ELEMENTARY
BOTANY

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EDMONDS.

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ELEMENTARY BOTANY
PRINTED BY
SPOTTISWOODE AND CO., NEW-STREET SQUARE
1ONDON
ELEMENTARY. BOTANY

A TEXT-BOOK DESIGNED PRIMARILY FOR STUDENTS OF SCIENCE CLASSES
CONNECTED WITH THE SCIENCE AND ART DEPARTMENT OF

THE COMMITTEE OF COUNCIL ON EDUCATION

By HENRY EDMONDS, B.Sc. (LOND.)

HONOURS IN BOTANY, SOUTH KENSINGTON

LECTURER ON NATURAL SCIENCE AND CHEMISTRY AT THE BRIGHTON SCHOOL
OF SCIENCE AND ART

SCIENCE LECTURER TO THE EVENING RECREATIVE CLASSES, BRIGHTON
ETC.

NEW AND REVISED EDITION

LONDON

LONGMANS, GREEN, AND CO.
AND NEW YORK . 15 EAST 16th STREET

ee

All rights reserved
PREFACE

TO

THE NEW EDITION.

 

THE favour with which the previous editions of this work have
been received has necessitated a reprint. Some changes and
modifications having been made this year in the syllabus
issued by the Science and Art Department, the opportunity

has been taken of thoroughly revising the work.

Chapters have been added on the movement of water in
plant tissue, on the influence of heat and light upon growth,
and the irritability of plants. The orders Boraginacez, Primu-
laceze, and Amaryllidaceze have also been substituted in the
new syllabus for the Chenopodiacez, Orchidacez, Graminacee,

and Cyperaceze.

In the present edition, whilst the old orders are retained,
the new ones, to meet the requirements of the Department,
have been added.

: H. EDMONDS.

BRIGHTON : October 1888.
PREFACE.

THE object of this text-book is as far as possible to cover the
subject of Elementary Botany as provided in the syllabus of
the elementary stage issued by the Science and Art Depart-
ment, and at the same time to avoid being a mere cram work,
but to give a general idea of the fundamental facts and prin-
ciples of the science.

In many elementary works the greater part of the book is
taken up with mere structural details, the Physiology of the
Plants being relegated to a short chapter at the end. I have
endeavoured, whilst tracing up the growth and development
of the plant from the seed, to treat of the functions of each
organ at the same time as its description.

Through the liberality of the publishers the book is well
supplied with diagrams. It will not do, however, for the
student to trust to these alone. No science can be properly
studied from. mere book-work, and this is especially true of
such a science as Botany, which deals with various forms of
natural objects. The student is strongly urged from the first
to carefully examine specimens. A sharp penknife and a
simple lens, which will only cost a few shillings, are all the
apparatus required for dissecting and examining most flowers,
and the commonest plants around us will well serve the
student’s purpose.

For some parts of the subject—as, for instance, the
examination of Cellular Tissues—a microscope is needful. An
excellent instrument can be obtained at any of the well-known
makers’ for about five or six pounds.

The student should also especially accustom himself to
writing out descriptions of plants according to the model
given at the close of the book.

H. EDMONDS.
BRIGHTON: May 1882,
CONTENTS.

CHAPTER

I.
II.
III.
IV.
Vv.

VI.
VII.
VIII.
Ix,

XI.
XII.
XIII.

INTRODUCTORY 2 ‘ a : :
STRUCTURE OF THE SEED . : " ‘ -
CELL STRUCTURE . ‘j

CELL GROWTH, SHAPE, AND FORMATION . 7

GERMINATION, RooT GROWTH, STRUCTURE,

FUNCTIONS . ‘

Stem STRUCTURE AND FUNCTIONS .
Bups AND RAMIFICATION 4
LEAF STRUCTURE AND FUNCTIONS .
BRACTS AND INFLORESCENCE . 5
FLOWER STRUCTURE AND FUNCTIONS
FRUIT AND SEED . . ‘ Z ‘
MOVEMENT OF WATER IN THE PLANT TISSUES
INFLUENCE OF HEAT AND LIGHT UPON GROWTH

IRRITABILITY OF PLANTS . ‘

CLASSIFICATION fi 4 ‘
QUESTIONS . : . . : :
INDEX , a . . . ‘ . F

15

25
40
59
69
92
100
135
145
148
151
153
193
199
ELEMENTARY BOTANY

 

CHAPTER I.

INTRODUCTORY—DEFINITION AND SCOPE OF THE
SCIENCE,

Botany is the science which deals with those special forms of
living organisms known as Plants. This at once raises the
question—What do we mean bya plant? The higher forms
of animal and vegetable life can be easily distinguished the one
from the other ; but when we descend to the lower forms we
find it most difficult, if not impossible, to draw a line of de-
marcation between them.

The old distinction between the three kingdoms of nature
was a simple one: minerals grow—plants live and grow—
animals move, live, and grow. Putting aside for the moment
the question as to whether minerals really grow, the phenomena
of motion cannot be accepted as defining the difference between
the two groups of living beings. Many plants, especially
amongst the lower forms, are capable of motion at some time
or other during their life. As an example, if we examine rain-
water that has been standing for some days, we generally find
minute green masses floating about in it. These on inspection
under a microscope prove to be true plants (Protococcus pluvi-
alis), each being a little rounded mass containing green particles.
After watching for some time, however, it will be seen that
some of these plants change their form, becoming more pear-
shaped, at the same time giving off two very minute threads or
cilia. These are thrown into rapid motion, propelling the plant

B
2 Ltementary Botany

through the water in which it floats. In this mode of motion
the Protococcus cannot be distinguished from many of the low
forms of animal life.

A better distinction is to be found in the food that is assimi-
lated. Plants, like animals, require food ; but they, as a rule,
possess the power of obtaining it from the mineral kingdom
only, whilst animals require for their food either vegetable or
animal substances. There are, however, exceptions to this
rule, and, as we have said, the two kingdoms appear to merge
gradually the one into the other in their lower forms.

Botany, then, being the science which treats of plants, has
several branches. Morphology deals with the forms of the
organs of plants. Axatfomy treats of their internal structure ;
and “Histology of the minute appearance they present under the
microscope. Physiology deals with the functions of the various
organs, and the phenomena attendant upon life. Classification
has to do with the grouping of plants according to their relation
one to another. Geographical Botany deals with the distribu-
tion of plants in space ; and Paleontological Botany with their
distribution in time. Of these we shall omit the two latter
branches in the present work, merely taking up in an elemen-
tary form the remaining departments.
CHAPTER II.

FLOWERING AND FLOWERLESS PLANTS—STRUCTURE

OF THE SEED.

AL the higher forms of plant life are distinguished as being
able, at some time or other of their existence, ta produce

flowers.

It is this fact which causes the Vegetable
Kingdom to be divided into the two sub-
kingdoms cf Flowering Plants or Phanero-
gams, and Flowerless Plants or Crypto-
gams,

In the present work we shall deal entirely
with the Phanerogams.

The point in which all of these plants
agree is that they spring originally from
seeds. To understand a seed thoroughly, it
is well to commence with a large specimen,
as, for instance, a Broad Bean, Haricot, or
a Pea.

If we examine a Broad Bean carefully,
we notice that it has an elongated shape.
At one end there isa scar or mark. This is
the point by which the seed is attached to
the fruit, and is known as the hilum. At
one end of this there isa minute hole. This
can be readily seen by allowing the bean to
soak in hot waterfor a short time ; then on
taking it out and squeezing it a drop of
water is seen to escape through the aperture.
This hole, which leads into the interior of
the seed, is called the micropyle.

Next, taking a sharp penknife, we find

 

Fic. 1.— Broad Bean.
A, seed, with one coty-
ledon removed: c, re-
maining __ cotyledon;
kn, the plumule; zw,
the radicle ; s, the sper-
moderm. JB, germi-
nating seed: s, sper-
moderm, a portion torn
away at Z; x, hilum;
st, petiole of one of the
cotyledons; 4, curved
epicotyledonary __ por-
tion of axis, z; he,
short hypocotyledonary
portion of axis; 4,
main root; ws, its
apex; kn, bud in axil
of one of the cotyle-
dons, (After Sachs.)

that we can peel
B2
4 Elementary Botany

the skin from off the seed, leaving a whitish fleshy mass within.
This skin ‘is really, however, double, as can easily be proved
by peeling from the interior a thin pellicle.

These coats are collectively known as spermoderm ; the
outer being called the testa, and the inner the tegmen.

The mass within the spermoderm forms the nucleus of the
seed. In the case of the Broad Bean this nucleus is entirely
made up of the young plant or embryo. At one end there is
a pointed portion which is directed towards the micropyle.
This is destined on germination to be prolonged to form the
root, and is known as the radicle (fig. 1).

  

Fic. 2.—Longitudinal section

of a seed of Oat: a, endo- Fic. 3.—Germination of the
sperm ; Cc, the single cotyle- Oat: a, cotyledon; ¢, axis
don; G, plumule; R, radi- of the embryo ; d, radicle ;
cle ; T, testa; o, hairs. J, plumule.

The great mass of the nucleus is made up of two fleshy
lobes, which can easily be separated from one another—the
cotyledons ; and between these at the top of the radicle there
1s a little portion curved over and divided at the end in a plume-
like manner. This, which is known as the plumule, will, under
favourable circumstances, grow into the stem and leaves of the
future plant.

In some seeds, as, for instance, those of the varieties of corn
and grass, there is in the nucleus a substance, albumen, in
addition to the embryo of the plant (fig. 2). This albumen
Structure of Seeds 5

may originate from two different parts of the ovule or unripe
seed, and hence’ is known either as endosperm or perisperm.
This will be more apparent when we have dealt with the growth
of the ovule.

The term albumen is rather a misleading one, as it might
lead the student to imagine that the substance contained within
the seed is identical in chemical composition with animal albu-
men, such as is found in the white of an egg, whereas it differs
in its characteristics in various plants. In cereals it is meady
or farinaceous ; in the Barberry and Heart’s-ease it is esky ; in
the Poppy and Cocoanut it is ozZy ; inthe Mallow, mucilaginous;
in the Vegetable Ivory and Coffee, horny.

Seeds containing albumen are spoken of as albuminous,
whilst those destitute of it are exalbuminous.

We may tabulate the structure of the most perfect seed as
follows :—

Peery Albumen ;
Spermoderm { Faas Nucleus {Bhan
8 Embryo <¢ Plumule
Cotyledons

There is another point in which seeds differ. On examin-
ing a grain of Wheat, or of an allied cereal, we find that there
is only one cotyledon present, instead of, as in the case of the
Bean, two. Several plants resemble the Bean-in having two
cotyledons present in their embryos ; whilst others, like Oats,
have but one. This causes the division of the sub-kingdom of
Flowering Plants into two groups: Dicotyledons include
those Phanerogams with two (or in some Conifers more)
cotyledons ; whilst Monocotyledons are those with only one.
As we proceed further we shall find that there are other differ-
ences between these two great classes.
6 Elementary Botany

CHAPTER III.
CELL STRUCTURE.

THE substance of the Bean seed is not homogeneous. The
whole of the various organs of plants are made up of a large
number of component parts—cells, so minute as a rule as to
be invisible separately to the naked eye. If a little brewer’s
Yeast be examined under a hand magnifying glass, it is seen
to present a granular appearance. If it be more highly magni-
fied, it is found to consist of a large number of minute rounded
particles (fig. 4); these are separate cells. We recognise in
them the outer pellicle or cell wall and the cell contents.

 

Fic. 4.—Beer Yeast (Saccha- Fic. 5.—A cell from the root of the Lizard
romyees (Torula| Cere- Orchis (Orchis hircina): a, the cell-wall,
visie). consisting of cellulose ; 6, the protoplasm,

contracted by alcohol; c, the nucleus
with a nucleolus,

The cell wall may be absent during a portion of the cell’s
existence ; it is simply inert, not-living matter; but in the
Vegetable Kingdom it is always sooner or later produced. ‘The
principal substance contained in it is cellulose, a compound of
carbon, hydrogen, and oxygen, having the chemical composi-
tion (CgH,90;)%.
Cell Walk 7

Cellulose is not coloured blue by means of iodine alone,
although it is so changed by the action of iodine and sul-
phuric acid, thus being distinguishable from starch, which has
the same percentage composition, but is turned blue by iodine,
Schultze’s solution ! will also stain it.

Cellulose is insoluble in water, both cold and boiling ; also
in alcohol, ether, and dilute acids. If it be treated with cold
concentrated sulphuric acid, it is converted first into dextrine
or British gum, which is the same composition as cellulose,
and then into grape sugar, C,H,.O,. It is found almost pure
in Cotton wool, but generally the cell wall contains mineral
ash and water in addition. .

During the growth of the cell the cellulose is often converted
into substances which are of an allied composition, but which
differ from it in various physical and chemical properties.

The chief of these are—

1. Suber, or Cuticularised Cellulose.—This is highly elastic
and almost impermeable to water; when treated with iodine
or Schultze’s solution it turns yellow ; when warmed (not
boiled) in concentrated solution of potash it is stained bright
yellow. It is met with in Cork, epidermis cells, and pollen
grains.

2, Lignin.—In this case the cell wall is hard, inelastic, and
permeable to water. Treated with a solution of aniline sul-
phate acidulated with a few drops of sulphuric acid, it is stained
yellow. It is met with in wood cells.

3. Mucilage.—When dry it is hard and horny, but it very
readily absorbs water, swelling and becoming gelatinous. The
reactions are the same as those of cellulose. Examples are to
be found in Linseed and Quince mucilage.

The cell contents are very various ; we will note some of
the principal :—

Protoplasm.—It is of this substance that the whole of the

1 Schultze’s solution :— Dissolve zine in hydrochloric acid ; permit the
solution to evaporate in contact with metallic zinc until it has attained 4
syrupy consistence. Saturate the syrup with potassic iodide, and then add
enough iodine to make a dark sherry-coloured solution. The object to be
stained must he placed in a little water, and then some of the above solu-
tion added,
8 Elementary Botany

young cell is at first made up. It is very complex in its chemical
constitution, but always contains nitrogen. Iodine colours it
brown, and concentrated sulphuric acid rose-red; whilst it is also
stained by magenta. It is soft and jelly-like in consistency,
never truly fluid. At times it is homogeneous and transparent;
more often it is granular. It forms the vital portion of the cell,
and possesses considerable power of movement. It readily
absorbs water, which, however, forms drops or vacuoles in its
interior.

The movements of protoplasm may be grouped under two
heads :—

1, Movements of protoplasmic masses destitute of a cell
wall.

{z) Swimming by means of cilia, as in the case of Proto-
coccus (p. 1). .

(2) Amcebiform movements, where a naked mass of proto-
plasm emits irregular projections (pseudopodia) at various parts
of its surface; the rest of the mass flowing after the processes.
This is seen in the remarkable animal the Amceba, or Proteus
animalcule, and is met with in some of the lower forms of plant
life.

2. Movements of protoplasm within the cell wall.

In many cases the protoplasm contained within the cellu-
lose wall shows a tendency to rotate or circulate in various
directions through the cell, often carrying with it substances
which may be imbedded in it. This is especially well seen in
the cells of many water plants. (See fig. 19.)

Chlorophyll is the substance to whose presence the green
colour of plants is due. It occurs (in the higher plants) in the
form of granules imbedded in the protoplasm of various parts
of the plant. These granules really consist of two parts—a
colourless more or less solid portion, which is formed out of
the protoplasm and builds up the chlorophyll granules ; and a
green colouring matter diffused through and colouring it. The
exact chemical composition is not yet known, but there appear
to be two separate colouring matters, the one yellow, phyllox-
anthin, and the other blue, phyllocyanin, which by their union
give the green tint.
Chlorophyll 9

The colouring matter of the chlorophyll is soluble in
alcohol, ether, chloroform, benzine, and essential oils and fats.

The chlorophyll granules
are produced in the proto-
plasm under the influence
of light, except in the case
of the germinating seeds of
some Conifers and the fronds ¥
of Ferns, in which cases high @
temperature alone appears to ~
be necessary for their forma-
tion.

If a growing plant be
placed in perfect darkness
no chlorophyll will be
formed ; the leaves and other
organs which would naturally
have a green colour present
a pale and sickly appearance.
Such organs are said to be
etiolated. An example is to
be found in the leaf-stalks of
Celery. In the natural state
they are green, but when cul-
tivated, earth is heaped up so
as to remove them from the
influence of the light. The :
result of this is to produce LN
the white leaf-stalk of the Fic. 6.—Chlorophyll granules in cells of leaf
edible varieties, this change aba angi Oinl couaueh eee sea

. : imbedded in the protoplasm of the cells. 2,
of colour being accompanied separated chlorophyll granules containing
by change of flavour. Peal eracnometias 2 a a oul ctianee
__ Gbloropliyll plays a most ot Gr watery tach. granales fernain,
important part in the plant ing after chlorophyll destroyed by action of

water. (After Sachs.)
economy, which we shall
notice when we treat later on of the food supply of the plant.

Starch has the same percentage composition as cellulose,

but appears to have a simpler molecule, its chemical formula

 
10 Elementary Botany

being C,H,,O;. It differs from it, however, in many of its
properties. It is insoluble in cold water, but swells up very
strongly on the addition of boiling water, forming a paste. It
is readily turned a dark blue by the addition of iodine. As
this blue colour, however, is removed by heat, the starch re-

 

Fic. 7.—Various forms of starch grain from the Potato.

quires to be cold, or nearly so, for its production. Exposed to
heat for some time, or to dilute sulphuric acid for a shorter
period, starch is converted into dextrine or British gum.
Starch occurs in the plant in the form of granules varying
in their size. Amongst the smaller are those of Rice starch,

 

Fic. 8.—I. Starch grain from the Scarlet Runner. II. a, 4, Starch grains from Rye.
ILI. Starch grain from the stem of the Sarsaparilla (Swilax Sarsaparilla).

which are frequently under 3,455 of an inch in diameter, whilst
those of the ‘Tous-les-mois’ are often as much as 1, of an
inch in length. In external form they vary very much, but
they usually present a central portion, the hilum, or nucleus,
round which the starch substance is arranged in concentric
Starch II

layers. Probably this striated appearance is due to a varying
quantity of water in the different parts of the granule.

The starch substance seems to be separable into two parts,
which are allied if not identical in composition, but which
differ in properties. The one, known as farinose or starch
cellulose, appears to form the skeleton of the granule, and is
either stained brown by iodine, or, as in some cases, remains
unstained ; whilst the
other part, granulose,
which forms 94 to 96
per cent. of the granule,
is coloured blue.

Granulose is readily
soluble in saliva, and is
thus separated from the
skeleton. The same
change takes place by

  

Fic. 9. — Starch Fic. 10.—Cell of endosperm of Zea Mais, Maize. Thin
grains from the la- plates of protoplasm separating the polygonal starch
tex of Euphorbia grains. a-g, granules from germinating seed of Maize
splendens. becoming dissolved and disintegrated. (After Sachs.)

the action of dastase, a substance occurring in germinating
seeds, whereby the starch stored up in the seed as a food sup-
ply is rendered soluble.

Starch granules, like those of chlorophyll, require “ght
for their formation ; the quantity needed, however, is greater
than that for the production of the green colouring matter.
The granules are at first formed within those of the chlorophyll ;
then in the dark they are converted into soluble substances
which are transferred to other parts of the plant, where they
are again fixed as reserve food materials in the form of starch.
12 Elementary Botany

Cell Sap.—In the young cell the whole of the wall, with the
protoplasm and other contents, is saturated with a watery fluid
containing various mineral and other substances in solution.
This constitutes the cell sap. As the cell increases in age this
sap collects in drops (vacuoli), which gradually run together

 

Fic. 11.—Cells from the root of F7itillaria
imperialis. A, very young cell from near
apex. , from 2 min. above the apex. C,
from about 8 mm. above the apex: /, cell

 

wall; Z, protoplasm ; 4, nucleus; 44, nu- Fic. 12.—Crystals of calcium oxa-
cleoli; s, vacuoles and cell-sap cavity. late in the cell wall. Wedzuit-
(After Sachs.) schia mirabilis, (After Sachs.)

until the whole of the interior of the cell is filled with sap,
presenting the appearance of being surrounded by two coats—
viz., within, the layer of protoplasm ; and without, the cell wall.
This sap is most important, as it contains much of the food
material of the plant.
Crystals 13

Raphides or Crystals.—Very often some of the mineral
substances contained in the sap become crystallised out, and
make their appearance either within the céll or in the wall. In
some plants the amount of these crystals is very great. In the
Old-Man Cactus, as much as 80 per cent. of the dried tissue
consists of them. Professor Bailey found in a square inch of
Locust bark no thicker than writing paper, as many asa million
and a half of these crystals. The root of Turkey Rhubarb
contains so many as to give a gritty character to it when chewed.
As arule the raphides are found in cells where there are no

  

Fic. 14.—Crystalloid, 47, in a
Fic. 13.—Cell from the stem of arenchymatous cell of the
iloé retusa, with raphides. Potts tuber ; 4, nucleus.
other granular contents, but this is not universal. In chemical
composition they consist of phosphate of calcium, or more
often of oxalate of calcium. Carbonate or sulphate of calcium
is sometimes met with. In shape they are either cubical, octo-
hedral, or needle-like (hence the name of vaphides, from the
Greek name for a needle).

' Crystalloids.—In some cells, especially those of fatty seeds
like the Brazil nut, bodies are found which are crystal-like in
appearance, but instead of being mineral in composition, con-
sist of proteinaceous or nitrogenous material closely allied to
14 Elementary Botany

protoplasm. They are insoluble in water, but break up in a
peculiar manner so as to appear to be composed of several
layers.

Aleurone Grains are minute rounded grains found in the
cells of many seeds just before ripening. They often contain
crystalloids. They are soluble in caustic potash. They are
often oily, and appear to be used as food reservoirs by the plant.

 

Fic. 15.—Cells of cotyledon of Pisum Fic. 16.—Sphere crystals of
sativum, Pea. St, starch granules with inuline in a parenchymatous

central hilum and concentrated strie; a, cell from a tuber of the
anules of aleurone ; 2, intercellular spaces Dahlia preserved in alcohol,
After Sachs.) after addition of nitric acid.

Inuline is a peculiar substance found in the roots of
Composite, and now and then in stems. It is very closely
related to starch and sugar, and in the living plant is only found
in solution in the sap; but by the addition of alcohol or
glycerine it separates out, either in a frothy condition or as
beautiful spherical masses known as sphere crystals.
15

CHAPTER IY.
CELL GROWTH, SHAPE, FORMATION, AND TISSUES.

CELLS grow by the process of intussusception. This is a
term which requires some amount of explanation. We must
look upon the cell wall as consisting, not of a continuous
homogeneous layer of cellulose, but of an immense number
of isolated, minute, solid particles or molecules, which are
comparatively speaking unalterable.

Between these it is supposed that water percolates so that
each molecule is surrounded by a layer of liquid. The neigh-
bouring molecules may vary in size, so that, if the aqueous
envelope remains the same, larger molecules will form a denser,
smaller a less dense, substance.

This hypothesis (for it is but an hypothesis, as the mole-
cules are too minute to be perceived even by the strongest
lens) was first suggested by Nageli, and it is supposed that
these molecules are held in their places by three forces, viz. :
1. The cohesion of the particles of which each individual
molecule is made up. 2. The mutual attraction which exists
between the adjacent molecules, and which gives them a ten-
dency to approach one another. 3. The av¢raction of their
surfaces for the watery envelope which counteracts this ten-
dency.

When fresh food material is brought to the cell, the new
molecules are intercalated between those already existing there,
and thus they cause an increase in the size of the cell wall.
Such a process of increase by means of intussusception is very
characteristic of the growth of organic beings, and is totally
different from the manner in which minerals increase in size.
If a crystal, say of alum, be suspended in a vessel containing a
16 Elementary Botany

strong solution of the same substance, it enlarges by 4 process
of accretion—that is, a series of fresh layers form upon its exterior.

 

Fic. 17.—I. Spherical cell from the flesh of the Peach. IJ. Ellipsoidal cell from the
flesh of the Peach. III. Hour-glass-shaped cell from the flesh of the Peach.

 

Fic. 18.—I. Fusiform cell from the
wood of the Spruce Fir, with bor-
dered pits. II. Fusiform bast-
fibre of the Larch.

Growth by intussusception often
produces a change in the shape of
the cell. The normal form is more
or less spherical ; this, however, is
rarely preserved except in the case
of unicellular plants. If the wall
grows more vigorously at the two
extremities than at the sides, the
cell will become oval or elliptical
(fig. 17), then elongated (fig. 19), and
lastly fusiform or spindle-shaped
(fig. 18).

On the other hand, if a very
vigorous growth takes place at cer-
tain parts whilst the rest of the
cell wall is but slightly developed,
several protuberances will be pro-
duced upon the surface, and a ste/-
late or star-shaped cell is formed
(fig. 20).

Another cause modifying the
shape of individual cells is to be

found in their mutual pressure the one upon the other during
Cell Shape 17

growth. By this means they may become flattened or tabular
(fig. 21), or polyhedral (fig. 22).
Other forms of cells are shown in figs. 23, 24, and 25.

 

Fic. 20.—Stellate cell from the hori-
zontal septum of the air-passages of
the Flowering Rush (Suomus um-
bellatus).

 

Fic. 19.—Circulation of protoplasm in
an elongated cell of the Celandine :
&, the nucleus with a nucleolus. The
arrows indicate the direction of the
currents.

 

Fic. 21.—Tabular cell from the epi-
dermis of Cadlitriche.

 

Fic. 22.—Polyhedral cell from the pith of Acacia lophantha:
a, seen in transverse ; 4, in longitudinal section.

At first the cell wall appears as a thin layer of cellulose per-
fectly permeable to liquids. In some cells but little thickening
takes place during growth ; in many others, however, very soon
layers of secondary deposit are formed lining their interior

c
18 Elementary Botany

surfaces. At first these layers are complete and continuous
like the original coat, but soon they are developed but slightly
or not at all at certain points, thus causing perforations in their
substance. As the holes thus produced in the contiguous

  

Fic. 23.—I. Disc-shaped cell; a uni-
cellular Alga, Coscinodiscus. II.
Crescent-shaped cell of a stoma Fic. 24.—Tetrahedral cells ; spore
(guard-cell). of a Fern in various positions.

layers correspond with one another, canals are gradually formed
leading towards the centre of the cell cavity.

Such cells, when seen under a microscope, transmit the

light differently through their pore canals and through the
thickened walls, and hence they present a pitted or dotted

  

Fic. 26.—Moderately thickened puit-
Fic. 25.— Branched bast- ted parenchyma from the pith of the
cell of the Larch. Beech.
appearance as though pierced by a number of holes (fig. 26).
These cells are known as pitted or dotted cells.
In other cases the secondary deposit takes the form of a
spiral band round the wall, thus producing a spiral cell
Secondary Deposit 19

(fig. 28). Or else it is deposited as separate rings, when an
annular cell is formed (fig. 29). When the thickening is
arranged in an irregular manner, producing a perfect network
over the wall, the cell is said to be reticulated.

 

Fic. 27.—Transverse section of a cell of Fic. 28.—A spiral cell from
the pith of Clematis vitalba: p, primary a Cactus, Opuntia Tuna,
cell wall; 4, innermost thickening layer ; with strongly thickened
P, pore-canal ; 7, intercellular space. spiral band,

Very often there is in the cell a gradual passage from a
spiral to an annular or reticulated marking (fig. 31). At other
times there is a spiral or reticulate marking in addition to the

 

Fic. 29.— Annular cell Fic. 30. — Reticulately Fic. 31. — Annular cell
from Arundo donax, thickened cell of the from an Opuntia with
with strongly thickened Touch-me-not (/ipa- rings passing over into
rings placed at different tiens noli-me-tangere). a spiral band.
distances and different
angles.

pits or dots. Such cells as these are known as tracheides

(fig. 32).

Fig. 33 shows another form of thickening, known as scalari-
form, or ladder-like. In this case the secondary deposit is
c2
20 Elementary Botany

arranged in transverse layers like the rungs of a ladder. Such
cells are well seen in the stems of Ferns.

A very important form of pitted cell is met with, especially
in the wood of the Fir trees and their allies. In these cases
the pit is funnel-shaped, being wide on the outside and gradu-
ally tapering till it
forms a tube or
pore canal leading
into the centre of
the cell.

 

 

 

Fic, 34.—Longitudinal section of wood
of Pinus sylvestris. Bordered pits,

  

Fic. 32.—Piece of a Fic. 33.—Scalariform 7 ¢' 2", increasing in age; a-e, wood
reticulately pitted cell from the under- cells, e, eldest, a, youngest ; cd, wood
tracheide from the ground stem of the cells of cambium; st, large pits,
Lime (Tilia gran- Brake (Pteris agui- where medullary rays touch wood
adifolia). dina), cells. (After Sachs.)

On examining these cells by means of a microscope, they
present the appearance of a central pit surrounded by a border,
and they are called cells with bordered pits. This appearance
is caused by a varying amount of light being transmitted through
the central pore which forms the pit, and the funnel-shaped
upper portion which forms the border.

Very often the cell wall between the two ‘borders’ becomes
absorbed. in which case a complete passage is made between
the two cells.
1

21

‘Besides these appearances due to secondary deposit, there
is, especially in older cells, a striation or stratification of the
cell wall, which appears to be due to the varying amount of

 

Fic. 35.—Two cells from the
wood of the Scotch Fir in
transverse section, each with
a pore, #, widened at its base.
By the disappearance of the ori-
ginal cell wall the two widen-
ings have united to form the
‘border,’ 4; 2, intercellular
space,

 

Fic. 36.—I. Sieve tube from the White Bryony
(Bryonia dioica), the horizontal partition

walls with peculiar thickenings.

verse section of a sieve-disc, the upper part
represented with the thickening substance,
which takes the form of wart-like elevations ;

the lower part without it.

