these aleurone grains is still not
certainly known. Some authors regard them as deposited by
a process something like crystallisation following the abstraction
of water from the cell. Others have described their formation
as one of secretion by the protoplasm. The latter view seems
the more probable one.

Fats or oils occur copiously in certain seeds, such as thoge
of the castor-oil plant (Ricinus communis), the Brazil-nut
(Bertholletia excelsa) and others. They are found also in the
cells of the floral leaves of many plants, and in many fruits.
They are probably formed by the protoplasm, originating in
small droplets in its meshes, which as the fat accumulates run
together, till the cell is saturated with it. In some plants
certain plastids have been described as forming oil, much as the
leucoplasts do the starch grains. These bodies have been called
elaioplasts.

Other reserve materials are known which are not so wide-
spread as those already described. Such are the glucosides
found in many of the Rosacex, the Crucifere, and allied orders.
These are bodies which when decomposed give rise to a sugar,
and various other bodies usually belonging to the so-called
aromatic compounds. Amygdalin, found in the Cherry Laurel
(Prunus Lawroccrasus), may be mentioned as an example.
When split up by chemical means, it gives rise to sugar,
benzoic aldehyde, and hydrocyanic acid.

All these bodies, when acted upon by a process analogous to
the digestion known in the animal kingdom, ure converted into
materials which can directly nourish the living substance, or
can be transported easily about the plant in a condition of which
the latter can readily take advantage, needing indeed very little
constructive change to fit it for actual assimilation.
4538

CHAPTER IX.

DIGESTION OF RESERVE MATERIALS.

WE have noticed in following the deposition of reserve materials
that their permanent form differs from that which they assume
for purposes of transport. They are generally insoluble, and almost
always indiffusible, whereas they travel in the form of soluble,
diffusible bodies. The removal of them from the seats of storage
takes place at times dependent on the resumption of activity of
growth or development; and as this removal is dependent upon
the same methods of transport, they must undergo a process
which, from analogy with similar processes in the animal body,
may be described as digestion. They nist, after such treatinent,
be presented to the protoplasm of the growing cells in much the
same form or condition as that in which they were first con-
structed from the simple bodies absorbed.

There is no special region in the plant where digestion takes
place. It may be looked for in any cell in which any form of
reserve material is deposited.

We have seen again that in a few rare cases nitrogenous
material is absorbed into the plant body through certain leaves
or modified foliar organs. The insectivorous plants are
materially assisted in their growth by capturing and digesting
various insects. Drosera does this by means of its sticky leaves,
which are furnished with peculiar outgrowths, which bend over
and imprison any small insect which alights upon them. The
leaf is covered with a sticky or glutinous secretion, which is
poured out from these so-called tentacles, and the insect becomes
entangled therein. The tentacles then close over the insect and
emit a fluid which has the property of digesting the dead bodies so
imprisoned, rendering the nitrogenous matters capable of absorp-
tion by the leaf tissue. Dzon@ea imprisons any insect visitors
by a different mechanism, and digests them by a similar secre-
tion. Many other plants have a similar power. Some plants,
such as Nepenthes and Sarracenia, are furnished with large
pitchers, which are modified leaves. These contain a watery
fluid, and insects falling into the liquid are drowned. Their
bodies become decomposed by the aid either of a secretion
from glands in the leaf, or by the action of bacteria, and the
pitcher absorbs into its tissues the nitrogenous products of the
decomposition.
454 MANUAL OF BOTANY

We have, then, to inquire how these processes of digestion,
whether internal or external, are brought about.

The protoplasm, among its many properties, no doubt has
the power of setting up these decompositions, and probably in
many of the lowest forms the work is altogether effected by its
instrumentality. Indeed, in every cell of a complex plant the
living substance is in a constant state of change, initiating many
decompositions in which its own substance takes part, and many
others into which it does not enter itself.

Though all protoplasm has this power, it is not usual in
plants, any more than in animals, to find it exclusively relying
on it. Usually the work is done by peculiar bodies which it
forms or secretes for the purpose. We have in plants a large
number of these secretions, which are known as enzymes or
unorganised ferments.

The action of these bodies is not at all completely under-
stood. They appear to take no part in the composition of the
bodies which are formed by their activity, and they seem
capable of carrying out an almost indefinite amount of such
work, without being used up in the process. They are inactive
at a very low temperature, but effect their decompositions freely
at the ordinary temperature of the plant. As the temperature
rises their activity increases up to a certain point, which varies
slightly for each enzyme, and is called its optemum point. It
usually ranges between 30° and 45°C. If the temperature be
raised above that point, the enzymes become less and less active
as it rises, and at about 70°C. they are destroyed. They work
best in darkness or very subdued light; if exposed to bright
sunshine they are gradually decomposed. They are often in-
juriously affected by neutral salts, alkalies, or acids.

The enzymes are manufactured by the protoplasm of the
various cells in which they occur, being produced from its own
substance, in a manner somewhat similar to that of the forma-
tion of the cell-wall. Usually their presence is manifested by
a marked granularity of the protoplasm, due to the formation in
it of an antecedent substance, known as a zymogen, which is
readily converted into the enzyme.

We find various degrees of completeness of differentiation of
the cells which produce these enzymes. In the simplest cases,
such as the mesophyll of the leaves of most plants, or the seeds
of the Leguminose and other Natural Orders, or the tubers of
the potato, the enzyme is found in all the cells which contain
the reserve materials, so that an active transformation of the
SECRETION OF ENZYMES 455

latter is readily possible. In the horse-radish and many allied
plants, the cells which form the enzyme do not themselves con-
tain any reserve materials, but are situated amovg those which
do, giving us as it were the starting-point of glands proper, whose
special function it is to secrete these ferments. In some of the
plants belonging to the Natural Orders Capparidacee and
Trope@olacee the glandular cell divides several times to form a
little mass or nodule of secreting cells, which must be regarded
as a rudimentary gland, though it is not provided with any
definite outlet or duct.

In the seed of many grasses where there is a special organ,
the scutellum, to effect the absorption of the nutritive material
of the endosperm and supply it to the growing embryo, the
outer layer of cells of this organ, called its epithelium, is a
very marked secreting structure, producing at least two enzymes,
which it discharges into the endosperm to effect the decompo-
sitions that must precede absorption. The tentacles of Drosera,
to which allusion has already been made, secrete an enzyme,
which, along with a weak acid, is present in the glairy matter
that they pour out over the captured insect. These tentacles
and the secreting structures of the leaves of Dionza and other
plants, and possibly similar bodies in the pitcher of Nepenthes,
must be regarded as actual glands, comparable to those of the
animal body, though less complex in structure. Glandular
hairs, which consist of a few cells situated on a stalk, are found
in great numbers on other plants, especially some species of
Saxifraga.

There are many of these enzymes present in different plants,
the function of some of which is still not understood. Many,
however, have been investigated with some completeness. They
are usually classified, according to the materials on which they
work, into four groups, viz. those which decompose respectively
carbohydrates, proteids, glucosides, and fats or oils. In nearly
every case the action is one of hydration, the body acted upon
being generally made to take up water, and to undergo a subse-
quent decomposition.

Of those which act upon carbohydrates we have two varieties
of diastase, which convert starch into maltose; inulase which
forms another sugar, levulose, from inulin; invertase, which
converts cane sugar into dextrose and levulose ; glucase, which
produces grape sugar from maltose; cytase, which hydrolyses
cellulose, and pectase, which forms vegetable jelly from pectic
substance occurring in the cell-wall. Of the second group pepsin

ee
456 MANUAL OF BOTANY

and trypsin convert albumins and globulins into peptones, the
latter decomposing peptone into amide bodies. Rennet is pro-
bably a member of this group, but its function in vegetable
metabolism is unknown. It possesses the power of clotting
milk. The enzymes acting upon glucosides are many ; the best
known are emulsin, myrosin, erythrozym, and rhamnase. The
fourth class has only one member which has been investigated at
present, the glyceride enzyme that decomposes castor oil.

Diastase appears to exist in two varieties, distinguished from
each other by their mode of action on the starch grain. One,
called diastase of translocation, dissolves the grain slowly from
without inwards; the other, diastase of secretion, disintegrates
it by a process of corrosion before dissolving it. The first of
these varieties has a very wide distribution in plants, being
present almost everywhere. The second is the body formed by
the glandular epithelium of the scutellum of the grasses.

The great function of diastase.in the plant is to transform
starch (and probably glycogen where it occurs) into maltose, or
malt sugar. Wherever starch is formed, whether in the living
leaf or in the reservoir set apart for storage, it must be regarded
as a reserve material. It has a rather large molecule, but
its exact formula is not thoroughly known. The formula
n (C,H,,0,) is taken to represent it, and the value of n is
probably 5. The starch molecule is possibly composed of four
amylin or dextrin-like groups, arranged about a fifth. It has
been suggested that the first action of the diastase is the libera-
tion of them from each other; and that four of them, by succes-
sive incorporation of water, are converted through a series of
malto-dextrins into maltose, while the fifth withstands the action
of the enzyme for a considerable time. After the enzyme has
been acting for a short time the resulting product is found to be
four parts maltose and one part dextrin. How far this series of
decompositions represents what takes place in the plant is un-
certain, but it is clear that the starch, which is insoluble, is
converted into sugar, which can be removed to the part of the
plant where it is required for building up the protoplasm.

‘Inulase occurs only in the tubers and roots of some of the
Composite, where inulin is abundant. It appears to convert
inulin into levulose, an intermediate body being formed in the
process. Invertase is easily extracted from the Yeast plant, in
which it is abundant. In flowering plants it has been found
in the seeds, buds and leaves. and pollen grains. In other fungi
than Saccharomyces it occurs in Fusarum and Aspergillus,
ENZYMES AND THEIR ACTION 457

besides many bacteria. Its action is the hydrolysis of cane-
sugar with the formation of dextrose and levulose, according to
the equation

C,,H,.0,, + H,O = 0,H,,0, + C,H,,0,

Cane-sugar. Dextrose. Levulose.

Gluecase occurs in the seed of the Maize. It converts
maltose into dextrose.

Cytase is chiefly known in the germinating grain of the
barley, where it is secreted by the scutellum together with the
diastase. It dissolves the walls of the cells of the endosperm,
setting them free and giving a curious mealy character to the
grain. Its presence is suspected in the Palms, where large
reserves of cellulose are found in the hard endosperm walls.
The embryo dissolves these walls and absorbs their products,
but whether the ferment has a free existence is not yet settled.
Cytase abounds in certain Fungi belonging to the genus
Botrytis.

Pectase is but little known, and its function is not very clear.
It is recognised by its power of forming vegetable jelly from the
pectic bodies of the cell-wall. This jelly appears to be a com-
pound of pectic acid with calcium.

The proteolytic enzymes pepsin and trypsin appear both to
be represented in plants, though to what extent the former exists
is somewhat uncertain. It is the enzyme which is found in the
insectivorous plants Drosera, Dionea, and others, and it con-
verts the native proteids of the insect’s body into peptones, which
are absorbed by the leaf. It only acts in the presence of a weak
acid and is only formed by the plant when the gland has been
stimulated by the absorption of nitrogenous matter. Trypsin
has a much wider distribution, being known to exist in the fruits
of the Papau (Carica Papaya), the Fig, a variety of the Melon
(Cucumis utilissimus), and the Pine-apple (Ananassa sativa),
also in many seeds, such as those of the Hemp, Flax, Barley,
and Lupin. In the latter structures it is of especial value in the
processes of germination, feeding the young seedling with nutri-
tive proteid or nitrogenous matter until the time when it is able
to begin the constructive processes.

It acts upon insoluble proteids, forming from them albumoses,
peptones, and amides, such as leucin, tyrosin, and asparagin.
The medium in which it works varies according to the source
of the enzyme; that prepared from the Papau requires a slightly
alkaline one, that from the Lupin works best in a weak acid.
458 MANUAL OF BOTANY

These tryptic ferments, no doubt, bring about hydrolysis of the
proteid, though it is difficult to prove it by analysis.

Whether rennet is proteolytic it is difficult to say. In the
animal body it effects a decomposition of one of the proteids of
milk, but the work it does in the plant has still to be ascertained.
It has a very wide distribution, existing in the fruits, flowers,
seeds, and shoots of various plants.

The enzymes which decompose glucosides are numerous, and
are varied in their distribution. A typical one is the emulsin
of the bitter almond and cherry laurel, which splits up the
glucoside Amygdalin according to the equation
C.,H,,NO,, + 2H,0 = C,H,COH + HCN + 2 (C,H,,0,)

Amygdalin. Water. Benzoic aldehyde. Prussic acid. Sugar.

This is, as in other cases, a process of hydrolysis. This enzyme
acts also on other glucosides. Myrosin, another of the group,
is peculiar in that it effects its decomposition without causing
the incorporation of water in the process ; thus:

C,,H,,NKS,0,, = C,H,CNS + C,H,,0, + KHSO,

Sinigrin. Sulphocyanate Sugar. Potassium-
of allyl. hydrogen
sulphate,

Others, such as rhamnase, existing in the seeds of Rhamnus
infectorius, erythrozym in the Madder, populin in the bark
of the Aspen, act similarly to emulsin on various glucosides.

The digestion of the glucosides, we may notice, is always
accompanied by the formation of sugar, which is one of the
products of their decomposition. The fate of the other bodies
into which they split is not well ascertained, though there is
some evidence that cyanogen compounds, even such as hydro-
cyanic or prussic acid, are used for nutritive purposes by certain
plants.

The digestion of fat or oil has not been very fully investi-
gated, though certain facts are known concerning its fate in
germinating seeds. The digestion is generally accompanied by
the production of starch grains in cells near the seat of diges-
tion, and it was formerly considered that the starch arose
directly from the oil. It appears now that the oil is split up
by an enzyme, with the formation of a free fatty acid and
glycerine. The fatty acid undergoes further decomposition,
being oxidised into simpler acid bodies which are crystalline
instead of being viscid like the fatty acid first liberated. These
pass into the general body of the seedling. The glycerine in its
turn is converted into some form of sugar, from which the
ENZYMES AND THEIR ACTION 459

plastids of the seedling construct the starch which has been
referred to, its formation indicating, as in other cases, a tem-
porary surplus of carbohydrate supplies.

There are other enzymes with a more restricted distribution,
about whose value to the plant little or nothing is at present
known. The cells of a particular yeast plant, known as Torula
Urea, decompose urea with the formation of ammonium carbo-
nate, and an enzyme having the same power van be extracted from
them. Many enzymes can be prepared from bacteria, which
set up various changes in proteids, partly peptonising and partly
putrefactive.

The fermentative activity of the protoplasm was alluded to
at the opening of this chapter. One of the most familiar of its
manifestations is the production of alcohol from sugar, which is
set up by yeast and which goes on not only in the yeast-cell but
in the fluid around it. The same transformation takes place in
some ripe fruits, the protoplasm of their parenchymatous cells
conducting the fermentation. Similar changes lead to the
formation of acetic acid from alcohol by the fungus Mycoderma
aceti, and of other acids in the cells of the higher plants. The
dependence of these fermentations upon the vital activity
of the protoplasm is evident from the fact that no enzyme can
be extracted from any of these cells which can set up the par-
ticular changes in question.

It is not difficult to prepare the enzymes from the tissues in
which they work, but it would be extremely rash to say that
they are in anything like a pure condition when obtained. Nor
is it easy to say much about their purification, as they are not
known except in close connection with the substances on which
they act, or with the products of the decompositions they initiate.
There is, therefore, no known test of their purity.

They can be extracted by treating the tissue, which should
be very finely divided or ground in a mortar, with glycerine or
with solution of common salt, or with water containing a trace
of an antiseptic. After a period of ten or twelve hours the
extract should be strained and subsequently filtered, when the
enzyme may be precipitated by strong alcohol. It is very
evident that this will not yield it pure, for the solvents em-
ployed will dissolve many constituents of the tissue besides the
enzymes, particularly proteids and sugars. The former will be
thrown down with the enzyme by the alcohol.
460 MANUAL OF BOTANY

CHAPTER X.

THE CATABOLIC PROCESSES.

WE have seen that the object of all the processes ot construc-
tion and digestion that we have examined so far has been to
present to the’ protoplasm materials which it can incorporate
into its own substance. The bodies which we have traced to it
consist, in far the greatest part, of some form of sugar and of
organic nitrogenous bodies, either proteids or the complex pro-
ducts of their decomposition, such as the amides. The proto-
plasm of the cell is continually reconstructing itself at the ex-
pense of such nutritive substances, which indeed constitute
its food in the strict sense of the term. But there is also
going on, side by side with this process of reconstruction, a
decomposition of the substance of the protoplasm, involving a
splitting off from its complex molecule of various bodies of
great variety but of less complexity than the living substance
itself. These often, in the first instance, include such carbo-
hydrate and nitrogenous residues as it made use of in building
itself up. These can again be used in reconstruction of the
protoplasm or can be further broken down into simpler bodies
still. So long as the protoplasm is living, it is continually in a
state of change or chemical activity, undergoing reconstruction
and decomposition continually.

Besides this power of initiating chemical changes in which
it takes itself a prominent part, it is also the seat of a large
number of processes of both oxidation and reduction which are
continually going on in its meshes at the expense of the various
materials which are found there, either from being transported
from other cells or from being formed in the processes of the
self-decomposition of the protoplasm.

The formation of simpler from more complex bodies by
either of these methods constitutes what has been called the
catabolism of the plants. It may sometimes go on to the
extent of producing such simple bodies as CO, and water, which
are given off from the organism. In most cases, however, the
catabolic changes are not so far-reaching, and there remains in
the plant a great accumulation of organic substance such as
woody or corky tissue. The relatively small extent of the
catabolism as compared with the anabolism finds its expression
in the enormous bulk which many trees and other plants attain.
SECRETION 461

Some of these processes of catabolism or, as it is some-
times called, destructive metabolism, are directly applied to the
production of substances which are, of great use to the plant.
The formation in this way of materials which are of value to
the organism is generally called secretion. In other cases
bodies are produced which are of no value to the plant and
which are as far as possible withdrawn from the spheres of
vital activity. Comparatively few of them are ever thrown off
from the plant, but they are generally deposited in such regions
as leaves which are about to be shed, or the bark of trees,
which is a collection mainly of dead matter, or sometimes in
special cells, or in cell-walls, or elsewhere. These bodies
really correspond to excreta, and the processes of their formation
are called’ processes of excretion. Many others occur whose
meaning is still obscure, and these constitute what are often
called the bye-products of metabolism.

Of the processes of secretion the most prominent perhaps
is that of the formation of cell-walls. We have seen that in
the division of a cell in any of the higher plants the nucleus
divides by a series of complicated movements, and forms two
daughter nuclei, which are at first connected together by a
structure called the spindle. Along the fibrils of this spindle
minute particles or granules, originating in the protoplasm,
pass to form a plate of extreme tenuity across the cell midway
between the two new nuclei. This plate soon undergoes a
transformation into the ordinary cellulose of the plant. The
cell-wall is thus seen to be formed from the protoplasm, or to be
secreted by it, the granules of which it is at first composed
being the result of decomposition set up in the living substance.

When cell-walls are growing in thiekness or in surface, a
similar decomposition of the protoplasm can be observed. Fresh
granules can be seen to be deposited by the latter upon the
surface of the original cell-wall, which are soon transformed into
the first thickening layer of cellulose. In all cases, there-
fore, the formation of cellulose can be traced to the self-decom-
position of the protoplasm.

A very similar phenomenon is observable in the formation
of starch grains. In most cases this is brought about by the
activity of a plastid, either a chloroplast or a leucoplast. We
have seen that these structures may be regarded as specially
differentiated protoplasmic bodies, and their mode of behaviour
has been described. Building themselves up at the expense of
sugar and probably nitrogenous residues remaining in the
462 MANUAL OF BOTANY

meshes of their substance, they break down to a certain extent,
splitting off a quantity of starch which is poured out by the
leucoplasts or deposited in their interior by the chloroplasts,
leading to the appearances already described. The formation
of starch is thus a secretion by the plastid, just as that of
cellulose is a secretion by the protoplasm of the cell. In those
cases where small grains of starch are formed without the inter-
vention of a plastid, the work is done by the protoplasm of the
cell.

The most recent researches render it highly probable that
the formation of aleurone grains is precisely similar in the way
in which it is brought about.

The formation of fat is due to similar behaviour on the
part of the protoplasm. It can be observed most easily in the
case of certain Fungi, when they are not well nourished. The
protoplasm is found to get less in amount, the vacuolation
becomes very considerable, and the cavities are found to contain
large drops of oil. The elaioplasts to which reference has
been made behave similarly, their substance diminishing at
the same time that fat or oil makes its appearance. The de-
composition of the protoplasm is here not accompanied by
much reconstruction, so that it is soon very greatly diminished
in amount, while the fat, the product of the catabolic processes,
increases,

The formation of the enzymes described in the last chapter is
another instance of the same kind. These are gradually
elaborated by the protoplasm from its own substance, their
development being attended by the formation of granules much
as is that of cellulose.

One of the most important of these secretions is the green
colouring matter, Chlorophyll, which we have already seen is
present in the form of a solution in the meshes of the chloro-
plasts. The formation of chlorophyll is a more specialised pro-
cess than any of those which we have just been considering,
and is dependent upon a variety of conditions. It probably
involves not only the self-decomposition of the protoplasm, but
also other processes taking place in its meshes.

The conditions necessary for the formation of chloro-
phyll are, Ist, access of light, 2nd, a particular range of tempera-
ture, 8rd, the presence of a minute quantity of iron in the
plant. Ifa plant be cultivated from seed in darkness, the re-
sulting seedling will not be green, but will have a yellowish-
white colour. When examined by a microscope the plastids
SECRETION AND EXCRETION 463

will be found in the cells, but they will be tinged with a pale
yellow pigment known as etiolin. When the etiolin is ex-
posed to light it will rapidly become green, being in fact re-
placed by or converted into chlorophyll. The etiolin is in the
first instance secreted by the protoplasm of the plastid, and sub-
sequent changes take place about which little is known, con-
verting it into chlorophyll. If the temperature be kept very
low, the etiolin remains unchanged, even though light be
admitted. Hence the first leaves of plants which spring up in
the winter are frequently yellow and not green. The function
of the iron is not understood ; plants cultivated in such a
medium that this element is not supplied to them have an ap-
pearance much like that of an etiolated plant. Their colour is
even paler, indeed they are almost colourless, though the
plastids are present. A supply of iron at once changes them
to the normal appearance. Plants so suffering from the absence
of iron are said to be chlorotic.

The excretions of plants, using the term in the wide sense
indicated above, and not implying that they are thrown off
from the plant body, are similarly produced. Perhaps the most
frequently occurring instance of these is the sugary solution
known as the nectar, which is so common in flowers. Other
instances are the resin produced in the resin glands of the
Conifers and of other trees, and the etherial oils found in
special receptacles in the leaves and other parts. Mineral
matters, chiefly carbonate and oxalate of calcium, are also
formed. The carbonate is in some cases excreted on to the
surface through special glands, as in certain Saxifrages; in
others it is deposited in the substance of the cell-walls or of
protrusions from them, as in the cystoliths of Ficus, the Nettle,
and other plants. The oxalate is frequently deposited in
special cells, where it forms the bodies described as raphides
and spheraphides. In these cases the cluster of crystals is
usually invested by a delicate skin derived from the protoplasm.
The oxalate is also sometimes deposited in the substance of the
eell-wall as in the bast fibres of Ephedra. Silica, again, is
accumulated in the epidermis of many grasses and Equisetuis.

Many of these excretions cannot be traced to the self-decom-
position of the protoplasm, but are probably formed by the
processes of oxidation and reduction which we have seen are
often associated with its activity. They are not, however,
formed withont its intervention in some way.

The bye-products of metabolism are too numerous to be
464 MANUAL OF BOTANY

discussed in detail in the present treatise. They include bodies
of varying degrees of complexity, some nitrogenous, others not.
Among the former may be mentioned many compounds of the
amides with fatty acids, xanthin and bodies allied to it, and the
great group of the alkaloids. It is possible that many of these
may be of use to the plant in its processes of reconstruction,
but some are certainly of no value in this respect. The alka-
loids come under the latter category, for though they contain
combined nitrogen they cannot minister to the growth of the
plant. Ifa plant is supplied with them, but with no other form
of combined nitrogen, it is rapidly starved. The amidated fatty
acids, leucin, tyrosin, glycin, &c., on the other hand, can be
absorbed and utilised in the processes of nutrition. The latex
of plants frequently contains many of these bodies. Caoutchoue
is also present in some.

Among the non-nitrogenous bye-products may be mentioned
the great variety of vegetable acids and many of the glucosides, °
such as salicin, coniferin, &c., which have a certain nutritive value
owing largely to the sugar they contain. Certain other products
derived from them may also be utilised in this way. Such bodies
may perhaps be best included among the reserve materials
already discussed. The vegetable acids, such as tartaric, malic,
citric, &c., are usually regarded as arising in the course of the
catabolie processes; it is, however, possible that some of them
may be formed in the elaboration of food from the raw materials
absorbed, having thus their origin in anabolism.

The bye-products include also a variety ofaromatic substances,
such as tannin, phloroglucin, and aromatic acids, such as benzoic,
salicylic, &c., but the nature of the processes which give rise to
them is not well understood.

Certain decomposition products of cellulose may also be
included here. The lignin and suberin, which are characteristi
of woody and corky cell-walls, arise in this way. During their
formation they can be removed by appropriate solvents, leaving
the cellulose skeleton which they are gradually replacing. These
differ from most of the bodies described in that they can be pro-
duced in the walls of cells that have lost their protoplasm, so
that their formation is independent of the latter.

Finally, we may include here the odorous substances and
the colouring matters, except chlorophyll. Many colouring
matters are the products of the decomposition of the latter,
especially canthophyll and erythrophyll, to which the autumn
THE RESPIRATION OF PLANTS 465

tints of leaves are due. The former appears to be always present
with chlorophyll in the chloroplasts.

Though many of these substances, both excretions and bye-
products, are of no value for nutrition, some of them may playa
very important part in the defence of plants against their
natural enemies, their nauseous smell or flavour preventing their
being eaten by animals, &c. Some odours and the nectar found
in flowers are doubtless of great service in attracting insects,
which assist in the process of cross-pollination, to be discussed
in a subsequent chapter.

CHAPTER XI.

THE RESPIRATION OF PLANTS.