 

 

 

 

water in the different
parts of the wall.
Another important
change in the history of
the cell is the formation
of vessels, or cell fusion.
Vessels are formed
by the union of several
cells (vascular cells),
the walls between them
being either partially or
entirely absorbed.

Fic. 37.—I. Portion of a scalariform

vessel from the Brake (Pteris aguz-
Zina): s, s, the transverse division
wall broken through in a reticulate
manner. IJ. Pitted vascular cell
from the stem of a Grass, Phrag-
mites communis, with numerous
small bordered pits.

When several cells standing one over another have the walls
separating them simply perforated in a sieve-like manner, sieve-
tubes or bast-vessels are formed. These are found in various
22 Elementary Botany

parts of plants, and contain nutritive materials necessary for
the nourishment of the plant. When the disappearance of the
separating walls is more complete, so that the cells form more
or less long tubes, true vessels are produced, and these are
known, according to the nature of their component cells, as
pitted, spiral, annular, reticulate, or scalariform vessels.

These true vessels usually possess a considerable quantity
of secondary deposit, and are seldom branched. As a rule

 

  

Fic. 39.—Vesicular vessel in longitudinal section of
scale of bulb of Onion (4Udinm Cepa): e, epider-
Fic. 38. — Fusiform mis with cuticle (c); 4, parenchyma; sg, coagu-

bast fibre of the lated contents contracted to show the porous

Larch. walls. (After Sachs.)
they contain nothing but air; but in the early spring, when
the stem is gorged with sap, they are often partly filled with
liquid.

Bast tubes or bast fibres are generally more pointed and
sometimes branching (fig. 25). The coalescence between the
component parts is so complete that the separate cells cannot
be distinguished when the fibres are examined by means of the

microscope. Bast fibres do not often communicate directly
Vessels 23

with one another; when they do so it is by means of their
lateral branches.

Very closely related to the sieve-tubes mentioned above,
especially in containing like them nutrient fluids, are vesicular
vessels and laticiferous vessels. ‘The former consist of elon-
gated cells containing a milky juice and bundles of needle-
shaped crystals.

Laticiferous vessels are tubes more or less branching,
often forming a complete network, and containing a fluid
known as /atex, which is often milky, sometimes coloured, and
varies in its composition in different plants.

 

Fic. 40.—Transverse section of phloém of root of Scorzonera hispanica,
showing branching and anastomosing laticiferous vessels.

Cells do not grow indefinitely ; the size of the adult cell
varies. Prosenchymatous cells vary from {5 to 7, of an inch
in length, and from +55 to s¢yq Of an inch in diameter.
Parenchymatous cells vary as a rule from 34, to qq of an
inch in diameter, whilst some in the pith of plants, in suc-
culent parts, and in water plants, are as much as 3); or even
gly Of an inch in diameter.

As the plant increases in size, fresh cells are produced,
being formed out of those already existing. This process is
know as cell formation. There are several modes by which
this takes place, but in the formation of the vegetative cells of
higher plants it is always by means of cell division. Vitally
active cells always contain a portion of the protoplasm more or
less distinctly separated from the general mass, known as the
nucleus, and which often contains small granules or nucleoli.
24 Elementary Botany

When cell division is about to take place, two nuclei are formed
either by the division of the original one, or by its disappearance,
and the formation of two fresh ones.

The whole mass of the protoplasm now aggregates around
these nuclei, and a cell wall is formed between the masses thus
produced, growing inwards from the circumference to the centre,
thus dividing the mother cell into two daughter cells, each of
which may grow to the size of the mother cell, and itself undergo
division. ‘The formation of reproductive cells we shall have
to notice later on (page 117). ,

Except in a few cases, cells do not remain through life
individually separate, but are united together to form ‘tissues.’
These may be grouped accord-
ing to either their function, or
their structure. Under the for-
mer method of division we have
two kinds, viz. meristem, which
is a tissue where the cells remain
vitally active and capable of di-
vision, and permanent tissue,
where the cells are no longer
able to divide. If we arrange
them according to their struc-
ture, we distinguish those tissues
which consist of elongated cells
overlapping one another, and
which are known as prosenchy-
ma, and those which are formed
of shorter cells placed end to
end, or parenchyma. These
Fri, 4x.—-Cells of stem of Ficia Faba. two forms of tissues, however,

Meristem cells in process of division : 4, a
nucleus ; dividing, a; fully divided, 2 pass the one into the other by
(After Prantl.) :

endless gradations.

Sometimes the term sclerenchyma is used to denote either
prosenchymatous or parenchymatous tissues, where the walls
of the cells have become very thick and hard, and often dark
coloured.

 
25

CHAPTER V.

GERMINATION, ROOT GROWTH, STRUCTURE,
AND FUNCTIONS.

IF a living seed be placed in the soil and be supplied with
moisture and warmth, and exposed to fresh air, germination
will ensue. The range of temperature between which this is

 

Fic. 42.—Ricinus communis. 1. longitudinal section Fic. 43.—Germinating

of ripe seed. //, germinating seed, the cotyledons seed of cabbage: 4,
still within the spermoderm, shown more distinctly axis; c, d, the two
in A and 2: s, spermoderm ; ¢, endosperm ; ¢, coty- cotyledons, which
ledon; he, hypocotyledonary portion of axis; w, have risen above the
primary root ; w’, lateral rootlets ; 2, the caruncle voil, the testa @ not
(or aril), a peculiar appendage to the ‘seeds of Eu- being yet completely
phorbiacee. (After Sachs.) thrown off. i

possible varies with different plants, but it may be stated gene-
rally as being between 5° or 6° C. and 40° C.

Either the roots at once lengthen and grow out through the
micropyle, or, which is more often the case, the lower part of
the cotyledon, known as the Aypocotyledonary portion of the
stem, becomes elongated, pushing the end of the root before
it out of the seed.
26 Elementary Botany

If we sow in some soil specimens of the following seeds—
Broad Bean, Acorn, Beech, Cress, Cabbage, Castor Oil, Pine,
Date, and Wheat—and watch the germination as it takes place,

 

Fic. 44.—Seeds of Pinus Pincain dif-
ferent stages of germination. /,ripe
seed in longitudinal section : s, sper-
moderm ; ¢, endosperm ; w, radicle of
embryo; c, the cotyledons; y, the mi-
cropyle end of seed, with the rootlet
directed towards it. 7/, germination
commencing: A, spermoderm, s,
ruptured, and rootlet, w, protruding;
7, red membrane inside spermoderm ;
, ruptured embryo sac : Z, portion
ot spermederm removed ; ¢, endo-
sperm: C, longitudinal section ; c,
cotyledons: JD, transverse section.
411, germination complete, the coty-
ledons, c, unfolding, and the hypo-
cotyledonary part of stem, /c, elon-
gated, the main root, w, developing
lateral rootlets, w'. (After Sachs.)

Fic. 45.— Germination of Phenix dac-
tylifera. J, transverse section of seed

before germination. J//, ///, lV,
different stages of germination. 4,
transverse section of seed at x, x, in
IV; B,atxy; C,at zz. The fol-
lowing letters refer to all the figures:
—e, endosperm ; s, sheath of cotyle-
don ; s#, its stalk; c, apex, forming
an organ of absorption by which the
endosperm is entirely removed, the
growing end occupying the place
of the absorbed endosperm ; w, pri-
mary root; zw’, secondary root; 2’,
6", leaves succeeding the cotyledon ;
6", the first foliage leaf; 4, pileo-
rhize. In J&B, C, the folded lamina is
seen cut across. (After Sachs.)

we shall find that there is a great difference with regard to the
growth and development of the cotyledon during the process.
In exalbuminous seeds, where the cotyledons are thick and
Germination 27

fleshy, as in the Bean (fig. 1) and Acorn, they remain within
the seed during germination, finally perishing after the food-
material contained in them has been used up for the growth of
the embryo. In the case of the Cress, Cabbage, and Beech
we have an exalbuminous seed where the cotyledons are thin,
and here they rise out of the soil to form the first leaves, carry-
ing the testa with them (fig. 43). The Castor-oil plant has an
albuminous seed ; in this case the cotyledons are not liberated
until after the exdosperm has been all absorbed (fig. 42). In
the case of the Pine we have an analogous growth (fig. 44),

Y.-C

 

Fic. 46.—Longitudinal section of fruit of Zea Fic. 47. — Germinating
Mais. c,rericarp ; 2, remains of the stigma ; embryo of Oat (the
Js, base of the fruit ; eg, hard yellowish part endosperm removed).
of endosperm; ew, white softer portion of Pp; the plumule; s, the
endosperm; sc, scutellum (cotyledon) of scutellum; 7, 7, the
embryo; ss, its apex ; ¢, its epidermis; 4, rootlets; co, the coleo-
plumule; w (below), the main root; ws, rhiza.

sheath covering main root; w (above),
lateral] rootlets springing from the first inter-
node ofthe stem, s¢. (After Sachs.)

the cotyledons (which are numerous) appearing above ground
after the absorption of the albumen, the peculiarity here being
the development of chlorophyll in the cotyledons before they
rise above the surface. All these are dicotyledonous seeds.
The remaining two illustrate the germination of monocotyledons.
28 Elementary Botany

In the Date Palm (fig. 45) the lower part of the cotyledon
lengthens, pushing the root and plumule out of the seed, whilst
the rest of it remains in contact with the albumen absorbing it.

In the Wheat (fig. 46) the cotyledon is developed to form
a plate where it is in contact with the endosperm, and is known
as the scutellum. This serves the purpose of absorbing the

 

 

Fic. 48.—Germinating Bean : a,4, Fic. 49.--Longitudinal section through the

cotyledons ; ¢, d, leaves ; ¢, ter- apex of a root of 4 sprdistra elatior:
minal bud; 4, primary root; g, wh, root-cap ; M, pith ; 0, epidermis ; ¢’,
lateral roots. narrow spiral vessels; G’’, broad reticu-

late vessels.

albumen, In this case there is at once a growth of the root
causing a rupture of the sheath surrounding it, which remains
attached to the axis forming the coleorhiza (fig. 47). In some
few monocotyledonous plants, where there are exalbuminous
seeds (as in the natural orders Naiadacez, Alismacez, &c.), the
Root Structure 29

cotyledon is freed from the integuments, and is raised up
through the soil.

When the cotyledons remain beneath the soil they are said
to be hypogeal, when they rise above epigeal.

There is also a great difference between dicotyledons and
monocotyledons with regard to the formation of the young
root. In dicotyledons the radicle is directly prolonged, and
no branching takes place until after the young root has left the
seed (fig. 48), so that the first root is a direct prolongation of
the radicle, and is known as a normal root.- Such a mode of
root development is called exorhizal. In monocotyledons, on
the other hand, there is a branching within the seed (fig. 47),
and the radicle is not directly produced. Such roots are known
as adventitious, and the growth is said to be endorhizal.

The term adventitious is applied to all roots which are not
developed by the direct growth of the radicle ; hence in dico-
tyledons adventitious roots may be developed later on from
various parts of the plants (as from stem, as seen in the Ivy,
&c.), so that it is only the first-formed roots which are always
normal in this group.

ROOT STRUCTURE.

Even whilst the radicle is within the seed a change of shape
and condition has come over some of the cells, which, however,
is more apparent after the ydung root has commenced to grow
(fig. 49). The outer layer of cells becomes more or less flattened,
forming a complete protective coat known as the epidermis.
At the extremity the cells are thickened in such a manner as to
produce what is known as the root-cap or pileorhiza, which is
intended to protect the growing extremity of the root during
its prolongation. Just behind the root-cap there is a mass of
meristem tissue, which forms the growing point of the root.
This by the constant subdivision of its cells produces on its
outer sides additions to the root-cap, thus making up for
portions that have become worn off by the growth of the root,
whilst on its inner side it forms fresh tissue, thus causing the
root to increase in length. Roots, then, increase in length
only by growth near the apex. The upper part of the root is
30 Elementary Botany

made up of permanent tissue, consisting principally of a mass
of parenchymatous cells forming the ground tissue, and in this
there are developed, more or less completely, bundles of pros-
enchymatous cells and vessels, forming what are known as
fibro-vascular bundles, running from the base of the root
towards the apex.

These bundles consist of xylem and phloém, very similar
to that which exists in the stem (see ne VI.). Each

 

Fic. 50.—Transverse section of root of Phaseolus. mM, pith; s, endodermis or sheath of
fibro-vascular bundles, with parenchyma of the ground tissue externally ; fc, peri-
cambium layer; 4, primary phloém of bast fibres ; g, primary xylem, with vessels ;
¢,cambium. (After Sachs.)

bundle contains prosenchymatous cells or fibres, vessels and

parenchyma, but they differ from the bundles of the stem and

leaves, in that the vessels are, as a rule, first formed near the
circumference of the bundle, and the xylem and phloém masses

(which vary in number in different plants) alternate instead of

being placed the one outside the other. The bundles thus

form an irregular star of three, four, or six rays.
Root Structure 31

In Dicotyledons there is, as a rule, a small number of such
bundles, whilst in the roots of Monocotyledons the number is
considerably larger.

Surrounding the bundles there is a ring of specially modi-
fied meristem cells known as the pericambium, and outside
this an enveloping layer of cells forming the bundle-sheath or
endodermis. Branches of the root are formed by outgrowths
of the pericambium which push their way through the adjacent
tissue, and thus form rootlets, which repeat the structure of the
original root (fig. 51).

Roots increase in thickness by the formation of a ring of

 

 

Fic. 51.—Longitudinal section of main root of
Vicia Faba. r,r, cortex of main root; 4
fibro-vascular bundles ; x, 2, lateral rootlets
developing from pericambium, and breaking
through cortical tissue ; 4, pileorhiza of side Fic. 52.--Epidermis of root with
rootlets. (After Prant].) hairs.

meristem between the xylem and phloém bundles, and which,

by the repeated division of its cells, produces new xylem and
phloém.

The cells of the epidermis often possess prolongations or
hairs (¢vichomes), which tend to increase the amount of surface
in contact with the soil (fig. 52).

FORMS OF ROOTS.

There are certain terms which are used in the description
of the form of the root. When it is broad at its base and
32 Elementary Botany

tapers towards the apex, as in the Carrot (fig. 53) or Monkshood,
it is conical. When it is broadest in the centre and tapers
towards the two ends, as in the Radish (fig. 54), it is fusiform,

 

Fic. 53. Fic. 54. Fic. 55. Fic. 56.
Conical root, Fusiform root Napiform root of Fibrous root of
ofthe Carrot. of the Radish. the Radish, a Grass.

or spindle-shaped. When it has become somewhat globular
with a tapering extremity, as in the Turnip, or some varieties
of Radish (fig. 55), it is said to napiform ; whilst the term
placentiform is applied to it if the tapering apex be absent, as

 

Fic. 57.—Double tuber, a, 3, Fic. 58.—Double palmate tuber, «, 3,
of Orchis Morio. of Orchis odoratissima.
in the Sow-bread. If a number of slender branches be given
off, as in the Grass (fig. 56), the root is fibrous. When some
of these fibres become swollen in an egg-shaped manner, as in
Forms of Roots 33

Orchis Morio (fig. 57), the term tuberculated is employed ;
whilst if the tuber is divided so as somewhat to resemble the

 

Fic. 59.—Tuberous fasciculated
root of the Dahlia.

fingers of a hand outstretched, as in
Orchis odoratissima (fig. 58), it is
called palmate.

The term fasciculated, or tufted,
is used where there are a number of
tubercles or fleshy branches arranged
in a bunch, as in the Dahlia (fig. 59).

When the fibres are enlarged
only at their extremities, as in the
Dropwort (fig. 60), the root is no-
dulose, or knotted ; whilst if there
be several swellings arranged like
beads on a necklace, as in Felar-
gonium triste, it is said to be monili-
form, or necklace-shaped.

   

YAWN

Fic. 60.—Nodulose root of
Spirea filipendula.

 

Fic. 61.—z, a piece of branch of an
Apple tree cut through length-
wise, into which a ,oung Mistle-
toe plant, 7, has driven its suck-
ing roots, s.

In Ipecacuanha the root is called annulated, it being marked
with several ring-like expansions upon its surface.
34. Elementary Botany

ROOT FUNCTIONS.

1. The root is a great organ of support, tending to hold the
plant fixed in the soil or other situation in which it may be
growing.

2. It is an organ for the absorption of food.

This raises three questions, viz. the source of the food, the
nature of the food, and the manner of its introduction into the
plant.

A. The source of the food.—The roots, as a rule, enter the
ground, and hence receive the plant-nourishment from that
source. In the case of some aérial plants the roots absorb the
food with the moisture present in the air, whilst in the case of
many parasites, as the Mistletoe (fig. 61), the sucking roots
penetrate into the stem of the plant upon which it grows, thus
obtaining their nourishment second-hand.

B. LVature of the food—A chemical analysis of the sub-
stance of a plant shows it to be composed of the following
elements :—

Carbon, C. Phosphorus, P. Potassium, K.
Hydrogen, H. (Silicon, Si.) Calcium, Ca.
Oxygen, O. (Chlorine, Cl.) Magnesium, Mg.
Nitrogen, N. Tron, Fe.
Sulphur, S. (Sodium, Na.)

The five placed in the first column are sometimes called
the organic elements, as they are required for the building up
of the protoplasm and cellulose. Those placed in brackets are
not so necessary or so universally met with as the rest.

Since, then, the plant body is built up of these elements,
it is evident that they must enter into the composition of its
food. They are not, however, absorbed in their elementary
condition, being obtained from various compounds which con-
tain them.

Carbon is obtained by green plants from carbon dioxide,
called also carbonic anhydride, and formerly known as carbonic
acid gas, CO,, a gaseous compound of carbon and oxygen ;
perhaps partly by means of the roots ; but especially, as we
Plait Food 35

shall see later on, through the pores of the leaves, these pores
performing the part of both lungs and mouths for the plant.
Carbon is one of the most important substances present, build-
ing up portions of all the plant-tissues, and usually forming
one-half of the dried plant by weight.

Hydrogen, another element present in every organic com-
pound, is obtained from water, H,O, which is taken up in large
quantities by the roots, and also, to a slight extent, from
ammonia, NH;.

Oxygen.—The sources of this element are to some extent
the two compounds H,O and CO, already noted, and also the
various oxygen salts of the metals, such as sulphates, phos-
phates, nitrates, &c. Besides this, the free oxygen of the
atmosphere enters the plant, combining with the tissues, as
we shall have to notice further on under the head of Respira-

tion.

Nitrogen, which is an essential element of protoplasm, the
albuminoids, and allied bodies, is obtained from ammonia,
NH,, and nitrie acid, HNO,, which latter, with the metals,
forms the salts known as nitrates. It must be borne in mind
that, although nitrogen exists to a very large extent in the air
in a free or uncombined state, yet that plants are only able to
absorb it from its compounds.

Sulphur is taken up as sulphates, that is, salts of sulphuric
acid, H,SO,; probably chiefly calcium sulphate or gypsum,
CaSO,. This element also is required for the protoplasm and
albuminoids.

Phosphorus is obtained from phosphates, principally calcium
phosphate, Ca3,2PO,.

Silicon is taken in as silica, SiO,, which is often largely
present in the soil; whilst the sources of chlorine are the
chlorides of the various metals, especially of sodium, the
chloride of which is common salt. The metals mentioned
above are all obtained as salts combined with the acids we have
noticed.

c. Method of introduction of the food substances into the
plant.—Before any food can be absorbed it is necessary for it
to be in a state of solution, The water present in the soil

D2
36 Elementary Botany

dissolves up the various food materials, and thus brings them
into a fit state to be taken.

The outside surface of the root is entire, not perforated by
holes, hence the solution of food has to be absorbed into the
cells of the plant itself. This is accomplished by means of the
process of osmosis. If two liquids be se-
parated by a membrane permeable to both,
they will flow through it and intermingle.

This can be very easily demonstrated
by means of a simple experiment. If a
vessel is closed below by a piece of bladder,
whilst a tube is tightly fastened in the neck
(fig. 62), and if a concentrated solution of
cupric sulphate is placed in the vessel so
that it stands a short way up the tube, and
then the whole apparatus is plunged into
a vessel of water as shown in the diagram,
x the two liquids will interchange, some of
the cupric sulphate passing through the
bladder into the outer water, whilst some
of the latter enters the vessel. The two
liquids do not, however, flow with equal
rapidity. The law in all such cases is that
the denser liquid flows more slowly than
Fic. 62.— Apparatus for the less concentrated. As cupric sulphate

measuring osmose: 4, a i ‘

vessel filled with cupric solution is denser than water, a larger
py Phate cestle maw amount of the latter passes through the
brane, and placed in'@ membrane than of the former, and therefore
Te viakde to ming the liquid will rise in the glass tube. The
with the cupric sul- passage inwards is called exdosmose, whilst

phate, the level of the .
fluid willriseinthetube that outwards is termed exosmose. Sugar

vin connection with the B =
vessel 4, but will fall at © syrup may be used in the above experiment
x in the outer vessel. :

instead of cupric sulphate.

Let us apply this process to the root. Within the cells
there is the sap, without there is the water with mineral salts
in solution; we have here two liquids of different densities
separated by a permeable membrane, the cell wall. As a con-

sequence osmosis ensues, some of the external water passing

    
     
 

   
 
 
 

i
nara
Rotation of Crops 37

into the cell, and some of the sap being excreted into the soil.
As, however, the sap is much denser than the water without,
the flow of this latter is more rapid. By the same means the
food material thus absorbed is transferred up the root from cell
to cell towards the stem. ‘The sap is densest in the upper cells,
owing to the evaporation which is going on, and hence the flow
is maintained. ‘This passage of food takes place especially by
means of the prosenchymatous cells or fibres, whilst absorption
goes on most actively in those cells which are near the growing
point and by means of the hairs.

The various food materials are not, however, taken up in-
discriminately by the plants. It is found, if plants are grown
in water containing equal amounts of the salts necessary for
food, that the quantities removed are very different.

There is what is known as se/ective power, each plant remov-
ing from the soil those substances which are more especially
necessary for its life, leaving other foods behind. Thus legu-
minous plants remove especially lime salts; potatoes and
turnips, compounds of potash ; cereals and grasses, silica ; and
so on.

If the same plant be grown year after year in the same soil
it gradually impoverishes the ground, whilst food materials
needful for other plants will be accumulated. Hence is brought
about what is known as rotation of crops—that is, growing a
well-chosen selection of plants in succeeding years in the same
soil.

The exact plan of rotation varies with the nature of the
soil and the plants desired to be grown. The following is an
example of what is known as the Norfolk or four-course rota-
tion:—

 

2 | 3 4 |

 

‘|
Fallow.
Turnips and | Barley | Clover Wheat |
Swedes | : }
\

 

That is, the farm will be broken up into four portions. The
first will undergo thorough tillage and be planted with root
38 Elementary Botany

crops, which need especially potash and lime, and, having short
roots, take their food near the surface, or are surface-feeders.
Division No. 2 has barley, which takes up very little lime and
potash but much silica, and is also a surface-feeder. Clover,
in division 3, takes much the same food as the root crops, but is
a subsoil-feeder— that is, sends its roots deeply into the ground.
The wheat in division 4 is also a subsoil-feeder, but like barley
takes up much silica,

The next year the position of the crops is changed. Barley
is grown on division 1, clover on division 2, wheat on 3, and
so on; so that once every four years each. part of the soil has
each kind of plant growing on it, and the full rotation is thus
shown :—

 

 

 

 

 

 

 

ist Year end Year 3rd Year | 4th Year
Ist Division | Root crops | Barley Clover | Wheat
and ,, Barley Clover Wheat Root crops
31d 335 Clover Wheat Root crops | Barley
4th ,, ‘Wheat | Root crops | Barley | Clover

 

At the same time various manures are employed to supply
the place of the different materials removed from the soil.

3. The root is also, as we have seen, an organ of excretion;
some of the sap, by osmosis, passes out into the soil, whilst the
food enters the root. This is most important, as the sap is
found to possess, as a rule, an acid reaction (that is, it turns
vegetable blues, such as litmus, red), and hence it aids the root
by dissolving up some of the materials present in the soil.
Many of these substances, which are very needful for the food
of the plant, are insoluble in water, but the acid sap dissolves
them readily.

This can be easily shown by means of anexperiment. Take
a piece of perfectly smooth marble, and cover it with sand to
the depth of about a quarter of an inch ; sow in this some seeds
of mustard or cress, and place in a position favourable for
germination. When the young plants have grown for a short
time, clear the whole off, and it will be found that the rootlets
will have eaten their way into the marble, dissolving the sub-
stance, and forming minute grooves where they had been,
Root Functions 39

This explains how it is that we sometimes see large trees
with their roots sunk into the solid rock. They have sprung
up in that position from seeds, and as the roots have grown the
acid sap has gradually eaten a passage for them until they have
attained their present firm condition. Added to this, the root
exerts a mechanical force, splitting the rock in the direction of
pre-existing grooves, and thus helping to form a passage for
their growth. On the high road between Buxton and Longnor,
at a village called Sterndale, several large trees are close
to the road-side, growing through immense blocks of lime-
stone, which blocks have been split by the expansive force of
the tree.

4. The preceding functions belong more or less to all roots;
there is, however, a fourth, which is only occasionally seen. In
some cases the root acts as a storehouse of food.

Let us take the case of a biennial plant, such as a Turnip.
During the first year there are no flowers, but plenty of leaves.
Food materials are absorbed and converted by means of the
leaves into starch and other substances, which are stored up in
the root, which latter becomes swollen. The next year the
plant flowers and fruits, and this reserve of food is used up
during the process, so that by the end of the second year the
root has become shrivelled and fivrous.
40 Elementary Botany

CHAPTER VI.

DEVELOPMENT OF THE PLUMULE—FORMATION,
STRUCTURE, AND FUNCTIONS OF THE STE.

Wuttst the radicle grows downwards to form the root of the
plant, the plumule is elevated above the soil, and produces the
stem, bearing leaves and other appendages.

Popularly the stem is looked upon as differing from the root
in growing above the ground, but botanically there is a wider
difference. Underground portions of many plants, as the
Onion and Potato, which are generally called roots, are in
reality stems.

The characters of stems as distinguished from roots are as
follows :— :

1. Their growing points are not covered with a root-cap,
but are surrounded by young leaves (buds).

2. They have developed-upon them appendages, variously
modified, but which differ in structure from the stems them-
selves ; whilst roots simply branch, the branches being repeti-
tions of the structure of the original root.

3. Whilst, as we have seen, the branches of the root
have their origin in the deep-seated layers of the pericam-
bium (endogenous growth), the branches and appendages of
stems take their rise from more superficial layers (exogenous
growth).

If we make a transverse section across the young stem
during the first year of its growth, we find that there is a great
difference in the appearance it presents in the two great groups
of Dicotyledons and Monocotyledons.

Fig. 63 shows the section of a portion of a young dicoty-
ledonous stem. On the exterior there is an epidermis of
flattened cells.
Stem Structure AI

At first this is like the epidermis of the root, consisting of
a number of similar cells, always completely in contact ; but
after a while some of these become separated from one another,
leaving an opening or stoma (plural, stomata) between them
(fig. 64).

These stomata are always surrounded by two or four cells,
which are generally smaller than the epidermal cells, are cres-
cent-shaped, and contain chlorophyll. These are known as
stomatal or guard cells, I.

 

Fic. 63.—Transverse section of petiole of Hed- Fic. 64.—I. Horizontal section through

Zeborus, showing the three systems of tissues : the epidermis of the under side of
e, epidermal ; /, fibro-vascular; x, xylem ; the leaf of ELuonymus japonicus
c, 6, phloém—c, soft bast ; 4, bast-fibres ; g, looked at from below: sf, stoma'a
ground or fundamental tissue. (After II. Course of development of the
Prantl.) stoma of A rthropodium cirrhatum i

sm, mother cell ready for division ;
sp', sp", spl, successive stages of

division, III. Mature stoma.
More towards the interior of the stem there are developed
some bundles of cells (fig. 63). At first these bundles consist
of meristem tissue, known as procambium, forming a string of
similar and growing cells. Very soon, however, the greater
part of this passes into the form of permanent tissue, which
is separated into an outer or phloém and an inner or xylem
42 Elementary Botany

portion, leaving a band of meristem (cambium) between them
(fig. 65).

The bundles, which now consist of fibres and vessels, with
a few parenchymatous cells, are spoken of as fibro-vascular
bundles. In many cases the fibres and vessels become very
much hardened by the
thickening of the second-
ary deposit, and the fibro-
vascular bundles can then
be easily separated from
the surrounding portions
of the stem. In other
cases there is very little
hardening in the bundles,
and they cannot be thus
separated.

The rest of the stem in
its young state is made up

can if

ES
SESS Sea. f of parenchymatous cells,

ES
Es forming what is known as
KD fundamental or ground
tissue, which is divided
into three parts—a portion
in the centre of the stem,

Fic. 65.—Transverse section through a young the pith or medalla ; a ring
internode of Bahmeria argentea: 0, epider- ‘ ‘ pf
mis ; CO, outer cortex (collenchyma) ; e ae underlying the epidermis,
cortex; S, intercellular space ; c, cambium o} :
the vascular bundle; c’, cambium ef the thick. from which the cortex or
ening ring ; B, bast portion ; H, xylem portion ‘ .
of we vascular bundle ; 8’, the bast formed bark is developed 5 and,
from the intermediate cambium ; z, medullary lastly, masses of cells
ray.