Ove of the conditions of life of almost every organism, whether
animal or vegetable, is that it shall be supplied with free oxygen.
Not only do all the vital activities of plants as well as animals
depend upon this, but the very life of the protoplasm ceases if
this gas is withdrawn. Consequently, as long as life is main-
tained, the organism must be continuously absorbing oxygen.
This is very evident in the case of an animal, but it is not so
obvious in that of a green plant, for the process of decomposing
the CO, taken in as a material for food construction is, as we have
seen, accompanied by an evolution of oxygen. In the case of a
plant which has no chlorophyll the absorption of oxygen can be
much more easily detected, as it is not masked by this converse
process of its exhalation. If a fungus, such as a mushroom, be
. placed in a closed receiver containing ordinary air, and be left
there for some hours, at the conclusion of the experiment the
vessel will be found to contain but little oxygen, which will have
been replaced by about an equal amount of CO,. Itis not diffi-
cult to devise an experiment which will show that a green plant
has the same absorbing power. If the light be excluded from
one placed in a similar vessel, no evolution of oxygen will take
place from it, as we have already noticed in a preceding chapter,
and that the oxygen diminishes even to extinction can be made
evident just as in the case of the mushroom. We have, however,
evidence that this is not caused by the exclusion of the light.
An apparatus can be easily arranged to show the absorption of
oxygen even when a green plant is exposed to a bright sunlight,
The atmosphere in which the plant is placed can be freed from
VOL. II. lH
466 MANUAL OF BOTANY

CO, by having a vessel containing a solution of caustic potash in
the receiver with the plant. The potash will absorb the CO, of
the original atmosphere admitted, as well as any CO, given off
by the plant during the experiment. If a capillary tube be fitted
into the receiver and its other end be made to dip into a vessel
of mercury, the latter will slowly and gradually rise in the tube,
indicating a diminution of the volume of the included air. If
the experiment be continued till the mercury ceases to rise in
the tube and the gas remaining in the receiver be measured at
the ordinary atmospheric pressure, it will be found that its volume
has been diminished by about twenty per cent. and that what is
left consists of nitrogen. The oxygen will have been completely
removed by the green plant, even when in sunlight. If the
caustic potash be examined, it will be found to have gained
considerably in weight and to contain a quantity of carbonate
of potassium. Thus there hasbeen proceeding an absorption of
oxygen, attended as before by an exhalation of CO,, the latter
having been combined with the potash.

This process of gaseous interchange constitutes what is
known as respiration. Though more easily detected when the
absorption of CO, and its decomposition by the chloroplasts are
suspended, it is nevertheless constantly going on so long as the
plant is living. It is observable in all living parts of the plant,
whatever be their environment.

If the plant be carefully weighed at the beginning and end
of the experiment, it will be found to have lost weight during its
stay in the receiver, so that respiration is associated with a loss
of weight to the plant. Not only is respiration attended with
the emission of CO,, but there is also a certain exhalation of
watery vapour, which takes place quite independently of any
supply from the root or the cut end of the stem. The nature of
the metabolism is such that the living substance gives off both
water and CO, while it coincidently absorbs oxygen. This is
quite independent of any constructive processes, for it can be
observed when no nutritive material of any kind is supplied to
the plant.

We may inquire what is the relation of the absorption of
oxygen to the elimination of CO, and water. Jt is conceivable

‘that the oxygen may unite in the plant with carbon and with
hydrogen to produce at once the exhaled compounds. A study
of the living organism at work, however, soon shows us that the
process .is not of this simple nature. If a study be made of
the germination of starchy seeds, the volume of oxygen absorbed
THE RESPIRATION OF PLANTS 467

is about equal to that of CO, evolved, butif oily seeds be examined
during germination, more oxygen is taken in in proportion to
the CO, given out. Various observers have shown that in certain
cases, succulent leaves, or the phylloclades of a Cactus, ar
capable of absorbing oxygen without the simultaneous evolution
of CO, at all. Nor is the oxygen absorbed without entering
into chemical combination, for it cannot be extracted by the air-
pump. Conversely CO, may be thrown off from a plant without
any simultaneous absorption of oxygen. If a seed be germinated
in a vacuum over acolumn of mercury, CO, is found to be
evolved. Ripe fruits have been found to give off CO, in an
atmosphere quite devoid of oxygen.

Again, it is found that the ratio of oxygen absorbed to CO,
exhaled varies according to the temperature at which the experi-
ment is conducted. Evidently the two processes are not
directly dependent upon each other.

It is evident from the foregoing considerations that the vital
activity of protoplasm is somehow associated with the two pro.
cesses. In the absence of oxygen it gradually ceases, the living
substance being in fact slowly asphyxiated. During its life one
of the manifestations of its metabolism is the formation and
exhalation of the two fairly simple compounds CO, and water.
To ascertain what is the true relation of the two processes, it is
necessary to look closely at the nature of the chemical changes
going on in the protoplasm itself, or at what we have called its
metabolism.

Respiration in the strict sense is, therefore, a process going
on in the living substance itself, or rather is the expression of
the beginning and end of a series of complex changes in which
the molecules of the living substance are involved. The details
of the absorption of the oxygen by the plant from its environment
and the ultimate evolution of the CO, and water from the plant
body should rather be regarded as the mechanism of respiration
than respiration itself, which is a function of the living substance
only. A distinction is often made by some writers between the
two, the latter being spoken of as intramolecular respiration. It
seems better on the whole to consider the latter phenomenon
only under the name of respiration.

We see, then, that the two processes are not immediately
connected in the sense of the CO, coming at once from the direct
oxidation of carbon, but that they are ultimately associated,
though separated in time by a series of chemical changes taking
place in the living substance. ~

HH2,
468 MANUAL OF BOTANY

In the metabolic changes going on in the protoplasm we find,
however, that while its own molecules are in a constant state of
decomposition and reconstruction, other changes also take place
in the various substances which are ‘enclosed in its meshes, into
which its own molecules do not-enter. Processes of slow
oxidation and gradual reduction are taking place there continu-
ally, excited, however, in all probability by the changes in the
protoplasm itself. Even these, however, are by no means
simple, and the direct oxidation of either carbon or hydrogen
has probably no place amongst them. An instance of them
may be seen in the oxidation of alcohol in the cells of
Mycoderma aceti, a fangus which converts alcohol into acetic
acid. This process, into which the molecule of protoplasm can
apparently not enter, yet can only go on in the living cell.
Other similar instances could be quoted.

The probable course of eventsis that the oxygen in some way
unites with the molecule of protoplasm, rendering it unstable
and initiating a series of decompositions which result in the
formation of many of the bodies already spoken of in the last
chapter. If the temperature be low, the breaking down of the
protoplasm proceeds but slowly, and reconstruction, either from
some of these residues or from food supplied to it from the cell
contents, or both; is rapid. Consequently the quantity of oxygen
absorbed or fixed by the protoplasm is greater than the quantity
of CO, formed by its decomposition: At a higher temperature
decomposition is much more easily carried on and its products are
more numerous and simpler. The decomposition and recomposi-
tion go on side by side, simpler bodies being gradually produced,
either by their splitting from the protoplasm directly, or by their
being formed at the expense of the more complex decomposition
products, during processes of slow oxidation in its meshes, till
finally.a certain production of CO, and water is arrived at. So
long as the protoplasm remains alive the amount of these is not
large, reconstruction continually taking place. When, how-
over, the protoplasin dies, simpler bodies such as CO, water, and
possibly Ammonia in addition, are produced abundantly from
the decomposition which attends its death.

The CO, is thus the final term in a series of decompositions
of which the living substance is the seat, and which are promoted
by the access of oxygen. In some cases, such as that of the
Cactus already alluded to, this final term is not reached, no CO,
being exhaled. In these cases the process stops short at the
THE RESPIRATION OF PLANTS 469

formation of certain organic acids which are found in abundance
in the tissues of the plant.

In the case of certain micro-organisms there is no absorption
of free oxygen; indeed these so-called anaérobic plants are
killed by exposure to the gas. We must not, however, conclude
that their metabolism is of a totally different kind from that of
others, but rather that they obtain what oxygen they require
from internal decompositions, or fermentative changes which
they set up.

The meaning of these complex metabolic processes must bé
looked for in relation to the question of the energy which
the plant requires for its vital functions. There are but two
sources of energy available for its use; one of these, the
radiant energy of the sun’s rays, can only be utilised through
the chloroplasts, and is not directly at the disposal of the proto-
plasm. But the construction by them of various complex
materials, food and plant substance, involves the expenditure
upon the latter of a considerable amount of this energy, which
can be again set free by the decomposition of the complex bodies
and the production of simpler ones from them. It is, of course,
an every-day experience that the combustion of coal or wood,
which is really the oxidation of its carbon and hydrogen to
the condition of CO, and water, is attended with the liberation
of a great deal of energy which takes the form of heat. So
with the decompositions of the protoplasm which are set up,
or at any rate facilitated, by the access of oxygen. The splitting
up of the complex molecule, and the formation of simpler ones,
at once set free certain potential energy, the amount being
proportionate to the extent of the changes. Part of this energy
is required at once by the protoplasm for the reconstruction
or building up of its substance from some of the residues, but
as some comparatively simple: bodies, such as CO, and water,
are always left to be given off, there is always liberated a
certain amount of energy available for other work. In many
cases this takes the form of heat. In germinating seeds and in
the opening of flower-buds, where respiration is particularly
active, there is always an appreciable rise of temperature,
sufficient indeed to be measured by a thermometer. In other
cases the released energy is utilised in causing movement; in a
few instances occurring among certain fungi, it takes the form
of light or phosphorescence.

The importance of respiration thus becomes evident ; it marks
the initiation, and is the accomraniment, of the catabolic pro-
470 MANUAL OF BOTANY

cesses which we have discussed in the preceding chapter, and these
coincidently place at the disposal of the plant a certain store of
energy which, originally derived from the radiant energy of
light, has been transformed from the kinetic to the potential
condition, and which is rendered again kinetic by the catabolic
changes. So constant is this relation that it may be said that
heat is always evolved where and while oxygen is being
absorbed.

Though respiration is always proceeding wherever there is liv-
ing protoplasm, the activity of the process is modified by different
physical conditions. The degree of illumination of most plants is
continually varying, and though respiration does not depend upon
light, its activity is not the same under all conditions of the
latter. We have already noticed that variations of temperature
affect differently the absorption of oxygen and the exhalation of
CO,. The absorption of oxygen is suspended if the tempera-
ture is too low, it increases as the latter rises to a certain
optimum point, which varies with different plants, and at higher
temperatures it progressively decreases. The exhalation of CO,
is smaller at low temperatures than the absorption of oxygen,
but is greater at higher ones.

The process of respiration is also affected to a considerable
extent by the nature of the substances which serve as nutritive
material for the reconstruction of the protoplasm. It has
already been pointed out that seeds containing oil absorb more
oxygen during germination than those whose reserve material is
largely starch. Organs which contain much proteid matter respire
more copiously than others which contain but little. The nature
of the inorganic salts absorbed also influences the process to a
certain extent.

CHAPTER XII.

GROWTH.

In studying the growth of plants we must consider the relation
which it bears to the processes of metabolism which we have
already discussed. We have seen that the constructive metabo-
lism or anabolism is much greater than the destructive, or cata-
bolism. There results from this a considerable increase in the
substance of the plant, as well as an accumulation of potential
energy which can be made available by the plant by the destruc-
GROWTH 471

tive processes. Usually we have therefore a great accumulation,
which is primarily manifested in growth. Here again we must
distinguish between the growth or increase of the living sub-
stance and the manufacture of other products such as wood,
which is not necessarily living.

The growth of the living substance is always the result of
constructive metabolism, and is attended by an increase of bulk
and weight. The growth of an organ sometimes appears to be
independent of such increase of weight; indeed, a diminution
of the weight of the whole structure is sometimes noticeable.
Thus, in the case of a potato allowed to germinate in such con-
ditions as prevent the absorption of food materials from without,
we have a marked change of form, but owing to the loss of
moisture by transpiration and of CO, as a consequence of its
respiration, or the catabolic processes going on in it, the result-
ing plant may weigh much less than the original potato.

This difference is, however, rather apparent than real. We
shall see that the actual growth, or the manufacture of new
cells, is confined to certain regions. In these regions there is a
considerable increase in bulk and weight, but as the materials
which are used for the purposes of this local growth are derived
from substances stored up in the body of the tuber, the latter,
which is not the seat of the growth at all, diminishes in weight
and size to such an extent as more than to counterbalance the
gain in the growing regions. Hence the whole plant weighs
less than the tuber, though considerable growth may have taken
place.

Growth is in the strict sense, then, always associated with
the formation of new substance; it is in nearly all cases
attended by a permanent change of form. Thisis perhaps not so
evident in the case of axial organs, though here it takes place to
a certain extent, as it is in that of leaves and their modifications.
In most cases the young leaves of a plant have a different shape
from the adult ones, and the appearance of the latter is gra-
dually assumed as the leaf grows older.

This change of form not only can be seen in the case of
such an crgan as a leaf, but may be noticed also in that of the
individual cells of which a plant consists. In the apical
meristem of the shoot of a flowering plant the cells when first
formed are almost cubical ; after a little while we find many of
them becoming prosenchymatous. Many other cases can be
noted, particularly the irregularly shaped cells of the spongy
472 MANUAL OF BOTANY

parenchyma of leaves, the stellate cells of the pith of certain
rushes, the laticiferous cells of the Spurges, &e.

Growth may, in the light of the considerations advanced
above, be defined as permanent increase of bulk attended by
permanent change of form. We must ‘not assume that increase
of bulk is necessarily growth, for, as we shall see, in growing
cells and members there is a constant stretching of the cell or
tissue by hydrostatic pressure or turgidity which can be dis-
tinguished from growth by the fact that it can be removed,
with the result ofa certain amount of shrinkage of size of the
part under examination.

Growth in the lowliest plants may be coextensive with the
plant body. In all plants of any considerable size, however, it
is localised in particular regions, and in them it is associated
with the formation of new protoplasts. We have already seen .
in the case of the sporophytes of all the higher plants that there
exist certain regions in which the cells are merismatic, that is,
which have the power of cell-multiplication by means of
division. In such regions, when a cell has reached a certain
size, which varies with the individual, it divides into two, each
of which increases to the original dimensions and then divides
again. These regions have been called growing points; they
may be apical, or intercalary, or may consist of definite layers
known as cambium layers, or phellogens. By the activity of
the protoplasts in these merismatic areas the substance of the
plant is increased. As they consist of cells, it is evident that
the growth of the entire organ or plant will depend on the
behaviour of the cells of which it is composed.

The growth of a cell will be found to depend mainly upon
four conditions: 1. There must be a supply of nutritive or
plastic material at the expense of which the formation of proto-
plasm can take place. 2. There must be a supply of water to
such an extent as to set up a certain hydrostatic pressure in the
cell. This condition we have already considered in the first
chapter of this section, where we discussed the relation of proto-
plasm to water. In the absence of this twrgescence no growth
is possible, for reasons that will presently appear.’ 3. There
must be a certain temperature in the plant, for the activity of
protoplasm can go on only within certain limits, which differ in
the cases of different plants. 4. There must be a supply of
oxygen to the growing cell, for, as we have seen, the protoplasm
is dependent upon this gas for the performance of its vital
functions. This is evident from the consideration that the
GROWTH 473

growth of the cells is attended by the growth in surface of the
cell-wall, and as the latter is a secretion from the protoplasin, a
product, that is, of its catabolic activity, such a decomposition
cannot readily take place unless oxygen is admitted.

When these conditions are present the course of events
appears to be the following; the young cell, immediately it is
separated from its fellow, absorbs water, and with the water its
contained nutrient substances. There is set up at once a cer-
tain hydrostatic pressure due to the turgidity, and the extensible
cell-wall stretches, at first in all directions. The growth of the
protoplasm at the expense of the nutritive matter for a time
keeps pace with the increased size of the cell, but by and by it
becomes vacuolated as more and more water: is attracted into
the interior. Eventually the protoplasm forms usually only a
lining layer to the cell-wall, and a large vacuole filled with cell-
sap occupies the centre. The growth of the protoplasm, though
considerable, is therefore not commensurate with the increase
in size of the cell. The stretching of the cell-wall by the hydro-
static pressure is fixed by secretion of new particles upon the
original wall, which as it thus becomes slightly thicker is
capable of still greater extensibility, much in the same way as
a thick band of india-rubber is capable of greater stretching than
a thin one. The increase in surface of the cell-wall is thus due
firstly to the stretching caused by turgidity, and secondly to the
formation of new cellulose upon the old. The latter only is the
growth of the cell-walls; the former can be removed by irrigat-
ing the cell with a solution of a substance, such as common salt,
which will rob the cell of its contained water. The constructive
changes leading to the formation of new protoplasm are attended
in this process by the catabolic formation of cell-wall and other
substances, such as the osmotic bodies which are necessary to
attract the water into the cell. The supply of oxygen is needed
to allow the protoplasm to undergo these catabolic decomposi-
tions, enabling it thus to produce these several products and to
gain from such decompositions the energy which must be ex-
pended upon the construction and reconstruction of the living
substance and used in the secondary chemical changes which
supervene.

This process of the growth of a cell is limited in its extent,
though the limits vary very widely. In some cases cells grow
only to a few times their original dimensions; in others they
may attain a very considerable size. In any case, however,
we can notice that the rate of growth is not constant; it begins
474 “MANUAL OF BOTANY

slowly, increases to a maximum, and then becomes gradually
slower till it stops. The time occupied by these varying rates
of growth is generally spoken of as the grand period of growth.

Changes in the shapes of cells arising during growth depend
upon two factors. The direction of hydrostatic pressure and the
power of the cell to respond to it may not continue the same in
all directions, and, consequently, the growth of the cell in the
direction of greater pressure or least resistance will be greater
than elsewhere. The extensibility of the cell-wall may also be
locally modified by the protoplasm, so that the growth becomes
irregular, and cells of curious form may result.

If we consider the behaviour of a growing organ in the light
of these facts, we shall see that it, like the cell, must show a
grand period of growth. If we take the case of a root, in which
the changes can be traced most easily from the simplicity of its
structure, we find that just behind the apex the cells are all in
active division. Growth is small, for the cells divide again as
soon as they have reached a certain size. As new cells are
continually formed in front of the merismatic mass, those
behind gradually cease to divide, and the process of growth
proper takes place. Here the actual extension in length of the
root goes on, and the cells are at the maximum point of their
grand period. They then gradually lose the power of growth,
the oldest ones, or those furthest from the apex, parting with it
first, and they pass over into the condition of the permanent
tissue. Thus every portion of the root goes through a grand
period of growth; at first, when the cells are merismatic, growth
is at w minimum, it gradually becomes accelerated, reaches a
maximuin, and slowly ceases, exactly as did that of the cell
which we first considered. By careful examination of a growing
root it can be found that the growth is greatest just behind the
merismatic region. If a young root be taken and marked with
a series of dots at equal distances apart, and then allowed to
continue its growth, it will be found that the dots remain close
together at the apex and for a very short distance fromit. Then
they become separated by broader spaces. Further back still
the original intervals between the dots are again unaltered. The
second region corresponds to the part where the cells are under-
going the enlargement described.

The same order of events may be ascertained to take place
in the stem, but in this region it is complicated by the occurrence
of nodes and internodes. Growth is confined to the latter,
each of which passes through a similar grand period. The
GROWTH 475

growth of the stem is the algebraical sum of the growth of
the internodes, many of which may be growing simultaneously.
They will consequently be at different parts of their grand period
at any particular moment. The region of growth in the stem is,
as a rule, much longer than that of the root.

The growth of the leaf shows a little variation. The apical
growth, as a rule, is not very long continued, and the subsequent
enlargement of the leaf is due to an intercalary growing region
near the base. This area has the merismatic cells at about its
centre, and regions of greatest growth are on both sides of it.
This can be traced more easily in the elongated leaves of
Monocotyledons than in those of Dicotyledons.

The grand period itself is not quite uniform, as the rates of
growth in the active region may and do vary with changes in
external conditions, and with differences in activity in the proto-
plasm from time to time.

For the sake of simplicity of description it has been assumed
in the foregoing account that the turgidity of the cells in the
growing organ is uniform. This, however, is far from being
the case. There is generally a fairly regular variation in this
turgidity in the different parts of the growing organ. In the
simplest case we may consider one which shows a difference
in structure on two sides; such a member is described as
dorsiventral. The two sides will often show a difference of
degree of turgidity, and consequently of rate of growth. If we
consider a leaf of the common Fern, we find that in its young
condition it is closely rolled up, the upper or ventral surface
being quite concealed. As it gets older, it gradually unfolds and
expands into the adult form. Thisis due to the fact that in
the young condition the turgidity and consequent growth are
greater on the dorsal side of the leaf, so that it becomes con-
volute. As it gets older the maximum growth changes to the
upper side, and so it becomes unfolded or expanded. These
two conditions are generally described under the names of hypo-
nasty and epinasty respectively.

These conditions are not confined to the leaves of ferns, but
may be detected in those of other plants, though to a less
degree. It is in consequence of them that the leaves of the bud
always fold over the apex of the stem from which they spring.

Cylindrical organs may exhibit similar variations in growth.
One side of a stem may be more turgid than another, and the
maximum turgidity with its consequent growth may alternate
between two opposite sides. The increased turgidity of the cells
476 MANUAL OF BOTANY

is often accompanied by an increased extensibility of the cell-
walls of the turgid region. The growing apex of such a stem will
alternately incline first to one side and then to the other, ex-
hibiting a kind of nodding movement in the two directions.
This is known as nutation, and it is of very frequent occurrence.

The region of greatest turgidity, instead of being alternately
on one side and the opposite, may pass gradually round the
growing zone. The apex in this case will describe a circle, or
rather a spiral, as it is elongating all the time, pointing to all
points of the compass in succession. This movement has been
described by Darwin as circumnutation, and has been said by
him to be universal in all growing organs. The passage of the
maximum turgidity round the stem may be regular or irregular,
causing the circle to be replaced by an ellipse. Indeed, the
simple nutation spoken of above may be regarded as only an
extreme instance of the latter.

By these movements, incident to growth, and proceeding
altogether from internal causes, many advantages are secured
to the plant. In the case of climbing stems the cireumnutation
enables them to reach supports round which they twine, so that
with but little expenditure of substance they can secure ad-
vantages of light and air which they could not obtain in its
absence. The roots by the same method are enabled more
easily to make their way through the crevices of the soil. The
axis of the embryo shows in one or other of its parts strong
hyponastic curvature, forming an arch, which enables it to leave
the seed coats and make its way through the soil without damage
to the young delicate plumule, its progress being helped by
simultaneous circumnutation. On reaching the surface epinastic
growth causes it to assume the erect position, while cireumnuta-
tion of the apical region replaces that of the arched portion of
the axis.

During the period of growth the young organ is extremely
sensitive to changes in its environment, responding to such
stimulating influences by further modifications of its behaviour ;
these will be considered in detail in the succeeding chapter.

Besides the hydrostatic tension set up in the cells of the
growing regions, the processes of growth are accompanied by
other tensions existing in their interior, which appear to depend
upon differences between their tissue systems as these develop.
If a petiole of Rhubarb be taken, and a thin strip be peeled
from one side, it will immediately curl outwards. If it be then
placed in apposition with the part from which it was cut, it
TENSIONS IN GROWING ORGANS 477

will be found to be appreciably shorter than the rest of the
petiole. Ifthe petiole be carefully measured, and then deprived
of its cortical covering by separation of successive strips, the
central part when measured will be found to be slightly longer
than the original petiole. In such a petiole the central part
was clearly compressed by the external portions, and when
these were removed it underwent an extension which was the
expression of the amount of such compression. Similarly the
external parts were stretched longitudinally by the central
region, and when they were freed from it, the recoil was ac-
companied by a diminution of their length. There was thus a
longitudinal tension in the petiole, due to the turgescence of
the central part, which stretched the outer portions, and was
itself compressed by their greater rigidity resisting the hydro-
static extension. This tension is due not to greater growth,
but to increased turgidity, for if the petiole be soaked for a
while in salt solution till the water is in great part removed
from its interior, and it has become flaccid, removal of the
cortex is not accompanied by the same changes of dimension.
A similar experiment may be performed on the hollow flower-
stalk of a Dandelion. If it be slit into two halves by a vertical
cut, the two parts curl outwards from each other, showing a
similar tension in the internal regions.

Transverse tensions in growing stems can also be demon-
strated. The cortex is found to be strained outwards by the
pith, so that if a ring of it be cut out of the stem, it will be
found to shorten on removal. The pith is in a state of com-
pression, and the cortical tissues in one of extension, as in the
other case quoted above. Transverse tensions of this kind are
set up in the course of the thickening of stems and roots by the
activity of the cambium layer, the bast and cortex being com-
pressed outwards and the wood compressed inwards on account
of the formation of the new material. This gives us a partial
explanation of the formation of the annual rings of such stems
and roots, and of the ruptures that are generally noticeable
on the exterior of such parts.

In the absence of the external stimulating influences re-
ferred to above, growing organs show a tendency to grow in
straight lines. Though the apex of any of them may con-
tinually show the movement of circumnutation, the mature
part generally takes up a fixed position, growing vertically or
horizontally as the case may be. This position is, however,
usually the resultant of a number of external forces acting
478 MANUAL OF BOTANY

upon the growing organ. The inherent tendency just spoken
of can be satisfactorily seen only when, by artificially eliminat-
ing the action of such forces, the plant is not exposed to their
stimulating influence. Such a tendency has been called
Rectipetality.

CHAPTER XIII.

INFLUENCE OF THE ENVIRONMENT ON PLANTS.

AccorpInG to the nature of their surroundings and the con-
sequent differences in mode of life, we find in many plants
certain peculiarities of form and structure which are different
from those of the bulk of the forms which we have hitherto con-
sidered. Of these the Spermaphytes which live in water may
be first discussed, as the direct influence of their environment is
most conspicuous in their case.

These aquatic Phanerogams may be divided into two chief
groups; those which are altogether submerged, and those which
bear floating leaves as well as or instead of submerged ones.

In the former case the plant body may be attached by roots
to the bottom of the stream or pool, or may be altogether
floating. The stems are almost invariably long and slender,
and easily swayed to and fro in the water. They depend for
their support upon the nature of the medium in which they
live, and though possessing a certain rigidity, this is not asso-
ciated with any great development of woody tissue. Generally
the latter is reduced to a minimum; the fibro- vascular bundles are
usually few and contain few lignified elements. The substance
of the plant is largely parenchymatous, and the cells have thin
walls. The intercellular space system is often very complex,
large lacune filled with air occupying a large space in the
distribution of the tissues. Their rigidity is secured by the
turgescence of the parenchymatous cells, and buoyancy is much
assisted by the air in the lacune.