 

which separate the fibro-
vascular bundles and unite these two portions, the medullary
rays.

The next change is in the cells which lie between the fibro-
vascular bundles and the epidermis. Here are produced
flattened cells filled with air, possessing flexible and elastic
walls forming a close tissue without interspaces. These are
cork cells. They are rarely (as in the Willow) developed from
the epidermis itself; sometimes (as in the Poplar) from the
Dicotyledonous Stem 43

cells immediately beneath it, more often from the more deeply
lying cells.

On the inner side there is developed a ring of meristem,
known as phellogen or cork cambium, whilst within this there
is a layer of cells containing chlorophyll, the phelloderma or
green layer. Sooner or later all the cells outside the cork
tissue dry up and shrivel, forming the outermost layer of the
bark.

SS Se ee

   

e

ve

Fic. 66. —Transverse section of one-year-o:d stem of A tlanthus glandulosus:
e, epidermis withered ; %, cork cells, formed by the inner cells with proto-
plasm, the cork cambium or phellogen ; 7, inner green cells, the phello-
derma. (After Prantl.)

The dicotyledonous stem now consists of the following
parts :—

1. A ring of epidermis and cells with it becoming dried and
dead.

2. A ring of cork tissue, the outer bark or epiphlceum, with
the cork cambium within.

3. A ring of phelloderma, the middle bark or mesophloeum.

4. A ving of phloém, interrupted by the passage of the
medullary rays, and forming the bast, liber, inner bark, or
endophleeum,
44 Elementary Botany

5. A ving of cambium, also interrupted by the passage of
the medullary rays.

6. An interrupted ring of xylem or wood.

4. A central pith or medulla.

8. The medullary rays, uniting the pith with the middle
bark. (See fig. 65.)

In the monocotyledonous stem (fig. 67) there is quite a dif-
ferent arrangement. On the exterior there is no differentiated
bark ; within, no separation into
pith and medullary rays ; but a
number of bundles of procambium
scattered amongst the general
ground or fundamental tissue.
These bundles differ in their de-
velopment as well as in their
arrangement from those of the
dicotyledonous stem. Instead of
leaving a layer of vitally active

cambium, they are entirely con-
wig he datibuton of the Sbrowas, verted into xylem and phloém.
de yr a ae ees Dicotyledonous bundles which
contain cambium are spoken of
as open, whilst those bundles which are destitute of this form-
ative tissue, as those of monocotyledons, are known as closed.

We must now note a little more fully the structure and
functions of the various parts of the dicotyledonous stem.

1. The medulla or pith consists entirely of parenchymatous
cells, generally dodecahedral in shape, and it forms a cylindrical
axis at or towards the centre of the stem. In the earlier stages
the cells usually contain a little chlorophyll, and are filled with
nutrient substances ; later on they become dry and colourless,
and filled with air, and no longer serve any purpose in the life
of the plant, so that the stem may be hollowed, all the pith
having disappeared, and yet the plant may be living vigorously.

The amount of pith varies much in -different plants. In
hard-wooded plants, as the Ebony, it is very small; whilst in
soft-wooded plants, as the Elder, it is much larger. Again,
we often find in many rapidly growing herbaceous plants, as

 
Dicotyledonous Stem 45

the Hemlock, the pith, not being able to keep up in growth
with the other parts, has left the stem hollow, with a rugged
attachment of pith at the sides ; whilst in the Walnut and Jessae
mine it has become broken up into thin discs (dscoid pith).

2. Surrounding the pith there is a layer of spiral vessels
(the medullary sheath), which is in reality the commencement
of the wood or xylem. The function of these vessels, as indeed
of all true vessels, is to serve as air carriers. Like the wood,
cambium, and liber, the medullary sheath is pierced by the
medullary rays.

 

Fic. 68.—Portion of the transverse section through a shoot of Ivy four years
old: R, cortex ; B, bast bundles ; H, wood, in which the four annual rings
are distinctly visible ; m, pith; s’, medullary rays; F, bast fibres; cé,
cambium ; s”, primary, s’”, secondary bundles.

3. Outside the medullary sheath comes the xylem or wood,
arranged in the form of concentric rings. These rings are
formed as follows. During the first year the cambium cells by
their division have caused the wood and liber to increase in
thickness. During the winter the cambium remains dormant,
but as soon as spring returns the cells once more become vitally
active, and form a fresh ring of wood on its interior outside the
old xylem, and a fresh ring of liber on its exterior zzséde the old
46 Elementary Botany

phloém. Thus year by year fresh rings of wood and liber are
formed (fig. 68), the oldest wood being towards the centre of
the tree, whilst the oldest bark is towards the exterior. Growth
such as this is sometimes spoken of as exogenous, and dico-
tyledonous plants are sometimes termed exogens. It is, how-
ever, only the wood which is exogenous in growth ; the liber
is endogenous.

As fresh rings of wood are as a rule formed every year, the
age of a tree can generally be approximately ascertained by
counting the number of the rings. The annual rings of various
trees differ very much in the extent of their thickness, much
depending not only on the nature of the plant itself, but also
on its age and the atmospheric conditions of the climate.
Also in the same plant the rings are not of equal thickness all
round, so that the pith instead of being geometrically in the
centre of the tree is generally more or less excentric.

When these wood rings are fully developed they consist of
three elements, viz. :—

a. Wood fibres or wood prosenchyma.
6. Vessels, either spiral, annular, pitted, or otherwise.
c. A variable quantity of wood parenchyma.

These three elements are variously arranged, and any one
of them may be absent. Generally there is plenty of secondary
deposit, so that the cells have become hard. The inner wood is,
as we have seen, the oldest, and hence the hardest, and is often
coloured by the secondary deposit having colouring matter.
This is especially well seen in such wood as Ebony, Mahogany,
Rosewood, &c. In other cases, as in the Poplar and Willow,
the old wood is nearly as colourless as that of the exterior.
This inner wood is known as the duramen or heart-wood.

The xylem on the exterior, which is younger, is permeated
with sap, and is known as the alburnum or sap-wood.

The heart-wood is principally useful in supporting the plant,
so that it may be absent as well as the pith without interfering
with the vital activities of the tree.

In the sap-wood the vessels are air carriers, whilst the fibres
are sap distributors carrying a current of sap from the root up
towards the leaves (see Chapter XII.),
Diucotyledonous Stent 47

4. Outside the xylem there is the interrupted ring of cam-
bium, consisting of prosenchymatous cells dormant during the
winter, and in full activity on the return of spring. After the
first year cambium is formed between the fibro-vascular bundles

 

Fic. 69.—Diagrammatic view of the structure of a dicotyledonous stem with
circumferential growth as seen in transverse section. 4—m, R, ground
tissue forming pith (m) and cortex (zk), the external ring representing the
epidermis. Six fibro-vascular bundles separate—+x the xylem, and / the
phloém of each bundle. 2—older stem: the bundlesnow united by cam-
bium ring of fascicular (/¢) and interfascicular (éc) cambium ; 4, 4, the pri-
mary bast fibres of the phloém. C-—still older stem. By the activity of
the Cambium new wood and bast have been formed. 4, wood formed by
fascicular cambium ; 7/4, wood formed by interfascicular cambium ; if,
interfascicular phloém ; x, y, medullary sheath. The shaded upper part
shows medullary rays. (After Sachs.)

(interfascicular cambium), thus making the cambium ring com-
plete (see figs. 65 and 69, B). By means of this interfascicular
cambium, not only are the medullary rays lengthened as the
48 Elementary Botany

stem increases in thickness, but also fresh phloém and xylem
are produced between the original bundles.

5. Outside the cambium there is the interrupted ring of
phloém, liber, or inner bark. Like the wood this consists of

: three elements, viz. :—

a. The bast vessels or sieve-
tubes (fig. 36).

4. Bast fibres (fig. 38).

_¢. Bast parenchyma or soft
bast.

The separate annual layers
of the liber cannot, as a rule,
be so readily distinguished as
those of the wood, they being
. much thinner and compressed
together by the growth in
thickness of the tree. In some
cases, however, the liber can
be separated into thin plate-
: like layers.

A good example of this is
to beseen in the Lace-bark tree
(Lagetta lintearia) of Jamaica,
where the inner bark separates
into thin sheets having the
appearance of lace, the holes
in it being the perforations for
the passage of the medullary
rays.

The fibres of the bast act
Fic. 70.—Part of a transverse section

through the bast of the Wild Lettuce 8 Sap circulators, bringing

(Lactuca scariola): Bf, bast fibres ; Bf, down the elaborated sap from
. bast parenchyma; Mm” outer, m’ inner

lati-ilerous vessels; RA, cortical paren- the leaves.

chyma ; HZ/, wood-fibres.

6. The green layer, or
phelloderm, consists of chlorophyll-containing cells, often inter-
mixed with laticiferous vessels.

7. The outer or cork layer with its formative phellogen

immediately beneath it. These two last layers form a pro-

 

 
49

After a short time the

showing secondary

wood parenchyma ; ¢, 74
with pitted and spiral mark-
7, medullary rays cut across.

Hes CS

SOE ANS
Fa

SSS

Bark

tective coat to the exterior of the stem.

cells generally become dead, and very often peel off under the

expanding influence of the growth of the stem.

 

-vascular bundles: g, g, wood vessels ; /,
yma, of two varieties ; 7, tracheides,

tudinal tangential section of stem of Azlanthus,
if, \ibriform or bast-like wood fibres; s:

2s
BEES
66 BG
Ae sug
I 7 aay
Ros ae
SEs ea
CRBES
&

This, as is seen in the Elm or Cork Oak, gives a rugged

In other cases, as in the Beech,

appearance to the bark.
50 Elementary Botany

owing to its capability of distension, the bark presents a smooth
appearance.

8. The medullary rays uniting the pith with the middle
bark, and separating the fibro-vascular bundles. They are
generally made up of flattened, six-sided cells, arranged like
bricks in a wall (muriform parenchyma).

The rays are rarely continuous from the top to the bottom
of the stem, being separated by the fibro-vascular bundles (s¢,
fig. 71).

The medullary rays form what is known as the ‘silver grain’
of the cabinet makers. The use of the rays is to distribute the
elaborated sap from the liber through the other parts of the
stem.

In most cases the fibro-vascular bundles are continuous
with those which form the veins of the leaves, and are known
as ‘common bundles,’ 7.c. common to leaf and stem. At the
nodes (the point of attachment of the leaf to the stem) these
bundles enter the stem and run down parallel to one another,
usually through two or three internodes. At the nodes the
bundles branch and interlace in various ways, whilst they thin
out the further they descend. In some few water plants, as the
Hippuris or Mare’s tail, the Myriophyllum or Milfoil, and a few
others, the fibro-vascular bundles run simply through the stem,
or are cauline, the foliar originating later.

The direction of the fibro-vascular bundles can be readily
traced by making a longitudinal section of a young stem,
taking care to cut through at least two nodes, and then soaking
it for five or ten minutes in a solution of aniline sulphate
acidulated with a few drops of sulphuric acid ; the lignin of
the bundles will be stained yellow, and hence their position
can be noted.

STRUCTURE AND FUNCTIONS OF THE PARTS OF A MONO-
COTYLEDONOUS STEM.

Even in their external form monocotyledonous stems present
a different appearance from the dicotyledonous stems described.
In this country we possess no indigenous monocotyledonous
tree (the Butcher’s Broom is the only indigenous shrub), but
Monocotyledonous Stems SI

‘the exotic Palms (fig. 72), instead of having tapering stems like
our forest trees, possess them of much the same diameter from
top to bottom.

 

Fic. 72.—Livistonia australis, a Fan Palm.

Within there is no separation into pith or bark. On the
exterior there is an epidermis and a cortex, or false rind made

up of the ends of the fibro-vascular bundles. ‘These bundles
E 2
52 Elementary Botany

enter the stem from the bases of the leaves being continuous
with the bundles present in them. At first they are narrow.
They grow inwards, and then pass down the interior of the
stem, gradually increasing in diameter. At length, having
attained their largest size, they begin to curve outward again,
thinning as they do till they end at the exterior (fig. 73).

 

 

 

 

Fic. 74.—Transverse section of fibro-vascular bundle of
Zea Mais: ~, thin-walled parenchyma of ground tissue
of, a, outer and, 2, inner part of stem, with thick-walled

Fic. 73.—Course of the prosenchymatous ground tissue internal to it ; g, g, large

 

vascular bundles of 77s pitted vessels ; s, spiral vessel ; 7, isolated ring of annular
in longitudinal section vessel ; Z, air cavity ; v, v, cambiform tissue or soft bast.
(diagrammatic). (After Sachs.) é

The bundles are closed, containing no cambium, hence
after their formation they cannot increase in size. A section
across the stem will show the younger bundles within and the
older ones without. Such a mode of growth is often termed
endogenous, but it must be borne in mind that it is only at a part
of their passage that this is true, as at the commencement and
end they grow outwards.

In annual and herbaceous monocotyledons the ground tissue
Monocotyledonous Stems $3

is soft and delicate ; but

in trees, as Palms, it is much hardened

by secondary deposit, forming woody parenchyma.

It follows from this
a stem to increase
in thickness after the
outer rind has become
thoroughly hardened.

In some Monoco-
tyledons of the Lily
tribe, as the Aloe and
Dragon-tree (fig. 75),
there is a provision for
the exogenous forma-,
tion of new bundles, but
in a different manner
from that which takes
place in Dicotyledons.

A layer of meristem
is formed in the outer
part of the ground tis-
sue, by means of which
the stem is increased
in thickness, and in
which new fibro-vas-
cular bundles are
formed.

In Monocotyledons
the sap rises to the
leaves through the
xylem of the bundles,
and descends through

structure that it is impossible for such

  
 

\ eae
ik

Fic. 75.—Transverse section of stem of Dracena, near
apex : e, epidermis ; 4, cork ; 7, cortical portion of
ground tissue ; 4, fibro-vascular bundle to leaf; 72,
ground tissue of centre of stem; g, fibro-vascular
bundles ; x, meristem zone, developing new fibro-vas-
ene bundles (g’) and new ground tissue(s¢). (After

acns,

the phloém, and apparently partly by the parenchymatous tissue.

EXTERNAL FORMS OF STEMS.

A section of the stem usually shows it to be more or less
cylindrical in shape ; at other times it is angular, being either
triangular, square, five-ribbed, etc. (fig. 76).

When the stem is herbaceous, and dies down annually, it is
54 Elementary Botany

called a caulis ; when woody and perennial, a trunk ; and when
jointed, as in Grasses, a culm.

Generally stems are able to support themselves in an up-
right position, and are erect ; if they trail on the ground they
are prostrate ; if, whilst thus
reclining, they rise towards
their extremities, they are de-
cumbent ; or if they gradually
rise from near the base, as-

Il. III.

   

  

 

Fic. 76.—I. Section of triangular stein! :
II. Section of square stem. III. Section cending.

Of Hveaie BeauBten Some stems are climbing,
attaching themselves to some object of support either by zoot-
dets (as in the Ivy), or by ¢endrils (as in the Passion Flower and
Sweet Pea). At other times they are twining around the
object of support (as in the Bind-weed and Hop, fig. 77).

Fic. 77.—I. Stem of Convolvulus arvensis twining to the left. II. Stem of
Hop twining to the right
There are certain terms which are applied to various forms
of stems, some of which describe the aerial or above ground,
and others the subterranean stems,
Forms of Stems 55

1. Aerial Stems.
a. The Runner.—This is well seen in the Strawberry, where
a branch springing from a plant creeps along the ground (often
with a modified leaf or scale upon it), and ultimately strikes in
5 the soil, producing
leaves and roots, and
forming a new plant

(fig. 78).

  

; Fic. 79.—The offset of
i the Houseleek (Semper-
Fic. 78.—Runner of Strawberry (Fragaria vesca). vivunt).

5. The offset, seen in the Houseleek, much resembling the
runner, but shorter and thicker (fig. 79).

¢. The stolon, as in the Gooseberry and Currant, is really
a branch given off above
the ground striking into the
earth and giving off roots
and leaves, forming a fresh
plant. This is often imitated:
by gardeners in the process
of layering, when they bend
down a branch into the soil,
thus causing it to take root
and produce a fresh plant.

d. The Sucker. — This
differs from the last in being
a branch springing from beneath the soil, and after proceeding
for a short time in a horizontal direction, giving off roots as it
does so, turns up and grows out of the ground, forming a new
plant. The Rose and Mint are examples. i

2. Subterranean Stems.

e. The rhizome or rootstock is a thickened stem creeping
either at the surface of the soil or just below it, giving off leaves
from the upper surface, and roots from the lower. As the
leaves fall off year by year, they leave scars marking where

 

Fic. 80.—Stolon.
56 Elementary Botany

they had been. These, together with other subterranean stems,
are popularly termed roots, but are distinguished from true
roots in the manner already indicated. Examples are to be
found in the Iris, Sweet Flag, Ginger, Solomon’s Seal, etc.

 
 
  

ib ‘

mn &

yi
aM ut &
Th W s 19
v G

ce

Fic, 82.—Rhizome of Solomon’s Seal
(Convallaria Polygonatum): a, ter-
minal bud from which is developed

Fic, 81.—Sucker. the next year’s stem; 4, this year’s

stem: ¢, d, scars of the stems of pre-

vious years.

    
         

 
 

 

 

 

Fic. 83.—Creeping rhizome of Carex.

Ff The soboles or creeping stem is thinner than the rhizome,
but otherwise resembles it. It is met with in the Sand Sedge
(Fig. 83) and Couch Grass. In the former plant it is often of
great use in binding together the loose sands of the sea shore,
whilst in the latter it is a pest to the farmer.
Forms of Stems 57

g. The tuber is an underground stem or branch, which is
much swollen by the deposition of a large quantity of starch
and other food materials. It posseses leaves which are more
or less modified. In the Potato (which is a good example of
the tuber) the eyes are the modified leaf buds. It is a well-
known fact that if the aerial branches of a Potato plant are
earthed, their growth will be arrested and tubers will be formed.

    

| yee
Fic. 84.—A six-weeks-old Potato plant, developed = Fic. 85.—Single tuber of the
from the seed, the upper branches, a, 4, being Pig Nut (Carum bulbocas-

cut off: @, cotyledons ; in the axils of the cotyle- tanum).
dons are developed the underground branches, e,

e, which penetrate into the ground and form

tubers, 4g, at their apex or in the axils of small

leaves. ‘The tubers are formed only on_ the

branches which are produced in the axils of the

cotyledons, never on the true roots 4.

Other examples of tubers are to be seen in the Jerusalem
Artichoke and in the Pig Nut.

The two following modifications of stem are only to be met
with amongst monocotyledonous plants.

h. The bulb consists of a more or less flattened disc-like
stem, giving off roots below, and scale-like leaves, together
with stem and flowers, above.

The scale-like leaves have the power of developing in their
58 Elementary Botany

axils smaller bulbs or buds known as cloves or bulbils (a, fig.
86). There are two forms of bulb. When the inner scales
are fleshy, and are covered by thin membranous ones, the bulb
is said to be ¢unicated, as in the Onion. If there be no outer
tunic, as in the Lily, the bulb is said to be sca/y or naked.

 

Vic. 86.—Scaly (squamose) bulb of Fic. 87.—Corm of Gladiolus segetum, a,
the Onion: 4, plate or disc; a, longitudinal section: a, last year’s, 4, this
bulbils. year's bulb; c, scape; d, scales; ., roots; B,

after removal’ of the enveloping scales : J
bud, which will develop into next year’s corm:
2y bulbil.

z. The corm differs from the bulb in being much more solid,
consisting of a larger disc and fewer scale-leaves. Examples
are to be met with in the Gladiolus, Snowdrop, Crocus, Col-
chicum, etc.
59

CHAPTER VII.
BUDS AND RAMIFICATION.

BRANCHES of the stem first make their appearance as buds.
These as a rule do not appear indiscriminately but at certain
definite parts of the plant, viz., at the extremities of the stem

 

¥FiG. 88.—a, terminal Fic. 89.—Diagram of a longitudinal section of the
; 3, axillary apex of the stem of a dicotyledonous plant; 22,

bud, the leaf in pith ; 4 fibro-vascular bundles, both developed
the axil of which from the pleurome (ZZ), the bundles sending
it was produced branches to the leaves ; ~, corticle tissue ; ¢, epi-
having been re- dermis ; 4, 4, young leaves, two showing their
moved. origin from protomeristem () ; 4, axillary bud.

(After Prantl.)

and branches, when they are called terminal buds ; and in the
axils of the leaves, that is to say, the angle formed between
the leaf and the stem, when they are termed axillary buds.
60 Elementary Botany

If they grow from any other part of the plant they are said
to be adventitious.

At first the bud consists entirely of parenchymatous tissue
connected with the parenchyma of the stem. There is a central
conical mass around which, after a while, vessels and wood
cells are developed; outside these, parenchymatous tissue which
forms bark, and which is covered with little scales of paren-
chyma variously overlapping one another, forming the rudi-
mentary leaves.

The portions of the young stem to which these leaves are
attached are known as nodes, whilst the stem between the
nodes forms the internodes.

  

Fic. 90.— Branch spines of the Sloe 4
(Prunus spinosa). Fic. 91.—Prickles of the Rose.

In cold and temperate climates, where the buds remain
dormant during the winter, unfolding during the following
spring, the outer surface is protected by modified scales, which
sometimes, as in the Horsechestnut and Poplar, possess resinous
secretions, and at other times, as in Willows, are covered with
hairs. These scales protect the young bud from the cold and
frosts of the winter, and fall off when it begins to develop in
the following spring.

The commencement of the development of the bud is by the
growth of the internodes, by which the young leaves become
gradually separated from one another and the branch is formed.
Spines and Tendrils 61

If all the normal buds of the plant were developed, the
branching would follow regularly the arrangement of the leaves.

This uniformity is often interfered with: 1st, by the non-
development of buds ; 2nd, by the formation of adventitious
buds.

Sometimes many of the buds remain entirely undeveloped.
At other times, instead of being developed into leaf-bearing
branches, they form subsidiary organs.

1. Spines are often modified branches. They are met with
in the Sloe or Blackthorn. At times they are small and desti-
tute of leaves ; often they bear leaves, and under cultivation
they become developed into leaf-bearing branches. Thus,
whilst the Sloe is spiny, the ,
cultivated Plum bears only
leafy branches.

There is a great difference
between spines (as in the Sloe
and Locust-tree) and prickles
(as in the Rose and Bramble).
In the former case the spines
are modified branches, and as
such are connected with the
internal parts of the stem ; in
the latter case the prickles are
simply hairs of the epidermis
which have become hardened
by the deposition of secondary
deposit.

2. Tendrils. — Sometimes
the buds become developed
as tendrils or cirrhi, as in the
Grape Vine, enabling the plant Fic. 92.—Stem tendrils of the Grape-vine :
to hold on to the object of eee state; v, bearing a
support.

Both spines and tendrils may be modifications of parts of
leaves. The spines of the Barberry, and of some species of
Acacia (fig. 129), and the tendrils of the Sweet Pea (fig. 93),
are examples.

 
62 Elementary Botany

We can tell, however, which they are by their position. If
they are in the axils of leaves they are modified branches ; if
upon the stem or forming part of the leaf they are modified

leaves.
In some cases adventitious buds are formed beneath the

 

Fic. 93.—Sweet Pea (Lathyrus odoratis).

bark, and are not developed externally. In such cases they
produce considerable variations in the figure and grain of the
wood. Bird’s-eye Maple is a very good example of this.

Buds are often capable of being removed from one plant
and made to grow upon another of the same family. Upon this
fact depend the important operations of grafting and budding.
Budding and Grafting 63

; In grafting, a branch of a superior variety, possessing buds,
is taken and implanted on a wild stock (fig. 94). The for-
mative cambium round the wound grows, forming a protective
succulent cushion of tissue known as a callus (fig. 95). The
graft grows independently of the stock, receiving, however, its
nourishment through it.

In budding, a bud, together with the surrounding bark, is

 

 

 

  

Fic. 95.—Diagrammatic repre-
sentation of a longitudinal sec-
Fic. 94.—Grafting : d, the stock tion through a graft: c/, the
to which the graft is attached. callus; 7, bark; 1, pith.

removed from a superior variety, and a T-shaped incision is
made in the stock, beneath which the bark of the bud is inserted,
the whole being bound round to protect it from the action of
the atmosphere (fig. 96).

The bud grows in the same way as the graft.

The terms vernation and prefoliation are employed to ex-
press the way in which the young leaves are arranged in the
bud. We have two things to notice, viz., 1st, the arrangement
64 Elementary Botany

of each individual leaf; 2nd, the disposition of the several
leaves in the bud.

1. The arrangement of the separate leaves.—In the buds of
the Firs they are flat. In other cases they are variously bent.

 

Fic. 96.—The various elements in the process of budding.

If the apex approaches the base, as in the Tulip-tree (fig. 97, 1.),
it is reclinate. If the two edges meet together, leaving the
midrib in the centre, as in the Oak and Magnolia (11.), it is

I. II.

 

 

Fic. 97.— Various methods of leaf-folding in buds.

conduplicate. If each side be folded several times like a fan,
as in the Lady’s Mantle, Beech, Sycamore, and Vine (111), it
is plicate. When the apex of the leaf is rolled up towards the
base, as in the Sundews, Ferns, and Cycads (1v.), it is circinate.
Vernation 65

When the leaf is rolled on itself, one margin being rolled to-
wards the midrib, and the other margin rolled over it, as in
the Apricot and Banana (v.), the folding 1s convolute. When
the two margins are rolled towards the midrib on the under
side of the leaf, as in the Dock and Rosemary (v1.), it is revolute.
When the margins are rolled in the opposite way, that is, to-
wards the upper surface of the leaf, as in the Violet and Water
Lily (vu), it is involute. .

(The diagrams of vernation are often at first hard to under-
stand, unless we remember they represent sectzovs cut across
the leaves. A good plan is to cut out a large leaf in paper and
to bend it in the forms described, after which an examination
should be made of actual specimens.)

 

Fic. 98.—Forms of leaf-arrangement in bud.

2. The disposition of the several leaves in the bud.—In this
case the leaves are either flat, or only slightly convex, or they
are bent or rolled.

(a) Leaves flat or only slightly convex.—The vernation is
valvate (fig. 98, 1.) when the leaves are placed in the same
level and simply touch one another by their edges. If they are
placed at different levels and overlap one another like tiles of a
roof, as in the Lilac (11. and 11.), it is imbricate. When the

F
66 Elementary Botany

overlapping is carried further (as in fig. 1v.), it is said to be spiral
or twisted.

(6) The separate leaves bent or rolled.—When, as in the
Columbine, involute leaves touch by their edges without over-
lapping (v.), the vernation is induplicate. When, as in the
Privet, conduplicate leaves are bent around one another (v1),
it is equitant ; whilst when, as in the Sage, they are only half
folded over one another (vi1.) they are obvolute or half equitant.

When, as in the Apricot, a convolute leaf has another rolled
outside it (vut.), the vernation is supervolute.

In considering branch-
ing, whether of root, stem,
or leaf, we must carefully
distinguish the main axis,
foot or podium, and the
branches. This, however,
is not always easy.

1. In somie cases the
main axis ceases to grow
when the branches are
formed. Such branching is
called dichotomy or dicho-
tomous branching. The
podium has at its extremity
two growing points, each of
which develops a branch.
Sometimes both of these
grow equally vigorously,

Fic. 99.—Diagrams of dichotomous branching. each bifurcating abt HES) EEE

A, normal dichotomy, the forked branches and a true dichotomy or
equally developed, and becoming the pea of .

new dichotomies. 3, Bostrychoid dichotomy, forked system 1s produced
one fork-branch only becoming the podium of fi :

a new ay in this ce the left(2). C, ( 8-99, A). Sometimes one
cicinnal dichotomy; one fork branch, alternately

left (2) and right (7), becoming the podium of branch becomes more

a apy enon, Fou © ee soenesel atrongly’ developed | thas
the other; the system now

becomes sympodial, the successive strong branches looking as
though they were the continuous axis, and the weaker branches
appearing to be lateral ones. If the stronger bifurcation is

 
Branch Systems 67

always on the same side, a helicoid or bostrychoid dichotomy
is formed (fig. 99, B). If the stronger bifurcation alternates,
first to the right and then to the left, we have a scorpioid or
cicinnal dichotomy (fig. 99, c).

2. If the axis is prolonged beyond the branch, a monopodial
branching is produced. If the main axis continues to develop
more strongly than the branches, the branching is said to be
racemose ; in other cases the main axis soon ceases to grow,
and the shoots become strong ; the branching is now said to be
cymose.

There are two varieties of this :—

a. When two or more shoots arise near the apex of the
podium and develop more strongly than the main axis, which
soon ceases to grow. This is called false dichotomy (or if
three branches, trichotomy, or if more than three, polytomy)
(fig. 100, C).

AG

 

 

Fic. 100.—Diagrams of sympodial varieties of monopodial branching. 4 and JS,
cicinnal monopodia. C.dicha-ium, or false dichotomy. D, bostrychoid monopodium.
The axes are numbered in succession from1to7. (After Sache)

6. When only one shoot grows it forms a pseud-axis or
sympodium, which may form a scorpioid or cicinnal cyme if
the branches come off on opposite sides (fig. 100, A, B), or a
helicoid cyme if they all come off on the same side (fig. 100, D).

F2
68 Elementary Botany

SUMMARY OF Forms OF BRANCHING.