The primary root is generally feebly developed, and, as a
rule, does not persist through the life of the plant. Adventitious
roots, however, are given off in large numbers from the various
nodes of the stem. The root-hairs which are so characteristic
of terrestrial roots are usually either very scanty or altogether
absent, The epidermis of both root and stem is not cuticularised,
CHARACTERS OF AQUATIC PLANTS 479

but the cells remain capable of absorbing the water in which
the plant is living. In the stem this tissue very frequently
contains chloroplastids.

The character of the leaves differs in relation to the
habitat. Those which grow in rapid streams are generally
either long and thin, or are very much and finely divided, so
that they offer in either case no resistance to the force of the
current. In more sluggish water they are often broader, some-
times attaining « considerable size. Their tissue is always
very weak, the parenchyma of the mesophyll sometimes being
much reduced, so that as the leaf grows old it becomes latticed,
asin Ouvarandra. ‘The epidermis is never cuticularised, and it
contains no stomata.

In plants with floating leaves the roots and stems are similar
in character to those of the first class. The leaves, however, which
lie upon the top of the water are usually tough and thick, their
undersides being sometimes deeply rugose. They have not the
much-divided outline characteristic of submerged leaves, but are
usually simple and sometimes of considerable size. Those of the
Victoria regia are often three feet in diameter, and are turned
up at the edges, forining a rim, which helps to preserve the upper
surface from being wetted. The upper epidermis of such fioat-
ing leaves is often either strongly cuticularised or impregnated
with a waxy secretion, serving the same purpose. The leaves
are consequently shiny in appearance, and water will not adhere
to them. These floating leaves bear their stomata upon the
upper surface only.

The petioles are long and flexible and possess a peculiar
power of adapting themselves to varying depths of water.
Should the stream in which they live become shallow, the leaves
still remain floating, owing to the power of the petiole to become
curved; should the water rise, the petioles respond by renewing
their growth, so as always to keep pace with the increased
depth.

Vegetative reproduction is very common, branches becoming
detached from the plant, which speedily put out adventitious
roots of their own, and form new plants.

From their close relation to the watery environment and
their power of absorbing liquid through their general epidermis,
we can easily explain the absence of the woody tissue. Their
transpiration is reduced to a minimum or altogether suppressed,
and there is, therefore, no need of a provision for the rapid
current of water so essential to the well-being of a terrestrial
480 MANUAL OF BOTANY

plant. Their food materials reach them dissolved in the water
in which they live, and hence they have no need of the com-
plicated root system with its absorbent root-hairs, which is so
characteristic of a plant growing in ordinary soil. Gaseous
absorption takes place also through the general epidermis as well
as from the cells of the lacunar passages.

It is noteworthy in this connection that the absence of the
transpiration current is associated with a comparatively small
development of the general plant body. Aquatic phanero-
gams are consequently never of large size.

The difference between the two groups spoken of may be well
seen in such plants as Cabomba, which bears both submerged
and floating leaves. These show respectively the characteristics
described in each case.

Another class of plants which show a definite response in
their structure to the conditions in which they live is that to
which the so-called rerophilous plants belong. These are
plants which grow in sandy deserts, exposed to great heat, and
frequently undergoing long periods of drought. Those which
are woody in habit show considerable tendency to diminish their
leaf surface, probably to diminish evaporation and conserve their
stock of water. Thus they often have many of their branches
transformed into thorns or spines. Others which contain but
little wood are succulent, and their surfaces are covered with a
very thick and tough epidermis, which is strongly cuticularised.
Many of them have leaves which show special absorbing struc-
tures that are often incrusted with chalk or a cake of salt.
This becoming wetted by the dew gives up its captured water to
the absorbing organ of the leaf, thus enabling the latter to
make use of what in the absence of this mechanism would be
lost to it. Many trees growing under the same conditions secrete
a kind of resinous balsam, which coats the surface of their leaves
and subserves a similar purpose. The water absorbed in this
way is very rarely pure, but contains traces of sulphuric acid
and ammonia, which, though trifling in amount, are no doubt
of value in the nutritive processes. The adaptation to their
environment which these plants exhibit is thus chiefly in the
direction of economising a limited water supply.

The influence of the environment on the form of the plant
body can be seen equally well in the case of such plants as grow
in Alpine regions where the cold is usually intense, and the atmo-
sphere for long periods so humid that transpiration is only pos-
sible at times, and where, consequently, the absorption of food
EPIPHYTES 481

materials ismuch impeded. The plants are generally of com-
paratively small size and bear thick, often rolled-up, leaves,
which are evergreen. The thick exterior and the general hard-
ness of the leaf are a response to and a defence against the cold ;
the rolled-up leaves bear on their protected faces abundant
stomata communicating with a relatively large spongy mesophyll,
so that transpiration, when possible at all, may be rapid. The
evergreen leaves also are an expression of the conflict against
the difficulty of food absorption, which in such atmospheric con-
ditions is possible for only a limited period of the year. By pre-
serving its leaves green the plant can take advantage of every
opportunity afforded it.

Some lowland plants show a similar response to their environ-
ment, the form and structure of different individuals of the same
species varying to a certain extent, according to their advantages
or the reverse, in such conditions as sunlight or shade, drought
or moisture, exposure to or protection from cold winds, &e.

Epiphytic plants show some conspicuous modifications
of their structure in consequence of their peculiar habit of life.
They live usually upon the surfaces of trees, to which they cling
by various means, but from which they derive no nourishment
except such as is afforded by accumulations of débris, &c., upon
the trunks. They are not parasitic, but merely live upon the
tree as many other plants grow upon rocks or cliffs. Mosses and
Liverworts are very largely epiphytic, as are certain species of
Phanerogams; the latter are very specialised forms and show
most adaptation of form and structure. Perhaps the most
remarkable feature about them is their aerial adventitious roots
which are given off in some cases from every node of the stem,
so that each internode has its own supply. These are often long,
cord-like structures which are of some thickness, often contain
chloroplasts, and are either covered with a special epidermal
development, or give rise to dense masses of root-hairs. In the
first case, which is common among epiphytic orchids, the epi-
dermis is many cells thick, and is known as the velamen. The
cells are small tracheids, with curious reticulated or spiral
thickenings and often perforated. The cells are empty, or con-
tain only air, and the velamen has consequently a curious glisten-
ing greenish appearance. The mass of tracheids forms a kind
of spongy covering to the root, and is capable of condensing and
absorbing aqueous vapour from the moist atmosphere which
usually surrounds it. The second case is illustrated by many
aroids, and the dense plexus of root-hairs borne upon the aerial

VOL. Il. II
482 MANUAL OF BOTANY

roots serve the same purpose as the velamen of the orchids.
Besides these roots, thus adapted to absorb watery vapour from
the air, epiphytes have frequently others which are closely
applied to the surface of the bark on which they are growing.
These are often strap-shaped, and cling very closely to the tree,
absorbing from the bark the soluble products of its decomposition
and any mineral débris that may be accidentally carried thither.
The small amount of such food stuffs available will explain the
relatively large development of the root system, which is in much
greater proportion than in ordinary land plants.

Parasites are another class of plants that have undergone
much modification of structure in consequence of their mode of
life. The parasitic habit is seen most completely in the group
of Fungi, but itis by no means confined to them. We find many
cases of partial or complete parasitism among flowering plants.

The fungus which is parasitic, derives all its nourishment
from the plant or animal whose tissues it has invaded. Others
of the same group are not parasitic, but live upon decomposing
organic matter, being known as saprophytes. Their mode of
nutrition is, however, essentially the same. In no case is
chlorophyll present in the plant body, a fact which causes
it to be unable to utilise and work up the food materials
which green plants absorb from the air. Instead therefore
of absorbing their carbon in the form of CO,, these parasites
must take it in the form of an organic compound of some
complexity, which is usually some form of sugar. Their
nitrogen can be absorbed much as that of a green plant,
but they appear to utilise compounds of ammonia in preference
to nitrates. No doubt their protoplasm is ultimately fed with
the same materials as is that of the higher plants, but they
lack a great deal of the constructive power of the latter.

Associated with the absence of the constructive processes
which depend upon the presence of chlorophyll we have a great
degradation of the plant structure. Their body is usually
composed chiefly of delicate hyphe, which ramify in the
nutrient substratum, either living or dead, and which absorb
elaborated products of some complexity freely by their whole
surface. There is therefore no need of differentiated absorbing
or conducting tissues, which are accordingly not developed. A
further consequence of the ease with which they obtain their
food is the readiness with which vegetative and asexual repro-
duction is brought about: hence sexuality in many cases is non-
existent among them.
PARASITISM 483

Phanerogams which are completely parasitic show a similar
degradation of structure. They possess no chloroplasts, their
leaves are absent or reduced to the condition of scales, while
their stems are often thick and succulent. Their roots are
the so-called haustoria, which penetrate into the tissues of their
hosts and often complete fusion of the tissue of the host and
the parasite takes place. Such parasites are represented in the
British flora by the Cuscutas and the Orobanchacee.

Many of the plants belonging to the Santalacee and the
Scrophulariacee show a partial parasitism of this kind. They
have short stems bearing green functional leaves, but in addition
their roots become attached by curious sucker-like bodies to the
roots of other plants growing near them, and from these suckers
absorbing cells are developed which penetrate into the substance
of the hosts and draw nourishment from them. The Mistletoe
behaves similarly, striking its haustoria into the tissue of the
branches of the apple, oak, poplar, &c.; but here the parasitism
is partly compensated by the fact that its leaves remain green
when the host has lost its foliage, and by their activity they to
some extent assist the tree on which the mistletoe is growing.
The relationship seems to be almost one of symbiosis rather
than of parasitism.

The habit of capturing insects, which we have seen to be
characteristic of several plants of very different forms, may
also be looked upon as connected with their environment.
Many of them, as Drosera, grow upon a substratum largely
composed of Sphagnum plants, which yield to them a very
limited supply of nitrogenous matter; others are found growing
on the surface of rocky mountains, into the chinks of the stones
of which their roots penetrate; others again flourish in the
sandy soil of deserts; in all of which situations compounds
of nitrogen exist only in very small amount. The organic
bodies yielded by the decomposing bodies of the captured
insects may therefore form a valuable supplement to the ordi-
nary sources of nitrogen.

Besides these influences of the environment, which are very
far-reaching, and modify very largely the shape and structure of
the plants exposed to them, ordinary terrestrial plants also show
great power of reacting to the different external conditions
which they meet. These will be considered in subsequent
chapters.
484 MANUAL OF BOTANY

CHAPTER XIV.

THE RELATION OF THE PLANT TO ITS ENVIRONMENT.
IRRITABILITY.

We have seen in the last chapter that the peculiarities of
form and structure which different plants present are to be
associated with the character of their environment. From
such facts as were there discussed it is evident that the plant is
capable of receiving impressions from without, and responding
to them in various ways. If we examine any plant which does
not show such marked adaptation to its surroundings, we can
find evidence of the possession of a similar power of appreciating
differences in its external conditions, and of responding to them
in various ways. Thus when certain zoospores of some of the
lower Alge, which swim freely in water, are suddenly exposed to
a brilliant light, they at once take up a definite position with
regard to it. When a leaf of Mimosa pudica, the so-called sensi-
tive plant, is roughly handled, it falls from its normal position
and takes upa new one, while its leaflets become folded together ;
when a filament of Mesocarpus is exposed to an electric shock
sent through the water in which it is floating, it is found not in-
frequently that it splits up into its constituent cells. This power
of receiving impressions from without is inherent in the proto-
plasm, and spoken of under the general term trretability.

Not only does it depend upon the protoplasm, but the latter
must be in a healthy condition to manifest it. When a dicotyle-
donous plant which has been growing under ordinary atmospheric
conditions, exposed to diffused daylight, isremoved into darkness
and kept there for some time, it becomes incapable of thus
being impressed byits surroundings. Nor is its irritability alone
affected by the absence of light, for many of its parts, particu-
larly its leaves, cease to grow under such conditions. The
condition which is thus induced by light, and upon which the
manifestations of irritability depend, is known as Phototonus.

Plants, then, when in a phototonic condition, have the power
to respond in various ways to alterations in their environment.
If we consider the nature of the environment in the case of
ordinary terrestrial plants, we find it usually as follows: the
root system is embedded in the soil, among the particles of
which the young root-branches ramify, and to them the root-
hairs become firmly attached; the stem rises vertically into the
INFLUENCE OF LIGHT ON STRUCTURE = 485

air and bears its branches and leaves ; the latter are consequently
surrounded by air containing a varying amount of aqueous
vapour. The aerial portion is subjected to the alternation of day
and night, and during these it meets with considerable varia-
tions of temperature as well as moisture; the whole plant is
constantly acted upon by the force of gravity. The subterranean
parts also find considerable differences from time to time in the
temperature of the soil, the amount of moistore which it
contains, and the scanty amount of light which penetrates into
the crevices between its particles. The environment, though to
a certain extent constant, is nevertheless continually varying in
these respects. Particular plants are also subject to other
disturbances which are more special in their nature.

In considering the ways in which these various factors in-
fluence the behaviour of plants, we may study first their
general relations to light of varying intensity, reaching them
equally on all sides. We find many degrees of illumination,
attaming in some cases an exceptional brilliance, as when a
plant is exposed to the rays of a tropical sun. On the other
hand we find cases where a plant is growing in almost total
darkness.

Ifwe consider first the latter case, we find such a plant much
modified in form and structure. The stem is usually very much
elongated and remains slender ; it is more succulent than the
normal one, and bears extremely small leaves which grow out
from it at a more acute angle than those which it bears when
light has access to it. In cases where the stem is normally
very small and the leaves are large and broad, the change in
form is different. The stem is but little changed, but the leaves
become much elongated and narrow. Certain phylloclades,
such as those of some of the Cacti, become elongated and slender
instead of being broad and leaf-like. The structure, too, is
modified ; the woody and sclerenchymatous elements are much
reduced, and the parenchyma of the cortex is increased in bulk.
It becomes more succulent, and the reaction of its sap is much
more acid. The chloroplasts do not become green, the pigment
which they contain, known as etiolin, being a pale yellow.
In the leaves the differentiation of the mesophyll into palisade
and spongy parenchyma does not take place. The parenchyma-
tous cells of the ground tissue of the stem usually become
considerably elongated; they have, indeed, grown much more
than when the plant receives the normal amount of illumination.
Plants thus affected by darkness are said to be etiolated.
486 MANUAL OF BOTANY

That these changes are to be attributed to the absence of
the light can be seen by comparing two similar plants, the first
cultivated in darkness and the second under ordinary conditions
of illumination, the other conditions being kept the same for both.

The explanation of the changes is somewhat difficult. The
absence of light is clearly the cause of the ditferent colour, for we
have seen that, under such conditions, the pigment chlorophyll
is not formed, but is replaced by the yellow etiolin. When an
etiolated plant is exposed to light, the etiolin is shortly replaced
by chlorophyll and the plant becomes green. Etiolin appears,
indeed, to be the antecedent of chlorophyll. The question of
the non-development of the woody elements and the generally
increased succulence is more difficult to explain, and many
hypotheses have been advanced to account for it. There is u
change in the metabolism, evidently, as shown by the greater
production of organic acids, to the osmotic properties of which
the increased succulence is partly due. The reason for this
change of metabolism is, however, not explained. Diminished
transpiration may, perhaps, account for a good deal, for, as we
have seen, in the absence of light there is but little output of
watery vapour.

It is significant in this connection that the parts which show
the excessive growth are in all cases those in which the water
accumulates as transpiration becomes checked. The effect
must, however, ultimately depend upon the protoplasm, which
we have seen regulates all these functions, and which is pro-
foundly susceptible to the influence of the altered conditions.

If we now examine the effects of too brilliant an illumination,
we find other changes taking place. Many plants which normally
have their leaves so arranged as to expose their upper surfaces
to the incident rays are found under bright sunlight to place
them so that their edges and not their surfaces receive the light.
This phenomenon has been called Paraheliotropism. The effect
is to preserve the chlorophyll from the destruction which follows
upon too bright an illumination.

Another phenomenon, having for its purpose the protection
of the chlorophyll, can be seen in many ordinary dorsiventral
leaves. When brilliantly illuminated they are of a lighter
green colour than when shaded, and this is found to be due to a
different arrangement of the chloroplasts in the two cases. In
the leaf exposed to diffused light these are collected on the
upper and lower walls of the superficial cells, and they present
their broader surfaces to the incident rays. When the light is cut
EPISTROPHE AND APOSTROPHE 487

off altogether for a considerable time and other conditions are
unfavourable, they collect on the lateral and lower walls. In
the illuminated leaf they are found to have partially rotated so
as to present their edges instead of their surfaces to the light,
and to have collected upon the lateral walls. In the first
case the chloroplasts lie parallel to the surface of the organ ; in
the last they are at right angles to the surface. These two
conditions are known as epistrophe and apostrophe respectively.
When the conditions of the incidence of the light are altered,

Fie. 1192.

 

Fig. 1192. Desmodium gyrans. a. Stem with leaves during the day. B, A
similar stem with leaves in the nocturnal position, pointing downwards.
(After Darwin.)

the chloroplasts change their positions accordingly. We see in
these phenomena a power of the protoplasm to respond to an
increase of illumination in such a way as to protect the plant
from injurious consequences.

The effect of light upon structure also can be noted in the
case of such leaves as are brightly illuminated; the palisade
parenchyma being much more fully developed than in leaves
which have grown in the shade. Indeed, the differentiation of
the mesophyll into palisade and spongy parenchyma may be
traced to the difference of illumination which the two faces
488 MANUAL OF BOTANY

receive, for when both are equally well lighted the palisade paren-
chyma appears on both sides, while etiolated leaves, as we have
seen, do not develop this tissue at all.

From a general consideration of the facts briefly summarised
above we may come to the conclusion that light tends to retard
growth in length. This is definitely borne out by actual
measurements of growing organs which have been simultaneously
cultivated under the two conditions of light and darkness. This
action of light is sometimes spoken of as a ‘ paratonic’ influ-

Fre. 1198.

 

Fig. 1193. Nicotiana glauca. A, Shoots with leaves expanded during the
day. B. The same in the nocturnal position, pointing vertically upwards.
(After Darwin.)

ence. It has been further ascertained that the rays of the
spectrum which exercise this influence are those of high re-
frangibility, the blue and violet. To these rays the protoplasm
seems to be excessively sensitive. No mere physical explanation,
such as a dependence on turgidity, or change in mode of nutri-
tion, is sufficient to account for the facts observed; they can
only be referred to the power of the protoplasm to respond to
the influence of the environment.

Rhythmic differences in the intensity of the illumination to

which a plant is exposed, in some cases, exercise a very powerful
NYCTITROPIC MOVEMENTS 489

influence on the behaviour of its leaves. This is best seen
in those plants whose leaves assume different positions during
the day and the night. The sensitiveness to the alternation
of light and darkness is not confined to ordinary foliage leaves,
but in many cases is shared by cotyledons also. The degree
of sensitiveness varies greatly in different plants.

This form of irritability is manifested in a very great degree
by many of the Leguminose. Mimosa pudica is perhaps the
most noteworthy of themall. When this plant is removed from
light to darkness its leaflets close; on being restored to light
they open again, but little time intervening before the change
of position is assumed in either case. Another very good
instance is afforded by Desmodium gyrans, the so-called tele-
graph plant. During the day its leaves are extended almost
at right angles to the stem (jig. 1192 a); as night draws on the
terminal leaflets droop until they assume a position almost or
quite parallel to the stem (jig. 11928). Many others assume still
more curious positions, in some cases becoming twisted on their
petioles or folded together in various ways. In some, as in
Nicotiana glauca (fig. 1198), they rise instead of falling, and
become somewhat closely approximated to each other.

These changes of position are generally spoken of as
nyctitropie or sleep movements, though the latter term is
misleading if it be interpreted to mean a sleep similar to that of
animals, It is not difficult to prove that these curious move-
ments are effected in response to the stimulus of the alternation
of light and darkness, or to a rhythmic difference in the amount
of light which they receive. When a plant which changes
the position of its leaves as described is placed for a time
in darkness, the periodic movement is soon very much
interfered with, and it ultimately stops. The cessation is not,
however, abrupt, but in most plants the movements will continue
for at least a day. Plants, again, which are found in other
countries to show this sensibility will when cultivatedin England
perform the movements at the normal hours and not at times
corresponding to day and night in the countries from which
they come. Nor is it the mere alternation of day and night; it
is rather the difference between the illumination they receive
during the two periods that serves as the stimulus, for some of
them will not assume the nocturnal position unless they have
been brilliantly illuminated during the day. The degree of sen-
sitiveness in this case is not so great as in those where the diurnal
and nocturnal positions are always regularly assumed.
490 MANUAL OF BOTANY

The peculiar movements which the leaves perform in response
to the stimulus are brought about by different mechanisms in dif-
ferent cases. In young leaves they are attendant upon growth,
and are brought about by variations of turgescence upon the two
sides of the leaf or its petiole, which are frequently followed by
growth. We have seen that during growth the internal turgescence
varies a good deal and leads to the curious movements of nutation
or circumnutation. The actual nyctitropic inovement is in these
cases a modification of the extent of the circumnutation and
takes place in response to the stimulus. Those leaves which
show it can be seen by careful observation to be cireumnutating
during the day. When they assume their nocturnal position it
is generally effected by their describing a much longer ellipse
than during their ordinary movement. In some cases only a
single ellipse is described during the twenty-four hours; in
others two ellipses, the nyctitropic one being much the greater
in amplitude. In yet other cases several ellipses may be de-
scribed in the same time. Adult leaves which show this move-
ment do so by virtue of a special pulvinus, or development of the
hypopodium. This becomes turgid alternately on its two faces,
causing the leaf to droop and to rise accordingly. These leaves
generally show the movement for a much longer period than
those in which it is brought about by variations of turgescence
followed sometimes by growth. This naturally follows from
the fact that the growth of leaves is not asa rule very prolonged.

That these movements are essentially dependent on the
power of the protoplasm to receive impressions from without can
be seen from a study of the conditions under which they are per-
formed. When the soil is too dry, or when from any other cause
the protoplasm in the cells is not supplied with water in suf-
ficient quantity, they cease. When the temperature is too low
they are interfered with. Violent disturbance of the protoplasm
by shaking the plant will in some cases prevent their occurrence
for one or two nights.

The purpose of the movement is probably to protect the
delicate leaves from excessive radiation, which affects them very
prejudicially. Their upper surfaces are especially liable to be
injured in this way, and it is noteworthy that in all cases these
surfaces are most sheltered when they take up their nocturnal
positions. Often the upper surfaces of leaflets are then closely
approximated together; in Bauhinia the leaf folds upon its
midrib as an axis, so as to hide completely the ventral face.

The relation of the plant to temperature may next be con-
TONIC INFLUENCE OF LIGHT 491

sidered. Plants are affected by variations in temperature in
ways very similar to those depending on changes in light.
In this case again we may discriminate between a tonic and
a stimulating influence, though both these afford evidence
of the ability of the plant to receive impressions from its
environment, and to respond to them in various ways. It is not,
however, always easy to ascertain the effects due to changes in
temperature alone, as usually other conditions, such as light and
moisture, vary at the same time as the temperature changes.

As we have seen, the environment of the plant is partly the
soil and partly the atmosphere, and the temperature of both may
or may not vary simultaneously. The tonic effects of differ-
ences in the aerial temperature have already been alluded
to more than once in discussing the metabolic processes.
There is for each of these a particular temperature at which
it progresses to the greatest advantage. At lower and at
higher points the protoplasm is less active, and in each case
there is a point below which activity ceases, and one above
which also it does not goon. The same thing is true of the
processes of growth. We call these points respectively the
optimum, the minimum, and the maximum temperatures for
each function. They vary for different functions, and they
vary also for the same function in different plants. We have
said that this may be called a tonic influence; the mani-
festation of it is seen constantly, and it modifies not only the
functions under consideration, but also the general power of the
plant to appreciate all the special stimulations that it from
time to time receives. We cannot say definitely how it affects
the protoplasm, but the constant round of activity, chemical and
physical, which constitutes its life, goes on for some reason
best at the optimum temperature, and is altogether suspended
at the minimum one. At the maximum temperature the death
of the protoplasm generally ensues. The average points of
minimum, optimum, and maximum temperature in the case of
metabolism are about 10°, 30°, and 50° C., though a good deal of
difference can be seen in different plants. The points observable
for growth are slightly lower than those noticed for metabolism.

Variation in the temperature of the soil has a considerable
influence on the absorption of water by the root-hairs, and in-
directly on the process of transpiration. It has been found
experimentally that warming the soil is attended by an increase
in the activity of both these functions. As the absorption of
water by the root-hairs is regulated by the protoplasm they
492 MANUAL OF BOTANY

contain, it is evident that this variation in activity is the cx-
pression of a form of irritability which it possesses.

An instance of the stimulating as contrasted with the tonic
influence of variation in temperature is seen in the opening and
closing of many flowers. Generally these are found to open
in the morning and to close at night, a behaviour which is very
similar to that of leaves showing nyctitropic movements. While
the leaves described above respond readily to variations in the
degree of illumination, flowers seem to be largely uninfluenced
by these, but to respond rather to the differences in the tem-
perature accompanying them. The variations, to be effective,
must lie, however, within the range already indicated as being
necessary for the manifestation of irritability at all. The
response made by the floral leaves seems, as in the case of the
foliage ones, to take the form of varying turgescence of the
two sides of the growing part, followed in many cases by
actual growth.

CHAPTER XV.

SPECIAL SENSITIVENESS AND ITS RESULTS.

Brsies the general reactions of protoplasm to variations in
those features of the environment which affect more or less the
whole plant, we find instances of special sensitiveness in various
parts to influences which are not appreciated by the whole of
the living substance. Of these the most prominent are lateral
light, gravity, contact with foreign bodies, and moisture. One
or two other cases of special sensitiveness affecting only par-
ticular organisms may also be discussed.

LateraL Licut.—The effect of the lateral incidence of light
may be studied very easily in the case of young seedlings. When
these are so placed that rays from a light-source illuminate one
side of their stem, very soon a curvature is apparent in the part
which is actively growing. This is of such a nature as to place
the axis of the plant in a position parallel to the incident rays.
It manifests itself sometimes very rapidly, at other times more
slowly. This response to a lateral stimulation is not confined
to the stems of seedlings, but may be seen to a greater or less
degree in many adult plants. It is a matter of common obser-
vation that geraniums grown in « window all bend their stems
towards the illuminated side.
HELIOTROPISM 493

The same stimulus may also produce in other cases the
opposite effect. When a young root is exposed to it, it curves
so as to place itself in the same position with regard to the
incident rays, but with its growing apex placed in the opposite
direction. Stems are said accordingly to grow towards, and
roots away from, the light-source. This behaviour is not,
however, confined to roots, it is exhibited by the tendrils of
Bignonia capreolata, by the peduncles of Cyclamen persicum,
and by many other organs.