Dichotomous Monopodial
pi mes re —_———_—~.
Forked Sympodial Racemose Cymose
Sr sgierepen vila
Helicoid Scorpioid False Dichotomy Sympodial

Helicoid Scorpioid
True Dichotomous branching is very rare, being seldom
met with in leafy shoots. It may be seen in the roots of
Lycopods, in the shoots of Selaginella, and in the fronds of
some ferns. Racemose branching is met with in the stem
of conifers, also in the compound leaves of umbellifers and in
the roots of dicotyledons. A false dichotomy is seen in the
inflorescence of chickweed and other plants of the order
Caryophyllaceze, also in the stem of Mistletoe. The sympodial
cyme is to be met with in the annual shoots of many of our
forest trees, such as the Elm, Beech, and Hazel.
69

CHAPTER VIII.
STRUCTURE AND FUNCTIONS OF LEAVES.

WHEN a leaf is perfectly complete, it consists of three parts :—
1. The flat expanded portion which is popularly called the leaf.
This is the lamina, or blade. 2. The stalk, which attaches

ip
¥,

YH

  

Fic. ror.—Oval leaf of the ;
Apple, with two free sti- Fic. ro2.— Sessile leaves of Shepherd’s-
pules. purse (Capsella bursa-pastoris).

this to the stem, the sstioie or leaf-stalk. 3. The little leaf-
like projections at the point of union between the petiole and

the stem, the stipules.
70 Elementary Botany

In very many cases, however, there are only one or two of
these parts present. If the petiole be absent, the leaf is said
to be sessile; if the stipules, exstipulate.

The Wallflower and Shepherd’s-purse (fig. 102) are ex-
amples of plants with leaves which consist of lamina only. In
some of the leaves of the Australian Acacias (fig. 103), we have
only the petiole developed. It grows in a flattened leaf-like
expansion know as a phyllode (fig. 103, a, 9).

  
 

a
2
|

“Sep yyyph
i] YS ©
)
Argh

Fic. 103.—Leaf of Acacia melanoxylon, showing phyllodes a, 4

In the Lathyrus Aphaca (fig. 104) the stipules are the only
parts which are developed in a leaf-like manner, the lamina
and petiole being converted into a tendril.

In structure the leaf consists of parenchyma, which is in-
timately connected with the outer parenchyma of the stem,
and prosenchyma forming the veins, and which is in like
manner connected with the xylem and phloém.

In a vertical section through the leaf we find the following

parts (fig. 105) :—
Stomata 71

t A flattened epidermis coating the upper (4) and under
(ec) sides. As a rule, the under surface possesses a greater
number of stomata than does the upper. ,

 

 

 

 

 

 

 

 

Fic. ro5.—Diagrammatic section of leaf:
a, cuticle of upper, 7“ of lower side ; 4,
epidermis of upper, ¢, of lower side; c,

Fic. 104.—Lathyrus Aphaca: 1, ten- cells of upper side; d, stellate cells of
dril; 4, flower; 7 fruit; 71, stipule. lower side ; g, g. stomata ; /, /, hairs.

 

Professor Bentley gives the following table of the number
of stomata found in a square inch of the two surfaces respec-
tively of the various plants :—

Upper Under

Surface. Surface.
Mezereon. : : . None 4,000
Peony . : : . : 39 13,790
Vine. , ‘ ; ‘ 9 13,600
Olive. : ¥ ‘ : fs 57,000
Holly. : F ; : 6 63,600
Laurustinus . ‘ é ‘ 3 90,000
Cherry Laurel ; ; ; 35 90,000
Lilac 3 3 $ ‘ 160,000
Hydrangea . : : ; 4 160,000
Mistletoe é ; a j 200 200
Tradescantia . ; ‘ + 2,000 2,000
Houseleek . é s . 10,710 6,000
Garden Flag . : : . 11,572 11,572
Aloe. si : : » 25,000 20,000
Yucca . . ‘ ‘ . 40,000 40,000

Clove Pink . ‘ : - 38,500 38,500
72 Elementary Botany

Besides stomata, the epidermis is very frequently provided
with hairs of various kinds.

These are simply prolongations of the epidermal cells,
sometimes unicellular (fig. 106, 1.), sometimes multicellular
(fig. 106, I1.).

They vary much in their shape, sometimes being simple
and at other times branched.

An interesting modification is seen in glandular hairs which
contain various secretions ; of these stinging hairs, as are found
in the stinging-nettle, are good examples. In this case there
is a little bag at the base of the hollow hair, containing an
acrid fluid, and surrounded by a number of elastic cells. The
point of the hair is sharp, and is protected by a little cap.
When the nettle is touched lightly, the cap is broken off, the
point of the hair pierces the skin, and a drop of the stinging
juice is forced into the blood. If the nettle be grasped firmly
the sting is broken lower down, and hence there is no sharp
point to pierce the skin, and the juice is simply poured out upon
the exterior.

2. The surface of the epidermis is generally covered with a
thin structureless layer, the cuticle (fig. 105, @ and /).

3. The parenchyma of the interior. of the leaf consists of
cells containing chlorophyll.

There is a difference, however, in their arrangement in the
different parts of the leaf. ‘Towards the upper surface the cells
are packed closely together (¢, fig. 105), whilst towards the
under surface we find examples of stellate parenchyma, leaving
air spaces between the cells (d, fig. 105). This is the cause of
the fact that in most leaves the under surface is lighter in colour
than the upper, as there is less chlorophyll packed there.

The upper parts of the veins are in direct communication
with the wood of the stem, whilst the lower parts are connected
with the liber. At the edges of the leaves there is a passage
between the upper and lower sides, so that the sap which
passes up the wood flows out through the upper part of the
veins, back through the under surface to the liber, and so down
the stem.

There is a great difference in the venation or arrangement
73

Hairs

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1 (22, 01p BIF4/)) EAE ap JO Wey Zursung—-*or ‘org

snoarna st] Vaya ATeY 9YI JO INO SOY PINB Burpo1s0d oy3

ee

 

 

 

 

sasuazoAag 12IUVALIL)
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jo ways sy) Woy Tey AL[NTPPONATL “TT

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CC ces

 
7A Elementary Botany

of the veins of the leaves in the two great groups of flowering
plants.

In Dicotyledons the smaller veins run together, forming a
complete network known as reticulate venation (fig. 108)

 

Fic. 108.—Reticulately veined leaf of Acer acutifolium.

In Monocotyledons, as a rule, there is no network formed
between the principal veins, and the venation is said to be

 

Fic. 109.—Parallel venation.

parallel (fig. 109), (Some Monocotyledons, however, as the
Aroids, have net-veined leaves.)

There are varieties of both net-veined and parallel-veined
leaves.
Venation 75

If we take the net-veined leaves, we find that there 1s either
a single principal vein or midrib, as in the Guelder Rose (fig.
110), when the leaf is said to be unicostate, or there are several
principal veins, as in the Maple (fig. 108), when the leaf is
multicostate.

Again, amongst unicostate leaves in some cases the smaller
veins curve towards the apex (fig. 110), when we may term the
leaf curved-veined ; in other cases they run more at right
angles from the midrib to the margin (fig. 111), when it is said
to be feather-veined. is

Dp

    

Fic. rro, — Dentate
ovate leaf of the
Guelder Rese, with
unicostate __ vena-
tion § (Viburnum
Opulus).

Fic, 112, — Converging
veined leaf of Cinna-
mon.

Fic. fe acct leaf
of the Dandelion, fea-
ther-veined.

There are also two varieties of the multicostate leaves. In
some cases, as in the Maple (fig. 108), the diverging ribs never
meet again. The venation of the leaf is then said to be
diverging or palmate. In other cases, as in the Cinnamon
(fig. 112), they meet again at the apex, and the leaf is con-
verging veined.
76 Elementary Botany

Of the parallel-veined leaves there are three varieties.
When, as in the Grass (fig. 109), the veins all run from the
base to the apex, it is straight veined. When, as in the
Banana, there is a central midrib, and the side veins run off to
the margin, it is transverse veined. When, as in the Fan
Palm (fig. 72), there are several veins diverging from a common
centre, it is radiating veined.

We may tabulate these forms of venation as follows :—

Reticulate-veined Leaves

—_—_—_—_

Unicostate Multicostate

—_— ——N
Curved Feather Diverging Converging
veined veined veined veined

Parallel-veined Leaves

 

Straight Transverse Radiating
veined veined veined

In describing leaves, besides the vena-
tion, we have to take into account the
following points :—1. Composition; 2.
Margin ; 3. Incision ; 4. Apex ; 5. General
Outline.

1. Composition.—Leaves are either
simple or compound. In simple leaves,
as in the Apple (fig. 101), there is only a
single lamina ; in compound leaves, as the
Acacia (fig. 103), the lamina is divided
into a number of leaflets articulated to
the common petiole.

2. Margin.— The condition of this
depends upon the extent to which the par-
enchyma is developed between the veins.
The margin may be entire, as in Grasses.
More often there are indentations.

If the teeth thus formed are rounded
Povnge tea (fig. 113), the margin is crenate. If they

leafof the White Mustard are sharp, and point straight outwards (fig.
EAI: 110), it is dentat>. If sharp and pointing
towards the apex, like teeth of a saw (fig. 101), serrate.

 
Margin and Apex of Leaves a4

Sometimes the teeth are themselves divided, and we get
bicrenate, duplico-dentate, and biserrate margins.

If the margin of the leaf be covered with numerous hairs
(fig. 114), it is ciliate. If there be alternate concavities and
convexities larger than crenated indentations, the margin is
sinuate (fig. 115).

When the teeth are very long and sharp, the margin is spiny
(fig. 116), and when the margin is very irregular, as in the
garden Endive and curled Dock, it is crisped.

 

Fic. 114.—Ciliate leaf Fic. 115, — Sinuate Fic. 116.—Spiny leaf

of the Beech, leaf of the Oak. of the Holly.

3. Incision.—We apply this term if the margin be more
deeply indented than in the instances already described. If
the indentations reach to midway between the margin and the
midrib or petiole, we speak of them as fissures, and the por-
tions of leaf between them as lobes, and the leaf is said to be
bi-, tri-, etc., id. If the divisions go nearly to the base, or
midrib, they are partitions, and the leaf is d7-, ¢ri-, &c., -parttte.
If quite down to the midrib or base segments, the leaf is dz-,
tri-, &c., -sected. (For further remarks on this point see under
the head of Outline.)

4. Apex.—If the apex of the leaf be rounded (fig. 115), i
is obtuse or blunt. If it be sharp pointed (fig. 110), it is acute,
and if it gradually tapers to a point (fig. 117), it is acuminate.
When there is a rounded head, and a broad shallow notch in
it, the apex is retuse, and when the notch is more triangular
78 Elementary Botany
(fig. 118), it is emarginate. When the apex is very abrupt as
though cut off, it is said to be truncate.

py

=

|

 

 

Fic. 117. — Acuminate Fic. 118.—Leaf of Oxralis Fic. 119.—Mucronate
leaf of the Pellitory micrantha, with three leaflet of the Lu-
(Parietaria). obcordate leaflets. cerne.

:

Fic. 120.—Pinus sylvestris, the Scotch Fir, with acerose Fic. 121.—Lanceolate
leaves. leaf of the Privet.

 

When the apex is flattened and has a sharp point projecting
(fig. 19), it is called mucronate.

5. General Outline.—Various terms are employed for the
description of the general outline.
Outline of Leaves 79

If, as in the Grasses (fig. 109), the two margins of the
lamina are nearly parallel and the lamina itself is narrow, the
leaf is linear.

If the leaf be sharp pointed and needle-like, as in many
Conifers (fig. 120), it is aecerose. When the leaf is somewhat
broad in the centre, and tapers towards the two extremities, as
in the Privet, it is lanceolate (fig. 121). If more rounded at
the extremities and broader in the centre, it is oval, or elliptical
(fig. ror), and oblong when rather long. When, as in the
Guelder Rose (fig. 110), the leaf is broad and rounded at the
base, tapering to a point at the apex, it is ovate or egg-shaped ;
and if the reverse, obovate, or inversely egg-shaped.

 

Fic. 122.— Orbicular leaf of Malva rotundi- Fic. 123.—Cordate leaf of
Solia, Lamium,

When the leaf is nearly round (fig. 122) it is orbicular or
subrotund. When, as in the case of the Lamium (fig. 123),
the leaf is somewhat hollowed out at the base, and pointed at
the apex, so as to be roughly like a heart in a pack of playing
cards, it is cordate or heart-shaped, and when the reverse (fig.
118), obcordate.

If the apex is rounded, instead of pointed, whilst the base
is hollowed, as in the Ground Ivy (fig. 124), the outline is
reniform or kidney-shaped.

When the apex is rounded, and the leaf gradually tapers to
the base (fig. 125), it is spathulate or spoon-shaped ; or if it is
more tapering, as in the leaflets of the Horse-chestnut (fig. 126),
the outline is said to be cuneate or wedge-shaped.
80 Elementary Botany .

When the leaf is somewhat of the form of an arrow-head
(fig. 127), it is called sagittate or arrow-shaped ; or if the barbs
of the arrow point out more at a right angle to the blade, the
leaf is hastate or halbert shaped (fig. 128).

There are also several terms which are applied to the out-
lines of compound and
much divided leaves.
Thus, if 2 compound leaf
has two leaflets it is bi-
nate; if three, ternate
(fig. 118). A quadrifoli-
ate leaf has four, a quinate
five, a septenate seven,
and a multifoliate leat
more than seven leaflets
Fic ee = Srila springing from a common

Daisy (Chrysanthe-
mum leucanthemum.)

 

Fic. 124.—Reniform leaf
of the Ground Ivy (WVe-
peta Glechoma).

 

  

Fic. 126. — Cuneate Fic. 127.--Sagittate Fic, 128. — Hastate
leaflet from the leaf leaf of Convolvulus leaf of Rusmex ace-
of the Horse-chest- arvensis. tosa.
nut.

point. When the leaflets are arranged on either side of the
central stalk, like barbs on a feather, the leaf is said to be
pinnate. Of these leaves there are two varieties, viz., impari-
pinnate or unequally pinnate, when there is an odd lobe at.
Compound Leaves 81

the extremity (fig. 129), and paripinnate, or equally pinnate,
when the number of lobes present is even (fig. 130).

 

SSL Fic. 130.—Paripinnate leaf of Za-
thyrus macrorhizus (with auri-
culate or ear-shaped stipules), the
rachis ending in a point.

 

Fic. 129.—Imparipinnate leaf .
of the ‘Acacia’ (Robinia
Pseudacacia) with oppo- 7 2
site leaflets (and spinous Fic. 131.—Pinnatisect leaf of the

stipules). Common Poppy (Pagaver Rheas).

 

When a simple leaf is divided in a pinnate manner, it is
pinnatifid, pinnatipartite, or pinnatisected (fig. 131), ac-
cording to the depth of the incisions. When a pinnatifid leaf

G
82 ‘Elementary Botany

has its terminal lobe large and rounded, and the side lobes
gradually getting smaller towards the base (fig. 113), it is lyrate ;

   
 
 

Qe Myon WHY pS
AKON “alld ie Sg Ny Sy
eo NG vaya (li: ir ry Nef
i Seif
ae om i ae = iy

 

pe

Fic. 132. cata leaf of Gleditschia triacanthos.

whilst if the terminal lobe is triangular, and the lobes are also
angular (fig. 111), it is runcinate.
When each of the pinnz of a pinnate leaf is itself pinnate.

 

 

‘
Fic. 133.—Tripinnate leaf of Thalictrum,
the leaf is said to be bipinnate. If the division be carried a
step further, it is tripinnate (fig. 133).
When the divisions of the leaf spread out like the fingers
Compound Leaves 83

of a hand, the leaf is palmate (fig. 134), palmatifid (fig. 108),
palmatipartite and palmatisected (fig. 135).

When a palmatisected leaf is itself cut up into segments, it
is dissected or laciniate (fig. 136).

 

Fic. 134.—Palminerved leaf of Geraniune Fic. 135.—Palmatisect leaf of the
pratense (nature printed). Monkshood (Aconitumz).

 

Fic. 136.--Heteromorphic leaves of the Fic. 137.—Pedate leaf of the Christmas
Water Crowfoot (Ranunculus aguatilis): Rose (Helleborus niger).
the floating leaves trilobed, the sub-
merged leaves laciniate.

Sometimes the lateral lobes of a palmate leaf are them-
selves divided, giving the whole somewhat the appearance of a
bird’s foot (fig. 137). The leaf is then pedate.

G2
84. Elementary Botany

There are certain terms which are applied to the attachment
of the leaves to the stem. Thus when placed one above the
other upon opposite sides of the stem, they are alternate. If
placed in pairs on opposite sides, they are opposite. If the
alternate pairs of opposite leaves are placed at right angles to

 

Fic. 139. -- Verticillate leaves of the |
Madder (Rubia tinctorum).

  

Fic. 138.—Decussate leaves of the Fic. 140.—Connate leaves of the
Scarlet Pimpernel (Axagadiis ar- Honeysuckle.
vensis), with axillary flowers.
one another (fig. 138), they are decussate. When there are
more than two leaves forming a whorl round the stem (fig. 139),
they are said to be verticillate. When two opposite leaves
have their bases so united as to form apparently but one (fig.
140), often thus producing a cup, as in the Teasel, they are
connate. If the base of the leaf, whether petiole, lamina, or
Functions of Leaves 85

stipules, embraces the stem, the leaf is amplexicaul, the part
surrounding the stem being called the vagina or sheath.

If the stem grows through the leaf, the latter is said to be
perfoliate (fig. 141), whilst, if any part of the leaf adheres to
the stem, causing the latter to be winged (fig. 142), the leaf is
said to be decurrent.

  

Fic. 142.—Decurrent leaf of Symphytum offi-

Fic. 141.—Perfoliate leaf of cinale, the stem hence becoming winged on

Bupleurum rotundifolium. one side,

If the leaves grow from the point of junction of the root
and stem, or if the stem be so reduced as to be almost obli-
terated, they are said to be radical. Leaves growing from the
main stem are called cauline, and those from the branches,
ramal.

FUNCTIONS OF THE LEAVES.

1. To absorb food for the plant.—We have already seen
how the roots take up from the soil the various substances
needed for the life of the plant. One very important substance,
however, is not taken up by the roots of green plants, and this
is carbon.

Thi& element exists in the atmosphere in the form of carbon
dioxide or carbonic acid gas, a compound of carbon and
86 Elementary Botany

oxygen, CO,. It is produced wherever breathing, burning, and
decay of organic bodies are taking place.

The composition of a thousand parts, by volume, of at-
mospheric air is as follows :—

Nitrogen. : 2 ‘ : »  779'50.
Oxygen. : : : ; . 206°10.
Water (variable) . ‘ : ; . 14°00.
Carbon dioxide . : ‘ : : "40.
Various gases. . . 3 . traces.

1,000°00,

That is to say that a thousand cubic feet of air contain
not quite half a cubic foot of carbonic acid. Small as this
quantity may appear to be, it is the source of the carbon of the
plant.

The carbon dioxide enters with the other constituents of
the air by means of the stomata into the interior of the leaf,
there to serve for the nourishment of the plant.

2. To assimilate the food absorbed.—The food materials
which are taken up by the root are not changed as they are
carried up to the leaves. The sap becomes thicker by evapora-
tion, but when it enters the leaves it still contains simply
mineral substances. In the leaves, however, it is brought into
contact with the carbon dioxide, and a marvellous change takes
place. In the presence of the chlorophyll and under the action
of light, the carbonic acid gas is decomposed : its oxygen is
restored to the atmosphere, whilst the carbon is chemically
united with the water and the mineral substances, to build up
new and organic compounds. These changes will only take
place in the light, and go on in all the green parts of the plants.
It is owing to this that the amount of carbonic acid in the
atmosphere is kept down, and the air purified and rendered fit
for man to breathe ; hence the importance of open spaces with
trees in the midst of our cities.

One of the first substances formed is generally oxalic acid,
which unites with the lime of the sulphate of lime, setting free
the sulphur which is required for the manufacture of the various
albuminoids. Other organic substances soon follow, and the
Breathing of Plants 8&7

food which passes down the liber isin a fit state to be absorbed
by the plant.

(It is generally stated that the presence of chlorophyll is
necessary to the decomposition of carbon dioxide. Recent
observations, however, have raised the suggestion that chloro-
phyll may be the vesu/f, not the cause, of the decomposition.
The question needs further investigation, but the presence of
chlorophyll and the decomposition of carbonic acid always go
together.)

A very important point to remember is, that the plant does
not absorb free nitrogen from the atmosphere. All the nitrogen
required by the plant is taken in either as ammonia or nitrates.

3. As a breathing organ.—Plants, like animals, carry on
a process of respiration, z.e. they take in atmospheric oxygen,
which combines with the carbon and hydrogen of the tissues
forming carbon dioxide and water, which are restored to the
air. The respiration, however, of plants is much less than
that of animals ; it differs in its amount in various plants, and
in the different parts of the same plant. The more energetic
the growth, the greater the amount of respiration: hence it is
especially well seen in quickly germinating seeds, and unfolding
leaf and flower buds.

The oxygen passes into the interior of the plant by means
of the stomata, and by the same openings the carbonic acid
gas is passed out into the atmosphere. This change goes on
continually, irrespective of the presence or absence of light.
During the daytime the feeding by the decomposition of carbon
dioxide and assimilation of the carbon is so greatly in excess of
the respiratory act, that it completely overshadows it, and ap-
parently nothing is going on but the decomposition of the car-
bonic acid ; but in the night time, when, owing to the absence
of the light, no assimilation is taking place, the breathing can
be perceived.

4. As an organ of transpiration.—A large portion of the
water which is taken in by the roots of the plant escapes by
the leaves. By means of this evaporation the sap becomes
thickened as it ascends the stem. The transpiration takes
place by means of the epidermis, and especially through the
88 Elementary Botany

stomata. The amount which is evaporated depends upon
certain conditions, viz. :—

a. The state of the atmosphere. All other things being
equal, more moisture will be given off in dry than in moist
atmosphere.

6. The amount of light. The greater the light, the greater
the transpiration.

¢. The structure of the epidermis. In many succulent
plants the epidermis is very thick, thus preventing an excess of
evaporation.

a. There is a greater evaporation from the lower than the
upper sides of the leaves.

The amount of water transpired is often very great, as is
shown by experiments which were first performed by Hales in
1724. A Sunflower plant, 3} feet high, weighing 3 lbs., and
with a surface of 5,616 square inches, exhaled a pint of water
a day ; a Cabbage plant with 2,736 square inches, 19 fluid
ounces ; a Lemon tree with 2,557 square inches, 6 fluid
ounces.

The action of Wardian cases depends upon this continual
evaporation. By this means the water which evaporates col-
lects on the glass, and running down once more, waters the
plants.

The transpiration of plants also plays an important part in
determining the humidity of the atmosphere where they grow.
We always find that if there are forests of trees the atmosphere
in the neighbourhood is moist ; whilst, on the other hand,
there have been numerous cases where the clearing of a tract
of country has materially interfered with the rainfall, producing
droughts.

5. As organs of circulation.—From the fact of transpira-
tion follows the next, that the leaves tend to produce a flow of
sap upwards. As evaporation takes place there is a continual
flow of water up the wood to take its place: the greater the
evaporation the more rapid the sap circulation. (See Chapter
XII.)

The foregoing functions are performed by all leaves ; the
following, however, are exceptional.
Carnivorous Plants 89

6. In some cases the leaves act as carnivorous crgans.—
Some plants seem to possess the power of absorbing their

 

Fic. 143.—Venus’s Fly-trap (Dionea muscipula).

nitrogen by means of organic compounds containing it. Good
examples are to be seen in Venus’s Fly-trap (fig. 143), and the
Sundews of our own country. If we examine the leaves of
go Elementary Botany

either of these plants, we find that their upper surfaces are
covered with glandular hairs which, when touched, exude a few
drops of a sticky liquid which adheres to the fingers, and will
be drawn out into a fine thread.

If an insect settles upon the leaf it becomes arrested, and
gradually the leaf folds over, enclosing it. It thus remains
closed for a short time, and on opening again there is found
merely the outer shell of the insect, all the nutritive part having
been absorbed by the plant. The leaf seems to contain a sub-
stance analogous to, if not identical with, the pepsine of the
animal stomach, which possesses the power of rendering nitro-
genous substancés soluble. Other carnivorous plants have the
same power of absorbing organic food materials by their leaves
in various ways.

7. In some cases the leaves act as organs of support.—
We have already seen that parts of the leaf may be converted
into tendrils (figs. 93 and 104), thus twining round the organ of
support and sustaining the stem. In the Tropzeolum the leaf-
stalk itself twines and supports the plant.

Parasites.—It has been noted (page 34) that some plants
obtain their food through the medium of others. Such plants
are known as parasites. We may divide them under three
heads.

(2) Semi-Parasites.—These can obtain some food from the
soil, but not sufficient to enable them to grow in a luxuriant
manner.

If some seeds of Yellow Rattle be allowed to germinate in
earth they will grow, but the plants will not be fully developed.
If, however, the seeds be sown amongst some grass, strong, well-
developed Rattles will be obtained. The Rattle sends its roots
into the roots of the grass and draws sap out of them, which is
afterwards elaborated in its own leaves.

() Green parasites.—Mistletoe (fig. 64) is a type of this
class. It cannot obtain any nourishment for itself out of the
soil, and has to depend entirely upon the tree into whose stem
it sends its roots. At the same time its leaves contain chloro-
phyll, and hence it can decompose the carbon dioxide of the
atmosphere, and assimilate food for itself.
Parasites gI

(c) Perfect parasites—Of this group the Broom-rape and
Dodder are types. These plants possess no chlorophyll, hence
they cannot decompose the atmospheric carbon dioxide, so
they obtain from the plants on which they live sap which is
already elaborated.

In the case of the Broom-rape the leaves are modified into

scales destitute of chlorophyll, whilst in the Dodder leaves are
entirely absent.
92 Elementary Botany

CHAPTER IX.

BRACTS AND INFLORESCENCE.

THE term bract is employed for those leaves in whose axils
flower buds instead of leaf buds arise, or for any appendage
growing upon the flower-stalk below the flower.

In some cases, as in the White Dead-nettle, bracts cannot
be distinguished, except by their position, froin the true leaves

 

Fic. 144.—Capitulum of Marigold, with
imbricate involucre.

of the plant ; in other cases,
whilst still leaf-like, they dif-
fer in shape from the other
leaves of the same plant. In
all these cases the bracts are
said to be foliaceous or leafy
bracts.

Sometimes the bracts are
coloured, being then often
mistaken for the true flowers,
as in the Hydrangea, and in
some species of Euphorbia.
In other cases the bracts are
small and scale-like.

When several bracts sur-
round a single flower as in
the Pink, or a head of flowers

as in the Marigold (fig. 144), they form an involucre.

When a single bract is enlarged and ensheaths a single
flower whilst in the young state, as in the Narcissus and Snow-
flake, or a head of flowers, as in the Cuckoo-pint or Palm, it is

called a spathe.

When bracts are scaly, they are said to be sguamous, and
Inflorescence 93

the special scaly bracts which enclose the flowers of the Grass
and Sedge tribes are paées and glumes.

If the bracts fall before, or soon after, the flower opens, they
are deciduous ; whilst if they remain (sometimes even to the
ripening of the fruit), persistent.

If bracts be present, the plant is said to be dracteate ; if
absent, edracteate.

 

Fic. 145.—Simple raceme of Fic. 146.— Longitudinal section through the capi-
Antirrhinum majus. tulum of the Burdock (Arctium Lappa).

The term inflorescence is employed to describe the arrange-
ment of the flowers upon the stem. In some cases, as in the
Tulip, there is a single flower at the top of the stalk, no others
being formed below. The inflorescence is then said to be
single-flowered. More often there are several flowers variously
arranged. Inflorescences are divided under two heads.

If we examine such a bunch of flowers as the Snapdragon
(fig. 145), or Wallflower, or Stock, we find that the oldest flowers
are towards the base, the younger ones being towards the apex.
Such an inflorescence is said to be indefinite. Sometimes in
the indefinite inflorescences, as in the Burdock (fig. 146), or
Thistle, or Dandelion, the flowers instead of being arranged
94. Elementary Botany

one above another are side by side. In this case the younger
flowers are towards the centre, and the older ones around them,
and hence the indefinite inflorescence is also spoken of as
centripetal, or centre-seeking. In the Pink, on the other
hand (fig. 147), the stalk is capped by a flower which is the
first to open, the younger ones budding below it. This is
termed definite inflorescence, or (since, when the flowers are

 

Fic. 147.—Dianthus Caryophyllus: portionof Fic. 148.—Simple spike of Ver-
plant with definite inflorescence. bena officinalis.
on the same level, the older ones will be towards the centre,
and the younger ones outside) centrifugal.
Of each of these forms there are several varieties.
Indefinite or Centripetal Inflorescence.—In the case of
the indefinite inflorescence the axis may either be lengthened as
in the Snapdragon, or arrested as in the Burdock and Dande-
lion ; and in either case the flowers may be sessile or stalked.
A spike is an indefinite inflorescence with a lengthened
Indefinite Inflorescence 95

axis and sessile flowers, as in the Verbena (fig. 148), Plantain,
or Wheat.

A raceme is an indefinite inflorescence with a lengthened
axis and stalked flowers, as
in the Snapdragon (fig. 145)
and Currant (fig. 149).

A capitulum is an indefi-
nite inflorescence with short-
ened axis and sessile flowers,
as in the Marigold (fig. 144),
Burdock (fig. 146), and
Dandelion.

An umbel is an indefinite
inflorescence with shortened
axis and stalked flowers, as
in the Cherry (fig. 150). If

  

Fic. 151.—Compound umbel of Fool’s Parsley
‘ (4thusa Cynapium); common involucre
Fic. 150,—Simple umbel of the Cherry. wanting ; involucels of three leaves each,

each branch of the umbel be itself branched, the compound
umbel is produced, as in the Fool’s Parsley (fig. 151). Gene-
rally the capitulum and umbel are surrounded by an involucre of
bracts, and sometimes the secondary branches of the compound
umbel have a special involucre which is called the zzvolucel.
Special names are given to varieties of some of these forms.
96 Elementary Botany

VARIETIES OF SPIKE.

A catkin or amentum is a deciduous spike of unisexual
flowers, as in the Oak (fig. 152), Hazel, or Willow.

A spadix is a fleshy spike bearing several unisexual flowers,
the whole enveloped in a spathe, as in
the Arum (fig. 153).

A strobilus is a spike of unisexual
flowers with membranous bracts, as in
the Hop.

 

Frc. 153.—Spadix of

Arum : a, barren sta-

Fic, 152.—Catkin oramentum mens ; 2, stamens; c¢, Fic. 154.—Cone of the
of the Oak. pistils. Scotch Fir.

  

A cone is a spike of unisexual flowers with lignified bracts,
as in the Fir (fig. 154).

VARIETIES OF RACEME.

A corymb is a raceme where the stalks or pedicels are of
different lengths, the lower ones being the longest, so that the
flowers form a flat-topped head, as in the Hawthorn and some
species of Cerasus.*

A panicle is a compound raceme, that is, one where each
branch is itself branched, as in some Yuccas.

A thyrsus is a panicle with very short pedicels, as in the
Horse-chestnut and Lilac.
Definite Inflorescence 97

VARIETY OF CAPITULUM.

The hypanthodium has the end of the stalk hollowed out,
the flowers growing within, as in the Fig (fig. 155).

 

Fic. 155.—I, Longitudinal section through the hypanthodium of a Fig, exposing the
flowers in its interior. II. A piece with five female flowers: s, pistil ; 6, perianth.

We may tabulate the forms of indefinite inflorescence as
follows :—
Indefinite Inflorescence.

 

With lengthened axis. With shortened axis.
OO ~ _—aqxt_"
With sessile With stalked With sessile With stalked
flowers. Jlowers. flowers. flowers.
SPIKE. RACEME. CaPITULUM. UMBEL.
a Amentum. Corymb. Hypanthodium. Compound
‘S | Spadix. Panicle. umbel.
‘5 | Strobilus. Thyrsus.
S Venn

Definite or Centrifugal Inflorescence.—The general name
for these is Cyme. We cannot well tabulate them in the same
way that we do the indefinite. In many cases we employ the
name of the indefinite inflorescence as an adjective to qualify
the term cyme. Thus we have a spiked cyme in Sedum,

H
98 Elementary Botany

racemose cyme in Campanulas, panicled cyme in Privet,
corymbose cyme in Laurustinus, etc.

The dichotomous cyme (fig. 156) is one where two branches
spring from beneath the terminal flower, each in its turn capped
by a flower and developing two branches just below it, as in
the Chickweed and Centaury. If there be three stalks the
cyme is ¢richotomous.

  

Fic. 156.—Dichotomous cyme Fic. 157.— Cymose inflorescence of
of Cerastinin. Myosotis.

If but one stalk be given off, which is again branched on
the same side, and this again repeated a number of times
always. on the same side, so that the young flowers become
coiled like a scorpion’s tail or a shepherd’s crook, the scorpioid
cyme is formed, as in the Forget-me-not, and many of the
Boraginacee (fig. 157).

The fascicle is a cyme which has a large number of flowers
on short stalks, as in the Sweet William.

The glomerulus is a cyme with a large number of sessile
flowers, as in the Box.
Mixed Inflorescences 99

The verticillaster consists of two cymose bunches placed
on opposite sides of the stem, so as apparently to produce a
whorl, as in the Lamium album (fig. 158), and other members
of the Labiate.

 

Fic 158.—Verticillaster of Lamium album.

Mixed Inflorescences.—Sometimes in a plant there is a
mixture of the two kinds of inflorescence. Thus in the Dead-
nettle, whilst each separate inflorescence is definite, being a
verticillaster, yet, taking the whole plant, the arrangement is
indefinite, the lower verticillasters opening first. On the other
hand, in most of the members of the natural order Composite,
whilst each capitulum is itself indefinite, yet, taking the plant
as a whole, the arrangement is definite, for the terminal capitu-
lum is the first to open.

Such an inflorescence is said to be mixed.
100 Elementary Botany

CHAPTER X.

STRUCTURE AND FUNCTIONS OF PARTS OF THE
FLOWER,

Tur flower is that part of the plant which subserves the pur-
poses of reproduction.

When complete, the flower consists of four whorls or series
of organs. The two outer ones are merely coverings, whilst
the inner ones form the essential organs.

Commencing at the exterior, the outer coat is known as the
calyx (fig. 159, K), and each division of which it is made up
is a sepal. The inner coat is the
corolla (fig. 159, B), and each sepa-
rate part of it a petal.

If both coats be present, as in
the Buttercup, the flower is said to
be dichlamydeous ; if only one, as
in the Anemone, monochlamydeous ;
if both be absent, as in the Ash,
achlamydeous.

The outermost whorl of the es-

 

Fic. 159.— Flower of S: tsymbrium : :
Alliaria: K, calyx; 8, corolla ; sential organs of the flower is the

s, stamens; sé, pistil.

andrecium (fig. 159, s), consisting
of one or more stamens ; whilst within there is the pistil or
gyneecium (fig. 159, s¢), consisting of one or more earpels.

This will be a convenient place to note the distinction that
is drawn between a complete and a perfect flower.

For a flower to be complete, all four of the whorls must be
present ; if any one be absent, the flower is incomplete. On
the other hand, the term perfect is applied to all those flowers
in which both andrcecium and pistil are present, although, as
in the Anemone, one of the coats may be wanting, or even, as
Complete and Perfect Flowers 101

in some flowers of the Ash, both coats may be absent. An
imperfect flower is one where there is only one whorl of the
essential organs, as in the Hazel and Oak.

Lt follows that every complete flower must be perfect, but every
perfect flower is not necessarily complete ; on the other hand, every
imperfect flower must be incomplete, but every incomplete flower
zs not imperfect.

Perfect flowers are sometimes spoken of as hermaphrodite.
Imperfect flowers are either
staminate (fig. 160) if the
pistil be absent, or pistillate
(fig. 161) if the stamens be
absent.

 

Fic, 160.—Staminate ($) flower
of Cadlitriche verna, with two
sickle-shaped bracts.

  

Fic. 162.—The Hazel (Corylus
Fic. 161.—Pistillate (9) flower Avellana); branch with male
of Cadlitriche verna. and female flowers,

If staminate and pistillate flowers grow upon the same
plant, as in the Hazel (fig. 162), Oak, and Birch, the plant is
102 Elementary Botany

said to be moneecious ; if they grow upon separate plants, as
in the Willow (fig. 163), Juniper, and Poplar, it is dioecious ;
whilst if on the same plant are to be found hermaphrodite,
staminate, and pistillate flowers, as in the Ash, it is polygamous.

We must now notice each part of the flower more par-
ticularly.

 

Fic. 163.—Sallow (Salix caprea). 1. Male catkin. II. Female catkin.

 

Fig. 164.—Flower of the Fic. 165.—Longitudinal section through the
Strawberry, with calyx flower of Ranunculus acris, showing the
in two rows. hypogynous calyx, corolla, and stamens.

CaLyx.—The sepals are generally arranged in one whorl,
but in some cases, as in the Strawberry (fig. 164), there may
be two (or even, as in the Cotton, three) whorls.

Generally the sepals are green, but sometimes, as in the
Fuchsia, Larkspur, and Garden Nasturtium, they are coloured,
or petaloid,
Position of Calyx 103

When the calyx is inserted beneath the ovary upon the end
of the flower-stalk (which is known as the thalamus), it is said
to be inferior, and the ovary is superior, as in the Ranunculus
(fig. 165, and fig. 166, H and P).

 

Fic. 166.—Diagrammatic section of hypogynous (1), perigynous (P), and epigynous(£)
flowers. a, axis, forming convex or concave receptacle, or wall of ovary: %, calyx:
¢, corolla ; s, stamens ; 7, carpels ; 7, stigma; s#, ovules. (After Prantl.)

In other cases the calyx is adherent to the sides of the
ovary, only the free limb springing from its upper part (or the
calyx springs entirely from the top of the ovary). Itis then said

 

Fic. 167.—Spurred calyx of Tvofpeolunt. Fic. 168.—Caducous calyx of Poppy

to be superior, and the ovary is inferior (fig. 166, £), as in the
Fuchsia, Willow-herb, Apple, etc.
When the sepals of the calyx are distinct from one another,
104 Elementary Botany

as in the Strawberry (fig. 164), it is said to be polysepalous.
If the sepals be united together (fig. 170), as in the Primrose,
the calyx is gamosepalous,

When the sepals are alike, as in the Buttercup (fig. 165), or
Primrose, the calyx is said to be regular ; if some be differently
developed from the rest, the calyx is irregular, as in the
Garden Nasturtium (fig. 167).

If, as in the Poppy (fig. 168), the calyx falls off as soon as
the flower-bud opens, it is said to be caducous; if, as in the
Ranunculus (fig. 165), it remains after the flower opens, but
falls off before the fruit ripens, it is deciduous; whilst if it re-
mains after the fruit has ripened, it is persistent, as in the
Strawberry (fig. 164).

   

Fic. 170.—I. Turbinate. II.
Fic. 169.—Tubu- — Urceolate calyx (represented Fic. 171.—Saccate calyx of
lar calyx. diagrammatically). Lunaria.

Sometimes the persistent calyx becomes very much enlarged
around the fruit ; it is then accrescent, as in the Physalis.

There are also certain terms which are used in describing
the shape of the calyx which are of great importance in De-
scriptive Botany.

Thus it may be tubular (fig. 169), as in the Centaury ;
ureeolate (fig. 170, 1.) or urn-shaped, as in the Campion;
inflated or swollen, as in the Bladder Campion; turbinate or
top-shaped (fig. 170, 1.); funnel-shaped or infundibuliform
(fig. 176), as in the Deadly Nightshade; saccate (fig. 171), if
there are four sepals, two of which are prolonged at the base,
as in most cruciferous plants ; rotate (fig. 164), as in the Straw-
berry ; bilabiate or two-lipped (fig. 177), as in the Dead-nettle ;
Pappus 105

spurred (fig. 167), as in the Tropzolum ; galeate or hooded
(fig. 172), as in the Monkshood.

When the calyx is polysepalous, it should be described as
bisepalous, trisepalous, etc. If gamosepalous, it may be de-
scribed as toothed, lobed, or incised, according to the depth to
which it is cut.

 

Fic. 172,—Monkshood (Aconitum Napellus). Fic. 174.-—Pilose stipitate pappus
Part of plant, showing galeate calyx. of Dandelion,

A remarkable form of calyx known as pappus is met with
amongst the composite and some other flowers. In this case
the sepals are converted into numerous hairs, which crown the
ovary, and are often very much enlarged upon the fruit, as is
seen in the head of the Dandelion after flowering.

The hairs may be either simple when the pappus is pilose
106 Elementary Botany

(figs. 173 and 174), or feathery when it is plumose (figs. 175
and 178). Again, they may be sessile upon the ovary (figs.
173 and 175), or stalked, when they are said to be stipitate
(figs. 174 and 178); so that there are four forms of pappus,
viz. :—
. Pilose sessile, as in Groundsel.

Pilose stipitate, as in Dandelion.

Flumose sessile, as in Salsify or Goatsbeard.

Plumose stipitate, as in Thistles.

    

Fic. _175.--Plumose Fic. 176.—Deadly Night- Fic. 177.— Bilabiate

sessile pappus of shade (Atroga Bella- five-toothed calyx
Tragopogon, donna) flower. of Lamium.

  

Fic. 178.—Pappus of Carlina vulgaris. Fic. 179.—Fruit, 4 of the Tansy
the feathery rays united below into (Tanacetum vulgare), sur-
several bundles and coherent at the base mounted by the coronate
into a ring. pappus.

In the Chicory and Tansy (fig. 179) the pappus is coronate,
forming a crown of broad hairs above the fruit.

CoroLta.—The second enveloping layer of the flower is
generally more delicate in its structure than the calyx, and is
Corolla 107

often highly coloured and possesses odour. If there be only
one coat present, as in the Anemone and Marsh Marigold,
whatever its appearance, it is spoken of as calyx.

The corolla is either gamopetalous or polypetalous—
regular or irregular.

If the petals are attached with the calyx beneath the ovary
(fig. 166, H), the corolla is said to be hypogynous ; if the ovary
be superior, but the petals, instead of being inserted under it,
are attached upon the calyx, forming a ring round the ovary,
the corolla is perigynous (fig. 166, p). When the ovary is
inferior and the corolla springs from the top of it with the
calyx (fig. 166, =), it is epigynous.

The corolla never remains to form a part of the fruit as the
calyx does sometimes.

  

Fic, 180.—Unguiculate petal Fic. 181.—Bifid unguicu- Fic. 182. — Tubular co-
of Dianthus, with toothed late petal of Lychuis, rolla from the disc of
lamina. with ligule. the capitulum of Cex-

taurea Cyanus

Terms are also employed to describe the shape of the
corolla, and of the individual petals.

When the petals are broad above and form a narrow limb
below, as in the Pink (fig. 180) and Lychnis (fig. 181), they are
said to be unguiculate or clawed.

When each petal is notched at its free edge, as in the Lychnis
(fig. 181), it is described as bifid. If there are several notches
it is toothed (fig. 180), or, if very much divided, fimbriated,
as in Dianthus plumarius.

Again, the corolla may be tubular, as in the Bluebottle and
other composite plants (fig. 182) ; campanulate or bell-shaped,
t08 Elementary Botany

  

Fic. 183.—Campa-
nulate corolla of

the Canterbury Fic. 186.—In-

 

ell. fundibuliform
Fic. 184.—Urceolate Fic. 185.—Globose corolla of
corolla of Vacci- corolla of Erica Convoloulus

nium Myrtillus. Tetralix. arvensis.

 

Fic. 187. — Hypo-
crateriform corolla
of the Jasmine.

 

Fic. 188.—Rotate corolla of | Fic. 189. — Cruciform
the Borage (Borago offici- flower of Lunavia, with
nalis). unguiculate petals.

  

Fic. 190 —Ligulate Fic, 191.—Bilabiate Fic. 192.—Bilabiate personate corolla
corolla of Globu/a- —ringent corolla of of Antirrhinum majus.
rig Alypum, Leminun album,
Forms of Corolla 109

as in the Campanula (fig. 183); wreeolate or urn-shaped, as in
the Bilberry (fig. 184); globose, as in many Heaths (fig. 185) ;
infundibuliform or funnel-shaped, as in the Convolvulus (fig.
186); hypocrateriform or salver-shaped, with the petals flat-
tened above, as in the Jasmine (fig. 187); rotate or wheel-
shaped, as in the Borage (fig. 188); eruciform or cross-shaped,
when there are four petals arranged like a Maltese cross, as in
the Wallflower, Stock, or Lunaria (fig. 189); ligulate or strap-
shaped, when the lower part of the corolla forms a tube and
the upper part is flattened out, as in the Globularia (fig. 190),
and the ray florets of the Daisy and florets of the Dande-
lion; spurred, as in the Violet and many Orchids; bilabiate

 

Fic. 193.—Papilionaceous corolla of Laburnum. I. Seen laterally. II. In front. III.
Standard. IV. Left wing seen from without. V. Keel.

or two-lipped, as in the Dead-nettle (fig. 191). Of this there
are two forms: if the lips are wide apart, as in the Dead-nettle,
it is ringent ; if closed, as in the Snapdragon (fig. 192), it is
personate ; papilionaceous or butterfly-shaped, as in the La-
burnum and other members of the Pea-flower tribe (fig. 193).
In this case there are five petals, one overlooking the rest, the
standard or vexillum (fig. 193, I11.); one standing out on each side,
the wings or ale (fig. 193, iv.) ; and two united surrounding the
stamens, the eel or carina (fig. 193, V.).

In some cases, as in many of the Orchids, there is a most
yregular shape of corolla which has received no special name.
The term caryophyllaceous is applied to the corolla as it is met
with in the Pink tribe (figs. 194 and 195), when there are five
110 Elementary Botany

petals attached by claws to the base of a tubular calyx ; whilst
if there are five petals, not clawed, and attached in a perigynous
manner (fig. 196), the corolla is rosaceous.

 

Fic. 194.—Caryophyllaceous Fic. 195.—Longitudinal section through
corolla of Lychnis vesper- the caryophyllaceous corolla of Diaz-
tina, with corona. thus.

There are sometimes attached to the corolla subsidiary
organs, which are variously arranged, and which, owing to their
not being universally present, are not treated of as separate
organs, They form the corona or paracorolla, and are petaloid

  

VL
Fic. 196.—Longitudinal section through Fic. 197.—Petaloid perianth
the rosaceous flower of the Rose; the of Narcissus, with 6-partite
pistil seated in the base of the urceolate limb and campanulate co-
calyx. rona.

and well developed in the Narcissus (fig. 197), or small as in the
Lychnis (fig. 194), or consist of several hairs as in the Passion
Flower and Dead-nettle, or scales with glandular hairs attached
Nectaries III

as in the Grass of Parnassus (fig. 199), or scales known as stami-
nodes closing the tube of the corolla as in the Borage (fig. 198).

NECTARIES, or glands for the secretion of honey, are some-
times spoken of as subsidiary organs, but various parts of the

 

Fic. 198. —Longitudinal section through the flower of the Borage ;
each bifid stamen bears the anther on its inner half, while the
other half forms an erect scale.
flower may be specially developed for this function. Thus,
there may be scales between the stamens as in the Grape Vine
(fig. 200), or spurs either of the calyx as in the Tropzolum
(fig. 167), or of the corolla as in the Valerian (fig. 201), or of

 

Fic. 199. —I. Longitudinal section through the flower of Parnassia palustris.
II, One of the petals ; a glandular scale belonging to the corona attached to
it in front.
both as in the Larkspur (fig. 202), or of the stamens as in the
Violet (fig. 204). There may be specially developed petals, as in
the Monkshood (fig. 203); or glands in hollows at the base of
the petals, as in the Buttercup.
PERIANTH.—The term perianth is generally employed in
112 Elementary Botany

 

Fic. 200,—Stamens and pistil of the Grape Fic, 201.—Spurred corolla of
Vine, with a honey gland (nectary) be- Vateriana.
tween each pair of stamens.

 

Fic. 202,—Longitudinal section of flower . Larkspur, with spurred calyx and
corolla.

 

SS
Fic. 203.—Monkshood (Aconitum Napellus). Flower, the coloured calyx having

been removed, showing the two petals, a, developed into nectaries, the remaining
petals being reduced to scales or altogether abortive.
Andrecium 113

those cases where the calyx and corolla resemble one another,
being both green or both petaloid, especially when it occurs
among monocotyledonous
‘ plants. In this case we
speak of it as being gamo-
phyllous or polyphyllous.
(Some botanists use the
term perianth for describing
the flowers which possess
only one floral envelope.) .
ASsTIVATION.—Just as Tig. pared Ma sos Vella est
thetermsvernationand pre-
foliation are applied to the arrangement of the foliage leaves in
the bud, so the terms estivation and prefloration are em-
ployed to describe the arrangement of the leaves in the flower- |
bud. The same terms already employed (see Chapter VII.)
can also be used in this case. Besides these, however, we apply
the term vexillary to the zestivation as seen in a papilionaceous
plant (fig. 205), and crumpled when the petals are crumpled
up as in the Poppy.

 

  

Fic. 206. —Mon- Fic. 207.—Diadelphous stamensof Fic. 208.—Polyadel-
adelphous sta- Lathyrus ; nine filaments united phous stamens of
mens of Malwa. fs a sheath at the base, one Orange,

ree.

ANDRacIuM.—We now come to the first whorl of the
essential organs of the flower. Each stamen of which the an-
drcecium is composed consists, when complete, of three parts,
viz., the stalk which attaches it to the rest of the flower, and

I
114 Elementary Botany

which is known as the filament.;: the knob on the summit,
which is in reality a little box, ‘the anther; and within this a
fine powder, the pollen, which is the essential part of the
stamen.

These stamens may be either distinct, when they are said”
to be free, as in the Ranunculus (fig. 165), or they are more or
less united.

If they are united by means of their filaments into one
bundle, whilst their anthers are free, as in the Mallow (fig. 206),
they are said to be monadelphous.

 

Fic. 209. — Syngenesious Fic. 210. — Stamens of Fic. 211.—Section of corolla
anthers of Thistle ; the Aristolochia _ sessile of Honeysuckle, with epi-
filaments free. upon the stigma. petalous stamens,

If there be two bundles, as in the Sweet-pea (fig. 207), the
androecium is diadelphous ; and if more than two bundles, as
in the Orange (fig. 208), polyadelphous. If the stamens are
attached together by means of their anthers, whilst the filaments
are free, as in the Thistle and other composite plants (fig. 209),
they are syngenesious. If the anthers are attached immedi-
ately upon the pistil, as in the Birthwort (fig. 210) and various
Orchids, they are gynandrous.

With regard to the attachments of the stamens, we apply
the same terms which we used in describing the position of the
Stamens 115

corolla. Thus the stamens may be hypogynous (fig. 166, 4),
perigynous (fig. 166, P), or epigynous (fig. 166, z). Inaddition
to these positions the stamens may be upon the corolla, when
they are said to be epipetalous (or epiphyllous when there is
a perianth), as in the Honeysuckle (fig. 211). If the filament
of the stamens be absent, as in the Verbena (fig. 212), the
anthers are said to be sessile.

More often there is a filament present which is generally
thin and thread-like, but sometimes, as in some of the stamens
of the Water-lily, it is broad and flat. Generally the various
filaments are about the same length, but in some cases there is
a constant difference between the stamens on this point. Thus

 

Fic. 212. -- Section of Fic. 213.—Tetradynamoussta- Fic. 214.— Flower of
corolla of Verbena, mens and pistil of Brassica Lamium, with
with sessile epipetalous nigra; a shorter, 4 longer didynamous _ sta-
anthers. stamens, mens.

in the Mustard (fig. 213), and allied plants of the natural order
Crucifere, there are four long and two short stamens, when
they are said to be tetradynamous ; whilst in the Dead-nettle
and most other plants of the order Labiate there are two long
and two short, and the stamens are didynamous (fig. 214).
If the anthers are attached immediately upon the top of the
. filaments they are said to be innate, or basifixed, in their at-
tachment. If the filament is prolonged up behind the anthers
they are adnate or dorsifixed ; and if it be attached loosely to
the centres of the anthers, so that they swing upon the point of
attachment, as in the Wheat (fig. 215), they are versatile.
12
116 Elementary Botany

The portion of the filament to which the anthers are attached
is called the connective. Usually this is not developed to a
noticeable degree, but in the Herb Paris it is prolonged beyond
the anthers, giving them the appearance of being placed half-
way down the stamen.

In the Hornbeam the connective is divided into two equal
branches, each of which bears an anther lobe (fig. 216), whilst
in the Sage (fig. 217) the branches of the connective are un-
equal in length; the long one bears a perfect
anther lobe, whilst the short one has an
abortive anther, or one destitute of pollen.

  

Fic. 215.—Stamen of  Fic.216.—Stamenof Fic. 217.—Stamen of Salvia,

Wheat, with versatile Hornbeam (Car#i- with connective branching into
anther, 4, lightly fixed nus Betulus), with two arms of very unequal length,
at the extremity of the branching connec- the right-hand arm bearing an
filament, a. tive. abortive anther.

The anther lobes are hollow, possessing cells or loculi, of
which there is generally one for each lobe, so that the anther is
two-celled or bilocular. In the early stage of its development
there are four cells, two in each lobe; but generally the
partition between the loculi in each anther lobe is absorbed,
producing the bilocular anther. In some plants, as the Flower-
ing Rush, this division never disappears, and the anther remains
four-celled or quadrilocular through life. In some few plants,
as the Mallow and Milkwort, there is but one cell, and the
anther is then said to be unilocula”.

The surface of the anther to which the connective is attached
is known as its back, whilst the other side is called the face.
This is generally grooved, showing the point of attachment
of the lobes. When the face is turned towards the pistil
the stamens are said to be introrse ; when towards the petals,
extrorse,
Pollen 117

Within the anther lobes there are developed the pollen
grains (fig. 218). In the early stages of the growth of the
anthers there are a large number of cells forming the central
part of each lobe. These are the parent or mother cells of the
pollen grains. Each of these, by cell division, becomes divided
into four special parent cells, and in each, by a process known
as free cell formation, a pollen grain is formed. In free cel
formation the protoplasm aggregates around the nucleus of the
mother cell, a cellulose coat is formed around it, and thus for a
while we have a cell within a cell. As the pollen grains grow
the walls of the special mother cells and mother cells generally
become absorbed and disappear, and the grains thus become

 

loose in the cavity of the lobe. Some-
times, however, the wall of the special
parent cells is not quite absorbed, and
there is formed a component body of four
pollen cells united, whilst in the Orchids
the pollen cells of each lobe are completely
united together, forming a pollen mass or
pollinium (fig. 218, v.). Each pollen grain

 

possesses two coats: the inner one, the
intine, is complete; the outer one, the
extine, is pierced by several openings, and
is often variously ornamented by spines,
protuberances, or reticulations (see fig.
218). The protoplasmic contents of the

Fic. 218.—Pollen grains
I. Cucurbita. Il.
Passiflora. Il. Cu-
phea platycentra. IV.

Dipsacus  fullonum.
V. Pollen-masses (pol-
linia) of Cynanchum
Tincetoxicun (Ascle-
piadez).

cell, known as fovilla, contain sulphur and fat globules. In

form the pollen granules are generally round ; in,the Chicory
they are polyhedral ; in the Evening Primrose, triangular; in
the Basella, cubical ; in the Tradescantia, cylindrical ; and in
the Zostera, thread-like.
118 Elementary Botany

In size they vary from gh5 to pJgq Of an inch. Generally
the grains are yellow, in species of Mullein they are red, in
some Willow-herbs blue, black in the Tulip, and in other plants
green or of a whitish colour.

“When the pollen is ripe the anther lobes open to let it fall
out. They open or dehisce in various ways.

1. Longitudinal dehiscence, as in the Pine (fig. 219) or
Tulip, when there is a slit running along the face of the anther
from top to bottom. This is the commonest form.

2. Transverse dehiscence, generally met with in unilocular
anthers, as the Lady’s-mantle.

 

Fic. 222,—Stamen
of Bay (Laurus

: nobilis), with

Fic. 219.—Stamen Fic. 220.—Stamen Fic. 221.—Stamen two glands at the

 

of Pinus sylves- of Barberry, the of Rhododen- base of the fila-
tris, with longi- anther opening dron, each an- ment, the anther
tudinal = dehis- by recurved ther-ldbe opening opening by re-
cence. valves. by a pore. curved valves.

3. Porous dehiscence, openings being produced either at the
apex of the lobe, as in the Rhododendron (fig. 221) ; or in the
side, as in the Heath (fig. 223).

4. Valvular dehiscence, when a portion of the anther lobe
lifts up like a trap-door, as in the Barberry (fig. 220) or Bay
(fig. 222).

Gynecium or PistiL.—Each of the earpels of which the
pistil is made up consists, when complete, of a swollen basal
portion, the ovary ; above this a stalk or style, which is capped
by the stigma. The ovary is a hollow box containing one or
more rounded bodies, the ovules. Generally the carpels of the |
Pistil 119

pistil are united together, either entirely, as in the Lily (fig. 224),
or, as is often the case, the ovaries are united whilst the styles
and stigmas are free, as in the Sea-lavender (fig. 225). In
these cases the pistil is said to -be syncarpous. When the
ovaries are distinct, as in the Buttercup (fig. 165), itis apocarpous

  

Fic. 223.— Stamen ot
Erica, the anther open-
ing by pores and bear- Fic. 224.—Pistil of Fic. 225. — Papillose
ing two appendages at Lily, with ovary, stigma of Statice.
its base. style, and stigma,

(when there is only one carpel to the pistil, as in the case of
the Pea, it is also said to be apocarpous). If there is but one
carpel, the pistil is saidto be monocarpellary. A bicarpellary
pistil has two carpels, a tricarpellary three, a polycarpellary
pistil more than three.

In a syncarpous pistil
we can often tell the num-
ber of carpels present by
the separate stigmas (or
styles) (fig. 225). In other
cases we find on making a
section that the syncarpous
ovary possesses several cells Fic. 226.—Capsule of Fic. 227.—Section of
or loculi, each correspond- Goer s trans: avaly of Viale.
ing with a single carpel, so
that from them we can count the number of carpels (fig. 226).
Sometimes we find that there is but a single loculus in the
ovary, and we can then often tell the number of carpels by

 
120 Elementary Botany

noticing in how many places the ovules are arranged (fig.
227).

In some few cases it is difficult or almost impossible to be
able to say definitely in an individual plant how many carpels
are present. The ovary, as we have seen, may be either zx/erior
or superior. In the former case it is either inserted in the
fleshy end of the flower-stalk, known as the ¢Aalamus or receptacle,
so that the calyx springs from above it; or the calyx tube is
adherent to the wall of the ovary, the free limb springing from
the top. We often find two lines running down the ovary from
apex to base. These are known as the sutures: the one to-
wards the centre of the flower is the ventral suture, whilst the
one turned towards the perianth is the dorsal suture.