Leaves in many cases show a similar sensitiveness, but the
position they assume is different again. They place themselves
so as to present their upper surfaces at right angles to the
incident rays.

These three movements in response to the stimulus of the
lateral light are spoken of as heliotropism, apheliotropism, and
diahelictropism respectively. The advantages thus secured are
in some cases very obvious; thus the heliotropism of the stem
places its leaves in the most favourable position for the action
of the chlorophyll in decomposing the CO, they absorb; the
apheliotropism of the root assists it in penetrating into the
crevices of the soil. The tendrils of Bignonia are aided by it in
coming into contact with a support about which they may twine,
while the apheliotropism of the peduncles of Cyclamen, which
are bent downwards in a hooked fashion, enables them to grow
towards the soil, into which they press the capsule, thus burying
the seeds.

The response to the stimulus varies sometimes with the age
of the organ. Thus the hypocotyl of the Ivy is heliotropic when
young, but becomes apheliotropic when old.

The sensitiveness varies very greatly in different organs.
Some of the seedlings of Phalaris examined by Darwin responded
to such a feeble degree of illumination that it was hardly
sufficient to cast the shadow of a pencil upon a piece of white
paper held close behind it. The rapidity of the response also
varies, some organs bending almost immediately, while others
do so much more slowly. To this point we shall return later.
The movement of apheliotropism is usually much slower than
that of heliotropism. :

The bending is not caused by a direct interference of the
light with the actual growing part. It would seem at first as if
the retarding effort of light upon growth might explain the
bending of the organ towards the light-source, the non-illu-
minated side continuing to grow while the illuminated one is
494, MANUAL. OF BOTANY

checked. This explanation .is directly’ contradicted by the
phenomenon of apheliotropism as exhibited by a root. It is
moreover proved to be an insufficient explanation by the fact
that the part which is sensitive to the stimulus is not the part
which actually bends. Darwin showed this by amputating
a small region about ‘1 inch in length from the tip of the
seedling, or by lightly covering the same part with an opaque
cap, when he found that the heliotropic curvature did not take.
place. Further, when the part normally curving under the
influence of the stimulus is mechanically hindered from bending,
the curvature takes place at « part a little lower down, which
normally remains straight.

‘When the lateral light is fairly intense, the resulting move-
ment takes place uninterruptedly ; when it is only weak, the
position is assumed by a series of zigzag movements, indicating
that the new movement is an exaggeration of the ordinary
circumnutation of the part. When the final position is reached
the organ is found to circumnutate about the new direction of
the axis.

A somewhat similar response to a lateral light is exhibited by
many unicellular organisms. When these are exposed to oblique
illumination they take up a definite position with regard to the
incident rays, placing their long axis parallel to them if the light
is weak, and at right angles to them if it is intense. This
behaviour is known as Phototaxis; it is exhibited by the
zoospores of many of the Alege and by certain Desmids.

Graviry.—The force of gravity exerts an influence upon
plants somewhat resembling that of lateral illumination. Thus
most stems grow vertically upwards into the air; primary roots
grow vertically downwards into the soil. A few organs, such as
certain rhizomes, the stolons of many plants, and most secondary
roots, grow at right angles to the direction of gravity. When one
of these is placed at an angle from the position it usually takes,
a curvature of the growing region results, which lasts till the
normal attitude is regained. Thus when a young seedling is
detached from the earth and laid upon its side, the stem
gradually curves through an angle of 90° and becomes erect,
while the young root curves in the opposite direction till it
points vertically downwards. Similarly when a stolon is placed
vertically, its apex is slowly deflected until it is parallel with the
soil. These movements are termed apogeotropism, geotropism,
and diageotropism respectively.

To prove these movements to be responses to the stimulus
GEOTROPISM 495

of gravity, it is necessary to eliminate the action of the latter
force and to observe the direction of growth under the new con-
ditions. This can be done by causing the plant to grow upon
an apparatus known as a Klinostat, which is a wheel rotating
upon a horizontal axis at a regular rate, a complete revolution
being made in about twenty minutes. The plant is placed in a
horizontal position on the revolving wheel, so that each side of
the axis comes alternately under the influence of the force. All
parts of it are so affected equally, and it is found that then no
curvature of the horizontal axis of the plant occurs in either
direction. Another experiment, due to Knight, pointing to the
same conclusion, is that of growing a plant upon a rapidly re-
volving wheel mounted on a vertical axis. When the wheel
revolves sufticiently rapidly, though the plant is exposed all the
time to the action of gravity, the centrifugal force of the apparatus
is so much greater than the force of gravity that the plant does
not respond to the latter. Instead, it responds to the stimulus of
the rapid rotation, and the roots grow outwards from the centre of
the wheel, while the stem grows inwards towards it. The force
acts much like that of gravity, and the plant responds to it in a
similar way, the root growing in the direction of the force and
the stem in one opposite to it.

As in the case of heliotropism, the part which receives or is
sensitive to the stimulus is not the part which curves. In the
case of a root it has been demonstrated by Darwin, and more
recently by Pfeffer, that the sensitive part is the tip, while the
curvature is some distance further back, where active growth is
taking place.

As in the former case, the movement of geotropism or
apogeotropism is not confined to growing organs. When the
haulm of a grass is placed horizontally on the ground, as is the
case when a patch of wheat or other grass is beaten down by
wind or storm, it after a time again becomes erect. The new
position is due to the renewal of growth on the under side of the
swollen nodes, which is excited by the stimulus and proceeds
till the stem is again vertical.

As in the case of heliotropism, the sensitiveness varies very
much in different plants. The movement is usually a modifica-
tion of cireumnutation.

CoNTACT WITH 4 FOREIGN Bopy.— Many instances of sensitive-
ness to this form of stimulus have been observed. When a leaf
of Mimosa pudica is handled, the leaflets all droop downwards
with great suddenness, and if the handling is very rough all
496 MANUAL OF BOTANY

the leaves on the plant behave similarly. When a stamen of
Berberis is touched at a point a little below the anther, the
whole stamen bends forwards towards the pistil. The stigma
of Mimulus, which is normally composed of two lobes extending
outwards from each other, will, if either lobe is touched with
a fine point, close, so that the upper surfaces come into contact
with each other. When an insect alights on the surface of a leaf of
Drosera, the tentacles with which it is furnished slowly curl over
so that their terminal glands are brought together at the point of
irritation; and at the same time the glands pour out a viscid,
slightly acid secretion which is capable of digesting the proteids
of the insect’s body. The leaf of Dionza, the Venus’s fly-trap,
which is normally widely expanded, closes with great rapidity
when ore of the six sensitive hairs which spring from its upper
surface is touched. The leaf closes as if the midrib were a
hinge, approximating the upper surfaces on each side so as to
imprison the body which touches it.

This form of sensitiveness is peculiarly characteristic of the
growing apex of young roots. If a seedling bean is taken,
and a small piece of cardboard is attached to one side of the
tip, a curvature speedily results which causes the root to bend
away from the irritating body. If the movement takes the
sensitive part away from the latter, the curvature is slight, but
if, as in the experiment, the foreign body accompanies it in its
displacement, the curvature will continue until the root is coiled
completely round. The stimulus in the case of this movement
must be prolonged, differing thus from the cases noted above,
where a mere touch is sufficient to bring it about.

The cause of the curvature must be the sensitiveness of the
protoplasm to the stimulus of contact. The movement cannot
result from any injury done tothe cells causing a hindrance to
growth, for if this were the case the curvature would be towards
the body touching the root, whereas it is in the opposite direction.
If the cells of the side of the root at some distance from the tip
are stimulated in this way, the curvature is round the stimulating
body and not away from it. This may very likely be due to
such a mechanical hindrance of the growth. In the first case,
moreover, the part which shows the curvature is not the part
irritated, but a region some little distance further back.

Perhaps the best instance of this susceptibility to slight
contact is afforded by the behaviour of tendrils, the twining of
these organs round their supports being altogether due to it.
A very slight touch is sufticient to bring about a perceptible
TWINING OF TENDRILS 497

curvature; in the case of the tendrils of Passiflora gracilis,
indeed, Darwin found that the contact of a small loop of thread
weighing not more than 4; grain induced it, while a mere touch
caused one to assume the form of a helix in about two minutes.
This is perhaps the most sensitive tendril known ; with others a
stronger stimulus is needed and the time taken for the response
is longer, the irritability varying greatly. Tne behaviour of
tendrils in twining is-somewhat peculiar. When young they
are generally circumnutating, and if in their movement they
come into contact with any foreign body they begin to curve
towards it. If the contact be not prolonged, the tendril will
curve for some time, but will ultimately become straight again
and move as before, till it touches something else. If, on the
other hand, the body first touched is one round which the
tendril can twine, it coils itself round it; the stimulus thus
persists and the resulting curvature increases it, till the support
is encircled many times by the sensitive twiner. The coiling is
seldom confined to the part of the tendril in contact with the
support, but the free part between the latter and the axis of
the plant also twists itself into a spiral coil. If the two be not
very close together, this spiral usually shows two parts, the coils
of which are in opposite directions. This is, however, only
because the filamentous body is attached at both ends.

The tendril, though thus sensitive to contact, does not
coil, according to Darwin, if its sensitive surface is struck by
drops of rain, nor in the case of the Passiflora already alluded
to, if contact takes place between two tendrils.

The sensitive region varies in different tendrils, but it
cannot be so strictly localised asin the case of the growing root.
They are usually irritable on one side only, which is slightlv
concave, though in some cases the sensitiveness extends all
round them. The lower part of the tendril is, as a rule, only
sensitive to prolonged contact. Their susceptibility further
varies with their age, being greatest when they are about three
parts grown. The part which first responds to the stimulus is
usually the part touched, but, as we have seen, the coiling also
takes place nearer their bases, so that we have an evident
transmission of the stimulus backwards, as in other cases
noted. The method of response is usually increased turgidity
upon the convex side followed by greater growth, though in cer-
tain cases careful measurement has shown that the concave side
becomes perceptibly shorter.

This sensitiveness to contact, which is so markedly shown

VOL. II. KK
498 MANUAL OF BOTANY

by tendrils, is possessed also, though to a much smaller extent, by
most climbing stems, whose behaviour has already been described.
It is shown also by the parasite Cuscuta, whose stem twines round
those of other plants growing near its germinating seeds, and
whose haustoria ultimately penetrate them. Twining petioles
of similar behaviour are also met with.

Another form of irritability is exhibited by growing shoots,
which is perhaps somewhat akin to sensitiveness to contact. If
a shoot be struck laterally several times near its base, its apex
curves over towards the side struck. Ifthe blows be given near
the apex, the curvature is in the opposite direction.

The mechanism whereby the response to the stimulus of
contact is brought about in growing organs, we have seen to be
an increased turgidity on the convex side, followed by growth.
In those cases in which the organ is mature, it is evident
that growth can have nothing to do with the movement. In
these instances we have rather to do with a modification of
turgescence, involving a redistribution of the water contained in
the organ. The falling of the leaflets and leaves of Mimosa is
due to a sudden change in the protoplasm of the cells in the
lower side of its pulvinus, in consequence of which water
escapes from them into the intercellular spaces between them.
It is attended by a change of colour, the pulvinus becoming of
a deeper green in consequence of the replacement ofair there by
water. If a leafhbe cut off, and after the plant has recovered from
the effects of the injury an adjacent leaf be sharply stimulated,
water is seen to exude from the cut surface of the pulvinus.
The cases of the irritable stamens and stigmas are probably to
be explained similarly. The closing of the leaf of Dionma is
due also to a redistribution of the water in the cells, brought
about by a rapid change in the protoplasm somewhat perhaps
akin to contraction. In Drosera the inflexion of the tentacles
has been found to be preceded by a peculiar churning movement
of the protoplasm in the cells upon the side which becomes
concave. This movement, which Darwin, who discovered it,
called aggregation, is attended by a loss of turgidity.

Morsture.—Sensibility to variations in the moisture of the
environment is not so widely distributed as are the forms of irrita-
bility hitherto discussed. It is exhibited chiefly by roots and by
the rhizoids of the Hepaticee among green plants, and by the
hyphe of certain Fungi. These tend to curve in the direction of a
moist surface if they are growing near one. When young seed-
lings are cultivated in a vessel which contains moist sawdust or
HYDROTROPISM—CHEMIOTAXIS 499

sand, and is perforated so as to allow the rootlets to protrude,
these grow vertically downwards, according to their geotropism.
As soon as they protrude, they curve to a greater or less extent
towards the moist surface, as if seeking the moisture. This
phenomenon is known as hydrotropism. The root-tip, as in
other cases, is the sensitive part, while the curvature takes place
further back, where growth is most active. Negative hydro-
tropism is very rare, being exhibited only by some of the
Myxomycetes, which move away from moisture.

The advantage of this form of sensibility is evident in the
case of the root, which, by virtue of it, is drawn towards the
moisture of the soil as it penetrates between its particles.

A curious instance of appreciation of lack of moisture is
afforded by Porlierta hygrometrica, which under such conditions
closes its leaflets much as nyctitropic plants do when light gives
place to darkness.

CHEMICAL STIMULI.--Besides the forms of sensitiveness which
we have discussed so far, there is evidence that vegetable proto-
plasm can appreciate stimuli of a different kind. These are less
widely manifested, but instances are fairly abundant among the
lower forms of plants.

A certain number of unicellular organisms are strongly
affected by the presence of free oxygen. The most interesting
case of this is that of Bacterium termo ; when a number of these
plants are placed in a drop of water on a slide, and examined
under the microscope, they are found to aggregate at the edges
of the cover-slip. Ifa small green Alga is placed in the drop
with them and the slide exposed to light of w sufficient inten-
sity to enable the decomposition of CO, to take place, the evolu-
tion of oxygen attracts the bacteria, which at once swarm round
the alga. So sensitive are they to this attraction, that if the
spectrum of sunlight is thrown upon the alga, the bacteria
accumulate at those parts which are illuminated by the red and
blue rays, the rays which we have seen to be capable of effecting
the decomposition of the CO,. This response to the attraction
of oxygen is not confined to these bacteria; it is afforded by
many zoospores, and also by the plasmodia of some of the
Myxomycetes.

It has already been observed that when the necks of the
archegonia of the Cryptogams open they discharge a certain
mucilaginous fluid which attracts to the organ the free-swimming
antherozoids. Careful experiments have been made in many

cases to ascertain what is the nature of the attraction, and it has
KK2
500 MANUAL OF BOTANY

been found that the mucilage contains various substances which
the antherozoids seek. Inthe case of the Ferns, and some Sela-
ginellas, it has been determined that the attractive body is malic
acid. When a capillary tube containing a weak solution of this
substance is inserted into water containing some of the anthero-
zoids, they make their way very quickly to the orifice of the
tube. In the case of Mosses the attractive substance is cane-
sugar. That there is a definite attraction appears from the fact
that strong solutions of either acids or alkalies are avoided by
them with equal earnestness.

A similar behaviour marks the plasmodia of certain of the
Myxomycetes. They move slowly towards a watery extract of
tan, but retreat from a solution of sugar, glycerine, or certain
neutral salts. Similarly, the zoospores of Saprolegnia are
attracted by a solution of extract of meat.

The sensitive tentacles of Drosera can respond not only to
contact, as before mentioned, but also to various substances
placed upon the leaf. They are easily induced to bend by drops
of liquid containing proteid matter, such as solution of albumen,
or milk. Certain inorganic salts, notably carbonate of ammonia,
produce the same effect.

A curious instance of this kind has been noted recently by
Miyoshi. He cultivated certain fungi in gelatin containing a
small proportion of sugar. Under the stratum in which the
hyphe were ramifying he placed another containing a larger
proportion of sugar, and between the two arranged a membrane.
The hyphe very soon grew towards the stronger sugar solution,
and to reach it penetrated the membrane.

Other instances of similar behaviour might be quoted. To
this form of sensitiveness the name of Chemiotaxis has been
given.

CHAPTER XVI.

THE NERVOUS MECHANISM OF PLANTS.

Ir is difficult to refrain from coming to the conclusion, from a
consideration of the facts examined above, that the nervous
system of the animal kingdom is represented in the vegetable
one. That plants are sensitive to variations in the conditions
surrounding them, and that the responses they make to such
variations are purposeful, and conduce to the wellbeing of the
NERVOUS MECHANISMS 501

organism, is abundantly evident. The response to any external
stimulus, moreover, has been seen to be dependent upon the
plant being in a state of health and vigour. If its wellbeing
has been interfered with by such disturbances as deprivation of
light, or lack of oxygen, or exposure to too high or too low
a temperature, no response is given, for its irritability is in
abeyance or destroyed. Its own age again has been seen to
have an important influence upon its power of receiving im-
pressions and its behaviour in responding to them.

In considering from this point of view the way in which
plants are affected by external influences, it is noteworthy that
an exceedingly small stimulus is able to bring about a very con-
siderable effect, and that there is no direct ratio between the
intensity of the stimulus and the resulting movement. The
tendrils of Passiflora, already alluded to, are caused to move
by the contact with them of a small piece of thread, weighing
not more than 4 of a grain, and the resulting movement is
of considerable extent and is prolonged for some time. The
sensitive hair of the leaf of Dionza needs only a touch to cause
a rapid movement of the whole leaf-blade; the pricking of the
staminal filament of Berberis causes a considerable movement
of a relatively bulky body. The seedlings of Phalaris bend with
some speed towards a light which is not sufficient to cause
a visible shadow at the distance at which they are placed
from it.

It can hardly be imagined that such slight disturbances can
act mechanically upon the parts that move. This point is
illustrated by the observation made by Wiesner, that if a part
which responds only to the stimulus of lateral light be exposed
for some time to such an illumination, and then, before the
curvature has begun, be removed into darkness, it will slowly
bend towards the side which has. been stimulated. The same
observation has been made by other observers in the case of
the stimulus of gravity. There is no other explanation possible
than that the stimulus brings about changes in the protoplasm
of the cells of the moving part which slowly modify their relation
to the water of their contents so that a great alteration of their
turgidity results. Moreover the separation of the part stimu-
lated and the cells which are the seat of the resulting action,
implies that there must be in the plant a means of rapidly con-
ducting such external impressions from one part to another.
To this point we shall return.

If then we admit that there is even a rudimentary nervous
502 MANUAL OF BOTANY

system in plants, we should expect to find a more or less evident
differentiation of it in the direction of sense organs. This
is in fact afforded in many cases. Darwin found that the
seedlings of Phalaris were not sensitive to the faint light em-
ployed in his experiments except at « small region extending
about 75 inch from the apex. If this part were covered
by an opaque screen in the shape of a small blackened cap, of
not sufficient weight to cause any flexion of the stem, the seed-
lings no longer bent towards the light. Similar careful experi-
ments made by the same observer pointed out that the tip of
the young root was its only sensitive part. Other observers
have proved the same thing. Cisielski amputated the tips of
certain rootlets and laid them horizontally on a support. They
then did not show any sensitiveness until they had recovered
from the wound and a new root-tip was formed on each. As
soon as the new tip was developed the rootlets showed a power
of reacting to the force of gravity, and the curvature resulted in
the usual place, More recently Pfeffer has demonstrated the
same localisation. The whole leaf of Dionea may be somewhat
roughly handled without closing, so long as no contact is made
with the hairs upon a particular portion of the blade. But so
soon as one of these is touched the leaf closes. It is impossible
to avoid the conclusion that we have to do here with a localisa-
tion of sensitiveness or the differentiation of sense organs.
True the differentiation is anatomically very slight, but physio-
logically it is considerable. The same sense organ again is
sensitive in very different degrees to different stimuli, and, as we
should expect, to different strengths of the same stimulus. Ifa
sensitive organ be acted upon at the same time by two stimuli
which usually produce opposite movements, the resulting posi-
tion is always that which would be caused by the stronger of
the two.

One of the characteristic features of the nervous mechanism
of an animal is the definite character of the response made to
a stimulus. This point is also brought out in considering the
behaviour of the parts under notice. If a root-tip is brought
into contact with an obstacle, the bending is invariably in such
« direction as to enable the root to pass it. When one is
allowed to impinge upon a plate at right angles to its direction
of growth, the curvature continues till the root has turned
through aright angle and can grow parallel to the opposing
surface. Ifon the other hand a part some little distance above
the tip is obstructed, the curvature is towards the obstacle, a
NERVOUS MECHANISMS 503

course which serves the same purpose. The stimulus causing
the movement of hydrotropism serves to bring the root-hairs
into contact with the moist surface, thus enabling them to dis-
charge their appropriate function. The behaviour of the tentacles
of Drosera is very interesting in this connection. The leaf is of
some size, and can therefore receive stimuli over a fairly large
area. When the tentacles bend over in response to the alight-
ing of an insect, they do not do so irregularly, but always place
their glandular apices directly upon the spot which is the centre
of the disturbance. This is very definitely purposeful, the
invader being captured and digested wherever it alights, as
all the tentacles are brought to bear upon it. The purposeful
character of heliotropic and diaheliotropic curvatures is also
very evident, the leaves being always placed thereby in the
most favourable position for the discharge of their functions.

This special sensitiveness can be distinguished again from
the general state of irritability in the plant. So long as the
conditions remain favourable the latter is considerably prolonged,
but the power of responding to particular impressions disappears
much sooner. In some cases this power can be ascertained to
have been lost by an organ while it still retains its power of
circumnutating. The effect of a prolonged stimulation some-
times is to fail to produce a movement. Thus in the case of
Dionea, repeated touching of one of the hairs, if the leaf be
prevented from closing, ultimately leads to such a touch having
no effect when the leaf is released. This is a result of exhaus-
tion or fatigue. At first it may seem doubtful whether or no
the interference with the free response of the leaf may have so
injured the motor mechanism as to make it incapable of acting.
The exhaustion, however, is shown to be that of the hair and not
of the hinge, by the fact that touching another of the hairs at
once causes closure.

The nervous sensitiveness is by this and many other similar
experiments shown to be capable of fatigue. A similar suspen-
sion of power may be demonstrated by exposing the sensitive
parts to anesthetics, such as the vapour of chloroform, ether,
&e. The effect of these drugs at once suggests a similar action
to that which they have on the nervous mechanism of an
animal. When the effect of the fatigue or the anesthetic has
passed off, the organ again becomes capable of responding.

Anervous system generally can be shown to possess three dis-
tinct parts : one means whereby external stimulation is received
and appreciated ; another whereby movements, &c., are caused ;
504 MANUAL OF BOTANY

and a regulating and controlling part which can co-ordinate the
response to stimulation, or can initiate movements, &c., in its
absence. In the higher animals these are well differentiated
from each other; we have the sense organs and the afferent
nerves; the efferent nerves, connected with the motor and other
mechanisms ; and the nerve-cells which possess the co-ordinating
power. Inthe much less differentiated plant-body the first two
of these at least are recognisable. If we compare the sense
organs of the animal with the sensitive parts of the plant, we
find a certain correspondence, though it must not be pressed
too far. The power of sight is very complete in the higher
animals, in consequence of the highly differentiated character

Fig. 1194.

 

Fig. 1194, Continuity of the protoplasm of contiguous cells of the endosperm
of a Palm seed (Bentinckia), «. Contracted protoplasm of a cell. 6b. A
group of delicate protoplasmic fibrils passing through a pit in thecell-wall.
(Highly maguified, after Gardiner )

of the eye. In the lower animals it becomes less and less
perfect, till in some it goes probably little further than the
power of appreciating light. This power we have seen to be’
possessed by certain parts of the young seedlings of various
plants in a very high degree, and by other organs to a less
extent. The sense of touch may be compared with the power
of responding to the stimulus of contact shown by tendrils and
by the tips of roots; the muscular sense, or-power of appre-
ciating weight, is not dissimilar to the property of responding
to the force of gravity, while the chemiotactic behaviour of the
organisms described above suggests a rudimentary power of
taste or smell, or both.

The conduction of the impulses received is due in animals
NERVOUS MECHANISMS 505

to the existence of differentiated nerves. The way in which itis
carried out in plants has been much debated, but since the dis-
covery of the continuity of the protoplasm through the cell-walls,
there is little doubt that we have here a similar mechanism.
There is scarcely any differentiation, but the power of the proto-
plasm to conduct disturbances from one part of the cell to another
is a matter of common observation. The connecting strands
between adjacent cells (fig. 1194) will suffice to suggest how
impulses from the tip of the root may reach the growing cells.

The motor mechanism seems at first to be entirely different
from that of the animal organism. Closer consideration,
however, lessens the difference considerably. The contractile
power is but little developed in vegetable protoplasm, but it
has its representative in the power of resisting or assisting the
transit of water. The effect is really similar in both cases;
in the one the disturbance to the protoplasm leads to a contrac-
tion of its substance, in the other to its modifying its resistance
to the passage of water through it. Each protoplasm responds
in its own appropriate fashion.

The plant shows, however, an almost complete absence of the
differentiation that reaches its highest point in the nerve-cell.
There is apparently no co-ordinating mechanism which receives
the impulses from the sense organs, and initiates in consequence
the resulting movement. This-need-not, however, lead us to
deny the existence of a nervous system, but only to remark
upon the very slight degree to which it is differentiated.
Darwin has called attention to one instance in which something
of the kind is seen. When a tentacle of Drosera is stimulated,
the actual bending is preceded by a curious motility of the
protoplasm of the cells of its stalk which has been called
aggregation. If a tentacle on the leaf is excited, the tenta-
cles of the margin are gradually inflected towards the excited
spot, as already described. If the cells of one of the marginal
tentacles are watched during the experiment, their contents are
found to undergo this aggregation, but those nearest its apex
manifest it first. If the aggregation were the direct ettect of
the stimulus, those which it reached first, z.e. those nearest
the base, would respond first. The stimulus, apparently, has to
travel up the tentacle to the gland, and a disturbance to originate
there in response, this disturbance travelling down the tentacle
in the direction of its base. Darwin has pointed out that this
corresponds in a measure to the reflex action of the animal
organism.
506 MANUAL OF BOTANY

If we are able from these considerations to recognise in the
plant a nervous system in any way comparable to that of the
higher animals, we are led to the view that the differences between
the two are to be referred to differences of degree of differentia-
tion. The latter is on the whole very slight in plants, nothing
at all corresponding to the powers of consciousness or volition.
There is, however, a differentiation in the sense organs in the
direction of sensitiveness, which will equal if not surpass the
powers of those of an animal. The tendril of Passiflora
appreciates and responds to a pressure which cannot be
detected by even the tongue; the seedlings of Phalaris readily
obey the stimulus of an amount of light which is hardly per-
ceptible by the human eye. The power of response to the
stimulus is of course very much less than in the animal, but
this, as we have seen, depends upon the differences in the motor
mechanisms. In the vegetable protoplasm we have a much
slower response, as well as one of a different kind, the effects
taking as a rule longer to manifest themselves, and lasting
for a longer time after the stimulus has been withdrawn. We
have, however, as in the animal mechanism, a much better
response to a cumulative or prolonged stimulation than to one
which is rapid and transitory.