 

Fic. 228.—Diagrammatic sections of ovaries: , the placenta, to which the seeds are
attached ; A, monocarpellary unilocular ; B, polycarpellary unilocular ; C, polycarpel-
lary falsely multilocular ; D polycarpellary multilocular ; 7, dorsal suture, or midrib ;
8, ventral suture, or margins of carpel. (After Prantl.)

When the pistil is apocarpous, each ovary contains but one
cell, or is unilocular, although sometimes there are false par-
titions growing partially across the cell.

In syncarpous ovaries there are often numerous cells
agreeing with the numbers of the carpels (fig. 228, D), when
the ovary is bi-, tri-, or multi-locular. In other cases there is
but one cell (fig. 228, B), the ovary being unilocular. Some-
times there are partial dissepiments formed by an infolding of
the edges of the carpels (fig. 228, c). In some few cases there
are actual divisions; thus the ovary of the Labiate and
Boraginacez is originally bilocular, but by a subsequent division
it becomes divided into four cells. The ovules are not, as a
rule, distributed indiscriminately over the surface of the ovary,
but are arranged on certain parts of the wall, each of which is
called a placenta, whilst the arrangement of the ovules is spoken

: ~~oLas_placentation.
Placentation 121

In the case of apocarpous pistils, where there are more
than one ovule, they are generally arranged along the ventral
suture, and the placentation is said to be marginal (figs. 229
and 228, a). In the multilocular syncarpous pistil the ovules
are generally arranged in the central axis, where the cells of the
ovary meet (fig. 228, D), and the placentation is axile.

When the ovary is unilocular the ovules are arranged either
upon the wall (fig. 228, 8), or upon slight projections (fig. 228,
c), and the placentation is parietal.

In some cases of a unilocular ovary, as in the Primrose and
Pink, the ovules are attached to the end of the flower-stalk
which grows up into the ovary (fig. 230). In this case, which

gorrrsemy

Fic. 229.—Marginal placentation.

   

Fic. 230. — Unilocular Fic. 231.—Lateral style Fic. 232. — Basilar
ovary of Hottonia, with of Strawberry. style of <Adche-
free central placenta. milla.

is known as free central placentation, the walls of the ovary
are perfectly free from the ovules, as can be seen by cutting
the pistil of a Pink or Primrose, when the walls can be cut
away, leaving the column of ovules in the centre.

The style, when present, forms a conducting tube from the
stigma to the ovary. In the Violet and Flowering Rush it
consists of a perfectly hollow tube; more often, although
hollow at first, it becomes afterwards filled up by the growth
of ‘conducting tissue,’ so that at the time of fertilisation no
channel is evident. As a rule the style grows from the top of
the ovary, when it is said to be terminal. If it springs out
from the side, as in the Strawberry (fig. 231), it is lateral ; if
from the base, as in the Alchemilla (fig. 232), it is basilar
122 Elementary Botany

Very often the style is absent, in which case the stigma is said
to be sessile upon the ovary.

The stigma is intended to receive the pollen grains, and
hence its presence is necessary in the perfect pistil. It varies
much in appearance. In some cases it is merely an opening
at the top of the style, upon which is secreted some glutinous
fluid. In other cases it is variously enlarged. It is capitate,
or forming a head, in the Primrose and Lily (fig. 224) ; petaloid

in the Iris (fig. 233) ; penicillate, with
a number of hair-like arms, in the Pelli-
tory of the Wall (fig. 234) ; peltate, or
shield-like, in the Poppy (fig. 235).

  

Fic. 233.—Petaloid stigmas Fic. 234.—Pistilof Pavie- Fic. 235.—Peltate stigma
of Jris. taria, with penicillate of Poppy, with hypo-
stigma. gynous stamen.

The ovule, when in a young state, consists simply of a mass
of parenchymatous cells ; these soon become surrounded by
coats, the primine (a7, fig. 236) and the secundine (72, fig. 236).
These coats are not complete, leaving an opening, the micropyle
(fig. 236, m), leading into the interior of the ovule, which is
composed of the original cellular mass forming the nucleus (),
amongst which is one cell, the embryo-sae (ev), larger than the
rest.

The ovule is generally attached to the placenta by a short
stalk, the funiculus (/), but at other times it is sessile upon the
ovary. The point by which the ovule is attached to the
funiculus (or placenta) is the hilum, whilst the point by which
the nucleus is attached to the integuments is the chalaza (¢).
Forms of Ovules 123

There are three forms of ovules, differing in the arrange-
ment of their parts :—

Orthotropous ovule (fig. 236, a). In this case the nucleus
is straight, the chalaza and hilum are in proximity, and the
micropyle is removed to a distance from the funiculus. This
form is rare, being met with in the Rhubarb and its allies in
the natural order Polygonacese. :

Anatropous ovule (fig. 236, 8). In this case the nucleus
is straight, but is inverted upon the funiculus, so that the micro-
pyle is brought down into close proximity with the stalk, whilst
the hilum and chalaza are separated, being united by a pro-
longation of the funiculus known as the raphe. This form is
well seen in the Dandelion and White Water-lily.

 

Fic. 236. Diagrammatic longitudinal sections of ovules: A, orthotropous or straight ;
&, anatropous or inverted; and C, campylotropous or bent ovule. az, outer integu-
ment or primine ; 7Z, inner integument or secundine ; 2, the micropyle; #, the nucleus,
with the embryo-sac, ez ; ¢, the chalaza or base of the nucleus; 7, the funiculus; 7,
the raphe of the anatropal ovule, formed by the fusion of the outer integument and
funiculus. (After Prantl.)

Campylotropous or bent ovule (fig. 236, c). In this case
the nucleus is bent, so that whilst the micropyle is brought near
the funiculus, as in the anatropous form, the chalaza and hilum
are in close proximity as in the orthotropous form, and there is
no need of a raphe. The Wallflower and Mallow are examples
of this kind. These three forms are united by many modifi-
cations.

Thalamus and Dise.—The thalamus, or end of the flower-
stalk upon which the various floral organs are inserted, is often
specially modified. Thus in all plants with a free central
124 Elementary Botany

placentation it is prolonged into the ovary, bearing the ovules.
In other cases, as in the Umbelliferse and Geraniacez, it is
prolonged between the carpels and beyond the ovary, and is
known as the earpophore (see page 139).

In other cases, as in some forms of Lychnis, Pink, and
Passion-flower, it is prolonged beyond the calyx, forming a stalk
for the ovary (fig. 237), and it is
known as the gynophore. In
many plants it is much swollen,
and the ovaries are sunk or em-
bedded in it, often giving them a
syncarpous appearance when they
are truly apocarpous.

We sometimes find between
the calyx and pistil a body or
bodies which are not universal
Bic: ny. = Sesion of Lpcnis Flos’ among flowers, and which cannot

be referred to any of the organs
above described. To this body the name of dise is applied.
In the Mignonette and Orange it forms a fleshy swelling below
the pistil ; in umbelliferous plants it surmounts the ovary, ad-
hering to the styles. In other cases it is variously developed.

Cohesion and Adhesion.—When the similar parts of a flower
are united together in growth, we speak of it as cohesion;

 

  

= Fic. 239.—Floral diagram Fic. 240.-_ Floral
Fic. 238.— —Floral diagram of Potato (Solanacea). diagram of Sweet-
of the Rose. pea.

when dissimilar parts are united, as adhesion. Thus the forma-
tion of a gamosepalous calyx, a gamopetalous corolla, or a
monadelphous stamen would be cohesion ; whilst the growth of
Fertilisation 125

the calyx to the ovary, or the epipetalous or gynandrous arrange-
ment of stamens, would be due to adhesion.

It will often give an idea of how the parts of a flower are
arranged with regard to cohesion and adhesion to make a floral
diagram of it. Figs. 238, 239, and 240 are examples of how
this should be done. In fig. 238 we have in a Rose a poly-
s¢palous polypetalous apocarpous regular flower, whilst in the
Potato (fig. 239) we have a gamopetalous syncarpous flower.
The diagrams show the different way that the petals and carpels
are represented in the two cases. Fig. 240 shows an irregular
flower, as seen in the Sweet-pea.

Fertilisation—In order that the ovary and ovules may
properly perform their functions, it is necessary that they should
be fertilised by the pollen. The
pollen grains adhere to the stigma
(fig. 241, 4), and being nourished
by the viscid secretion present, a
portion of the intine protrudes
either through an opening already
existing in the extine, or forcing
its way through a part where the
outer walls are thinner. The pro-
longation thus formed is known
asa pollen-tube (fig. 242). These
tubes grow down the loose con-
ducting tissue of the style and enter
the ovary.

The time necessary for this

Li
Ve

Ton

 

varies from a few hours to several
weeks. In the Crocus it takes from
twenty-four to seventy-two hours ;
in the Arum over five days, and
in the Orchids even some months.
Just previous to this, or about
the same time, a change has been
going on in the embryo-sac of
the ovule.

Fic. 241. — Longitudinal section
through the uniovular ovary of
Polygonum Convolvulus at the
time of flowering: @, stigma; 4,
pollen grains; ¢, pollen-tube; d,
wall of the ovary gm, the erect
orthotropous ovule ; se, its embryo-
sac ; ch, chalaza: two pollen-tubes
have penetrated through the con-
ducting tissue of the style, one of
which has entered the micropyle of
the ovule, the other not.

Usually one or two cells are produced within the

embryo-sac at the end away from the micropyle. These are
126 Elementary Botany

known as antivodal cells (fig. 243, g), and their function is
unknown. Soon after their formation two nuclei are produced
at the other end of the embryo-sac, round which the protoplasm
becomes aggregated, forming two embryonic or germinal
vesicles or cells (fig. 243, 4). These vesicles appear to be

B
WK

   

Fic. 242.—Pollen grains put-
ting out their pollen-tube ;
a, Dipsacus fullonun ; B,
Cucurbita.

 

Fic. 244.—The process of fertilisation in Gladiolus
segetum. \. The two embryonic vesicles at the
apex of the embryo-sac; x’ x”, the filiform ap-
paratus ; y’y", the balls of protoplasm ready for
fertilisation ; se, the wall of the embryo-sac.
II. A pollen-tube, 74, which has just fertilised

 

Fic. 243.—Upper part of the the two embryonic vesicles in contact with it ;
nucleus of the ovule of Cro- the cell-walls which surround the balls of proto-
cus: p, the embryo-sac with plasm are still very thin. III. A somewhat later
its nucleus, 24; 4, the em- stage ; the cell walls are thicker; the fertilised
bryonic vesicles; g, the vesicle y’ is beginning to develop and to divide
antipodal cells. into two.

membraneless before fertilisation, but on the approach of the
pollen-tube a cellulose coat is formed round each. The pollen-
tube passing into the ovary enters the micropyle of one of the
ovules, and, arriving at the apex of the embryo-sac, comes in
contact with one of the embryonic vesicles, fertilising it by the
passage of the fovilla of the pollen into it by osmosis (figs. 244
Formation of Embryo 127

and 245). The first change that takes place (after the sur-
rounding of the embryonic vesicle by a cellulose coat) is the
division of the vesicle into two (fig. 244, 11, %); the upper
cell being developed into a suspending cord, the suspensor
or pro-embryo (fig. 246, e¢), at the end of which the embryo
or young plant, formed by the division of the lower cell,
is attached (fig. 246, e). At the same time a number of cells
are produced within the embryo-sac by free cell formation ;
these are filled with nutritive materials, and are known as
endosperm. Sometimes nutritive cells are produced within the

 

Fic. 245.—Fertilisation of Canna, I.Apex Fic, 246.— Formation of the embryoof

of the embryo-sac, ¢, at the time when Heliotropium : ed, endosperm ; e?, sus-
the pollen-tube, Zs, has just come into pensor ; ¢, rudiment of the embryo, its
contact with the embryonic vesicle, 2. enveloping membrane being already
II. Fertilised embryonic vesicle sepa- formed; a, cells developed out of the
rated. two embryonic vesicles.

nucleus outside the embryo-sac. In this case the term perisperm
is employed. Very often as the embryo increases in size the
nutritive cells around are absorbed, until, as we have seen is
the case with the Broad Bean, the young plant occupies the
whole of the nuc‘eus, In other cases a part of the endosperm,
128 Elementary Botany

or of the perisperm, or of both, persists, forming the so-called
albumen, so that this latter may consist of endosperm, or of
‘perisperm, or of both.

In the fertilisation of the Fir trees and their allies there is
a modification of this process. In the first place the pollen

   

  

os mee
Ry
SEER eae
Es R77

   

Fic. 247.—Viola tricolor. A, longitudinal section of anatropous ovule after fertilisa-
tion: A/, placenta; w, swelling on the raphe ; aouter, 7, inner integument ; 4, pollen-
tube entering micropyle; ¢, embryo-sac, with the fertilised germinal vesicle at the
micropyle end, and numerous endosperm cells at the other. 3, apex of embryo-sac,
e, with young embryo, eé, of three cells, and one cell forming the suspensor or pro-
embryo. C, same, further advanced. (After Sachs.)

grains divide into two cells before pollination, and the tube,
instead of being formed from the entire grain, is produced by one
of the cells (fig. 249). In the next place the ovules, instead of
being enclosed in an ovary,
are naked (whence the plants
are said to be gymnosperms,
or naked-seeded plants, whilst
other flowering plants are an-
Fic. 248.—Viola tricolor. Posterior part siosperms, or enclosed-seeded
of embryo-sac: ¢, wall; S, cavity of plants), so that the pollen falls
the cell; AK, K, young endosperm cells i :
formed by free cell formation in the direct upon the micropyle (fig.
protoplasm, gr. (After Sachs.) 250)
The embryo-sac soon after pollination is filled with endo-
sperm, which disappears after a short while, and a second
quantity is subsequently formed. In the upper part of this

 
fertilisation of Gymnosperms 129

there are several cells which enlarge and form secondary
embryo-sacs or corpuscula. These split up into two cells, the
upper or neck cell breaking up into several, which form a tube

 

Fic. 249.—Fertilisation of Cupressus sem- Fic. 250.—Fertilisation of Adies
pervirens (Conifere). I. A pollen grain excelsa: p, pollen grains; gs,
with its two cells: a, extine ; 4, intine. pollen-tubes; ¢, two corpuscules
II. Pollen grain in which the pollen-tube, in the embryo-sac, ¢.

¢, has been formed.

or neck leading into the lower cell, which enlarges, forming the
oosphere. The pollen-tube grows down to the oosphere, fer-
tilising it and causing it to break up into a pro-embryo or sus-
pensor, which forces its way through the embryo-sac, and at
the end of which the embryo is produced.

Recent investigations seem to point out that in the fertilisation of
Angiosperms there is a certain
approach to this process as seen
amongst the Gymnosperms. In
‘Nature’ for July 1879 an inte-
resting paper appeared, giving
an account of the researches of
Messrs. Strasburger and Elfving
at Jena. They treated pollen
grains with osmic acid so as to
render the contents more visible,  F¢ amie .of Tulip, a, B; and of

= lowering Rush, c.
and then they grew them arti- :
ficially in sugar solutions. In a number of the cases observed there seemed
to be a breaking up into two or three cells previous to the emission of

K

 
130 Elementary Botany

the tube, which latter was given off from one of the cells (fig. 251), as we
have seen is the case with Gymnosperms. It is a question which requires
further investigation.

As a general rule the pollen is not capable of fertilising the
ovules of the same flower, and hence has to be taken to another,
and the process known as cross-fertilisation is brought about.
The pollen is carried from flower to flower by various means.
The first agency we shall notice is the wind. In the Hazel, for
example, we have a moncecious plant with unisexual flowers.
It is evident that the pollen must be transferred from one flower
to another. The male and female catkins are on the same
plant (fig. 162), the former pendulous with numerous anthers
and a large quantity of pollen, the latter erect with the red
stigmas appearing through the enveloping bracts. When the
pollen is fully ripe it is shed from the anther cells and scattered
by the wind ; the greater portion is wasted, but some falls upon
the stigmas, fertilising them. Such a plant is said to be anemo-
philous, or wind-fertilised. Other examples of anemophilous
plants are to be found in the Oak, the Fir, the Yew, and various
Grasses and Cereals. In all these cases the flowers are small
and inconspicuous and destitute of odour, whilst the pollen is
produced in a far larger quantity than is actually needed for
fertilising purposes. Often in Fir forests the pollen is given off
into the air in such enormous quantities that it is washed down
by the rain as a yellow powder, and is popularly known as
sulphur vain.

More important agents in the fertilisation of flowers are
insects. In all cases of insect-fertilised (entomophilous) plants
the flowers possess either rich and variegated colours, or sweet
odours, or have both qualities. ‘These serve to attract the
insect, whilst in some part of the flower honey is stored up in
anectary. Whilst endeavouring to obtain this the insect comes
into contact with the anther, and the pollen is scattered over
portions of its body, and, being carried away, adheres to the
glutinous stigma of the next flower visited.

The mechanical contrivances and arrangements to ensure
this proper distribution of the pollen are very numerous. In
an elementary book such as this it is only possible to notice-a
few typical forms.
' Cross-fertilisation 131

In many cases it is impossible for the flowers to be self-
fertilised, as either the anthers are ripened before the stigmas,
or the stigmas before the anthers. This is known as dicho-
gamy, and in the former case the flower is protandrous, and
the pollen has to fertilise the pistil of a flower which preceded
it in opening ; whilst in the latter case the flowers are protogy-
nous, and the pollen fertilises a later flower.

A good example of a protandrous plant, and one which at
the same time shows mechanical arrangements for ensuring the
delivery of the pollen upon the right part of the insect’s body,
is to be found in the Sage. Fig. 252 shows in diagrammatic
form the arrangement of the parts in Saluda officinalis. The
corolla is bilabiate, the lower lip forming a convenient resting-
place for the insect to stand upon, whilst the upper lip protects
the stamens and pistil from the rain.

The stamens, two in number, have branched connectives ;
the lower lobes are abortive and united together (4), so that if
either be pushed it affects both
stamens. The upper lobe is full po
of pollen, and is poised upon
the movable connective in such
a manner that if the abortive
lobes are pushed backwards and
upwards the upper ones come
downwards and forwards. In

 

   

i)

Tic. 252.—Sage fertilisation.

the corolla tube honey is secreted. The style and stigmas

at first are placed well back against the upper lip, and are not

matured until after the pollen. When they are matured, how-

ever, the style bends forward (d@), bringing the stigmas near the
K 2
132 Elementary Botany

centre of the mouth. If a bee visits one of the flowers which
has its pollen matured, in order to seek for honey, it will, on enter-
ing the flower and plunging its proboscis into the tube, strike
its head against the lower anther lobes, bringing the fertile
lobes down against its sides, covering its body with pollen ().

If it now visits another flower in the same condition, it will
simply have its stock of pollen increased ; but if it visits a
flower which has its pistil bent over, evidently the stigmas will
strike against the insect’s back, and some of the pollen scattered
there will adhere to the glutinous stigmatic surface.

Other protandrous flowers are met with in the Mallows, the
Geraniums, many Campanulas, the Pinks and other members of
the Caryophyllaceze, many Composite, Umbellifere, and others.

Protogynous flowers are much less common, but they are
met with amongst the Plantains, the Scrophularias, the Mag-
nolias, and other species of plants.

Another arrangement is known under the name of hetero-
stylism, where the pistils and stamens of different flowers are
of various lengths. A good example of a heterostylic flower
is to be found in the common Primrose. If we examine a
bunch of common Primroses we shall find the flowers of two
different kinds. Some have a little knob filling up the mouth
of the corolla tube, and others a rosette. On making a vertical
section of one of each kind of
flower, we find the arrangement
as shown in fig. 253. In the
first case we have the pistil with
a long style (253, 1.), the stigma
of which forms the ‘knob’ filling
up the corolla tube, whilst the
ul Al stamens are placed low down in
Fic. 253.—Dimorphic flower of Pri- the tube. In the other case the

mula, 1. Long-styled, II. Short- ‘ 3
styled form : a, corolla; 4,anthers; stamens are high up, forming the

¢, ring of hairs ; d@, pistil. : "i :
rosette’ (253, 11), whilst the
style is short and the stigma at about the same height as the
stamens in the preceding variety. Such a flower is said to be
dimorphie, and we can speak of the ‘long-styled’ and ‘short-
styled’ varieties of Primrose. There isa slight difference in the

1

   
Fleterostylism 133

pollen and the stigmas in the two cases. The pollen grains of
the short-styled flowers are larger than those of the long-styled
flowers, and the stigma in the latter case is globular, whilst in
the former it is depressed in the centre. A number of careful
experiments by Professor Darwin and others show that long-
styled flowers are fertilised by the pollen from short-styled, and
vice versé the short-styled are fertilised by the pollen from the
long-styled. Such a cross Mr. Darwin calls Zgitimate union,
whilst the term 7/egitimate union is applied to the union of
long-styled pollen with long-styled stigma. ‘This illegitimate
union will not produce seeds to the extent that the legitimate
will, and in some dimorphic flowers none at all are formed.

   

~~. qa

Fic, 254.—Trimorphic forms of Lythrum.

In some species of Lythrum we have trimorphic flowers :
one with long style, six medium stamens, and six short stamens;
one with medium style, six long stamens, and six short stamens ;
and one with short style, six long stamens, and six medium
stamens. In such cases we always find that the long style is
fertilised by the long stamens, the medium style by the medium
stamens, and the short style by the short stamens, as shown by
the lines in the diagram.

Whilst these provisions for cross-fertilisation are the rule
amongst flowers, in some few cases there is a special arrange-
ment for self-fertilisation. The Sweet Violet is a good example.
The well-known flowers that appear in the spring do not,
134. Elementary Botany \

although fertilised by insects, bear fruit. They are followed in
the summer by small inconspicuous apetalous flowers, where the
stamens and pistil are enclosed in a calyx which does not open.
The result is, the flowers are fertilised by their own stamens.
Such flowers are said to be cleistogamous. Besides this there are
other examples where self-fertilisation is specially provided for.

RELATION OF FLOWER TO OTHER PARTS OF THE PLANT.

The parts of the flower must be looked upon as modified
foliar organs. This is pretty evident in the calyx and corolla,
but not so well seen at first in the stamens. We have proof,
however, in the facts, rst, of the tendency in double flowers to
form petals instead of stamens; and and, the gradual transition
from petals to stamens as seen in the white Water-lily, or
Rosa centifolia (fig. 255).

 

Fic. 255. Stages of transition between the petals and stamens of
Rosa centifolia,

In some cases the filament appears to represent the petiole,
the connective the midrib, and the anther the blade, when ihe
pollen would represent the general internal tissue of the leaf.
In other cases the filament appears to be the leaf-blade, and
the anthers and pollen appendages upon it.

We must regard the carpels as leaves (carpellary leaves),
either folded over so that their edges meet, when the dorsal
suture marks the midrib, and the ventral the margin of the
leaves, or, in a unilocular polycarpellary pistil, the carpellary
leaves unite by their margins. The placenta is developed on
the margin of the carpellary leaves, or in the free central placen-
tation on the prolongation of the stem. The ovules are ap-
pendages of the carpellary leaves, or, in the case of the free
central placentation, buds upon the prolonged axis,
135

CHAPTER XI.
FRUIT AND SEED.

AFTER fertilisation a change takes place in the ovary ; it enlarges
and changes very much in appearance, forming the fruit.
Botanically the fruit is the ripened ovary. Many so-called
fruits, however, have in addition to the ovary some other part
of the flower attached. Thus, in the Straw-
berry and Apple, the fleshy edible part is the
enlarged receptacle or thalamus, the pips of
the Strawberry and the core of the Apple
being the true fruits. In these cases the term
pseudocarp is applied. Sometimes the whole
inflorescence will be matured into a single “SZ
fruit-like mass, when the term synearp is Fic. 256.—Multiple
used ; whilst if the bracts or any other part — fyrypocsrp of the
of the floral organs are added in so as to

produce a pseudocarp, as in the Pineapple and Mulberry, the
term pseudosyncarp is employed (fig. 256).

(Care must be taken not to confound the terms syzcarp and
syncarpous pistil or fruit; the latter term being, as we have seen,
restricted to those ovaries and fruits where the carpels are
united together, whilst the former term is used for matured in-
florescences even if the pistil be apocarpous.)

The walls of the ovary consist of three layers : hence in the
fruit we find three layers present—the outer or epicarp, the
middle or mesocarp, and the inner or endocarp. Often these
three layers cannot easily be distinguished from one another ;
at other times they are very evident. The number of cavities
or loculi in the fruit generally corresponds to that in the ovary;
sometimes, however, some of the partitions disappear, so that
the fruit possesses fewer loculi than the ovary.

 
136 Elementary Botany

We may divide fruits into those which are dehiscent or
break, and those which are indehiscent or do not break, when
ripe.

DEHISCENT FRUITS.

When a dehiscent fruit opens so that the seeds fall out, it
is known as a capsule. The dehiscence may take place longi-
tudinally or from top to bottom of the fruit, breaking it into
several valves; it is then said to be valvular. Or it may take
place in a transverse manner, opening off like a lid, when it is

 

Fic. 257.— Capsule of Fic. 258.—Capsule orpyxis  F 1G. 259.—Capsule of Poppy
Primula dehiscing by of Anagallis, with cir- dehiscing by pores beneath
ten teeth, cumscissile dehiscence. the peltate stigma,

described as transverse or circumscissile dehiscence (fig. 258).

Or, lastly, there may be small openings or pores, when the dehis-

cence is porous (fig. 259).

I. ai,

Q\

Fic. 260.—I. Diagram of a loculicidal capsule. II. Diagram of a septicidal capsule.
I. Diagram of a septifragal capsule.

If the longitudinal dehiscence is partial, so as to only take
place at the top of the fruit by means of a number of teeth, it
is dehiscent by teeth (fig. 257).

If the dehiscence is complete, it may either take place by
Dehiscent Fruits 137

the ventral suture, or by the dorsal suture, or by both. Again,
in some cases the walls of the loculi split open, leaving the
septa attached to them, as in the Lily and Iris ; the dehiscence
is then said to be Joculicidal. It is septicidal when the fruit
breaks up into its separate carpels, the dehiscence taking place

 

Fic. 263. — Legume of Pea split
lengthwise: outer, EN inner
layer of the pericarp; L, placenta ;
F, funiculus ; 0, seed.

  

Fic. 262.— Capsule or pyxis Fic. 264.—Fruit of /2Ziciam or Star-
of Plantago, withcircum- Anise, consisting of a number of
scissile dehiscence. follicles.

down the septa themselves, as in the Rhododendron and Col-
chicum ; and it is septifragal when, the carpels opening by their
dorsal sutures, the dissepiments separate from the valves, being
still attached in the centre, as in the Thorn-apple (see figs.
260 and 261).

Some forms of capsules have received special names, A
138 Elementary Botany

pyxis is a capsule dehiscing transversely, as in the Anagallis
(fig. 258) and Plantago (fig. 262).

A legume, or pod, is a unilocular monocarpellary capsule
dehiscing by both dorsal and
4 ventral sutures, as in the Pea
wv? (fig. 263).

A follicle is a monocarpel-
lary capsule dehiscing by ventral
suture (figs. 264 and 265), or,
in some Magnolias, by dorsal
suture, only.

Fic. 265,—Fruit of Peony, consisting of A siliqua isa syncarpous bi-

pap eMneles: carpellary capsule, one-celled,
with a false division or replum
running up the centre. It is
long and narrow in shape, and
the two side walls break away,
leaving the central replum with

 

  

Fic. 267.—Silicula of — Fic. 268.—Cremo-

 

Cochlearia, open and carp ot the Fen-
Fic. 266,—Wallflower (Chetranthus showing the seeds at- nel: a, carpo-
Cheir?). Siliqua. tached to the replum, phore,

the seeds. An example is seen in the fruit of the Wallflower
(fig. 266).

A silicula resembles the last, except that, instead of being
long and narrow, it is short and broad (fig. 267).

When a dehiscent fruit breaks up into several portions which
are usually one-seeded and remain closed, although they do in
some few cases open to allow the seeds to fall out, it is called
a schizocarp, the divisions being called mericarps.

There are also several varieties of schizocarp.
Schigocarps 139

A eremocarp is a bicarpellary schizocarp dehiscing into two
mericarps attached to a central carpophore. Examples are found
in the Fennel (fig. 268) and the other members of the order of
Umbelliferze.

A samara is a winged fruit : in some cases, as in the Maple
(fig. 269), it is a schizocarp breaking up into two one-seeded

 

Fic. 269.—Bipartite schizocarp of Fic. 272.—Quad- Fic. 273. — Tripar-
the Maple, consisting of two ripartite schizo- tite schizocarp of
samare. carp of Ajuga, Tropeolum.

consisting of
four nucules,

   

Fic. 270.—Bract of the Fic. 271.—Lo-

Birch (Betuda), with mentum of Fic. 274.—Quinquepartite schizocarp, of
three samarz in its Hedysarum. Geranium Robertianum. I. The im-
axis. mature pistil. If. ‘The mature fruit.

portions ; in other cases, as in the Birch (fig. 270), it is an
indehiscent fruit.

A lomentum is a schizocarp dehiscing transversely into two
or more one-seeded mericarps, as in the Hedysarum (fig. 271)
and Radish.

A carcerulus is a quadripartite schizocarp, as seen in the
140 Elementary Botany

Bugle (fig. 272) and other labiate plants. Each of the four
divisions is often called a mucule. In other cases the schizo-
carp may be ¢ripartite (divided into
three mericarps) as in the Indian
Cress (fig. 273), guinguepartite (five
mericarps) as in the Geranium (fig,
274), or multipartite (many mericarps)

Fic. 275.—Multipartite schizo as in the Mallow (fig. 275).
carp of JZaiva.