CHAPTER XVII.
AUTOMATISM.—RHYTHM.

THE instances of sensibility we have been considering have been
seen to be such as are manifested in response to external stimu-
lation of various kinds. The responses made have been found
usually to take the form of what are generally called movements
of either the whole plant or of some of its members. Though
called movements, however, they must not be interpreted in all
cases to be such in the strict sense. They are rather changes of
position brought about by varying turgescence, or alteration of
the rate of growth in particular aggregations of cells. The
protoplasm has been seen in many instances to play rather a
passive than an active part in bringing about the change in
position. ,

Besides these, however, we have yet to consider some similar
phenomena in which the protoplasm is more directly concerned,
and the nature of the stimulation, or the exciting cause of the
AUTOMATIC MOVEMENTS 507

changes involved, is very obscure. Such phenomena are roughly
classed together under the name of automatism, or automatic
movement.

We have seen that certain plants at particular times emit
from their body small masses of naked protoplasm which are
furnished with a varying number of long filaments. These
filaments, which are protoplasmic, are ordinarily in a state of
active vibration, causing currents in the water in which they
live, which float them quickly from place to place. Such free-
swimming cells include the zoospores of the Alge and the
antherozoids of these and higher plants. The movement is
brought about in the absence of any external stimulation, though
the cells are capable of receiving such impulses. The cause
of the movement is probably the contraction of each side of the
filament, or ciléwm, alternately, or of the part of the cell just at
its point of attachment. The impulse leading to the movement
must be sought in some decomposition originating in the
protoplasm itself, and not excited by any stimulus from without.
The phenomenon is often spoken of as ciliary motion.

Of a somewhat similar character is the curious creeping
movement of the Myxomycetous fungi. Hach of the zoospores
of these organisms consists of a mass of naked protoplasm
which makes its way over the surface of its substratum by
putting out blunt processes of its own substance, known as
pseudopodia. These are protrusions of the ectoplasm, and the
more fluid endoplasm is in some way drawn into them, so that
the rest of the cell follows the movement of the pseudopodium.
Which part of the operation really corresponds to the act of
contraction is disputed, but it seems probable that it is the
second, and that the first protrusion is of the nature rather of
relaxation. In either case, however, the movement is indepen-
dent of any external stimulation.

The Diatoms, which we have seen to form a sub-class of the
Algw, are capable of a curious gliding movement, which enables
them to make their way with some rapidity through the water
in which they live; they also are found to do this in the absence of
any apparent stimulus; the Oscillatorie, which are filamentous
alge anchored to a substratum by one end of the filament, are
also in constant wavy motion to and fro; a movement the
mechanism of which is still unexplained, and which possibly
resembles that of the diatoms. These are instances of the same
automatism, the protoplasm in all probability originating the
movement and carrying it ont.
508 MANUAL OF BOTANY

In certain lowly organisms such as Chlamydomonas there is
to be seen in the protoplasm a clear space or vacuole, which
exhibits a more or less regular pulsation, appearing slowly as
a nearly spherical cavity, and then suddenly disappearing,
recalling the active contraction of animal protoplasm. These,
like the last-mentioned plants, are instances of movement in
consequence of internal changes and not of external stimula-
tion.

In the higher plants evidence of this special automatism is
not lacking. Setting aside what is common to all plants, the
inherent power of living substance to construct itself from food

Fie. 1195.

 

Fig, 1195. A portion of a branch, with a leat, of Desmodium gurans. The leaf,
which is compound, consists of a large terminal leatlet, a, and two smaller
lateral oues, 0,6. There are also two other rudimentary leaflets, marked c,
near the terminal leaflet,

materials, to carry on respiration and other vital functions,
which are of course evidence of automatism, we have in a few
cases distinct power of automatic movement. The protoplasm
of the cells of the leaves of Vallisneria, of the internodal cells
of Chara, of the pollen-tubes of many plants, of the cells of the
staminal hairs of T'radescantia, and others quoted in discussing
the structure of the cell, is in constant rotation round the cell,
or movement within it in definite directions.

These instances impress upon us the belief that all protoplasm
is the seat of active molecular movement, the intensity or vigour,
however, varying very greatly in different cases. Indeed the
RHYTHM 509

life of the protoplasm is intimately bound up with such a motile
condition. Manifestations of this motility have from time to
time been noticed above ; especially we may again allude to the
regulation of turgescence, which we have seen to be one of the
properties of vegetable living substance.

In many cases it can be noticed that these automatic move-
ments set in with a certain definite intermittence, recurring,
so long as conditions are constant, at- regular intervals. The
pulsating vacuoles already alluded to may be instanced in
this connection. Such regularly intermittent actions may be
described as rhythmic and the intermittence spoken of as
rhythm.

When we look back upon the various functions we have
examined we tind evidence in them that rhythmic changes in
the protoplasm are very widely met with in the life of the
vegetable organism. Very conspicuous instances of it are
afforded by certain movements often exhibited by the leaves of
particular plants. Perhaps the most familiar of these is the so-
called telegraph plant, Desmodiwm gyrans. The leaves are
ternate, the terminal leaflet being very large in comparison
with the two lateral ones (fig. 1195). If the plant be watched
while exposed to a suitable temperature, the lateral leaflets are
found to move up and down on the rachis, sometimes passing
through an angle of 180°, and twisting slightly as they move.
They thus describe a kind of ellipse, the duration of the move-
ment being about two minutes. Many other instances of a
similar kind are known, the Leguminose furnishing many
~ examples. All of them do not exhibit them with the same ease,
as they are much interfered with by the changes in position
caused by external stimulation. They can often be made
evident by keeping the plant either in the dark, or exposed to
light of uniform intensity. Darkness, however, if too prolonged,
results in the cessation of the movements, as these can only
take place while the plants are in a condition of phototonus.
The mechanism of the movement in most of these cases is the
varying turgescence of pulvini at the bases of the leaflets. The
alterations in this turgescence are the expression of rhythmic
changes in the protoplasm of the cells.

The same rhythmic changes have place in all young growing
organs, leading to the variations in turgidity that cause the
movements of nutation and circumnutation which accompany
growth.

The nyctitropie movements we have discussed may be quoted
510 MANUAL OF BOTANY

in support of the existence of rhythm. Though they are ordi-
narily exhibited in response to the stimulus of alternate periods
of light and darkness, many plants continue to exhibit them
when altogether removed from light. That they cease after a
day or two of darkness, is probably due to the fact that the
plants are then no longer in a phototonic condition. Many
flowers continue to open and close their corollas when removed
from variable to constant conditions.

The same tendency to rhythmic change is shown in what
is called the periodicity of the various vital functions. If, for
instance, the root pressure of a plant be examined by the aid of
the apparatus already described, in which the water taken up
is made to support a column of mercury in a mamometer,
when the column of mercury has reached what we may call
its mean or average height, it does not remain there, but begins
to oscillate. It rises in the morning till about midday, then
sinks somewhat, rises again towards the evening, and falls
during the night. There is thus roughly a daily variation of
the absorbent activity of the roots, which is very little affected
by changes in the environment ; it isin fact automatic.

There is a similar daily variation in the bulk of a plant, the
diameter of the various organs diminishing from night till
some time in the afternoon, and increasing thenceforward till
dawn. These variations largely depend upon the distribution
of the water which the plant contains, which is regulated by
the living substance.

Many other instances of the same periodicity or rhythm
might be quoted, but it is hardly necessary to multiply examples.

Though this rhythmic alteration of the protoplasm in
various ways is no doubt inherent in plants, as appears from
its occurrence when conditions are kept constant, it is easily
affected by external causes. The effect of continuous darkness,
we have already seen, is that the movements are made irregular
and ultimately stop. In many cases the difference in degree of
illumination between day and night affects the readiness with
which the nyctitropic movements of the leaves are brought
about. After brilliant sunshine they set in more quickly than
after a dull light.

These movements may indeed show an artificially induced
rhythm, superposed upon a normal one, in the same way as
the movements of heliotropism, geotropism, &c., have been
seen to be based upon the ordinary movement of cireumnuta-
tion, to be, indeed, an exaggeration of it. In some cases the
RHYTHM 511

tendency to rhythmic change can be manifested by the produc-
tion of an altogether artificial rhythm, induced by submitting
the plant to intermittent stimulation. Darwin and Pertz have
described a very interesting experiment of this nature. A plant
was fixed to a spindle placed horizontally, which, by an ar-
rangement of clockwork, was made to make a semi-revolution
atintervals of thirty minutes. The force of gravity thus exerted
its effect on alternate sides for this interval of time, so that each
side of the stem tended to become convex apogeotropically in
turn. After a period of exposure upon the instrument the clock-
work was stopped. Instead of the side which was then under-
most increasing its convexity till the stem was vertical, the two
sides continued to become alternately convex, as if the reversal
of the instrument was still taking place. There was, in fact,
an artificially induced rhythm manifested.

The conflict between the natural rhythm and the movement
due to stimulation can be observed in the heliotropic curvature
of many organs. The heliotropic position is not brought about
by a direct movement of the organ, but by its describing a series
of ellipses. The organ at the time of the incidence of the light
stimulus is performing its ordinary cireumnutation, the apex
describing a circle. The effect of the stimulus is to turn that
circle into an ellipse ; when the rhythmic impulse coincides with
the stimulus of the light the movement is accelerated, and the
resulting curve takes the direction of the long axis of the ellipse ;
when the two act in the opposite direction to each other, the short
curve of the same figure is described. The same result is
obtained under the stimulus of geotropism.

The slow response to the action of a stimulating foree may
frequently be explained in the same way. Often, however, the
long delay in responding is due to the sluggish nature of the
protoplasm, a considerable time being taken up in inducing the
necessary change in its motility. We have then what is called
a latent period, before the manifestation of the irritability.
Similarly the results of the stimulation continue for some time
after the exciting cause is removed, giving what is called an
after effect. An example of this is afforded by some experi-
ments of Cisielski’s; he laid some geotropic roots horizontally
on moist sand, and allowed them to remain there for some time.
Before they began to show their geotropic curvature, he am-
putated the tips, which we have seen to be the sensitive parts
or sense organs. After a time the geotropic curvature never-
theless took place. The stimulus was received while the roots
512 MANUAL OF BOTANY

were intact, but its manifestation in the form of curvature took
place as an after effect, even after the stimulus had altogether
ceased to act.

CHAPTER XVIII.
REPRODUCTION.

THE phenomena we have hitherto been considering all concern
the life of the individual plant. As this, however, at the best
is comparatively limited, we find plants endued with the
power of giving rise to new individuals. The process of ori-
ginating each new individual from its parent or parents is
known as reproduction.

We have already seen that this process may be brought
about in one of three ways. In the simplest cases, in what is
known as vegetative reproduction, no special cell is produced
for the purpose, but some part of the parent becomes detached
and grows into the new individual at once. We see this easily
in the reproduction of the lower Fungi, such as yeast, where the
cell divides into two, which almost or quite immediately
become free from each other, each being a yeast plant. It can
be noticed through all the families of the vegetable kingdom,
though as we advance upwards in the scale the new body
becomes more and more complex. We have the gemme of
certain Alge and Bryophytes, which are multicellular ; we have
in many Mosses branches which become detached by the dying
off of the shoot behind them; in many Ferns buds are de-
veloped upon the pinne of some of their leaves, which when
separated from the latter grow into complete ferns. In the
Phanerogams we find this method illustrated by cuttings, which
are pieces of the stem bearing buds; these, when detached and
planted in suitable soil, put out adventitious roots from the
base of the cutting, and develop into plants like the original one.
Another instance is afforded by the buds which many leaves,
notably those of Bryophyllum, put out when wounded. These
also develop adventitious roots, and young plants arise which
become independent. Other plants produce underground buds,
tubers, &c., as already noticed. One of the chief features of
vegetative reproduction is that the new plant represents the
same phase of the life cycle as its parent did. Thus the
gemme of Mosses, which arise on the gametophyte, give rise to
REPRODUCTION 513

other gametophytes; the buds of the ferns, the cuttings or buds
of the Phanerogams develop into new sporophytes like their
parents. Alternation of generations is thus left altogether un-
affected by vegetative reproduction.

Some curious cases of this vegetative method are known.
Thus in the embryo sac of Celebogyne there is no fertilisation
of the oosphere, but still one or more embryos arise. This is
caused by a vegetative budding of certain cells of the nucellus,
which grow into the interior of the embryo sac and develop
into embryos.

A further peculiarity of vegetative reproduction is that the
new individual is developed continuously on its origination.
There is no resting period, such as we find in most cases to mark
the behaviour of the more specialised reproductive cells to be
discussed below.

Besides vegetative reproduction we have two cases of the
production of special cells to subserve this purpose. In the
first of these cells are differentiated which, after a longer or
shorter period of quiescence, can grow out into new plants.
These cells, possessing in themselves the power of producing
new individuals, are known as asexual cells. They are differ-
ently named according to the phase of the plant on which they
originate ; those borne upon the sporophyte being called spores,
those on gametophytes gonidia. There is, however, no further
difference between them; indeed, by many writers the name
spore is applied to both.

The fact that they do not usually germinate till after a period
of rest, though this is often not very prolonged, suggests that
they originated in a need for the plant to develop certain cells
which should possess the power of passing through times of un-
favourable conditions without destruction. Such unfavourable
conditions would be likely to kill the more delicate vegetative
reproductive bodies. This view is supported by the fact that
many of the lower plants, particularly Yeast, donot produce gonidia
when conditions are suitable for the life of the ordinary indi-
vidual, but can be made to do so by cultivating them under
adverse conditions of moisture, food supply, &c.

The gonidia which occur upon the gametophytes of the Alge
and Fungi are produced in various ways; they may occur
singly or in large or small numbers in the interior of particular
cells known as gonidangia; they may be produced by abstricticn
from a cellular outgrowth of the thallus; in this case again the
aumber produced from a single cell may vary within wide

VOL. II. LL
514 MANUAL OF BOTANY

limits. The various names given to them, such as ascogonidia,
stylogonidia, teleutogonidia, indicate various conditions of this
kind, and not any difference in their own structure. As a rule,
they are small spherical or flattened bodies, clothed with a cell-
wall; in both Alge and Fungi cases occur where they have no such
coating and are able to swim about by means of cilia. These
forms are called zoospores, or zoogonidia,

In the higher plants, in which they originate only on the
sporophyte, though possessing fundamentally the same structure
as in the lower ones, their walls show more differentiation,
possessing two coats, and often having the outer one curiously
sculptured or furnished with projecting ridges or spines. Some
have a third coat derived from the disintegrated mother cells
and tapetum.

In some Pteridophyta an important variation makes its
appearance ; the spores are no longer all alike, but two kinds
are produced, the microspores and the macrospores. This
phenomenon is known as heterospory, and it extends also
throughout the next group, the Phanerogams.

The microspores have the structure already described ;
the macrospores in the Pteridophyta are much like the micro-
spores, except in size; in the Phanerogams they are simpler,
having, with the exception of those of the Cycads, a single wall
which remains thin and delicate. In this group too the macro-
spore is never set free from the sporangiuim, nor is the latter:
detached from the plant until after the germination of its spore.

The body produced from the germinating spore or gonidium is
always a gametophyte, though often it only produces other gonidia.

In the second case in which there is a production of special
reproductive cells, these are incapable alone of producing a new
individual, but must fuse together in pairs to bring about this
result. They are consequently called serwal cells or gametes.
These probably took their origin from the asexual form. The
pase of the plant on which they occur is always the gameto-
phyte. The latter can consequently give rise to either sexual or
asexual cells or both, while the sporophyte can only produce the
latter.

In all the higher plants the gametophyte and sporophyte
regularly alternate with each other, each producing the other
phase of the life cycle. This phenomenon is known as anti-
thetical alternation of generations. In the lower forms it is not
at all regular in its occurrence; the sporophyte being altogether
unrepresented in some, and only occurring at intervals in others,
ALTERNATION OF GENERATIONS 515

We get in some of the former a succession of gametophytes,
which reproduce themselves many times in succession by gonidia
and do not develop sexual cells at all. After a number of genera-
tions have been thus produced asexually, a form arises which
bears gametes, and these after fusion produce again a gameto-
phyte which only develops gonidia. The gametophyte which
does not develop its gametes is called a potential one, in contra-
distinction to one which does, and which is known as an
aetual gametophyte. The alternation of actual and potential
gametophytes, where the resulting plant is in all cases similar
to its parent, is called homologous alternation in contradistinc-
tion to antithetical, explained above. In such an alternation
there is usually an absence of regularity, many potential game-
tophytes being developed in succession before an actual one
arises.

The latter fact appears to indicate that in most plants con-
tinuous reproduction by asexual cells is attended with some
deterioration of the plant’s constitution, which becomes again
invigorated by the occurrence of the sexual mode.

The phenomenon of heterospory involves the production of
two gametophytes to one sporophyte, as each of the former pro-
duces its appropriate prothallus. Such plants show in their life
cycle, therefore, three forms, one sporophyte, and two gameto-
phytes, the latter occurring synchronously.

It is noticeable, further, that as we pass through the several
divisions of the vegetable kingdom the predominant form of the
plant changes. In the Thallophyta itis always the gametophyte ;
the sporophyte is not universal there, and is never more than a
small structure, which nearly always remains attached to the
gametophyte. In the Bryophyta the two phases are more nearly
alike in degree of development; the gametophyte is always the
vegetative body, while the sporophyte often shows the greater
histological differentiation. It is always parasitic upon the
gametophyte, and never attains a higher degree of morphological
value than a thallus. In the Pteridophyta the sporophyte is the
predominant form, and takes on the vegetative functions. The
gametophyte shows continuous retrogression, and in the highest
members of the group is almost entirely enclosed in the spore.
In the Phanerogams the reduction in size is still more marked ;
in the Angiosperms the female gametophyte consists of only a few
cells developed in the interior of the spore, while the male one is
a tubular outgrowth from the pollen grain.

The gametophyte was doubtless the primitive form of the

LL
516 MANUAL OF BOTANY

plant. The gradual appearance of the sporophyte can be observed
still in the group of the Algw. In Cidogonium the fertilised cell
does not grow out into a new filament, but produces in its
interior four zoospores which escape from it, and after a period
of rest germinate and produce new plants. The fertilised cell
here represents the sporophyte, which is reduced to a single
sporangium. In Coleochete the zygote is invested with a cover-
ing derived from the adjacent cells, and after sinking to the
bottom of the water it germinates, producing inside its coating
a small mass of cells, each one of which liberates a zoospore.
There is here a sporophyte of a slightly higher type than that of
GEdogonium. Somewhat more complex sporophytes occur among
the Rhodophycex. An indication of the sporophyte may perhaps
be seen in Spirogyra, where the nucleus of the fertilised cell
divides into four, though no definite cells are formed. On ger-
mination of the zygote, however, only one filament grows out.

It was suggested above that probably the sexual cells were
originally derived from asexual ones. A study of such forms
as Hematococcus and Ulothrix leads us to this view. In the
former two forms of zoogonidia are produced, which differ from
each other only in size. In Ulothrix the same thing is seen, but
there isa difference in their behaviour. The larger ones are asexual,
but the smaller generally conjugate or fusein pairs. They repre-
sent, therefore, the sexual cells or gametes. Thisisthe more likely,
as the cells which fuse are generally, if not always, produced
by different plants. The sexuality is not, however, well pro-
nouticed, for if one does not become fused with another, it can
still germinate independently.

The gradual differentiation of the gametes into definite
male and female individuals has already been traced in the
section on the Thallophyta. When completely differentiated
the male cell, which is known as an antherozoid, is a small
free-swimming body, furnished with cilia. This form, which is
the most perfect known, is not, however, of universal occurrence.
In the Fungi the male gamete is almost always an undiffe-
rentiated mass of protoplasm which sometimes becomes free
from the cell in which it is produced, but is then clothed with
a cell-wall and has no power of locomotion. Sometimes it is
not set free until it actually passes into the oogonium. In the
Rhodophycee it is similarly unciliated, though at first it is a
naked cell. The same want of differentiation is seen in all the
Phanerogams, where the male gamete is represented by a
portion of the protoplasm of the pollen tube.
REPRODUCTION 517

The female gamete is more uniform, being generally a larger
mass of protoplasm, with no cell-wall, and in all but the lowest
forms incapable of motion. Below the Chlorophycee it is
always set free and is fertilised in the water; in and above that
group if remains in the cell in which it is produced, an oogonium
or an archegonium as the case may be. In the Angiosperms it
isnot even developed in an archegonium. A curious peculiarity
is noticeable in the Rhodophycee, where the female organ,
known as a procarp, contains no differentiated female cell. In
the Ascomycetous fungi the same absence of differentiation is
seen, though possibly here there is no sexuality.

The peculiarity of sexual reproduction is that the gametes
are incapable of giving rise to a new individual without fusion
of a male and female together. In this process nucleus unites
with nucleus and protoplasm with protoplasm. In the fusion of
the nuclei in the Phanerogams, however, the chromosomes do
not unite, so that the nucleus of the zygote or fertilised cell has
twice the number of these that that of each gamete possessed.
When the zygote germinates, the first nuclear division is so
carried out that each daughter-nucleus receives half the chromo-
somes from each sexual nucleus.

The cells which fuse may be alike, or may be dissimilar; in
the former case the process is spoken of as conjugation, in the
latter case fertilisation. The resulting body is called the
zygospore or the oospore respectively ; the term ‘zygote’ is
now generally used instead of either of these. Conjugation only
occurs among the comparatively undifferentiated Thallophyta.

The mode of bringing the gametes together varies with the
habit of life of the plants. Where the antherozoid is motile it
makes its way to the oosphere by means of its cilia, which
enable it to swim freely in water. In those forms with a
terrestrial habit, such as the Bryophyta and Pteridophyta, in
which the antherozoid is ciliated, fertilisation can only be
brought about when the gametophytes are moistened, as is
the case from time to time. The antherozoids are attracted to
the archegonia by some constituent of the mucilaginous matter
which is excreted from their necks when they open. In the
Mosses this has been ascertained to be cane-sugar; in the Ferns
it is malic acid or one of its salts. In the Rhodophycee and
such Ascomycetes as possess sexual reproduction the passive
male gamete, known as a spermatium, is floated to the female
organ or its trichogyne by currents in the water.

In the Phanerogams, where the female gametophyte is always
518 MANUAL OF BOTANY

attached to the parent sporophyte, such a means of fertilisation is
of course impossible. For fertilisation to occur it is necessary
that the two gametophytes shall be produced in close pro-
pinquity to each other. This is effected by the bringing
together of the two spores concerned in developing them.
The microspore or pollen grain is carried by various means to
the neighbourhood of the macrospore; in the Gymnosperms
it falls upon the macrosporangium itself; in the Angiosperms
upon the stigma of the pistil in which the macrosporangia are
hidden. As it germinates, its gametophyte, the pollen-tube,
makes its way through the intervening tissues till it reaches the
macrospore itself, close to the archegonium in the first case, and
to the oosphere when there is no archegonium. Fusion of the
gametes produced in each gametophyte then becomes possible,
and by a deliquescence of the separating walls they come into
contact with each other and their union takes place.

In these higher plants we have two processes necessary for
sexual reproduction, the one the approximation of the spores,
or pollination, the other the fusion of the gametes, or fertilisa-
tion. Frequently the latter term is loosely and erroneously
applied to the former process, as when the fertilisation of
flowers is spoken of. The process is one of pollination, and
may be followed by fertilisation or not according to circum-
stances.

When the cells which fuse are derived from the same game-
tophyte, the term self.fertilisation is applied to the process;
when they come from different ones it is called cross-fertilisa-
tion. Self-fertilisation in the strict sense is extremely rare;
even in the Thallophytes the uniting cells usually originate
on different plants. The term ‘self-fertilisation ’’ has been used
very generally to indicate the pollination of a pistil by pollen
from the same flower; it is however better to speak of this as
self-pollination. Speaking strictly, self-fertilisation cannot take
place in heterosporous plants, as each spore produces its
appropriate gametophyte and the two sexual cells never arise
upon the same one. Cross-fertilisation has been found always
to result in stronger and healthier plants than self-fertilisation.
Cross-pollination, or the bringing together of spores from
different flowers, or from different plants, of the same species,
also yields more and better seeds than self-pollination.

Very many mechanisms have been developed in different
plants to secure this end. Pollen may be carried from flower
to flower by wind or water, or by the agency of insects or other
CROSS-POLLINATION 519

animals. From this point of view plants have been classed as
anemophtlous or wind-pollinated, hydrophilous or water-
pollinated, entomophilous or insect-pollinated, or zoophilous or
those pollinated by other animals.

Of these methods of pollination the anemophilous and the
entomophilous are the most wide-spread. In the former case
certain structural features are associated with the mode of
transference of the pollen. It is produced in such flowers in
great abundance, is extremely light and dry, and in some cases
furnished with bladders to aid its transport. The receptive
organ is sometimes a bulky cone, the leaves of which are sepa-
rated from each other and from the common axis by spaces
into which the pollen may drop; sometimes it is a much
divided or plumose stigma, often furnished. with hairs, so that
pollen falling on it may be readily retained. The method is a
wasteful one and involves the production of a superabundance
of pollen. On the other hand anemophilous flowers are always
inconspicuous and of a comparatively humble type.

Flowers which are pollinated by insects are usually much
larger and more showy, not infrequently possessing irregular
corollas, and are often very highly coloured and provided with
characteristic odours. Their perianths and sometimes their
sporophylls are highly modified to adapt them to the habits
of their insect visitors. As a further attraction to the latter
they usually produce honey in some part of the flower, in’
such a situation as will lead to the removal of pollen by the
insect in its search for the attractive liquid. The pollen itself
also is often the object of the insect’s visit. Many special
mechanisms to secure the removal of the pollen from the
microsporophyll and its deposition upon the stigma of another
flower are to be met with; indeed, almost every Natural Order
shows some modification in this direction. The consideration of
them in detail, however, is beyond our present purpose.

Something akin to cross-pollination occurs in Azolla as
already described; the massule or collections of microspores
being floated to the macrospores, to the floats of which the
glochidia attach them.