 

INDEHISCENT FRUITS.

The drupe, or stone fruit. In this case the three layers of
the fruit are always distinct. The endocarp is hard, forming
the so-called stone. The epicarp and mesocarp differ in their

Fic. 277.—Longitudinal section of
Coconut : a, epicarp; 4, endo-
carp; c, testa; d, endosperm

   

Fic. 276.—I. Longitudinal section through or albumen; e, embryo; 4
the unilocular drupe of the Peach. II. cavity in the endosperm which
Through the bilocular drupe of Corizs. contains the milk.

consistency. In the Plum, Cherry, and Peach (fig. 276) the
epicarp forms the skin, and the mesocarp the succulent edible
portion. In the Coconut (fig. 277) both epicarp and meso-
carp are dry and fibrous, whilst in the Almond and Walnut
they are leathery. In some few cases, as in the Cornel (fig.
Indehiscent Frutts 141

276, 11), there are two loculi in the drupe, usually there is but
one.
The berry, as seen in the Gooseberry (fig. 278), Grape, or
Currant, has the endocarp soft and succulent as well as the

 

Fic. 278.—Transverse
section through a
Gooseberry ; the
firmer outer layer of

  

the pericarp encloses Fic. 280,—Achene.
the succulent flesh ;

the seeds lie imbed- Fic. 279. — Longitudinal section

ded in the latter, and through an Apple: c, dry persis-

are attached by long tent calyx limb; 8, loculi with

funiculi to two oppo- cartilaginous pericarp; T, meso-

site parietal placenta. carp.

mesocarp, whilst the epicarp forms a skin. In the Gourd and
Cucumber we have a fruit much resembling the true berry, but
the outer layers are firmer and harder ; such a variety of berry

 

Fic. 281. —I. Acorn of Quercus sessiliflora, with two empty cupules. II. Longitu-
ae) section through the fertilised pistillate flower, with the cupule in an early
is known as a pepo. The fruit of the Orange, known as a
hesperidium, is a multilocular berry; whilst in the Apple we
have a berry-like pseudocarp, the fleshy edible portion being
the enlarged thalamus, and the scales above forming the re-
142 Elementary Botany

mains of the calyx, whilst the core is the true fruit. This
variety is known as a pome.

In the achene (fig. 280) all three layers of the fruit are dry ;
whilst if they are lignified, as in the Nut and Acorn (fig. 281),
the term glans is employed.

Sometimes we have several fruits produced from the ripening
of the apocarpous pistil of a single flower, and the name of
eterio is applied.

  
    
    

   
 

or

fee

   

     

|

Fic. 282. —Fruit of Dewberry Fic. 283.—Pseudocarp Fic. 284.—Section of
(Rubus cesius). I. Natural size. of the Strawberry. fruit of Rose.
II. A single drupel.

Thus in the Raspberry, Blackberry, and Dewberry (fig. 282)
we have an eterio of drupes. In the Buttercup and Straw-
berry we have an etzerio of achenes (in the latter case, as we
have seen, the edible portion is the enlarged thalamus).

In the Rose (fig. 284) we have an etzrio of achenes con-
tained within a hollow receptacle, and the whole pseudocarp is
called a eynarrhodum.

THE SEED.

We have already, in Chapter II., described the seed in a
general manner ; there are, however, a few details which it is
necessary to note at this point. Various terms are used to
describe the arrangement of the radicle and cotyledons in the
embryo. When the two cotyledons lie flat upon one another,
and the radicle is placed upon the line which separates them,
as is the case with many cruciferous plants (fig. 285), the em-
bryo is pleurorhizal.

When the cotyledons are flat upon one another, but the
radicle is placed upon the back of one of them (fig. 286), the
embryo is notorhizal. :
Seeds 143

When the two cotyledons are folded upon one another
leaving a hollow channel in which the radicle is placed (fig

  

Fic. 285.—Pleurorhizal embryo of Luxaria. I. Transverse, II. Longitudinal section
through the seed.

Ill.

   

Fic. 286.—Seed of Weslea paniculata, 1. Entire. I1., III. Sections in two different
directions, showing the notorhizal ‘embryo.

 

BGs 287.—Seed of Eruca sativa. 1. Entire. II., Fic. 288.—Spiral embryo of
III. Sections in two different directions, showing Bunias Erucago.
the orthoplozic embryo.

  

Fic. 289. — Peripheric Fic. 290. Peripheric em- — Fic. 2¢1. — Lateral embryo
endosperm surround- bryo surrounding — the of ALlenispermum cana-
ing the central em- central endosperm in dense.
bryo in the Pansy. Alivabilis falapa.

287), the embryo is orthoplozic. When, lastly, the flat coty-
ledons are spirally coiled (fig. 288), the embryo is spiral.
Again, in albuminous seeds, if the embryo is in the centre
144 Elementary Botany

surrounded by the endosperm, as in the Pansy (fig. 289), the
former is said to be central, and the latter peripherie.

The case is just reversed in the AZiradilis Jalapa (fig. 290),
where the peripheric embryo is bent round the central endo-
sperm.

At other times the embryo and albumen are placed more
side by side, when they are said to be lateral.

 

Fic. 292.—I., II., II. Development of the arillus of the Yew. IV. Longitudinal sec-
tion through the ripe seed.

In some plants a peculiar appendage is developed from the
hilum of the ovule after fertilisation, and, growing up round the
seed, forms either a complete coat as in the Yew (fig. 292), a
perforated coat as in the ‘mace’ of the Nutmeg, or hairs as
in the case of the Willow. This is known as the arillus.
145

CHAPTER XII.

THE MOVEMENT OF IVATER IN THE PLANT
TISSUES.

In the tissues of a living plant there is a continual movement
of water, the amount of movement being governed by various
circumstances. This movement may be readily described under
three heads.

1. Slow Movement.—Wherever cells are growing water is
needed to aid their growth. Again, during the process of
assimilation, water is the chief source of the hydrogen which
is required for the formation of the organic materials. Also
water is needed in the reservoirs where the assimilated food is
stored up in order to re-dissolve that food and convey it to the
growing parts. All of these necessities cause a flow of water
towards these parts. This flow, like the growth and assimila-
tion, is slow. It is caused by osmosis, the growing cell ab-
sorbing water from the next, and so on till the source of water
is reached. It takes place in the parenchyma and meristem of
the stem. It is greatest during the spring and early summer—
the time of most rapid growth.

2. Rapid Movement.—In plants which grow entirely under
water the slow movement is the only one which exists. In all
ordinary plants there is, however, another kind of movement
going on due to the transpiration which we have seen takes
place in the leaves. As water thus escapes a fresh supply has
to be obtained, and this passes up entirely through the lignified
cells of the xylem. If the supply is not sufficient to replace
the loss, the leaves droop and wither. This is the reason why a
branch cut from a tree so soon withers, as there is no water to
compensate for evaporation, If such a branch is placed in

L
146 Elementary Botany

water it cannot, as a rule, obtain a sufficiency of the needed
liquid, owing to the fact that cutting the stem in the air acts
upon the cut surface in such a way as to diminish its absorbing
power. If, however, the stem is cut under water, absorption
takes place as usual. That the current does take place through
the wood can be shown—(z) If a ring of bark is cut off
the stem of a growing plant, as long as the wood is uninjured
the leaves will not droop; and (2) if the plant is watered
with some coloured solution it is found to rise in the wood,
staining jt. The amount of the flow of water in the wood de-
pends upon the amount of transpiration. It is greatest in the
summer, when the transpiration is most rapid. At this time
the wood cells and vessels are

} full of air, hence the water

must pass not through the cell

cavities, but in the cell walls.

Trees can be much more
readily transplanted in the
late autumn and winter than
in the summer, because at the
former times they are not
so full of sap as when the
leaves are fully expanded, and
when they are transplanted
at first the roots do not take
up much water.

3.  Root-pressure. — We
may regard both of the move-
ments of water of which we
have been speaking as due to
suction. There is, however, a
third movement which is due
to root-pressure, and which

Fic. 293.—Apparatus for measuring root- depends neither upon growth
pressure, 3

nor evaporation. If the stem

of a plant is cut, and the surface is protected from evaporation,

water is found to ooze out. This is caused by the pressure

of the root, The amount can be measured by means of a

 
Root Pressure 147

manometer (fig. 293). Sometimes this root-pressure causes an
exudation of water in various parts of plants. Examples are
to be seen in many Grasses, Aroids, and Alchemilla, where the

water escapes in drops along the margins and at the tips of the
leaves.

It is especially in spring that this root-pressure is noticeable.
In summer, when active transpiration is going on it is reduced
to a minimum,

L2
148 Elementary Botany

CHAPTER XIIL.
INFLUENCE OF HEAT AND LIGHT UPON GROWTH.

THE various vital phenomena can only be carried on within
a certain range of temperature. There is a minimum below
which and a maximum above which the activity ceases. The
maximum and minimum vary with different plants and for the
different processes of the same plant. Roughly speaking, how-
ever, from 0° C. to 50°C. may be looked upon as the range.
Between the maximum and minimum there is always a tem-
perature, the optimum, at which the vital function is most
active.

Thus, taking the germination of Maize, 9*5° C. is the lowest
temperature at which it is possible ; as the temperature is in-
creased the Maize germinates more readily until the optimum
is reached at 337°C. Beyond this the germination is less
and less active until the maximum is reached at 46°2° C.

Comparing Wheat with this, we find that the minimum of
germination is 5°C., the optimum 28°7°C., and the maximum
aT 7G

The injurious action of high and low temperatures upon
plants depends to a great extent upon the amount of water
present. Dry peas do not lose their power of germination even
if exposed to a temperature of 70°C. for an hour, whilst if wet
a temperature of 54°C. will kill them. In the case of low
temperatures the injury is due to the water being separated from
the protoplasm. Itnever freezes within the cell, but is separated
and forms crystals of ice outside the cell wall. These crystals
often considerably injure the tissues. If afterwards the thaw-
ing is gradual the tissues may recover, but if it is too rapid the
water cannot be reabsorbed, and either rotting ensues, or the
water evaporates and the plant dries up.
Action of Light 149

A curious effect of cold upon some plants is to change the
colour of the chlorophyll. Thus the leaves of Yew, Pine,
Juniper, Box, and other plants turn red or reddish brown under
the influence of cold.

Light also plays an important part in the life and growth of
plants. We may divide the effects of light under two heads.

1. Chemical Action of Light.—This is seen in the formation
of chlorophyll and in the decomposition of the carbon dioxide of
the atmosphere, the assimilation of carbon, and the production
of starch and other organic compounds. These changes can
only take place in the light. A plant grown in perfect darkness
will, as we have seen, be etiolated, and no starch will be formed.
A very slight amount of light—the diffused light at the back
of a room—will be sufficient to produce the green colour ; but
for the production of starch much brighter light is necessary.
Metastasis, that is, the conversion of one kind of organic
material into another (such, for instance, as the conversion of
starch into sugar during the germination of many seeds), can
go on without the aid of light. A plant that contains a large
reservoir of food material will grow, nay even produce flowers
and fruit, in the dark ; losing, however, instead of increasing in
weight. The growth of tubers and bulbs in the dark and the
germination of seeds are cases in point.

2. The Mechanical Action of Light.—Upon the develop-
ment of the internodes of growing shoots light exerts a retard-
ing influence. If a plant, such as a Broad Bean, is grown in
darkness, it is found that not only does it present an etiolated
appearance, but that the internodes are much longer than those
of a corresponding plant grown in the light.

Again, if a plant is grown in a window, so that the sunlight
falls upon only one side of it, very soon the stem will be found
to bend over to the window. Such a bending is known as
heliotropism. It is produced by the retarding influence of the
light upon that side of the plant which is turned towards it.
In some few cases the bending is in exactly the opposite direc-
tion. When the bending is towards the light it is called posi-
tive, and when away from it negative heliotropism.

The mechanical and chemical actions of light are brought
150 Elementary Botany

about by different series of rays. The least refrangible, those
towards the red end of the spectrum, have the greatest chemical
effect ; the most refrangible, those towards the blue end of
the spectrum, possess the greatest retarding influence.

Sachs gives the following table as the result of’ his expeti-
ments upon the amount of carbon dioxide decomposed by the
various rays of the spectrum (that decomposed by the yellow
being reckoned roo) :—

Red . . 4 : i cs 3 ; 25°4
Orange : 3 > . : : 63°0
Yellow : 2 is : : 7 + 100'0
Green . ‘ : c : ; f . 37°2
Blue . 2 r 7 . ; 3 i 22°1
Indigo . . . _ . * . 13°5
Violet . ‘ . 5 . : . 71

If plants are grown surrouhded by glass vessels, in the one
case filled with a solution of potassium bichromate, which only
allows red, orange, and yellow rays to pass through, and in the
other case with a solution of ammoniacal copper oxide, which
only allows gréen, blue, and violet rays to pass, in the former
case no bending takes place, whilst in the latter case the helio-
tropism is as great as in the light.
isi

CHAPTER XIV.
IRRITABILITY OF PLANTS.

Not only is there a movement of plants or parts of plants
during growth, but also certain fully formed organs of plants
are motile, especially under the influence ofan external stimulant.
One of the best known examples is the Sensitive Plant (AZ/mosa
pudica) (fig. 298). The leaves of this remarkable plant are
bipinnate, and are articulated to the stem. The four pinne
and the separate leaflets are also articulated. Spontaneously
at evening, or under the influence of any irritant, the leaflets
fold upwards, whilst the leaf-stalk as a whole bends downwards.
The movement is due to the presence at the base of the stalk
and of each leaflet of a mass of succulent parenchyma—the
pulvinus. The cells are saturated with water, rendering them
turgid. On irritation some of the water escapes into the
intercellular spaces, and the elastic cell walls contract, producing
the movement. When the irritation is removed the sap flows
again into the tissue, causing the return of the leaf to its normal
position.

The movement only takes place between the temperatures
of 15° C. and 40° C. Oxygen appears to be necessary, as under
the exhausted receiver of an air-pump, or in an atmosphere of
hydrogen, nitrogen, or carbonic acid, the leaves of Afimosa
cease to move. Anssthetics, as chloroform, also cause a
cessation of the movements.

The leaves and leaf-hairs of Venus’s Fly-trap (fig. 143)
and Sundew are irritable. When a fly alights upon the surface
of the leaf it causes a bending over of the sides of the leaf to
enclose it.

The stamens of many flowers are irritable. The Barberry
152 Elementary Botany

is a good example. There are six stamens surrounding the
pistil. If one is touched it springs forward towards the ovary.
At the base of the stamens are honey glands ; insects visiting the
flowers in search of honey strike against the stamens, causing
them to fall forward, scattering the pollen over the intruders’
bodies.

In the Centaurea and some other Composite the stamens
contract on touching. Some leaves, although they are not
sensitive to touch, close at the approach of night. The leaflets
of Wood-sorrel fold down, those of Clover fold up. Changes
of ternperature and variation in the amount of light produce
these movements.

The opening and closing of flowers at certain hours of the
day is a phenomenon due to similar causes.
153

CHAPTER XV.
CLASSIFICATION.

UNDER the head of Classification we include the grouping of
plants into classes according to their affinities. There are two
great systems of classification, the Arzjicial, or (as it is often
called) the Linnzean, and the JVatural. In the former case the
plants are arranged simply according to the number, position,
and relation of their stamens and carpels ; in the second case
the general structure and arrangement of the plant as a whole
is taken into account. The result is that although the Artificial
system is a most useful one for the purpose of tracing out a
flower whose name we may wish to discover, yet since it de-
pends solely on the arrangement of one set of organs, it often
separates plants which are evidently closely allied, and on the
other hand unites those which possess no common properties
beyond the structure of their flowers. For these reasons, for the
purposes of classification, ‘the Natural system is now always
employed.

The sub-kingdom of Flowering Plants is divided into two
classes, the Dicotyledons and Monocotyledons, most of the
distinctive characteristics of which we have already noted, and
hence it will only now be necessary to tabulate them as follows.

DICOTYLEDONS. MONOCOTYLEDONS.
Embryo with two cotyledons. Embryo with one cotyledon.
Primary root-growth exorhizal. Primary root-growth endorhizal.
Growth of wood with open Growth of wood with closed bundles,
bundles, exogenous. ; endogenous.

Leaves net-veined. Leaves parallel-veined.

Parts of the flower arranged (as Parts of the flower arranged in
a rule) in fours or fives. threes.

Each of these classes is divided into sub-classes, of which
154. Elementary Botany

there are four in the Dicotyledons, and two in the Monoco-
tyledons.

If we examine four such flowers as the Buttercup, Rose,
Dead-nettle, and Hazel, we shall easily be able to understand
the grouping.

In the first three specimens the flowers are complete ; in the
Hazel incomplete, the calyx and the corolla being absent.
The Hazel stands, then, as a representative of the sub-class
Incomplete.

In the first two specimens the flowers are polypetalous ; in
the Dead-nettle the corolla is gamopetalous. The latter, there-
fore, is an example of the sub-class Corolliflore or Gamopetale.

In the Buttercup the petals and stamens are hypogynous,
which characterises the sub-class Thalamiflore ; whilst in the
Rose they are perigynous (in some members of the group they
are epigynous), and the sub-class is known as the Calyciflore.

We may tabulate these results thus :—

Petals and stamens

4 | hypogynous . THALAMIFLORA

°

2 Complete Polypetalous Petals and stamens

pe ( perigynous or epi-

8 gynous . » CALYCIFLORA

A Gamopetalous . . « « COROLLIFLORE
Incomplete . . ‘ e . . « INCOMPLET&

The Monocotyledons are divided into two sub-classes : the
Petaloide, which, like the Lily or Tulip, possess an evident
perianth ; and the Glumaces, which, like the Grasses, have
their flowers arranged in those peculiar bracts known as glumes.

Each of these sub-classes is divided into several natural
orders ; in this work we shall deal with a few of the principal.

DICOTYLEDONS.

THALAMIFLORA,

Pistil apocarpous. Petals few, stamens many . RANUNCULACEA.
Corolla cruciform, stamens

tetradynamous . » CRUCIFERA,
Leaves opposite, stem

swollen at nodes, sepals

and petals 5. Free

central placenta . . CARYOPHYLLACE.

Pistil syncarpous

»
Classification

CALYCIFLORA.

Flowers papilionaceous, sta-
mens 10, mono- or di-adel-
phous, pistil monocarpellary

Flowers regular, petals 5, sta-
mens and carpels numerous

Flowers arranged in umbels,
petals and stamens epigy-
nous, fruit a cremocarp.

Pistil apocarpous

Pistil syncarpous

COROLLIFLORA,

Flowers compound
Guscapitdan) J ens syngenesious . .
Stem square, leaves opposite,
corolla bilabiate, stamens
didynamous, ovary 4-lobed

; Stamens didynamous, ovary
2-lobed . : F ‘i
Stamens five, ovary 2-lobed,
inflorescence scorpioid ‘
Stamens five. Free central

Flowers simple

placentation . a :

INCOMPLETA,
Flowers not a Calyx present, stamens oppo-
catkins site sepals, ovary I-celled .
Flowers in catkins. Trees or shrubs. ‘ :

MONOCOTYLEDONS.

PETALOIDA.

Flowers irregular, ovary inferior, stamens gynan-

drous. ‘ 7 3 . . ;: :

Flowers regular, ovary superior, 3-celled ; perianth

6 divisions, stamens6 F - . é

Flowers regular, ovary inferior, 3-celled ; perianth

6 divisions, stamens6 . 7 A - -
GLUMACEA.

Stems solid, sheaths of leaves not split, no ligule
present . j : : . e ,
Stem hollow, leaf-sheath split, ligule present ‘

155

LEGUMINOSA,

ROSACEA.

UMBELLIFER.

CoMPOSITA.

LABIATA.
SCROPHULARIACE&,
BORAGINACEA.

PRIMULACEA.

CHENOPODIACEA,
AMENTACEE

ORCHIDACEA.
LILIACEA.

AMARYLLIDACE.

CYPERACE.
GRAMINACEA,
156 Elementary Botany

Each of these orders contains numerous plants, which are
arranged in genera and species. A genus is an assemblage of
plants which resemble one another more closely in general
structure and appearance than they do other species of plants.
Thus, if we examine a Sweet Violet, a Dog-vioiet, and a Pansy,
we find that although they differ in many minor points of
detail, yet there is a great resemblance between them which
causes them all three to be grouped under the genus Mo/a.
By a species we mean an assemblage of individuals which
whilst possessing the characteristics of the genus, possess in
addition distinctive characters which separate them from the
allied plants of the same genus. Thus the points in which the
Sweet Violet, Dog-violet, and Pansy agree would be their
generic characters ; whilst the points in which they differ are
their specific characters. When the seed of a plant is grown it
always reproduces the same species as the parent. In giving
the name of a plant we place the generic name first, followed
by the specific name. Thus the Sweet Violet is Viola odorata,
the Dog-violet Viola-canina, and the Pansy Viola tricolor.

Sometimes the pollen of one species will fertilise the ovule of
a closely allied species, and a plant is thus obtained which com-
bines the properties of both. Such a plant is said to bea Ayédrid.

We will now give a detailed account of the various orders,
in each case mentioning a typical plant that should be carefully
examined and compared with the description of the order.

DICOTYLEDONS.

THALAMIFLORAL ORDERS.
RANUNCULACEAE.

Plant for examination, Buttercup (there are several species
any of them will answer for the purpose).

Note that the plant is an herb (the Clematis is a shrubby
climber ; otherwise the plants of the order are all herbs). If
you have a specimen with leaves on the stem, they are arranged
in an alternate manner (in the Clematis they are opposite)
Often the bases of the leaves sheath around the stem. : Examine
the flower, making a vertical section through one (fig. 165),
Ranunculacee 157

and removing the parts of another. The sepals are five (in
the order they vary from three to six, usually five), inferior.
Corolla usually of five petals (varies in order from three to
fifteen), hypogynous. (In some plants of the order, as Marsh-
marigold (fig. 287) and Anemone, the corolla is absent.)
Stamens numerous, hypogynous; carpels distinct, numerous,
superior (sometimes in the order they are few). Fruit, an
eterio of achenes. Some Ranunculacez have follicles (figs. 265
and 294, 11.). The flowers in the case of the Buttercup are

II.

   

Fic. ‘go4:--Marsh-miatigold (Caltha palustris). 1. Part of plant.

II. Fruit, consisting of follicles.
reguiar ; in other cases, as in the Aconite (fig. 172) and Larkspur
(fig. 202), they are irregu/ar. Plants of this order contain a
watery acrid juice which is often poisonous. They grow in
damp and marshy places, especially in the temperate regions.

Principal Plants of the Order.

Aconitum. The British plant, 4. Mage/%s, the Monkshood,
is easily recognised by its hooded calyx (fig. 172), the petals
being small and developed as nectaries (fig. 203). The plant
is very poisonous : the root has been mistaken for Horse-radish
with fatal results ; it is, however, much more conical in shape.
It is most useful for medicinal purposes.

Adonis, Pheasant’s-eye (fig. 295). Much like the Buttercup,
but the petals are bright scarlet and have no nectaries at the
base.. Flowers in the summer and early autumn in corn-fields.
158 Elementary Botany

Anemone, Wind-flower. No corolla present, the calyx
either coloured as in the Pasc 1e-flower, or white as in the
Wood-anemone. Flowers in tl > spring; several species cul-
tivated in our gardens for their showy colours.

Aguilegia, Columbine, with its five sepals petaloid, and
five petals with spurs twisted up ina horn-like manner. Grown
in gardens.

Caltha, Marsh-marigold (fig. 294). A marsh plant with
large flowers, yellow sepals, and no petals.

(Note, although this and other plants of the order are in-
complete, the corolla being absent, yet we place them in this
thalamifloral order because their general affinities resemble
those of the other plants of the group. The same remark is
true of many incomplete plants of other orders.)

 

Fic. 295.—Pheasant’s-eye (Adonis). I. Longitudinal section through achene.
II, Longitudinal section through flower.

Clematis, Old Man’s Beard, or Traveller’s Joy. A shrubby
climber with opposite leaves. The sepals are petaloid (greenish
white in the British species), and petals absent. Many exotic
Clematis are cultivated for their beautiful flowers.

Delphinium, Larkspur (fig. 202). Flowers with one sepal
spurred. Two petals small and united within the spurred sepal..
Stavesacre is obtained from an exotic Delphinium.

Helleborus, Hellebore. Sepals large and petaloid, petals
small and tubular. The Christmas Rose is an exotic Helle-
borus.

Myosurus, Mousetail. Small clawed petals, and carpels
arranged in a dense cylindrical spike, whence the name.
Crucifere 159

Paonia, Peony. Large showy flowers with deep red petals,
and stamens inserted in a prominent disc.

Ranunculus, Crowfoot or Buttercup. A numerous genus,
the flowers usually yellow, in some few cases white, but all
characterised by the presence of nectaries at the base of the
petals.

CRUCIFERA.

Typical plant, Wallflower (Cheiranthus Cheiri) (fig. 296).
Note, the stem is shrubby below and herbaceous above (the

  

  

 

Fic. 296. — Wallflower Fic. 297.—1. Schizocarps of /satzs tinctoria.
(Chetranthus Cheiri), II. Transverse section of angustisept sili-
Siliquose. Part of cula of Cafsella. III. Transverse section
plant. of latisept silicula, a, of Camedlina ; 6, four

seeds. IV. Lomentum o: Raphanus.

plants of the order are generally herbs, sometimes under-shrubs).
Leaves alternate and exstipulate ; flowers are arranged in a»
raceme; calyx four sepals, saccaze ; corolla four petals, cruci-
form; stamens six in number, tetradynamous (fig. 213) (note,
in cultivation there is always a tendency for the stamens to be-
come the same length); pistil with single ovary and two stigmas;
fruit a séligua. (Besides the siliqua there is also met with in
the order the s7/cula, the lomentum, and an indehiscent fruit
as seen in the Woad, figs. 271 and 297.) This is a large and
160 Elementary Botany

widely distributed order, easily recognised by the cruciform
corolla and tetradynamous stamens. No plant of this order
is poisonous. Many‘are used for food purposes. Many of the
plants contain sulphur and are pungent in taste.

Principal Plants of the Order.

Brassica., A large and important genus. Leaves irregularly
pinnate ; flowers yellow ; fruit a siliqua, often beaked at the end.
Principal species are—B. Sinapis, Mustard ; B. oleracea, which
yields all the varieties of Cabbage, Cauliflower, Broccoli,
Brussels Sprouts, and Savoys; B. Mapus, Rape ; B. campestris,
Swedish Turnip, the seeds of which with some other species
yield colza oil; B. Maga, Turnip.

Capsella (fig. 102), Shepherd’s-purse. One of the com-
monest weeds, and a good example of a silicula-bearing
crucifer. Flowers small, white; fruit a silicula with replum
running across the narrow diameter ee (fig. 297, 11).

Cheiranthus, Wallflower.

Cochlearia. Fruit a silicula with replum running across the
broad diameter (/atiseft) (fig. 297, 1.), so that the fruit is
nearly globose. There are two British species, the Horse-
radish and the Scurvy-grass.

Crambe, Sea-kale. Fruit two-jointed, upper joint with one
seed indehiscent, lower joint forming a stalk above the calyx ;
might be mistaken for a gynophore.

Jberis, Candytuft. Petals unequal, the two exterior petals
larger than the interior ones ; fruit silicula, angustiseptate.

Lsatis, Dyer’s-woad. Small numerous yellow flowers ; fruits
pendulous, flattened, indehiscent. The plant yields a blue dye.

Lepidium, Cress. Numerous small white flowers, petals
equal ; fruit silicula, angustiseptal, one seed in each cell.

Matthiola, Stock. Plants hoary from minute hairs ; large
purple flowers ; fruit a cylindrical siliqua.

Nastevtin. Watercress. Small yellow or white flowers ;
fruit a siliqua, generally somewhat curved. (This must not be
confounded with the garden Nasturtium, which is a Tropzeolum,
belonging to quite a different order.)

Raphanus, Radish, Fruit a lomentum.
Caryophyllacee 161

CARYOPHYLLACEA.

Typical plant, the Greater Stitchwort (Ste//aria Holostea).

Note, the plant is herbaceous ; the leaves are opposite, ex-
stipulate ; in some few genera there are small scarious (scaly)
stipules. The stem is swollen at the nodes. Inflorescence a
dichotomous cyme (fig. 156), usually to be found in the order ;
calyx five separate sepals (in some genera calyx is gamose-
palous) ; corolla five petais notched (this is often met with in
the order, and in many cases the petals are unguiculate, figs.
180, 181, and 195); stamens ten, seldom in the order fewer ;
pistil with syzcarpous ovary, three styles (in the order the number
varies from two to five); free central placentation, very cha-
racteristic of order. A very wide-spread order, found in all parts
of the temperate regions, especially in the Northern Hemisphere.

Principal Plants of the Order.

Cerastium, Mouse-ear Chickweed (fig. 156). A numerous
genus. Flowers with separate sepals, two-cleft petals, five
styles; the fruit often prolonged in a horn-like manner, and
opens by ten valves or teeth.

Dianthus, Pink (fig. 147). Calyx gamosepalous, with two
or more scales (bracts) outside, two styles. There are several
species cultivated, such as the Clove Pink or Carnation, Maiden
Pink, Cheddar Pink, Sweet-william, &c.

Lychnis (fig. 194). Gamosepalous calyx, ebracteate; ovary
with five styles. Several species grow as common weeds, such
as Ragged Robin, Evening Campion, and Corn-cockle.

Silene. Differs from the Lychnis in having three or four
styles. Several species of Campion and Catchfly.