These mechanical adaptations are, however, not the only
means we find to secure cross-pollination. There are peculiari-
ties connected with what we may call the receptivity of the
pistil for any particular pollen. Of these the most generally
occurring is dichogamy, or the maturing of the microsporophylls
and the macrosporophylls at different times. Two varieties of
520 MANUAL OF BOTANY

this condition are met with ; in the first, known as protandry,
the stamens with their pollen are mature while the stigma is
still too little developed to be pollinated. Examples may be
found in the Gentianacee, Onagracee, Campanulaces, Compo-
site, kc. In Parnassia the receptive surface of the stigma is not
even formed until the anthers have discharged their pollen. The
second condition is called proferogyny, and is the converse of
the first, the stigma withering before the pollen ismature. This
condition occurs in both anemophilous and entomophilous
flowers; certain of the plantains (Plantago) and some grasses
(Anthoxanthum, &e.) show it in the former group, as does
Scrophularia among the latter.

Something corresponding to dichogamy is found among the
Ferns, where the antheridia and archegonia on a prothallium
do not mature simultaneously. Cross-fertilisation must con-
sequently be the only form possible. The same peculiarity may
be observed among the Mosses.

Another means often observed to secure cross-pollination is
diclinism, or the production of the stamens and carpels in
different flowers. Diclinous plants may be monecious where
the staminate and pistillate flowers are on the same plant,
dicwciows where they are on different plants, or polygamous
where a plant bears hermaphrodite flowers as well as either
staminate or pistillate ones.

The same terms ‘ moncecious’ and ‘ dicecious’ are often applied
to the Cryptogams, when their sexual organs are upon the same
or different plants. They then refer, of course, to the game-
tophyte and not the sporophyte phase as in the cases just
quoted.

Some flowers show a peculiarity in form, which is sometimes
an adaptation favouring cross-pollination. The plants possess
flowers of two kinds, which are specially related to each other.
The most familiar instance in our own flora is the common
Primrose, which has five stamens and a club-shaped stigma.
In some flowers the stigma is placed just in the throat of the
corolla and the stamens some little way down its tube. In the
remaining flowers the positions are reversed. We have here an
adaptation to the visiting insect, for when it touches the stamens
of a short-styled form it covers with pollen the part which will
come in contact with the stigma of the next long-styled flower
it alights upon. The best seeds are produced when each
stigma is supplied with pollen from stamens occupying a, corre-
sponding position,
CROSS-POLLINATION HYBRIDISATION 521

This arrangement is generally spoken of as dimorphism, of
which, however, it is only one form. Lythrum Salicaria is
trimorphic, having two sets of stamens of different lengths and
a style which differs from both. There are three modes of
arrangement of these organs, and, as in the Primrose, the most
serviceable pollination is that which takes place when pollen
from a stamen of a certain length is applied to a stigma of the
same length.

Other arrangements are physiological rather than structural.
Of these the strangestis what is called prepotency. When a stigma
of a flower exhibiting this property is pollinated by pollen from
its own stamens and at the same time by pollen taken from
another flower, the latter is always the originator of the gamete
by which fertilisation is effected. Some flowers show self-
sterility, that is, they are never fertilised if only pollinated by
pollen from their own stamens; in some few cases their own
pollen acts as a poison to them.

Though cross-pollination is thus seen to be most advantageous,
it is not universal. Self-pollination occurs in many plants;
indeed, in some, special means have been developed to secure
it in case cross-pollination fails to be effected. Only one of
these need here be alluded to; this is cleistogamy, or the pro-
duction of special flowers which do not open, in addition to the
normal ones. The pollen grains put out their pollen tubes in
the unopened flowers, sometimes not even escaping from the
sporangia. The tubes grow towards the stigmas, and, penetra-
ting them, reach the ovules as in the case of the normal flower,
fertilisation resulting in the same way.

Though cross-fertilisation is seen to be most advantageous, it
is only possible within certain limits. For a new individual to
be produced, the sexual cells taking part in the process must
have a certain degree of relationship; thus the antherozoid of a
moss cannot fertilise the oosphere of a fern. The most favourable
degree of relationship is that the two gametes shall be produced
by different plants of the same species. Such a union results in
greater numbers and greater vigour in the offspring. Plants,
however, not so closely related, may produce offspring ; thus we
may have the union of gametes of plants standing to each other
in the relation of varieties of the same species, or very frequently
of distinct species belonging to the same genus, or even of
species of different genera. Such fertilisation is known as
hybridisation.

Hybrids generally exhibit peculiarities of form and structure
 

522 MANUAL OF BOTANY

intermediate between those of their parents; they are generally
fertile with either of the parent species, but not usually so with
another hybrid, or to a much less extent. When crossed with
one of the parent forms the offspring tend to revert to that
form.

The result both of pollination and of fertilisation is generally
to stimulate the parts concerned to increased growth. In some
Orchids the ovules are not formed in the ovary until the stigma
is pollinated and seem to arise in consequence of that process.
The stimulus of fertilisation is still more marked. In the
Mosses its result is to cause not only development of the
sporophyte from the oosphere but a considerable additional
growth of the archegonium, forming the calyptra. The
same thing may be noted in those Rhodophycee where a
bulky cystocarp is produced. The stimulus is, however, most
easily observed in the Angiosperms, where not only is the
oosphere excited to growth, forming the embryo, but the definitive
nucleus of the embryo sac gives rise to the endosperm, and the
pistil or collection of macrosporophylls and sometimes other
parts of the flower undergo remarkable development, forming
the fruit.

We have noticed that the asexual reproductive cell, whether
spore or gonidium, is generally found to remain in a state of
quiescence for some time after its formation. The same thing
is seen in the case of the zygote. In the Thallophytes this
resting period is sometimes a long one; in the higher Crypto-
gams it is not so noticeable, and in the Phanerogams, where the
zygote is always developed inside the sporangium, it usually
proceeds to active growth at once. In the latter plants, however,
a resting period takes place later, after the seed is fully formed.
The development of the young sporophyte in fact takes place in
two stages, the one ending with what may be called the maturity
of the seed, the other beginning with the process of germination.
Seeds when detached from the parent plant preserve their
vitality for a variable length of time, sometimes even for years,
and are capable of germinating freely when exposed to favourable
conditions.

The germination of the dicotyledonous seed occurs in one of
two methods. In the first of these the cotyledons are thick and
fleshy and remain under ground. As the seed absorbs water
and swells, the radicle makes its way out through the micropyle,
the testa bursts, and the plumule makes its way upwards, the
epicotyl, or part between the cotyledons and the first leaves,
GERMINATION 523

circumnutating and emerging in the form of an arch, owing to
the greater growth of one side. After reaching the air the
region of greatest growth changes to the opposite side and the
epicotyl straightens itself. During this time it subsists upon
the nourishment stored in the cotyledons. This is called hypogean
germination. In the other method, that of the so-called epigean
germination, the cotyledons rise above the ground and become
green, the hypocotyl behaving as did the epicotyl in the first
case. These are generally, though not always, albuminous
seeds, and the nutritive matter is stored outside the embryo.
In both cases the root makes its way into the soil by virtue
of its geotropism and apheliotropism, aided by the movement
of cireumnutation, and by the adhesion of the root-hairs to
particles of the soil. In Monocotyledons the upper part of the
single cotyledon generally remains in the seed and absorbs the
nutriment from the endosperm, while its base elongates and
thrusts the young plant downwards.

Sometimes the usual alternation of sexual and asexual re-
production in the higher plants is interfered with by the sub-
stitution of the vegetative method for one of them. In the
‘phenomenon of apospory noticeable in some Ferns we have
small prothallia developed on the back of the leaves in the place
of spores. This is a case of the production of a bud instead of
an asexual cell. Conversely, among the same group of plants,
the sporophyte sometimes arises as a bud or vegetative outgrowth
upon the prothallium, a phenomenon known as apogamy.

There is another kind of apogamy known which is generally
termed parthenogenesis. This occurs among the Fungi, where,
as in Saprolegnia, oospheres are formed in oogonia, which do
not become fertilised and yet have the power of growing out
into new plants. The formation of azygospores, described as
occurring in Mucor and other plants, is another case of the same
phenomenon. This parthenogenesis differs from the phenomenon
described as occurring in Celebogyne, where nevertheless an
embryo is produced without pollination. This we have seen to
be due to a vegetative budding of the cells of the nucellus of
the ovule, the buds growing into the macrosp-re and there de-
veloping into embryos.
GLOSSARY AND GENERAL INDEX
TO VOL. II.

 

Absence of pericycle, 130, 140, 143, 154

Absorption by root-hairs, 416, 436

— of gases, 438

—— nitrogen by Leguminose, 437 ; by

pitcher plants, 440, 453

Accrescent. A term applied to the calyx,
when it continues to grow after pol-
lination of the pistil

Achlamydeous. Having neither calyx nor
corolla

Acropetal succession. The regular deve-
lopmeut of leaves or branches in such
order that the youngest is always
nearest to the apex of the axis which
bears them :

Actinomorphie flowers. Flowers which
can be divided into two precisely
similar halyes by every possible ver-
tical section

Acyclic flowers. Those in which the
leaves of the flower are arranged spi-
rally on the axis instead of being in
whorls

Adhesion. The condition of union to, or
freedom from, one another of the
separate whorls of the floral leaves

Adventitious. Arising irregularly, or not
in acropetal succession. Applied to
certain branches of stem or root

Ecidiospores, 89

Aicidium, 74, 87

&stivation. The mode in which the
leaves of the perianth are arranged in
the flower-bud

After-effect, 511

Aggregation, 498, 505

Aleurone grains, 451

Alliances, 6

Alternation of generations (antithetical).
A regular alternation of gametophyte
and sporophyte in the life cycle of a
plant, 514

— — — (homologous). An irregular suc-

cession of gametophy tes, some
of which produce sexual cells
while the remainder only de-
velop gonidia, 31, 515

Amentaceous. Having its flowers ar-
ranged in catkins

 

Amides, 444, 467

Ameboid mevements. The creeping
movements of masses of naked proto-
plasm, 67, 76

Amphigastria, 110

Amphitropous, Semi-anatropous

Anabolism, 433

Anatropous ovule. One whose nucellus
remains straight but which becomes
inverted during development, owing
to the greater growth of one side

Andrecium. The collection of stamens
in a flower

Androphore. The column or tube formed
by the coalescence of the filaments of
the stamens when the latter are
monadelphous

Androspore, 61

Anemophilous, 519

Annulus, 120, 184, 150

Antheridial cell in Gymnospermis, 175

Antheridiophore. Auy special part of the
gametophyte on which antheridia
arise

Antheridium. The organ in which the
male gametes, usually aAntherozoids,
are developed

Antherozoids or spermatozoids. Male
ciliated gametes, with no cell-wall

Anthesis. The period at which the
flower-bud opens.

Anticlinal. A term applied to those
cell-walls which are formed at right
angles to the surface of the growing

point
Antipodal cells, 182
Antitropous. Inverted, A term applied

to the embryo

Apheliotropism, 493

Apocarpous. A term applied to the
pistil when its constituent carpels are
not coherent together

Apogamy, 126, 523

Apogeotropism, 404

Apophysis, 119

Apospory, 120, 126, 523

Apostrophe, 487

Apothecium, 84

Aquatic phanerogums, 478
526

Archegoniophore. Any special part of
the gametophyte on which archego-
uia arise

Archesporium. The cell or cells which
by division give rise to the mother
cells of the spores

Archicarp, 70, 82

Avril. <A third integument which grows
completely or partially over the seed
springing from its base

Ascending sap, 416

Ascidia. The pitchers of such plants as
Sarracenia, Nepenthes, «&c.

Ascocarp, 83

Ascogonium, 83

Ascospores, 87

Ascus, 82

Asexual reproduction, 513

Ash of plants, 436

Astely =schizostely

Asymmetrical flowers. Those which
cannot be divided into similar halves
by any vertical section

Autecious, 90

Auxiliary cells, 51

Auxospores, 41

«il. The angle formed by the junction
of leaf and stem

Azygospores, 55, 78

Basidia, 90

Basidiospores or basidiogonidia, 92

Bicollateral bundles. Those which have
astrand of bast both before and be-
hind the strand of wood

Bye-products of metabolism, 461, 464

Caducous sepals. Those which become
detached from the flower when the
flower-bud opens

Callus. The material which is developed
upon the surface of sieve-plates. Also
applied to the tissue which grows over
and covers wounds made in a stem or
root .

Campylotropous ovule. One whose nu-
cellus is curved so that the micropyle
is placed close to the hilum

Capillitium, 77

Capitulum (of Chara), 63

Carpogonium, 82

Carpophore. The part of the axis of the
flower which is between or above the
carpels, and to which they are at-
tached

Carposporangia, 51

Caruncles=strophioles

Catabolism, 433, 460

Caudicles. The stalks of the pollinia in
the Orchidaceze

Cell-wall, composition of, 421

Chalaza. The point at which the vas-

cwar bundle reaches the ovule
Chemiotaxis, 499, 500
Chlamydospore, 78

 

MANUAL OF BOTANY

Chlorophyll, 440, 462

Chloroplasts. The chlorophyll corpus-
cles, 434

Chlorotic plants, 463

Chorisis. An increase in the number of
the parts of a floral whorl due to the
division or splitting of its primary
members

Chromatophores=chromoplasts

Chromoplasts. Small protoplasmic bodies
found in certain cells and containing
colours other than green

Cilia, ‘Vibratile filaments of protoplasm
found on zoospores, gametes, &c. Also
applied to the inner row of teeth of
the peristome of mosses

Ciliary motion, 507

Circumnutation, 476

Cirrhus, A tendril

Cladode, A branch which in shape re-
sembles a leaf

Cleistogamy, 521

Cleistothecium, 83

Ccenobium, 54

Cenocyte. A plant body in which the
constituent protoplasts are not sepa-
rated from each other by cell-walls.
Usually a common cell-wall invests
the whole

Cohesion. The condition of union or
freedom of the separate members of
the whorls of the floral leaves

Cohorts, 6

Collenchyma. A parenchymatous or
prosenchymatous tissue, the cells of
which are thickened at their angles

Columella, 77, 118

Comose, A term applied to seeds which:
bear a tuft of hairs

Conceptacles. Depressions in the surface
of the thallus of certain alge in
which the reproductive orgaus are
borne, 43

Conjugation, The fusion of two similar
gametes, 517

Coriaceous, Leathery—applied to leaves

Cormophyte. A plant which possesses
stem and leaf

Corona, +A cup-shaped body formed by
the lateral union of scales borne upon
the perianth leaves at the junction of
claw and limb, as in the Daffodil

Cryptostomata, 45

Crystalloids, 451, 452

Cupule, The involucre of the female
tiower of the Oak, Hazel, &c.

Cushion. The central thick region of
the prothallus of the fern, 136, 137

Cystocarp, 32, 51

Cytase, 455, 457

Deduplication, A doubling of the num:
ber of parts of a floral whorl

Definitive nucleus, 182

Diageotropism, 494

Diaheliotropism, 493

Dialystely. A variety of polystely in
GLOSSARY AND GENERAL INDEX TO VOL. II.

which the separate steles remain for
the most part independent during
their longitudinal course

Diaphragm of Salvinia, 148

— — Selaginella, 163

Diarch. A term applied to the stele of a
root which has only two protoxyleon
groups

Diastase, 455, 456

Dichogamy, 519

Dichotomous branching. Branching
which results from the division of a
growing point with two equal parts

— — in Liverworts, 105

— — in Selaginella, 160

Diclinism, 520

Diclinous. A term applied to plants
whose flowers contain either stamens
or pistil, but not both

Didynamous. A term applied to an an-
dreecium which consists of two pairs
of stamens, one pair being shorter
than the other

Differentiation, histological. The de-
velopment of various kinds of cells in
the interior of a plant

— morphological. The’ segregation of
the plant body into different members

— physiological. The assignment of
different functions to different struc-
tures, or different parts of a plant

Dicecious. Producing the male and
female gametes ou different plants.
Also applied to Phanerogams in which
staminate and pistillate flowers are
produced on different plants, 520

Diplostemonous. A term used to indicate
that an andreecium consists of two
whorls of stamens in regular alterna-
tion with the perianth leaves

Dissepiments. The partitions which are
found in some compound ovaries

Distribution of seaweeds, 34, 48

Dorsiventral leaves. Those whose upper
and lower halves have a different
structure

Dwarf-male, 61

LEctoplasm, The outer la, er of the proto-
plasm of a cell

Egg-apparatus, 182

Elaioplasts, 452

Elaters of Hepaticx, 102

— — Equisetum, 154

Embryo of Cycadez, 177

Embryonic branches of Chara, 39

Emergences. Outgrowths from a plant
which consist of ground tissue, covered
by epidermis

Emulsin, 456

Endophytic. Living in cavities in other
plants, 40

Endosperm of Selaginella, 163

— — Gymnosperms, 173

— — Angiosperms, 183

Entomophilous, 519

Enzymes, 446, 454

 

527

Epiblema. The outermost layer of cells
covering the root

Epicotyl. The part of a seedling which
extends from the insertion of the coty-
ledons to that of the first foliage leaves

Epigynous. Springing apparently from
the summit of the ovary. A term
applied to corolla and stamens

Epinasty, 475

Epiphragm, 119

Epiphytes. Plants which grow attached
to other plants, but do not derive
nourisumient from them parasitically,
4

Epiplasm, 85

Episperm. The outer coat of the seed

Epispore, 147, 154

Epistrophe, 487

Erythrophyll, 464

Erythrozym, 456

Etiolated plants, 485, 486

Etiolin, 485

Eusporangiate. Having sporangia which
arise from more than one cell, 122

Evolution of sex, 47, 55, 59, 516

— — sporophyte, 516

Exceptions to typical characters
Calyciflorze, 261, 364

Exceptions to typical
Disciflore, 261, 330

Exceptions to typical characters
Gamopetale, 2

Exceptions to typical characters
Thalamiflore, 261, 303

Excretion, 46

Exodermis. A peculiarly thickened layer
of cells, lying generally immediately
under the epiblema of the root

in

characters in

in

in

Fatigue, 503

Fertilisation. The fusion of two dis-
similar gametes. The term is some-
times used to signify the application
of the pollen of a flowering plant to
the stigma or ovule. This should,
however, be called pollination, 517

Floats of macrospore of Azolla, 147

Foliose liverworts, 104

Formation of carbohydrates, 442

— — proteids, 444

Frustule, 41

Fungus-cellulose, 69

Gametangium. The structure in which
sexual cells are produced

Gametes, Sexual cells

Gametophore. Any special part of the
gametophyte on which gametangia,
antheridia, or archegonia are borne

Gametophyte. The phase of the plant
which is marked by the power of pro-
duction of sexual cells or gametes. It
may be actual or potential, 31, 515

Gamodesmic. A term used to indicate
that the several vascular bundles of a
stele are fused together instead of
528

being separated by conjunctive or
ground tissue

Gamopetalous. Having the petals coher-
ing laterally (similarly gamosepalous)

Gamostelic. The condition when the
steles of a polystelic stem are arranged
in a ring and more or less completely
fused together laterally

Gemme. Vegetative reproductive struc-
tures found among the Thallophyta
and Bryophyta, 38, 65, 104, 110, 117

Genera, 4

Genetic spiral. The line which may be
drawn round a stem with alternate
phyllotaxis, passing in regular succes-
sion through the bases of the leaves

Geotropism, 494

Gills (of Mushroom), 91

Globoids, 451

Globule. The antheridium of Chara

Glochidia, 147

Glucase, 455, 456

Glucosides, 462, 458

Gonidangia. The structures in which
gonidia are produced

Gonidia. The asexual reproductive cells
produced upon gametophytes. They
are sometimes also called spores

Gonidiophore, 71

Gonidiophylls. Leaves of the gameto-
phyte which bear gonidangia

Gonimublasts, 51

Growing points, 36

Growth, 470

— effect of light upon, 488

— grand period of, 474

Gynandrous. A term used to indicate
that the filament or filaments of the
audreecium ofa flower are united with
the upper part of the pistil, forming
a central column

Gynobasic style. One which springs from
the base of the carpel instead of its
apex

Gynacium. The pistil, or collection of
carpels in a flower

Gynophore. The part of the axis of the
flower between the insertions of the
stamens and ovary

Iaptera. The organs of attachment of
certain Alga, 36

Haustoria. The outgrowths through
which many parasites absorb nourish-
ment from their host plants. They
are generally of the nature of roots

Heliotropism, 493

Hemicyclic flowers. Those in which the
perianth leaves are arranged in whorls
and the sporophylls in spirals

Hermaphrodite, A term applicd to
flowers possessing both stamens and
carpels, also to gametophytes produ-
cing reproductive cells of both sexes

Heterocysts, 39

Heterodromous, A term used to indleate
that the genetic spiral of the leaves of

 

MANUAL. OF. BOTANY

a stem turns in a different direction
from those of the branches

Heterecious. A term applied to certain
fungi, which in different phases of
their life infest two different plants,
90

Heterogamous. Having differentiated
male and female gametes

Heteromerous, 96

Heterospory. The peculiarity of produ-
cing macrospores and microspores, pos-
sessed by many of the Pteridophyta
and all the Phanerogamia, 514

Homodromous. A term used to indicate
that the genetic spiral of the leaves
turns in the same direction in the
stem and its branches

Homoiomerous, 96

Homosporous = isosporous.
only one kind of spore

Homotropous. Erect. A term applied to
the embryo

Hormogonia. Vegetative reproductive
bodies of the Cyanophycez, 39

Humus, 416

Hybridisation, 521

Hydrophilous, 519

Hydrotropism, 499

Hymenial layer, 84, 91

Hypha. The thread-like cells or fila-
ments of the fungi

Hypocotyl. That part of the axis of a
seedling which lies between the base
of the radicle and the insertion of the
cotyledons

Hypoderma. The region immediately
underlying the epidermis

Hypogynous. Springing from the axis
of the flower below theovary. Applied
to petals and stamens

Hy ponasty, 475

Hypophysis, 185

Hypsophyll. Bract

Possessing

Indusium. The membrane covering a
sorus or collection of sporangia, 133,
145. Also applied to the cup-shaped
expansion of the upper part of the
style in the Goodeniacew, 374

Integuments, 171

Inulase, 455, 456

Tnvertase, 455, 456

involucre. A whorlor collectioa of bracts
at the base of a flower or an inflores-
cence

Irritability, 484

Jso-bilateral. A term applied to leaves
whose upper and lower halves have
the same structure

Isogamous. Having gametes which are
not differentiated into male and
female

Isomerous flowers, Those which have
the same number of parts in each of
the ficral whorls

Tsosporous. A term applied to plants
which have spores of only one kind
GLOSSARY AND GENERAL INDEX TO VOL. II.

Isostemonous. Having the same number
of stamens as of sepals and petals

Karyokinesis. The process of indirect
division of the nucleus
Klinostat, 495

Latent period, 511

Leptosporangiate. A term applied to
those plants whose sporangia arise
each from a single epidermal cell, 122

Leucoplasts. The plastids which form
starch grains in parts of plants not
exposed to light, 449

Ligule of grasses, 216

— — Lycopodinz, 160

Localisation of sensitiveness, 502, 504

Loculicidal. Splitting down the dorsal
sutures. Applied to the dehiscence of
capsular fruits

Lodicules, 217

Lysigenous spaces. Such as are produced
by the absorption or disintegration of
cells

Macrosporangia-development in Phane-
rogams, 171

Macrospores. The larger spores borne
by heterosporous plants

Manubrium, 63

Marcescent. A term applied to the
calyx or corolla when it withers after
pollination but does not become de-
tached

Massula, 147

Megaspores=macrospores

Meiostemonous. Having fewer stamens
than petals

Merismatic. Capable of division. A
term applied to groups or bands of
cells which undergo continuous multi-
plication

Meristeles. The branches of the stele
which enter the leaves

Meristem. A collection of cells which
increases continuously by cell-division

Metabolism. The chemical changes as-
sociated with the life of protoplasm,
433

Micropyle. The aperture left at the
apex of the ovule in consequence of
the integuments not completely en-
closing it

Microsporangia-development in Phane-
rogams, 169

Microspores. The smaller spores borne
by heterosporous plants

Monadelphous. A term used to indicate
that the stamens of a flower are united
by the bases of their filaments

Monandrous. Having only one stamen

Monochiamydeous. Having only one
whorl of perianth leaves

Monecious, A term applied to those
Phanerogams which producestaminate
and pistillate flowers upon the same
plant. Also used to indicate gameto-

VOL. Il.

 

529

phytes which bear both antheridia and
archegonia, 520

Monopodial. A term applied to such
branch systems as have a main axis
produced by the continuous activity of
a single growing point

Monostely. The condition in which the
centre of the axis of the plant is occu-
pied by a single stele which is con-
tinuous with the plerome

Mycelium, The delicate network of
thread-like cells or ccenocytes which
form the body of a fungus ,

Myrosin, 456

Natural Orders, 5

Nitrification, 437

Nucellus. The body of the ovule, 171

Nucleoplasm. The substance of which
the nucleus is composed

Nutation, 476

Nyctitropic movements, 489

Obdiplostemonous. A term used to indi-
cate an andreecium, which consists of
two whorls of stamens, those of the
outer whorl being opposite to the
petals

Occurrence of Monochlamydeous flowers
in Polypetale and Gamopetaiz, 261

Ochrece. The stipules of the Polygonaceze

Oidium, 73

Ooblastema filament, 51

Oogamous. Producing gametes of two
kinds, one male, the other female

Oogonium. The organ in which the
female gametes of the Thallophytes
are developed

Oosphere. The female gamete before
fertilisation
Oospore. The body formed by the fer-

tilisation of an oosphere. Often called
a zygote

Operculum. The lid of the capsule of a
moss

vrcnostichies. The vertical ranks of the
leaves upon a stem

Orthotropous. A term applied to ovules
which grow vertically from the pla-
centa, so that the chalaza aud the hilum
are close together at the base, and the
micropyle is at the opposite end or
apex

Osmosis, 411

Ostioles, 43

Palee. Scarious leaves which form the
outer covering of the! flowers of
grasses ; also scales which are found
at the bases of the flowers in the capi-
tula of certain Composite.

Pappus. The hairy or feathery calyx
of the flowers of the Composite and
allied orders

Paraheliotropism, 486

MM
530

Paraphyses. Hair-like outgrowths formed
among the sexual organs or sporangia

of Thallophytes, Bryophytes, and
Ferns, 44
Parasites. Plants which live upon other

plants or animals by absorbing nutri-
tive materials from their tissues, 482

Paratonic action of light, 488

Parthenogenesis. The development of a
new plant from a sexual cell without
fertilisation, 523

Pectase, 455, 457

Peloria. Aterm applied to the condition
when flowers which are normally ir-
regular in form become regular

Pepsin, 455, 477

Periblem, The embryonic tissue which
gives rise to the cortex of vascular
plants

Pericambium. An old name for the peri-
cycle of the root

Pericheetium, 107

Periclinal. A term applied to cell-walls
which are formed parallel to the sur-
face of the growing point

Pericycte. The circumferential layer of
the stele

Peridium, 92

Perigynium, 108

Perinium, 147

Periodicity, 510

Peripherical. A term applied to the
embryo when it more or less completely
surrounds the endosperm in the seed

Periplasm, 79

Perisperm. The remains of the nucellus
of the ovule when it is notall absorbed
by the macrospore or embryo sac during
the development of the latter, 177

Peristome, 118

Perithecium, 85

Phototaxis, 494

Phototonus, 484

Phragmata. Spurious dissepiments cross-
ing the ovary horizontally, asin Cassia

Phycocyanine, 26

Phycoerythrine, 36

Phycopheine, 36

Phycoxanthine, 36

Phullaries. The bracts forming the invo-
lucre of the Composite and allied orders

Phyllotaxis, The arrangement of the
leaves upon the stem
Pileus, 91

Placenta, The part of the sporophyte on
which the sporangia arise

Plasmodium. The body of a Myxomy-
cete, 67, 76

Plerome. The embryonic tissue which
gives rise to the stele

Pollination, 518

Pollinia, The masses of pollen produced
in the lobes of the anthers of the
Orchidacez and Asclepiadaceae

Pollinodium, 70, 79

Pollinoid, 50

Polygamous, 520

Polustely. The condition in which the

 

MANUAL OF BOTANY

vascular tissue of the axis is arranged
in several steles, each containing more
than one vascular bundle

Prefloration, The arrangement of the
leaves in the flower-bud

Prefoliation, The arrangement of the
foliage leaves in the bud

Prepotency, 521

Primordial cells. Cells with no cell-wall

Primordial utricle. The part of the
protoplasm of a cell which lines the
cell-wall

Procambium. The embryonic tissue that
develops into the vascular bundles

Procarpium. The female organ of the
Rhodophycee and the Ascomycetes

Pro-embryo of Chara, 65

Pro-mycelium, 66, 78

Protandry, 520

Proteids, classification of, 445

Proterogyny, 520

Prothallium, 125

Protobasidium, 88

Protonema, The body produced from the
spore of a Bryophyte, on which the

_. gametophyte is developed vegetatively

Protoplasts. The separate aggregations
of protoplasm, each of which consti-
tutes the living substance of a cell, 409

Pseudocarp. A fruit into the compo-
sition of which other parts than the
pistil enter

Pseudopodia, 76, 507

Pyenidia, 85

Pyrenoids, 37

Quincuncial. A term applied to the
eestivation of such flowers as have
five leaves in a whorl, arranged so that
two are overlapped on both sides by
their neighbours, two are not over-
lapped at all, and the fifth is overlapped
on one side only

Races, 3
Ramenta, 129
Raphe. The part of the funiculus which

is adherent to the side of an anatro-
pous or amphitropous oyule

Receptacle. The dilated apex of a
peduncle on which several flowers are
borne, as ina capitulum. Sometimes
applied to the axisof the flower within
or above the calyx

Rectipetality, 478

Rejuvenescence. A process in which the
protoplasm of a cell withdraws from
the cell-wall, rounds itself off in the
cavity, and secretes a new cell-wall
for itself. It is one of the processes
of the formation of new cells

Rennet, 456

Replum. The spurious longitudinal dis-
sepiment of the siliqua and silicula,
It is formed by an outgrowth from the
two placentas, and not by the edges of
the carpellary leaves, 274
GLOSSARY AND GENERAL INDEX TO VOL. II.

Retinacula. Glandular bodies at the
bases of the pollinia in some Orchids

Rhamnase, 456

Rhizophores, 161

Rhythm, 509

— artificial, 511

Root-hairs, action of, 417

Root-parasitism, 440

Root-pressure, 418, 425

Rostellum. A peculiar projection into
the flower of some Orchids. It is
formed by a modification of one of the
stigmas

Saprophytes. Plants which grow on
decaying organic matter, from which
they derive their nourishment, 66

Sarcocarp. The fleshy middle layer of
the drupe

Schizostely. A condition in which an
axis has several steles, each of which is
composed of only one vascular bundle,

151

Sclerotia, 73, 86

Secondary growth in'thickness in Thal-
lophytes, 31, 35, 36, 43, 46

— in Isoétes, 123, 164, 165

— — Ferns, 123, 140

Secretion, 461

Seed, structure of, 177

Self-sterility, 521

Septicidal. Splitting down the ventral
sutures. Applied to the dehiscence of
capsular fruits

Septifragal. A term applied to the mode
of dehiscence of capsules in which the
pericarp becomes detached and leaves
the seeds adhering to a central column
formed by the axile placentas

Series, 6

Sexual reproduction, 514

Shields, 63

Sleep movements, 489

Soredia, 97

Sorus. A collection of sporangia

Species, 2

— derivation of names of, 8

Spermatium, 50, 70, 83

Spermatozoid =antherozoid

Spermogonium, 70, 83

Sphacelia, 86

Sporidium, 88

Sporophore. The part of the sporophyte
which bears the sporophylls. Usually
applied to the inflorescence of Phane-
rogams

Sporophylis. Leaves which bear spo-
rangia

Sporophyte. The phase of the plant
which is characterised by the produc-
tion of spores, and cannot produce
sexual cells

Sports, 3

Starch grains, formation of, 449

Stele. A strand of tissue in which are
embedded one or more vasenlar bun-

 

531

dles, and which is surrounded by an
endodermis

Stereome. The supporting tissue of the
plant. It includes the vascular bun-
dies and the sclerenchyma and collen-
chyma

Sterigma, 70, 83

Stipes, 91

Stipules. Branches of the hypopodium
or leaf-base

Stoma of Marchantia, 105

Stomata, action of, 429

Stomium. The cells of the annulus of
the fern which rupture to allow of the
escape of the spores, 134

Stromata, 87

Strophioles. Small protuberances grow-
ing from various regions of the testa
of the seed. They are never developed
before fertilisation

Stylogonidia, 71

Stylopodium. The epigynous dise found
in the flowers of the Umbellifers

Sub-classes, 6

Suspensor, 124, 155, 176, 184

Symbiosis. A term employed to denote
the living together of two plants to
their mutual advantage. The best
example is afforded by the Lichens,
110, 144

Synangium, 122, 142, 158

Syncarpous. Having the carpels coher-
ing together to form a compound ovary

Synergide, 183

Sungenesious. A term applied to sta-
mens whose anthers are united to-
gether, while their filaments are free

Systems of classification, 16, 17

Tapetum, A nutritive layer usually
surrounding the sporogenous tissue of
the archesporium

Teleutospore or teleutogonidium, 71, 83

Tendrils, 496

Tensions in plants, 476

Tetradynamous. A term applied to the
arrangement of the stamens in the
Cruciferee

Tetraspores or Tetragonidia. The asexual
reproductive cells of the Rhodophyce

Thallose liverworts, 104

Thallus. A plant body showing no dif-
ferentiation into stem, leaf and root

Thyloses. A tissue often found in the
interior of vessels or tracheids. It is
formed by a cell of the adjacent tissue
boring its way into the vessel through
a pit and then multiplying by cell-
division

Trama, 91

Transfusion tissue. A tissue surrounding
the vascular bundles in the meristeles
of the leaves of the Conifers

Transpiration, 419, 425, 427

— conditions of, 429

— importance of, 430

— current, 442

MM 2
5382 MANUAL OF BOTANY

Trichogyne, 37, 50, 70, 82
Trypsin, 456, 457
Tiillen=thyloses
Turgescence, 413

Uredospores or uredogonidia, 88

Vacuole, formation of, 410
— contractile, 508
Vallecular cavities, 151
Varieties or sub-species, 2
Vegetative reproduction, 512
— — in Cyanophycee, 39
— — — Lichens, 97

— — — Fungi, 73

— — — Liverworts, 105, 110
— — — Mosses, 116

— — — Pteridophyta, 125
Yelum partiale, 91

— universale, 92

 

Ternation. The arrangement of the
foliage leaves in the bud

Xanthophyll, 441, 464
Xerophilous plants, 480

Zoocwnocyte. A free-swimming cceno-
cyte, 59

Zoogleea, 75

Zoogonidia or zoospores. Asexual repro-
ductive cells with cilia but no cell-
wall

Zoophilous, 519

Zugomorphic flowers. Those which can
be divided into two precisely similar
halves by a vertical section in one
plane only

Zugospore. The body produced by the
coalescence of two similar gametes

Zugote. The body produced by the pro-
cess of fertilisation or conjugation.
It may be a zygospore or an cospore
INDEX OF PLANTS

Abieteze, 178

Abietinez, 176

Acacia, 333:

Acanthacezx, 234, 398, 405

Acanthus, 398

Acer, 325

Aceracez, 229, 325, 329, 330

Acerinez, 325

Acetabularia, 57

Achlamydosporex, 24, 225,
246

Achlya, 72, 73

Achyranthes, 236

Aconitum, 263

Acorez, 209

Acorus, 209

Acotyledones, 18, 19

Acramphibrya, 22

Acrobrya, 21

Acrogens, 23

Actinocarpus, 211

Adiantum, 123

Acidiomycetes, 74, 87

4aschynanthus, 397

Aisculus, 324

ABthalium, 77

ithusa, 357

Agaricus, 31, 90

Agave, 198

Aglaia, 317

Agrostis, 218

Aizoon, 356

Alangiacez, 231, 361, 362

Alangiuin, 361

Alchemilla, 335

Algz, 27, 34, 437

Alisma, 187, 211

Alismacez, 189, 210, 220

Allamanda, 385

Alnus, 256

Alona, 392

Aloysia, 399

Alsine, 287

Alsinez, 287, 305

Alsodeve, 280

Alsodeia, 280

Alstreemeria, 198

 

Althaea, 297

Alum-root, 337

Amarantacex, 224, 235, 260,
262

Amaranthus, 235
Amaryllidacez, 188, 195, 219
Amaryllis, 198
Amentales, 26
Amomales, 26
Ampelopsis, 323
Amphibrya, 21
Amyridacez, 316
Anacardiacez, 229, 261, 326,
328, 330
Anacardium, 327
Anacharis, 190
Anagallis, 381
Ananassa, 194, 457
Andromeda, 377
Andromedez, 377
Aneimia, 132
Anemones, 264
Aneura, 112
Angiopteris, 141
Angiosperma, 28, 168, 181
Angiospermia, 24
Anomalous Orders, 229, 234,
327, 401 |
Anona, 267 i
Anonacez, 226, 267, 300, °
302, 304, 404
Anophyta, 21
Anthemis, 373 :
Anthoceros, 40, 102, 110
1

*

Anthocerotacee, 104, 192

Anthoxanthum, 218, 520

Antbriscus, 358

Antiaris, 252

Antidesma, 250

Antirrhinum, 395

Apetale, 22, 27

Aphelia, 214

Aphylle, 19, 20

Apocarpze, 25, 26, 189, 210

mae tenCer, 233, 384, 405,
4

Apocy num, 385

Apostasia, 192

Apostasiaceze, 188, 192, 219

Aquifoliaceze, 229, 319, 331,
404

Aquilaria, 245

Aquilariacez, 225, 245, 261,
404

Arabis, 276

Araceae, 189, 209

Arales, 26

Araliacez, 231, 262, 359, 363,

64

Araucaria, 178 <

Arbutez, 377

Arbutus, 377

Archidium, 102

Arctium, 373

Areca, 207

Aristolochia, 241

Aristolochiaceze, 224, 240,
259, 262

Armeria, 380

Aroidacex, 189, 209, 220

Aroides, 209

Artocarpaces:, 226, 250, 252,
260, 319

Artocarpus, 252

Aran, 2U8, 209

Asarales, 26

Asarum, 241

Asclepiadacee, 233,
404

Asclepias, 181, 386

Ascolichenes, 93

Ascomycetes, 71, 74, 81, 93,
51

385,

Asparagez, 201
Asparagus, 2U1
Aspergillus, 456
Aspidium, 133
Aster, 371
Asterales, 25, 232, 369
Asteranthos, 346
Asteroidez, 373
Astrantia, 358
Astrocarpus, 278
Astroloma, 378
534

Ataccia, 198

Atherosperma, 243

Atherospermacez, 225, 243,
259, 261

Athyrium, 126

Atriplex, 236

Atropa, 394

Atropee, 394

Attalea, 207

Aucuba, 360

Aulocomnion, 103, 117

Aurantiacer, 314

Auranties, 313, 314, 329

Autobasidiomycetes, 93

Avena, 217

Averrhoa, 313

Avicennia, 399

Azalea, 377

Azolla, 40, 142, 519

Bacteria, 73, 75, 499
Balanophora, 247
Balanophoraceee, 225, 247,

261
Balsaminacez, 228, 309, 329,
330, 331
Balsamodendron, 316
Bangiacee, 53
Banksia, 244
Barclaya, 270
Par sina, 314
Barringtonia, 345
Barringtoniaceee, 230, 345,
362
Bartonia, 350
Basella, 237
Basellacee, 224, 236, 260
Basidiolichenes, 93
Basidiomycetes, 69, 74, 90,
93

Bassia, 382

Batidacese, 224, 237

Batis, 237

Bauera, 339

Bauhinia, 490

Beatsonia, 286

Begonia, 354

Begoniacew, 231, 262, 353

Bellis, 373

Belvisiacew, 230, 346, 364,
403

Berbereze, 268

Berberidaces, 227, 268, 301,
308, 304

Berhberis, 269, 496, 501

Bertholletia, 345, 452

Beta, 236, 419, 450

Betula, 256

Betulacer, 226, 256, 260, 262

Betulew, 256

Bicarpellatee, 25, 233, 383

Bignonia, 397, 493

Bignoniaceee, 234, 397, 405

Bil'ardiera, 283

Bixa, 282

Bixacee, 227, 261, 281, 801,
304

 

; Campanulacese,

Blasia, 110

Boerhiaavia, 235

Boraginaceze, 233, 389, 390,
392, 403, 406

Borago, 390

Boronies, 314

Boswellia, 316

Botrychium, 140, 141

Botrydium, 57

Botrytis, 457

Brassica, 186, 275, 276

Brexia, 338

Brexiaces, 338

Bromeliacez, 188, 194, 219

Bromus, 218

Brugmansia, 240

Bruguiera, 343

Brunia, 342

Bruniacee, 230, 342, 363

| Bryonia, 353

Bryophyllum, 512

Bryophyta, 27, 98

Bunias, 277

Burmannia, 190

Burmanniacez,
219

188, 190,

Burseracer, 228, 316, 328,
3

30
Butomecez, 189, 211, 220
Butomus, 212
Buxus, 249
Byrsonima, 307
Byttneriacezx, 261, 298

Cabomba, 270, 480
Cabomber, 270, 300, 302
Cactacere, 231, 354, 362, 364
Cactus, 420
Cadaba, 278
Ceesalpinia, 333
Cesalpinies, 332
Caesarea, 311
Cakile, 275
Caladium, 209
Calamites, 154
Callitrichacese, 230, 348, 364
Callitriche, 343
Calluna, 377
Calycanthacee,

302, 304
Calycantbus, 266
Calycera, 370
Calyceracese, 232, 370, 402
Calyciflorae, 19, 24, 25, 229,

331, 361
Calycine, 25, 189, 205
Camellia, 293
Camelliaceze, 228, 293
Campanales, 25, 232, 374
Campanula, 375

375,

226, 265,

232,
403, 406, 520
Campylospermes, 358
Candollea, 265
Conellace, 227, 281, 303,
4

3
Canna, 193

 

 

MANUAL OF BOTANY

Cannabinacee, 226, 250, 251,
262

Cannabis, 252

Cannacea, 188, 193

Capparez, 278

Capparidacesr, 227, 277, 301,
302, 304, 455

Capparis, 278

Caprifoliaceze, 232, 366, 403,
405, 406

Capsella, 275, 276

Carex, 214, 215, 216

Careya, 345

Carica, 351, 457

Carludovica, 207

Carpinus, 256

Carpoasci, 93

Carya, 254

Caryocar, 294

Caryophyllacee, 227, 261,
286, 302, 304, 305

Caryophyllales, 227, 286

Caryophylles, 22

Caryophyllinez, 25

Casearia, 349

Cassia, 333

Casuarina, 255

Casuarinaceee, 226, 255, 261

Caucalis, 358

Caulerpa, 30, 35, 36, 57

Cellrelacet; 228, 316, 317,
329

Celastracese, 229, 261, 320,
329, 330, 331

Celastrales, 25, 229, 320

Celastrus, 320

Cellulares, 19

Celosia, 235

Celtex, 253

Celtis, 253

Centaurea, 373

Centranthus, 369

Ceratophyllacer, 226,
261, 262

Ceratophyllum, 258

Cereus, 355

Ceropegia, 386

Cestrum, 394

Cheerophyllum, 358

Chailletia, 318

Chailletiaces, 228, 261, 317

CL ARIEIS TELS A er 230, 346,

62

Ohamelaucium, 346

Chameerops, 207

Chara, 36, 39, 62, 508

Characeze, 62

Cheiranthera, 283

Cheiranthus, 275, 276

Chelidonium, 272

Chenopodiacer, 224,
259, 260, 261, 262

Chenopodiales, 26

Chenopodium, 236

Chili Nettles, 350

Chimaphila, 378

Chimonanthus, 266

Chlamidomonas, 508

236,
INDEX OF PLANTS

Chleenaceze, 228, 295, 301, 303

Chlora, 388

Chloranthacewx, 225, 242, 259

Chloranthus, 242

Chlorophycer, 32, 39, 53,
112, 517

Cheelanthera, 371

Choripetale, 27

Chroococcus, 97

Chrysobalinez, 334, 336

Chrysobalanus, 334

Chrysophyllum, 382

Chymocarpus, 311

Chytridiacez, 78

Cichoracez, 372

Cichore, 373

Cichorium, 371, 373

Cinchona, 368

Cinchonacez, 368

Cinnamomum, 244

Circeea, 349

Cistacer, 291, 278, 301, 304

Cistus, 279

Citrus, 314

Cladophora, 57

Claviceps, 86

Claytonia, 289

Clematidez, 264

Cleome, 277

Cleomex, 277

Clerodendron, 399

Clintonia, 376

Club-mosses, 121

Clusia, 293

Clusiaceze, 228, 292

Cobzea, 388

Cochlearia, 275

Coecoloba, 238

Cocos, 2U7

Celanthum, 287

Ceelebogyne, 513, 523

Ceelospermez, 358

Colchicacez, 188, 201, 220

Colchicez, 200

Colchicum, 202

Coleocheetaceze, 97

Coleocheete, 62, 516

Collema, 83, 97

Columellia, 396

Columelliaceze, 234, 896, 403

Combretaceze, 230, 262, 285,

 

343, 363, 364
Combretum, 344
Commelyna, 205
Commelynacez,

220
Commelynales, 26
Composite, 22, 232, 370, 402,

406, 450, 456, 520
Comptonia, 255
Confervoidez, 59
Bee 22, 27, 169, 176,

8

189, 204,

Conium, 357, 358

Connaracee, 180, 230, 331,
362, 364

Connarus, 331

Convallaria, 201

Convolvulacer, 234, 390,
392, 404, 407

Convolyulus, 392

Copaiba, 306

Corallinex, 52

Corchorus, 300

Cordia, 390

Cordiacev, 233, 390, 404

Corema, 258

Coriandrum, 358

Coriaria, 327

Coriariaces, 229, 327, 329

Cormophyta, 21

Coruacex, 231, 360, 364

Cornus, 360

Corolliflore, 19, 231, 386, 402

Coronarize, 25, 188, 199

Corrigiola, 289

Corydalis, 274

Corylaceze, 255, 256, 259

Corylez, 256

Corylus, 256

Corymbiferee, 372

Coty ledlonuex, 19

Crassula, 340

Crassulacer, 230, 340, 362,
364, 404

Crassulez, 340

Crategus, 336

Cratoxylon, 292

Cremosperme, 353

Crescentia, 397

Crescentiaceze, 234, 397, 405

Crocus, 195, 196

Cruciferee, 22, 227, 274, 302,
304, 452

Cryptogame, 19, 20

Cryptonemiacez, 52

Cucubalus, 288

Cucumis, 457

Cucurbitacez, 231, 352,
403

Cunonia, 339

Cunoniaceze, 230, 262, 337,
339, 363, 364

Cunoniee, 337

Cupressez, 178

Cupressinez, 169, 176

Cupressus, 178

Cupuliferee, 22, 226, 255, 256,
262

Curcuma, 193

Curvembrye, 24, 224, 235

Cuscuta, 391, 392, 483, 498

Cuscuteze, 392

Cuspariez, 314

Cutleria, 37, 47

Cutleriacese, 42, 47

Cyanophycee, 39

Cycadaces, 180

Cycadeze, 27, 169, 177

Cycas, 174, 180

Cyclamen, 381, 493

Cyclanthaceze, 207

Cynares, 373

Cynarocephalz, 372

Cynoglossum, 390

Cynomorium, 247

364,

 

535

Cyperaceze, 189, 215, 222
Cyperus, 216
Cypripedium, 191, 192
Cypselea, 356

Cyrilla, 319

Cyrillacer, 229, 319, 329
Cyrtandra, 397
Cyrtandre, 396
Cystopus, 79
Cystoseira, 43
Cytinacez, 224, 239, 261
Cytinus, 240

Dactylis, 218

Daphonales, 24, 26, 225, 243

Daphne, 245

Darwinia, 346

Datisca, 354

Datiscacew, 231, 262, 354, 364

Daucus, 358

Dendrobium, 192

Desmarestia, 36

Desmids, 60

Desmodium, 487, 489, 509

Desvauxia, 214

Desvauxiaceze, 189, 213, 221

Deutzia, 338

Dialy petal, 22

Diamorpha, 3 10

Diamorphez, 340

Dianthus, 287, 288

Diapensiacez, 232, 379, 404

Diatomacer, 34, 39, 40

Diatoms, 507

Dicarpiee, 24, 25, 383, 406

Dicentra, 273

Diclines, 18

Dicotyledones, 224

Dicotyledous, 24, 28, 186

Dictyogens, 23

Dictyota, +7

Dictyotacez, 47

Dielytra, 274

Dillenia, 265

Dilleniaces, 226, 265, 300,304

Dionza, 341, 440, 453, 455,
457, 501, 503

Dioscorales, 26

Dioscorea, 199

Dioscoreaceze, 188, 198, 220

Diosma, 314

Diosmez, 314

Diospyros, 382

Diplecolobez, 277

Diploclinium, 35+

Diplozygieze, 358

Dipsacex, 232, 369, 402, 406,

Dipsacus, 369, 370

Dipteraces, 228, 294, 301,
304

Dipterocarpee, 228

Dipterocarpus, 295

Dirca, 245

Disciflorae, 24, 25, 228, 305,
328

Dodonea, 324
Dodonex, 324
536

Dorstenia, 251

Doryphora, 243

Draczna, 31

Drosera, 341, 440, 453, 455,
457, 483, 496, 505, 560

Droseraceze, 230, 341, 361,
364

Drupacez, 334, 336
Dryobalanops, 295

Ebenacee, 233, 382, 404, 406

Ebenales, 25, 233, 381

Echium, 390

Ehretia, 390

Ehretiaces, 233, 390, 404

Elaagnaceze, 225, 246, 260,
262

Eleagnus, 246
Elatinaces, 227, 290, 3
05

3
Elatine, 290
Eleocarpus, 300
Elephantopus, 373
Elettaria, 193
Empetraces, 226, 258,
262
Empetrum, 258
Endogene, 19
Endogens, 23
Entomophthoracee, 78
Epacridacez, 232, 378,
406
Epacris, 378
Ephedra, 177, 180, 463
Epicorollee, 18
Epigyne, 24, 25, 188, 193,
219, 231, 366, 405
Epimedium, 269
Epipetale, 18
Epiphyllum, 355
Epistamine, 18
Equisetaceve, 21, 122, 423
Equisetinz, 28, 150
Equisetum, 121, 159, 463
Eremascus, 83
Ergot, 86
Brica, 377
Ericacez, 22, 232, 377, 403,

406
Ericales, 25, 232, 376
Erices, 377
Erigeron, 373
Eriocaulacee, 189, 213, 221
Eriocaulon, 213
Erodium, 309
Eryngium, 358
Erythroxylaces, 306
Escallonia, 338
Escalloniacee, 230, 336, 338,

364

Escalloniese, 337

Eudorina, 56

Euouymus, 320

Euphorbia, 249

Euphorbiacez, 226, 248 259,
260, 262

Euphorbiales, 26

 

Eupatoriez, 373
Eupatorium, 373
Euscaphis, 326
Eusporangiatz, 127
Eurotium, 73, 83, 84, 85
Exoasci, 93

Exogene, 19

Exogens, 23

Fadgenia, 360

Falconeria, 250

Ferns, 121

Festuca, 217

Ficoidaces, 231, 355

Ficoidales, 25, 231, 354

Ficus, 463

Filices, 21

Filicine, 28, 127

Flacourtia, 282

Flowers of Tan, 77

Feeniculum, 358

Folios, 19, 20

Forstera, 374

Francoa, 338

Francoacez, 230, 336, 337,
362

Francoee, 337

Frankenia, 286

Frankeniacez, 286, 802, 304

Fraxinus, 383, 384

Fritillaria, 200

Fucacee, 43

Fuchsia, 349

Fucus, 32, 44, 45

Fumaria, 273

Fumariacee, 227, 272, 302,
304

Funaria, 116, 117

Fungi, 27, 66, 422, 431

Fusarum, 456

Galanthus, 198

Galiaceze, 368

Galium, 367, 368

Gamopetale, 22, 24, 25, 231,
366, 402

Garcinia, 293

Garden Thyme, 401

Garrya, 360

Garryacee, 231, 360, 364

Gasteromycetes, 92

Geissoloma, 246

Gelides, 51

Gentiana, 388

Gentianacese, 233, 387, 404,
405, 407, 520

Gentianales, 25, 233, 383

Gentianez, 388

Geraniacer, 228, 261, 308,
310, 330, 331

Geraniales, 25, 228, 305, 383

Geranium, 309

Gesnera, 396

Gesneracen, 234, 396, 405,406

Gesnereze, 396

Giesekia, 237

 

MANUAL OF BOTANY

Gigartinaces, 51

Giukgo, 177

Gladiolus, 195

Glaux, 381

Globularia, 398

Gloxinia, 396

Glumacez, 25, 189, 213, 222

Glumales, 26

Gnetacee, 27, 174, 179, 180

Gnetum, 177, 180

Gomphia, 315

Gomphocarpus, 386

Gomphrena, 236

Goodenia, 375

Goodeniacew, 232, 374, 403,
406

Gossypium, 297

Graminacee, 189, 216, 222

Graminee, 21

Grape Vine, 323

Guaiacum, 308

Guarea, 317

Gustavia, 345

Guttiferae, 228, 292, 301, 302

Guttiferales, 25, 227, 290

Gymnogens, 23

Gymmnosperbure, 22, 28, 168,

4

Gymunospermia, 25
Gymnostomum, 119
Gynandropsis, 277
Gynopleura, 351
Gypsophila, 288

Hemanthus, 198
Heematococcus, 29, 516
Hemodoracee, 188, 194, 219
Hemodorum, 195
Haloragacee, 230, 262, 342,

364
Hamamelidacew, 230, 262,

342, 364
Hamamelis, 342
Haplozygiese, 358
Hedera, 359
Hedyosmum, 242
Heisteria, 318
Heliamphora, 271
Helianthemum, 279
Helianthus, 428
Helicteres, 298
Heliotropium, 390
Hellebores, 264
Helminthostachys, 140
Hemiasci, 93
Hemibasidii, 93
Hemidesmns, 386
Henslovia, 339
Hensloviacez, 230, 336, 339
Hepatice, 21, 27, 98, 104
Heracleum, 358
Hesperis, 276
Heteria, 204
Heteromere, 232
Heterosciadiem, 358, 376
Heterosporex, 127
Heterosporous Ferns, 142
Heterosporous Lycopodine,
159

Heuchera, 337

Hibisceze, 297

Hibiscus, 297 _

Hippocastanes, 324

Hippocratea, 321

Aipoooratencer, 229, 320,
3

Hippophaé, 246

Hippuris, 342

Holly, 320

Homaliacex, 231, 349, 362

Homalium, 349

Horsechestnut, 324

Horsetails, 121

Houttuynia, 242

Hoya, 386

Huminiaeee, 228, 306, 328,
3

Humirium, 307
Humulus, 252
Huacinth, 429
Hyalostemma, 242
Hydnora, 240
Hydrales, 26
Hydrangea, 339
Hydrangeacez,
338, 363, 364
Hydrangez, 337
Hytrocharidacets, 188, 190,
2
Hydrocotyle, 358
Hydrodictyon, 57
Hy drophy laces, 233, 388,
404

Hydrophyllum, 389
Hydropteridex, 127, 142
Hydrostachys, 239
HymenophyUacee, 130
Hypecoum, 273
Hypericacer, 227, 290, 300,
302, 305
Hypericum, 291
Hypocorolle, 18
Hypopetale, 18
Hypostamine, 18
Hypoxis, 198
Hysterophyta, 21

230, 336,

Iberis, 275

Icacina, 319

Icacinacee, 229, 318, 329

Tlex, 320

Tlicacese, 229, 319

Ilecebrum, 289

Impatiens, 310

Incompletz, 24, 235, 258

Inferz, 24, 25, 26, 219, 231,
366, 405

Inocarpus, 245

Tonidium, 280

Ipomea, ’392

Iridacez, 21, 188, 195, 219

Tris, 195, 196

Isatis, 275, 276

Iscetaces, 127

INDEX OF PLANTS

Isoetes, 122, 123, 159, 164

Isonandra, 382

Isosporex, 127

Tsosporous Ferns, 127, 139
3 Lycopodinee, 155

Isotoma, 376

Itea, 338

Ixora, 368

Jacaranda, 397
Jasminacez, 383
Jasmine, 383

Jasminum, 384
Jateorhiza, 268
Juglandacee, 226, 254, 259
Juglans, 254

Juncacez, 189, 205, 220
Juncaginacez, 189, 213, 220
Juncus, 206
Jungermannia, 111
Jungermanniacez, 104
Juniperus, 176, 178
Jussizea, 349

Justicia, 398

Kalmia, 378
Kokoona, 321
Kokra, 249
Krameria, 285

Labiate, 22, 234, 399, 405,
4

06

Labiateflore, 372, 373

Lacis, 239

Lacistema, 257

Lacistemacez, 226, 257, 260

Lamiales, 25, 234, 398

Laminaria, 31, 35

Laminariaceee, 45
* Lamium, 400, 401

Lapageria, 201

Lardizabalacez,

Lathraa, 395

Lauracee, 225, 243, 260

Laurales, 26

Laurelia, 243

Laurus, 244

Lavradia, 281

Lawsonia, 348

‘Tec eliidaces, 230, 345, 362,

64

Lecythis, 345

Leguminose, 22, 230, 261,
331, 36], 364, 422, 437

Lejolisia, 52

Lemna, 210

Lemnacez, 189, 209, 223

Lemon Thyme, 401

Lentibulariaceze, 234, 395,
405, 406

Leontice, 269

Lepidodendron, 166

Lepidostachys, 249

Leptanthus, 203

Leptocarpus, 214

Leptospermen, 344

268, 301,

 

 

537

Leptospermum, 344

Leptosporangiate, 127

Leschenaultia, 375

Leucocarpus, 370

Leucojum, 197

Leucopogon, 379

Leucosmia, 245

Lewisia, 356

Lichenes, 27, 95

Liliacez, 21, 188, 199, 220

Liliales, 26

Lilie, 200

Lilium, 200

Ligulatz, 160

Ligulifloree, 373

Ligustrum, 383, 384

Limnanthace, 228, 311, 329

Limnanthes, 311

Limnocharis, 212

‘Linneer, 228, 305, 328, 330,
33

Linum, 306

Liquidambar, 342

Liriosma, 318

Lissanthe, 379

Listera, 191

Litchi, 325

Littorella, 402

Liverworts, 104

Loasa, 350

Loasacer, 231, 350, 362, 364

Lobelia, 376

Lobeliacez, 232, 375, 402, 405

Loganiaceew, 233, 387, 404

Lolium, 218

Lomentacee, 275

Lonicera, 366

Lophira, 295

Lophiracese, 295

Lophophytum, 248

Loranthacez, 225, 246, 259

Loranthus, 247

Luzula, 206

Lychnis, 287, 288

Lycium, 394

Lycopodiaceze, 155

Lycopodine, 28, 121, 155

Lycopodium, 155, 422

Pybhracen, 2205 261, 347,361,
364

Lythrum, 348, 521

Macadamia, 544
Macrocystis, 30, 46, 60
Magnoliaceee, 226, 266, 3u1,

304
Magnoliez, 266
Malaxis, 192
Malesherbia, 351
Malesherbiacee, 231, 351,
362
Malpighia, 307
Malpighiaceze, 228, 261, 307,
329, 330
Malva, 297
Malvacee, 182, 228, 296, 298,
301, 304, 305
538

Malvales, 25, 228, 296
Malveee, 297

Mammillaria, 355

Maranta, 193

Marantacez, 188, 193, 219
Marattia, 122

Marattiacez, 139, 141
Marcgraavia, 294
Maregraaviacere, 228, 293,

301
Marchantia, 103, 104
Marchantiaces, 104
Marjoram, 401
Marjorana, 401
Marsilea, 142, 144
Marsileacez, 142
Mayaca, 204
Mayaces, 189, 204, 220
Medecea, 351
Medinilla, 347
Melaleuca, 344
Melanthacez, 188, 201
Melastoma, 347
Melastomaceze, 230,
364
Melia, 317
Meliacese, 228, 316, 329, 330
Melianthez, 308
Melianthus, 308
Meloca, 237
Melocactus, 355
Meliosma, 324
Meliosmem, 324, 326
Menispermaceze, 227, 261
267, 302, 304, 326
Menispermum, 268
Mentha, 401
Mentzelia 350
Menyanthez, 388
Menyanthes, 388
Merimea, 290
Mercurialis, 249
Mertensia, 253
Mesembryanthacer,
262, 355, 362, 364
Mesembryauthea, 356
Mesembryanthemum, 356
Mesocarpee, 37
Mesocarpus, 484
Mesomycetes, 93
Micrembryez, 24, 225, 241
Micrococcus, 75
Microspermae, 24, 188, 190
Mimosa, 333, 361, 414, 484,
495, 498
Mimoser, 333
Mimulus, 496
Mirabilis, 235
Modecca, 351
Mollugiveze, 287, 356
Mollugo, 287
Monetia, 384
Monimia, 243
Monimiacee, 225, 242, 259,
261

346,

 

231,

Monnina, 285
Monochlamydea, 19, 24, 26,
224, 235, 258

 

Monocotyledones, 24, 26, 28,
186, 188, 219
Monodora, 267
Monoepigynee, 18
Monohypogyne, 18
Monoperigyne, 18
Monotropa, 378
Monotropacex, 232, 378, 403,
401

6
Moracee, 226, 250, 251, 260
Moringa, 328
Moringaces, 229, 327, 329,
330

Morus, 251

Mosses, 98, 113

Mucor, 30, 72, 77, 523

Mucorini, 79, 94

Multiovulate, 24

Multiovulatz aquatice, 224,
38

~ terrestres, 224, 239

Musa, 194

Musaceze, 188, 193, 219

Musci, 21, 27, 113

Mushroom, 91

Mutisia, 373

Mutisiea:, 373

Mycoderma, 459, 468

Mylocaryum, 319

Myoporaceze, 234, 399, 405

Myoporum, 399

Myrica, 255

Myricacez, 226, 254, 259, 262

Myricaria, 290

Myristica, 242

Myristicaces, 225, 242, 261

Myrrhis, 358

Myrsinaces, 233, 381, 403,
406

Myrsine, 381

Myrtaceae, 230, 262, 344, 362

Myrtales, 25, 230, 343

Myrtez, 344

Myrtle, 344

Myrtus, 344

Myxochitridinez, 32

Myxodendron, 247

Myxomycetes, 68, 74, 76, 93,
489, 500, 507

Naiadacez, 189, 212, 221
Naias, 213

Nandina, 268
Napoleona, 346
Narcissales, 26
Narcissus, 197, 198
Nassauvia, 873
Nassauviee, 373
Nectandra, 244
Negundo, 325
Nelumbium, 270
Nelumbonee, £70, 300
Nemalionacez, 51
Nemophila, 389
Nepenthacez, 224, 239, 261 «
Nepenthales, 26 |
Nepenthes, 239, 440, 453, 455

 

MANUAL OF BOTANY

Nephelium, 324
Nicotiana, 488, 489
Nitella, 62
Nitraria, 307
Nolana, 392
Nolanacez, 234, 392, 403
Nostoc, 29, 39, 97, 110, 144
Notorhizee, 276
Nucumentaces, 275
Nudifloree, 25, 189, 207
Nuphar, 269
yetaginacez, 235, 260
yetagines, 224
yctanthes, 384
ymphea, 269, 270
ympheeacerx, 227, 269, 300,
304
ymphze, 270, 301, 302
Nyssa, 361

Ochna, 315
chnacesze, 228, 315, 327, 329,
30

cymum, 401

Edogonium, 61, 516

fnanthe, 358

inothera, 349

Olacaceze, 229, 318, 328, 330

Olacales, 25, 229, 318

Olax, 318

Olea, 384

Oleaceze, 233, 262, 383, 404,
406

 

eaqo_°
wo

Ombrophytum, 248
Omphalobium, 331
Onagraceze, 230, 262, 348,

364
Oncidium, 192
Qneoba, 282
Oomycetes, 74, 77, 79, 93
Ophiocaryon, 324
Ophioglossaceze, 123, 139
Ophbioglossum, 141
Ophiria, 342
Opuntia, 354
Orchidaceee, 21, 184, 188, 190,
219, 222
Orchidales, 26
Orchis, 192, 522
Ordines, anomali, 24, 226,

Origanum, 401
Ormosciadium, 358
Ornithopus, 332
Orobanchacere, 234, 395, 405,
406, 483
Orobanche, 395
Orontiess, 209
Orontium, 209
Orthoploceze, 276
Orthospermee, 353, 358
Osmunda, 132, 133
Osmundaceze, 130
Ouvarandra, 479
Oxalidacese, 228, 311, 330,

dats, 313
INDEX OF PLANTS

Peeonier, 264

Peony, 422

Palmacez, 21, 189, 206, 220

Palmales, 26

Panax, 359

Pandanaces, 189, 207, 221

Pandanus, 207

Pandorina, 56

Pangiabe, 252

Pangium, 282

Panicum, 218

Papau, 457

Papaver, 272

Papaveracez, 227, 261, 272,
301, 302, 304

Papayacex, 231, 351, 362,
364

Papilionacee, 332

Parietales, 25, 227, 271

Parietaria, 251

Parmentiera, 397,

Parnassia, 520

Paronychiaces, 227,
289, 303, 304, 305

Passiflora, 351, 497, 501

Passifloracez, 231, 262, 350,
351, 363, 364

Passiflorales, 25, 230, 349

Pedaliace, 234, 397, 405

Pedalium, 398

Pelargonium, 309

Pelvetia, 44

Penza, 246

Penzacez, 225, 245, 261

Pentacyclice, 27

261, |

 

Pentaloba, 280

Penthorum, 340

Pericorolle, 18 i

Peripetale, 18

Peristaminz, 18

Peronosporee, 79, 94

Personales, 25, 234, 394

Petaloidex, 219

Petiveriacese, 224, 237, 259

Peumus, 243

Peziza, 84

Pheophycee, 35, 39, 41

Phajus, 450

Phalaris, 493, 501, 502

Phanerogame, 19, 20

Phanerogamia, 24, 28, 167

Philadelphaces, 230, 336,
338, 362

Philadelphez, 337,

Philadelphus, 338

Philesia, 201

Philesiaceze, 188, 201, 221

Philydracea, 189, 203, 220

Philydrum, 204

Phleum, 216, 218

Phlox, 388

Phycomycetes, 71,74, 77, 93

Phyllodoce, 377

Phylloglossum, 155, 156, 157

Phyteuma, 375

Phytecrena, 319

Phytocrenacez, 229, 319

Phytolacca, 237

. Podostemon, 239

_ Polemonium, 388
| Polycarpes, 287, 305

| Polygala, 285

Phytolaccacesx, 224, 237, 261

Phytophthora, 79

Picea, 176

Pilularia, 142, 145

Pimelea, 245

Pimpernel, 168

Pinacez, 178

Pinguicula, 396

Pinus, 171, 178

Piper, 241

Piperaceze, 225, 241, 259

Piperales, 26

Piriqueta, 350

Pisonia, 235

Pistacia, 327

Pistia, 210

Pisum, 451

Pittosporacez, 227, 276, 282,
303, 304

Pittosporum, 283

Plagivspermeze, 353

Planera, 253

Plantaginacee, 234, 401,
405, 406

Plantago, 402

Plant-fountains, 319

Platanacese, 226, 253, 259

Platanus, 253

Pleurorhizex, 276

Plumbaginacer, 233,
403, 405, 406

Plumbago, 379, 380

Poa, 217

Podophyllum, 268

Podostemacez, 224, 238, 259,

379,

Polemoniaceze, 233, 388, 404,
Polemoniales, 25, 233, 388

Polycarpon, 287

 

Polygalacex, 227, 283, 302,
304, 305

Polygales, 227, 282

Poly galinez, 25

Polygamia, 372

Polygonacez, 224, 238, 259,
260, 262

Polygonatum. 200

Polygonez, 22

Polygonum, 238

Polyosma, 340

Polypetale, 24, 25, 226, 263,
402

Poly podiacez, 130
Polypodium, 133
Polyporez, 92

' Polytrichacez, 423
Polytrichum, 100, 115, 119
| Pomex, 335, 336
Pontederia, 203
Pontederiales, 26
Pontederiacez, 189, 203, 220
Populus, 257

Porlieria, 489

_ Primulaceze, 233, 262,

539

Portulaca, 289

Portulacacez, 227, 289, 301,
303, 304, 305

Potamales, 26

Potamogeton, 213

Poterieze, 335

Poterium, 335

Primula, 381, 520

381,
403, 406

Primulales, 25, 232, 379

Prinos, 329

Printzia, 373

Protea, 244

Proteacez, 225, 244, 260

Protobasidiomycetes, 92, 93

Protococcacex, 56

Protococcus, 97

Protophyta, 21

Prunus, 334, 452

Psilotaces, 155

Psilotum, 155, 186

Pteridophyta, 28, 121

Pteris, 132, 133

Puccinia, 73, 87

Punica, 344

Pyrola, 378

Pyrolez, 378

Pyrus, 336

Pythium, 79

Quassia, 315
Quercinese. 256
Quercus, 255, 256
Quernales, 26

Radiola, 306

Rafflesia, 240

Rafflesiaceze, 224, 780, 261

Ranales, 25, 226, 263

Ranunculacer, 29, 226, 201,
263, 300, 302, 304

Ranunculee, 264

Ranunculus, 263

Rapatea, 204

Rapateacez, 204

| Raphanus, 275, 276

. Ratsbane, 318

' Ravenala, 194

Reaumuria, 290

Reaumuriacez,
300, 302

Reseda, 278

Resedacew, 227, 278, 302, 304

Restiacex, 189, 214, 221

Restiales, 26

Restio, 214

Rhamnacez, 229, 261, 321,
328, 330, 331

Rhamnus, 322, 458

Rheum, 238

Rhizanthee, 21

Rhizobolacez, 228, 294, 301

Rhizocarps, 127, 142

Rhizogens, 23, 261

Rhizophora, 343

227, 290,
540

230,

2

Rhododendron, 378

Rhodomeniacez, 51

Rhodophycew, 37, 39, 48, 517

Rhodoresx, 377

Ribes, 340

Libesiace, 230, 337, 339, 363

Ribesiex, 337

Riccia, 110

Ricciem, 102, 104

Ricinus, 249, 451, 452

Ripogonum, 203

Robinia, 414

Romneya, 272

Rosa, 334

Rosacex, 22, 230, 261, 333,
361, 364, 452

Rosales, 25, 229, 331

Rose, 334, 336

Roxburghia, 199

Roxburghiacez, 188, 199, 221

Royena, 382

Rubia, 367

Rubiaceze, 232, ‘67, 403, 406

Rubiales, 25, 231, 366

Rubus, 334

Rumex, 238

Ruscus, 199

Rust of Wheat, 87

Ruta, 314

Rutacew, 228, 261, 304, 313,
329, 330, 403

Rutez, 314

Ruyschia, 294

Rhizophoracez, 343,
64

Sabiaceee, 229, 324, 326

Saccharomyces, 456

Saccharomycetes, 85

Sage, 401

Salicacea, 226, 257, 258, 262

Salicornia, 236

Salisburia, 179

Salix, 257

Salsola, 236

Salvadora. 384

Salvadoraceze, 233, 384, 405

Salvertia, 286

Salvia, 401

Salvinia, 122, 125, 142, 173

Salviniaces, 142

Sambucus, 366

Samolus, 381

Samyda, 349

Samydacer, 231, 262, 349,364

.. Sanguisorbee, 335, 336

Santalaceze, 225, 247, 259,
262, 483

Santalales, 26

Santalum, 217

Sapindace, 229, 323, 325,
326, 329, 330

Sapindales, 25, 229, 323

Sapindez, 324)

Sapindus, 324

Saponaria, 288

Sapotacez, 233, 381, 404

 

Saprolegnia, 72, 500, 523
Saprolegniz, 79, 80
Saprolegniacese, 94
Sarcolzena, 295
Sarcostigma, 319
Sargassum, 36, 43
Sarracenia, 271, 440, 453
Sarraceniacez, 227, 271, 301,

Satureia, 401

Saururaces, 225, 241, 259

Saururus, 242

Sauvagesia, 281

Sauvagesiacesx, 227, 281, 303

Saxifraga, 337, 455

Saxifragacese, 230, 262, 336,
363, 364

Saxifrageze, 337

Scabiosa, 368, 369

Seepa, 249

Scepaceze, 226, 249, 260

Schizan dracee, 300

Schizandrez, 266

Schizocapsa, 198

Schizomycetes, 71, 74

Sciaphila, 210

Scilla, 200

Scirpus, 215, 216

Scitaminacew, 188, 193

Scleranthacee, 261, 304

Sclerauthes, 289

Scrophularia, 395, 520

Scrophulariacese, 231, 394,
405, 407

Scrophularineze, 22

Scytonema, 97

Sechium, 353

Sedum, 340

Selaginacea, 234, 398, 405

Selaginella, 159, 160, 173

Selago, 398

Senebiera, 277

Senecio, 371, 373

Senecioides, 373

Sepulatae, 275

Sesamum, 398

Sesuviee, 356

Sesuvium, 356

Sicyos, 353

Sida, 297

Sideze, 297

Silene, 288 i

Silence, 287, 304

Siliculose angustiseptz, 275

— latiseptee, 275

Siliquosz, 275

Simaruba, 315

Simarubacez, 228, 314, 329
330

Siphonez, 57

Smmilacea, 188, 202, 221

Smilax, 203

Smuts, 94

Solanacee, 234,
407

Solaneze, 393

Solanum, 394

Sollya, 283

392, 404,

 

MANUAL OF BOTANY

Soulamea, 285
Soymida, 317
Sparganium, 208
Spergula, 287
Spermaphyta, 28, 167
Sphacelaria, 38
Spheeroplea, 55, 57, 58
Sphagnaceze, 102
Sphagnum, 114, 119
Spigelia, 387
Spinacia, 236
Spirolobece, 277
Spirillum, 75
Spirogyra, 58, 59, 61
Splachuidium, 46
Stachys, 401
Stackhousia, 321
Sige UBIAGE, 229, 321,
3

Stanhopea, 192

Stapelia, 386

Staphylea, 326

Staphyleaces, 229, 325, 330

Stellaria, 287

Stellate, 368

Sterculia, 298

Sterculiaceze, 228, 261, 297,
301, 303, 304 =

Stephanopodium, 318

Sticta, 95

Stilaginaceze, 226, 249, 260

Stilago, 250

Stilbacew, 232, 379, 405

Stravadium, 345

Strychnos, 387

Stylidiaces, 232, 374, 403

Stylidium, 374

Styracez, 233, 382, 404, 406

Styrax, 383

Subularia, 277

Summer Savory, 401

Superee, 24, 25, 26, 220, 232,
376, 406

Sweet Marjoram, 401

Swietenia, 317

Sympetale, 27

Symphoricarpus, 367

Symplocos, 383

Syncearpe, 26

Syngeneticz, 48

Synzyganthera, 257

Syringa, 383

Tacca, 198

Taccaceze, 188, 198, 219

Taccales, 26

Tacsonia, 351

Tamaricaces, 227, 289, 303,
304

Tamarix, 290

Tamus, 199

Taraxacum, 373

Taxacex, 178, 179, 180

Taxeee, 178,179

Taxinez, 178, 179

Taxus, 174, 179

Tecoma, 397
Terminalia, 344

Ternstroemia, 293

Ternstreemiacee, 228, 293,
301, 804

Tetilla, 338

Tetracyclice, 27

Tetragonia, 356

Tetragoniaces, 356

Tetragoniex, 356

Tetrameles, 354

Tetraphis, 117, 119

Tetratheca, 283

Thalamiflore, 19, 24, 25, 226,
263,300

Thallogens, 23

Thallophyta, 21, 27, 29

Theobroma, 298

Theophrasta, 381

Thesium, 247

Thibaudia, 376

Thismia, 190

Thuja, 176,

Thymelacee, 225, 244, 260,
262

Thymus, 401

Tilia, 300

Tiliaces, 228, 261, 298, 301
303, 304, 305

Tilier, 300

Tillandsia, 194

Tmesipteris, 155, 156

Toddalia, 314

Toddaliez, 314

Tofieldia, 202

Tontelea, 321

Torula, 78, 459

Tradescantia, 205, 508

Trapa, 342

Tremandra, 283

Tremandracee, 227, 283, 303

Trianosperma, 353

Trichilia, 317

Trichodendrez, 266

Trifolium, 332

Triglochin, 213

Trilliacess, 222

Trilobium, 332

Trimeria, 349

Tripterococcus, 321

Triurales, 26

Triuridacee, 189, 210, 221

Triuris, 210

Trixis, 373

Trollius, 263

Tropxolacex, 228, 311, 329
330, 455

INDEX OF PLANTS

 

Tropeolum, 311
Tubulifloree, 372

Tulipa, 200

Tupa, 376

Turnera, 350
Turneracer, 231, 350, 364
Tussilago, 373

Typha, 208

Typhacew, 189, 208, 221

ULEX, 332

Ullucus, 237

Ulmacew, 226, 250, 252, 260,
62

Ulmee, 253

Ulnuus, 253

Ulothrix, 37, 58, 59, 516

Umbellales, 25, 231, 356

Umbelliferae, 22, 231, 356,
363

Unisexuales, 24, 225, 248

Urceola, 385

Uredinew, 71, 90

Urtica, 250

Urticacese, 22, 226, 250, 260,
262

Urticales, 26
Usnea, 95, 96
Ustilagineze, 90
Utricularia, 396

Vacearia, 288

Vacciniaces, 232, 376, 403,
406

Vaccinium, 376

Valeriana, 369

Valerianacez, 232, 369, 402,
406

Vallea, 300

Vallisneria, 190, 508

Vantanea, 307

Varronia, 390

Vascular Cryptogams, 121

Vasculares, 19

Vaucheria, 38, 57, 58, 59

Vellozia, 195

Venus’s Flytrap, 341

Verbascum, 395

; Verbena, 399

Verbenaceze, 234, 398, 405,
407

Vernonia, 373

Vernoniez, 373

Veronica, 395

 

541

Viburnum, 366

Vicia, 832

Victoria, 270, 479

Villarsia, 388

Vinea, 385

Viola, 172, 280

Violaces, 227, 279, 303, 304

Violeze, 280

Viscum, 247

Vismia, 291

Vitacez, 299, 322, 330

Vitis, 323

Viviania, 311

Vivianiacese, 228, 310, 328

Voebysia, 286

Moehysinceres 227, 285, 308,
04

Volvoccaceze, 56
Volvox, 56

Water-vines, 319
Weinmannia, 339
Welwitschia, 174, 177, 180
White Mangrove, 399
Winter Savory, 401
Winterez, 266

Xanthoxylacese, 261, 314,
829

Xanthoxylez, 314, 329
Xanthoxylon, 314
Ximenia, 318

Xylopia, 267
Xyridacex, 189, 204, 220
Xyris, 204

Yeast, 29, 85, 456

Zamia, 180

Zanardinia, 47

Zannichellia, 212, 213

Zingiber, 193

Zingiberaces, 188, 193, 219

Zizyphus, 322

Zostera, 181, 213

Zygnema, 61

Zygneme, 37, 59

Zygogonium, 60

Zygomycetes, 70, 74, 77, 93

Zygophyllaceee, 228, 307,
, 330

Zygophyllum, 308

 

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