Stellaria. Differs from Cerastium in having three styles,
and capsule opening by six valves or teeth. Several species of
Chickweed and Stitchwort.

We now come to the—
162 Elementary Botany

CALYCIFLORAL ORDERS.

LEGUMINOS&.

Typical plant, Sweet-pea (Lathyrus odoratus, fig. 93.

Note, the plant is herbaceous (in the order there are also
shrubs and trees) ; leaves alternate, stipulate, often compound
and pinnate, as in this case;
calyx gamosepalous, with five
teeth; corolla papiliona-
ceous; stamens ten, diadel-
phous (in several genera they
are monadelphous) ; pistil
monocarpellary ; fruit a le-
gume.

There are three sub-orders
of this important order. All
the British plants, however,
belong to one of these, the
Papilionacez, which is dis-
tinguished by having papilio-
Fic. 298.—Sensitive Plant (Mimosa pudica). NaCeous flowers, and hence

can be easily recognised.

In the other two sub-orders, which are exclusively extra-
European, the flowers are regular, the petals being imbricated
in the Cesalpinea, and valvate in the Mimosee (fig. 298). The
order is a very large one and widely distributed, very varied in
its properties, some of the plants being most useful as food
and fodder plants, others as drugs, whilst others again are
poisonous.

 

Principal British Plants.

Astragalus, Milk Vetch. Leaves imparipinnate ; stamens
diadelphous ; keel of corolla blunt; legume not jointed, but
more or less divided into two cells by a partition. A good
fodder plant.

Genista, Greenweed and Dyer’s-weed. Leaves simple ;
stamens monadelphous; calyx bilabiate. The Dyer’s-weed
(G. tinctoria) yields a yellow dye.
Leguiminose 163

Lathyrus, Peas and Vetchlings. Leaves inparipinnate,
ending in tendrils, with few leaflets, and sagittate or half-sagittate
stipules ; stamens diadelphous, style flattened above. Several
species used as fodder plants. The Sweet-pea (Z. odoratus)
and Everlasting Pea (Z. Jatifolius) are exotic species. The
edible Pea is separated into another genus, Pisum.

Lotus, Bird’s-foot Trefoil. Leaves trifoliate, with large leaf-
like stipules ; stamens diadelphous ; calyx with five equal teeth;
legume imperfectly many-celled. A good fodder plant.

Medicago, Medick or Lucerne. Leaves trifoliate ; stamens
diadelphous ; legume more or less spirally twisted (fig. 299),

  

Fic. 299.—Twisted legume of Fic. 300.—Abbreviated inflorescence of

Lucerne (Medicago sativa). ‘lover.
sickle-shaped, indehiscent. Much cultivated as a fodder plant,
especially JZ. sativa, the Lucerne.

Melilotus, Melilot. Leaves trifoliate ; flowers in long loose
racemes ; stamens diadelphous ; legumes with one or very few
seeds, longer than the calyx. Fodder plants.

Onobrychis, Sainfoin. Leaves imparipinnate; stamens di-
adelphous ; legume flat, hard, one-seeded, and indehiscent. A
valuable fodder plant.

Sarothamnus, Broom. Leaves trifoliate, three digitate
leaflets ; stamens monadelphous ; calyx campanulate, with two
lips, minutely toothed ; legume flat, many-seeded.

Trifolium, Trefoil or Clover. Leaves trifoliate; flowers in

abbreviated heads (fig. 300); stamens diadelphous ; legume few
M 2
164 Elementary Botany

seeds, concealed within calyx and often indehiscent. Many
species are very largely cultivated as fodder plants.

Ulex, Furze. Leaves simple and acerose; two sepals;
stamens monadelphous.

Vicia, Vetch and Tares. Leaves imparipinnate, ending in
tendrils and with many leaflets; stamens diadelphous ; style
thread-like. Very useful fodder plants. One exotic species,
V. Faba, gives us the Broad Bean.

The following are important exotic plants belonging to this
sub-order :—Used for food purposes: Arachis, Ground-nuts ;
Lroum, Lentils; Phaseolus vulgaris, the French Bean; and
L£. coccineus, the Scarlet Runner ; Pisum, Pea. Used for various
purposes: Balsam of Tolu, Indigo, Kino, Laburnum, Liquorice,
Ordeal Bean, Rosewood, Tonquin Bean.

The following important plants belong to the other two
sub-orders :—Braziletto-wood, Cassia, Copal, Copaiba Balsam,
Locust-tree, Logwood, Sandal-wood, Sanders-wood, Sensitive
Plant, Tamarind.

ROSACEE,

Typical plant, Bramble (Audus fruticosus) ; also compare
with it Blackthorn or Sloe, Rose, and Apple.

Note, the plant is a sud (in the order there are also herbs
and trees) ; leaves alternate, stipules present, adhering to the
petiole (stipules are seldom absent in the
order) ; calyx gamosepalous, five divisions,
inferior (there may be but four divisions to
the calyx—in the Rose it forms a cup-like
tube enclosing the carpels [fig. 196], and in
the Apple and Pear it is adherent to the
carpels, figs. 301 and 279); corolla poly-
petalous, five petals, perigynous (in a few
cases there are four petals, and in some cases
tet ae none); stamens numerous, perigynous ;

section through the Carpels numerous (in the Blackthorn there
flower of the Pear. : é i

is but one), apocarpous ; fruit an eterio of

drupes. (In the order the fruit is very various. Thus it

may be. a single drupe, Blackthorn; eterio of achenes, Straw-

 
Rosacee 165

berry ; cynarrhodum, Rose ; follicles, Meadow-sweet ; or pome,
Apple.)

This large and important order is widely distributed, espe-
cially in the temperate regions. Many of the plants very much
resemble those of the Ranunculacez, but a careful examination
will show the great distinction from that order in the perigynous
stamens and petals.

The Rosacez are divided into four sub-orders :—

1. DRUPACEZ or AMYGDALE#. Trees or shrubs with
simple leaves ; fruit a drupe. Many parts of the plants con-
tain hydrocyanic or prussic acid.

Prunus is the only British genus of this sub-order. It has
the nut of the drupe smooth or slightly seamed. The native
species include the Sloe, Wild Plum, and Cherry. Amongst
exotic species of the same genus which are largely cultivated
are the Apricot, Cherry Laurel, and Portuguese Laurel.

Amygdalus is the exotic genus which yields us Almonds,
both bitter and sweet, Peaches, and Nectarines.

2. RosE&. Shrubs or herbs; stipules adherent ; ovaries
one or more, not adherent to calyx ; fruit eteerio or follicles.

Principal British Plants.

Agrimonia, Agrimony. Flowers in loose spikes; calyx
five-cleft, top-shaped, with hooked bristles ; stamens not more
than fifteen; carpels two. The plant was formerly used by
herbalists.

Fragaria, Strawberry. Calyx ten-cleft, in two rows ; fruit
an eterio of achenes on an enlarged and fleshy receptacle.

Potentilla differs from the Strawberry principally in the fruit
being on a dry receptacle ; P. Zormentifia has but four petals.

Rosa. Calyx urn-shaped ; fruita cynarrhodum. There are
several species of wild Roses and Briars, from which many
of our cultivated Roses are obtained ; others come from exotic
- species.

Rubus, Bramble. Calyx five-cleft ; fruit eteerio of drupes.
The genus includes the Raspberry, Blackberry, Dewberry, ang
Cloudberry,
166 Elementary Botany

Spirea. Calyx five-cleft ; fruit three to twelve follicles.
Several species of Meadow-sweet. Some of the exotic plants
are cultivated for their flowers.

3. SANGUISORBE&. Herbs or under-shrubs ; flowers often
unisexual ; petals absent (fig. 302); carpel solitary ; fruit an
achene (fig. 302, 11.).

 

iN

Fic. 302.—Sanguisorba officinalis. 1. Flower. I. Fruit

British Plants.

Alchemilla. Calyx eight-cleft, in two rows ; stamens one
to four. The species of Lady’s-mantle and Parsley Piert are
used as fodder plants.

Poterium, Salad Burnet. Calyx four-cleft, petaloid ; flowers
unisexual ; stamens numerous. A good salad plant.

Sanguisorba, Great Burnet. Calyx four-cleft, petaloid ;
stamens four. Grown in Germany as a fodder plant.

4. Pome. Trees or shrubs ; carpels one to five, adhering
more or less to one another, and sunk in the receptacle, thus
becoming inferior ; fruit a pome.

British Plants.

Crategus, May or Hawthorn. Fruit hard or bony; calyx
divisions sharp.

Mespilus, Medlar. Differs from the May in its larger flowers
and foliaceous calyx divisions.

Lyrus. Calyx divisions small; fruit fleshy. Its species
include the Apple, Pear, Rowan-tree or Mountain Ash, and
Umbellifere 167

Wild Service-tree. The exotic genus Cydonéa yields us the
Quince.

From many of the plants of this sub-order also prussic acid
is obtainable.

UMBELLIFERA,

Typical plant, Cow-parsnip (Heracleum Sphondylium).

Note, the stem is herbaceous, Zo//ow, except at the nodes ;
leaves alternate, sheathing at base, bi- or tri-pinnate (leaves in
the order are generally much divided) ; flowers in compound
umbels (in Aydrocotyle the umbels are simple, in Sanicuda and
Evyngium the flowers are arranged in tufted heads); calyx
adherent to ovary, free limb absent, or as five small teeth ;
corolla polypetalous, five petals, epigynous; stamens five,
epigynous ; pistil zxferior,
two cells, two styles ; fruit a
cremocarp.

This is a very large and
wide-spread order, easily
recognisable by its umbel-
late flowers and two-celled
ovary with cremocarp. The
plants of the order are,
however, very difficult to
identify, as the distinctions
of the genera and species
depend principally upon
small points of detail in the
structure of the seed and
the fruit.
ord a ee scious, igs" Hk Fete iit Seton a
some members yield us food plants, others are very poisonous ;
and again others yield useful drugs.

 

Principal British Plants.

Angelica. Fruit two flattened carpels united by their faces,
with three sharp ridges at the back of each, and two at the
168 Elementary Botany

side expanding out. The leaf-stalks are used candied as sweet-
meats.

:thusa, Fool'’s-parsley (fig. 303). Fruit nearly globose ;
no general bracts, but three partial bracts to each secondary
umbel, which hang down (figs. 303 and 151). A very poison-
ous plant, liable to be mistaken for true Parsley ; distinguished
by its bracts.

Apium, Celery. Fruit roundish egg-shaped, the carpels
flattened and united by the narrow edge, five slender ridges
on each; no bracts. In the wild state poisonous; when
blanched by etiolation, fit for eating.

Bunium, Earth-nut. Oblong fruit of flattened carpels united
by narrow edge with five blunt ridges; no general involucre,
but a slight partial one. The tuberous root is esculent.

Carum, Caraway. Oblong fruit of flattened carpels united
by narrow edge with five slight ridges; no bracts, or at most
but one general bract. Roots and leaves are edible, and fruit
used under the name of Caraway-seed.

Cherophyllum, Chervil. Fruit contracted at sides, with
short beak, five blunt ridges on each carpel; several partial
bracts. Formerly cultivated as a culinary herb.

Cicuta, Water-hemlock. Fruit of two globose carpels
united by narrow edge with five
broad flattened ridges. A most
virulent poison.

Conium, Hemlock. Fruit
egg-shaped, with five wavy
ridges on each lobe. Plant
emits, when bruised, a nause-
ous ‘mousy’ smell. A most

Fic 304.—I. Fruit of Coriander (Corian. poisonous plant, useful medi-

drum sativum). II. Transverse 5
section. cinally.

 

Coriandrum, Coriander.
Fruit globose (fig. 304), scarcely prominent ribs, very aromatic.
Fruit used under name of Coriander seed.
Crithmum, Samphire. Leaves succulent; fruit elliptical,
with spongy lobes, The plant is edible, being used as a
pickle,
Umbellifere 169

Daucus, Carrot. Fruit slightly flattened, prickly (fig. 305),
there being rows of prickles between the bristly ridges. The
root is edible, forming the cultivated Carrot.

Eryngium, Sea-holly. Flowers in dense prickly heads.

Feniculum, Fennel. Fruit
elliptical (fig. 268), carpels with
five bluntly keeled ridges. Leaves
much divided. Plant esculent.

flelosciadium, Marshwort,
or Fool’s Watercress. Plant
much resembling Watercress,
but leaves more pointed and
serrate. No general bracts, five
partial. Very poisonous, hence
importance of distinguishing it Fic. 305.—I._ Fruit of Carrot (Daucus

 

Carota). II. Transverse section: the
from Watercress. four secondary ridges are conspicuous ;
Fleracleum, Cow-parsnip. of the primary ridges the two lateral

ones are scarcely visible, the median
Very common weed. Flowers (carina) and intermediate ones are

white, the outer petals of umbel *””
larger than the inner ones, else very like the true Parsnip.
Might be used as an esculent herb.

Lffydrocotyle, White-rot. A marsh plant with simple umbels
and peltate leaves.

Ligusticum, Lovage. Fruit elliptical, not flattened, the five
ridges to each lobe sharp and winged. Used as a vegetable
in many parts.

Myrrhis, Sweet Cicely. Very aromatic; fruit large, with
deep furrows between carpels, and five sharply keeled ridges.
Potherb.

@inanthe, Water-dropwort. Fruit egg-shaped, with five
blunt ridges ; petals notched. Very poisonous plant.

Pastinaca, Parsnip. Fruit very flat, with broad border ;
flowers yellow, all small. Root edible.

Petroselinum, Parsley. Fruit very much like Celery;
numerous partial bracts. Esculent plant.

Pimpinella, Burnet Saxifrage. Fruit much like Celery, but
ribs less prominent. Aniseed is obtained from an exotic species
of this genus,
170 Elementary Botany

Sanicula, Sanicle. Flowers in tufted heads, imperfect, the
outer pistillate, inner staminate. Was formerly supposed to
possess healing qualities.

The following exotic plants belong to this important order:—
Anethum, Dill; Anthriscus, Chervil; Cuminum, Cummin ;
Dorema, which yields gum ammoniacum ; féruéa, yields asa-
foetida ; and Ofoponax, yielding the gum resin of that name.

COROLLIFLORAL ORDERS.

COMPOSIT.

Typical plant, Dandelion (Zaraxacum dens-leonts); also
compare with it a Daisy.

Note, the plant is herbaceous (some exotic Composite are
shrubby) ; leaves exstipulate ; flowers arranged in a capitulum,
surrounded by an involucre of bracts ; calyx superior, a pappus
(note, the pappus absent in the Daisy) ; corolla gamopetalous,
epigynous, ligulate (note, in the Daisy the florets of the disc
have tubular corollas, whilst those of the ray have ligulate
corollas), jive teeth; andrcecium five stamens, epipetalous,
syngenesious ; pistil syncarpous, single style, and bifid stigma.

The plants of this order are easily recognised by their
flowers being arranged in capitula with syngenesious stamens,
the latter characteristic distinguishing them from the allied
Teasel family.

It is the largest of all natural orders, containing one-tenth
of the known plants of the world. The members of the group
differ much in their properties and uses.

The British plants are divided into two sub-orders :—

TUBULIFLOR#, which have all their florets (as the Corn Blue-
bottle), or inner ones only (as Daisy), tubular.

LIGULIFLOR# have all their florets ligulate (as Dandelion).

Principal British Plants.

TUBULIFLORE.

Anthemis, Chamomile. Flowers arranged on a convex re-
ceptacle, with tubular perfect florets in disc, and ligulate pistillate
Composite 17I

flowers in ray ; the receptacle has scales between the flowers.
Used medicinally.

Arctium, Burdock. All flowers tubular, perfect, and in a
convex head ; a globose involucre present, with hooked points to
the bracts ; pappus short. Various parts of this plant may be
eaten, either as a salad or cooked (fig. 146).

Artemisia, Wormwood. All flowers tubular, perfect, in a
flat head ; no pappus; only few flowers in the head. A very
bitter plant, used in the manufacture of absinthe.

Bellis, Daisy. Flowers as in Anthemis, but without scales
on receptacle ; involucre of two rows of equal bracts.

Carduus, Thistle. All florets tubular, perfect, in a convex
head ; involucre swollen below, with thorn-like scales.

  

Fic. 306.—Common receptacle Fic. 307.—Neuter flower
of Anthemis arvensis, with of Centaurea Cy-
palez between the flowers. anus.

Centaurea, Knapweed and Bluebottle. Florets tubular,
inner perfect, outer large and neuter, somewhat irregular (figs.
182 and 307).

Chrysanthemum. Disc florets tubular and perfect, ray
florets ligulate and pistillate ; involucre flat ; receptacle naked,
and no pappus.

Jnula, Elecampane. Disc florets tubular and perfect, ray
ligulate, all yellow ; pappus present ; many-rowed involucre.
Formerly used as a sweetmeat.

Senecio, Ragwort and Groundsel. Disc florets tubular and
perfect, ray ligulate and pistillate (latter wanting in Groundsel),
all yellow ; simple pappus ; scales outside the involucre.

Tussilago, Coltsfoot. Flowers appear in spring before the
leaves ; flower-stalks covered with scale-like bracts ; few disc
172 Elementary Botany

florets, tubular, perfect; many narrow ray florets, ligulate,
pistillate ; all yellow. Often used as a remedy for colds and
coughs.

LIGULIFLOR&.

Cichorium, Chicory. Flowers blue, sessile, upon tough
stems; involucre of two rows. It is the root which is used to
mix with coffee.

Lactuca, Lettuce. Few florets, with hairy pappus and oblong
imbricated involucre. The garden Lettuce is an exotic species
of this genus.

Taraxacum, Dandelion. Lyrate leaves, radical; flower-
stalk hollow, leafless ; outermost bracts of the involucre re-
curved ; receptacle dotted. The young plant forms a good
salad, and is often used by herbalists as a tea.

The following exotic genera yield important plants :—
Arnica, used medicinally in case of bruises; Calendula,
Marigold, also used as an external remedy for cuts, and to
adulterate saffron ; Carthamus, Safflower, or Bastard Saffron,
often used instead of true Saffron to yield the pink dye ; Cyzara,
Artichoke ; Helanthus, Jerusalem Artichoke and Sunflower.

LABIATA.

Typical plant, White Dead-nettle (Zamium album, fig. 158).

Note, the plant is herbaceous ; stem square ; leaves oppo-
site ; flowers in verticillasters ; calyx inferior, five-toothed (it
may be ten-toothed in the order) ; corolla (figs. 308 and 191)
bilabiate, ringent (in some cases the corolla is almost regular,
fig. 309); stamens didynamous, epipetalous, fig. 214 (in the
Sage there are only two stamens with branched connective, fig.
217; andinthe Mint the four stamens are equal, fig. 302) ;
pistil superior, four-lobed ; fruit a carcerulus (fig. 272).

The four-lobed ovary is a most important point, as it dis-
tinguishes the order from the next, where there are only two
lobes. No plant of the order is poisonous. Many contain
aromatic essential oils, and are used for flavours and perfumes,
It is chiefly distributed in temperate regions,
Labiate 173

Principal British Plants.

Calamintha, Wild Basil and Basil Thyme. Calyx with
thirteen nerves upon it; corolla longer than calyx, lower lip
with three broad lobes ; outer stamens longest, but not diver-
ging from inner ones.

Lamium, Dead-nettle. Calyx ten ribs and five teeth ;
corolla with upper lip arched, lower lip with large middle
lobe, two side ones small.

Marrubium, White Horehound. Stamens shorter than the
tube of the corolla; calyx with five or ten teeth and ribs ;
upper lip of corolla deeply notched. Used as a remedy for
coughs.

  

Fic. 309.—Nearly regular flower
Fic. 308.—Lamium album. Longi- of Peppermint (Mentha pipe-
tudinal section of flower. vita).

Mentha, Mint. Corolla nearly regular ; stamens four, equal.
There are many species used as flavours and odours ; principal
are Spear-mint, Peppermint, and Pennyroyal.

Origanum, Marjoram. Flower in panicles or corymbs ; a
bract under each flower. Used as a potherb.

Salvia, Sage or Clary. Two stamens with branched con-
nectives.

Teucrium, Germander. Upper lip of corolla apparently
wanting, but appearing as two small teeth, one on each side of
the lower lip. :

Thymus, Thyme. Calyx bilabiate, upper lip three-toothed,
174 Elementary Botany

!

lower two-toothed ; corolla with upper lip flat and erect, lower
spreading ; outer stamens diverging from the inner ones.
Amongst exotic genera we have Hyssopus, Hyssop ;
Lavandula, Lavender ; Melissa, Balm ; Ocymum, Basil ; Pogo-
stemon, Patchouly ; Rosmarinus, Rosemary ; Satureia, Savory.

SCROPHULARIACEA.

Typical plant, Great Snapdragon (Antirrhinum majus, fig.
145).

Note, the plant is herbaceous ; leaves opposite (rarely alter-
nate) ; corolla bilabiate, personate, fig. 192 (it may be almost
regular, as in the Foxglove, fig. 310;
or ringent, as in the Scrophularia) ;
stamens epipetalous, didynamous
(only two in Veronica, and five in
Mullein) ;  pistil superior, two-
lobed ; dumb-bell-shaped placenta
(fig. 311).

It is most important to note the
two-lobed ovary, which distinguishes
this order from the last, as many

  

Fic. 310.—Flower of Foxglove Fic. 311.— Bilocular ovary of Antirrhinum,
(Digitalis purpurea), with axile placenta.

plants of the Scrophulariaceze are poisonous. Distributed all
over the world.

Principal British Plants.

Antirrhinum, Snapdragon. Corolla personate, not spurred,
but with a protuberance at base.
Digitalis, Foxglove. Corolla irregularly bell-shaped ; leaves
alternate. Very poisonous ; used medicinally.
' Euphrasia, Eyebright. Calyx four-cleft ; corolla ringent,
upper lip two-lobed, spreading.
Boraginace@ 175

Linaria, Toadflax. Differs from Snapdragon in having
spurred corolla.

Melampyrum, Cow-wheat. Calyx four-cleft ; corolla rin-
gent, upper lip compressed laterally.

Lhinanthus, Rattle. Differs from the last in having the
calyx much swollen, with four small teeth.

Scrophularia, Figwort. Calyx five-lobed ; corolla ringent,
nearly globose ; flowers small. Poisonous.

Verbascum, Mullein. Corolla rotate, five-lobed; five stamens.

Veronica, Speedwell. Corolla rotate, four-lobed; two
stamens.

BORAGINACE:.

Typical plant, Forget-me-not (JZyosotis palustris, fig. 157).

Note, plant herbaceous (in many Boraginacez the herbage
is very coarse and rough with numerous hairs—hispid) ; leaves
alternate ; flowers in a scorpioid cyme ; calyx inferior, gamo-
sepalous, five-lobed; corolla regular, gamopetalous, five-
lobed, the throat closed by five short notched scales (in some
Boraginaceze the corolla is almost irregular, and in some cases
the scales are absent); stamens five, epipetalous ; pistil
superior, four-lobed, composed of two carpels, each divided by
its dorsal suture being bent inwards ; style gynobasie—that is,
growing up between the four ovaries and looking as though it
were a prolongation of the thalamus.

The plants of the order are chiefly natives of the temperate
regions of the Northern Hemisphere.

Principal British Genera.

Anchusa, Alkanet. Corolla funnel-shaped with a straight
tube, the throat closed by five blunt white scales, An exotic
species, cultivated in S. Europe, has a dark blood-red root,
which is chiefly employed to colour oils for perfumery and other
purposes.

Borago, Borage. A very coarse hispid herb ; corolla rotate,
with five broad notched scales (figs. 188 and 198). It contains
nitrate of potash, which gives coolness to beverages in which
it is steeped, hence is used in claret cup.
176 Elementary Botany

Echium, Viper’s Bugloss. A very coarse hispid herb ;
corolla unequally five-lobed, the throat naked; stamens much
protracted.

Myosotis, Forget-me-not and Scorpion-grass. Corolla small
and rotate, the throat closed by five short notched scales.

Symphytum, Comfrey. Coarse herb; stem more or less
winged by the decurrent leaves (fig. 142) ; corolla campanulate,
with five awl-shaped scales. The young leaves and shoots are
sometimes eaten as a vegetable.

PRIMULACE:.

Typical plant, Common Primrose (Primula vulgaris).

Note, an herb with radical leaves (many plants of the order,
however, possess cauline leaves) ; flowers regular ; calyx gamo-
sepalous, inferior, five-cleft ; corolla gamopetalous, five-cleft ;
stamens five, epipetalous, OPPOSITE THE COROLLA LOBES (the
flowers being dimorphic, the stamens are sometimes inserted
just in the throat of the corolla, sometimes some little distance
down the tube) ; ovary one-celled; free central placentation,
single style ; stigma capitate.

The plants grow mostly in the north temperate zone, espe-
cially in mountainous districts.

Principal British Genera.

Anagallis, Pimpernel (fig. 138). Calyx split to the base ;
corolla rotate ; hairy stamens; capsule dehiscing transversely
(fig. 258).

Cyclamen, Sow-bread. Calyx split halfway down ; corolla
rotate, with reflexed segments ; capsule dehiscing by five teeth.

flottonia, Water-violet. A water plant with submerged
divided leaves; calyx divided almost to the base; corolla
salver-shaped ; capsule dehiscing by five teeth.

Lysimachia, Loosestrife, Yellow Pimpernel, Moneywort,
Creeping Jenny, &c. Calyx divided to the base ; corolla rotate ;
stamens without hairs ; capsule dehiscing by valves.

Primula, Primrose, Cowslip, Oxlip. Calyx tubular, five-
cleft ; corolla salver-shaped or funnel-shaped.
Chenopodiacee 177

INCOMPLETAZ.

CHENOPODIACE.

Typical plant, White Goosefoot (Chenopodium album).

Note, plant herbaceous (some plants are somewhat shrubby),
succulent ; leaves alternate (often in the order very succulent) ;
flowers inconspicuous (in many plants of the order we have
separate staminate and pistillate flowers) ; calyx inferior, five-
lobed (in the order it is from two- to five-lobed, usually five),
persistent (often in the order it very much enlarges as it
surrounds the fruit) ; corolla absent ; stamens five, opposite the
sepals (rarely in order one or two) ; pistil superior, syncarpous ;
two or three sty/es.

This order is widely distributed, the plants growing especially
in salt marshes. Many of the plants are esculent, others were
formerly much employed in the manufacture of soda, which was
obtained from their ashes, known as Jarvil/a.

Principal British Genera.

Atriplex, Orache and Purslane. Flowers generally uni-
sexual ; perianth five-cleft in staminate and two-cleft in pis-
tillate flowers, very much enlarged round fruit, which is one-
seeded. Several species of common weeds.

Beta, Beet. Fruit one-seeded, immersed in succulent base
of calyx ; three small bracts beneath the calyx. Edible ; much
cultivated for manufacturing sugar. Mangel-wurzel is a variety
of the Beet.

Chenopodium. Flowers differ from above in having no
bracts, and the perianth not becoming fleshy on fruiting.
There are several species. C. album is the commonest, a
plant which overruns gardens and grows on waste places. It
may be used as a potherb. C. Bonus-Henricus, Good King
Harry, or All-good, is also edible. Spinacea oleracea, Spinach,
is an exotic genus with four styles cultivated for food purposes.
178 Elementary Botany

AMENTACEZ.

Typical plant, Common Hazel (Corylus Avellana, fig. 162).

Note, the plant is a shrub or small tree (trees and shrubs
are met with in the order); leaves alternate; flowers in
catkins, monecious (in many plants of the order, as the
Willow, the flowers are dicecious) ; staminate catkins pendulous ;
numerous wedge-shaped bracts; no perianth; eight stamens
attached to each bract, fig. 312 (in the order the number of
stamens present varies from two upwards, and a slight perianth
is sometimes present) ; pistillate inflorescence a bud-like catkin

 

Fic. 312.—The Hazel (Corylus Avellana). I. Maleflower. II. Female flower.
II. Fruit with laciniated spurious cupule.

with two flowers within surrounded by numerous bracts, each
flower consisting of a two-celled ovary with two red stigmas (in
the order the pistillate catkins are either pendulous like the
staminate, with one, two, or three flowers on each scale-like
bract, or in a bud-like head with two or three flowers in the
centre) ; fruit a one-seeded nut (in some plants of the order a
capsule). This isan important and extensive family, distributed
all over the globe, especially in temperate regions, and yields a
large number of timber trees as well as esculent plants.

It is divided into several sub-orders, four of which are
represented in this country, viz. :—
Amentacee 179

SALICINEH. Generally dicecious ; pistillate flowers in cat-
kins ; fruit a capsule.

BETULINEZ. Flowers generally moncecious; pistillate
flowers in catkins ; fruit a flat nut.

Myricea. Flowers generally dioecious ; pistillate flowers
in catkins ; fruit a false drupe from the scaly bracts becoming
fleshy.

CUPULIFER. Pistillate flowers in tufts or spikes ; bracts
grow up around fruit to form a cup or cupule (figs. 281 and
312).

Principal British Plants.
SALICINEA.

Populus, Poplar. Stamens eight to thirty ; stigmas deeply
forked, slight ; perianth present. Several species grown as
ornamental and timber trees.

Salix, Willow and Osier. Stamens one to five; stigmas
slightly forked ; no perianth present. Very numerous species,

BETULINEA.

Alnus, Alder. Fruit not winged ; two flowers on each
pistillate bract. The wood is very durable and yields good
charcoal.

Betula, Birch. Fruit winged, three in each bract (fig. 270).
The timber is utilised, and from the sap Birch wine, which is
used medicinally, is obtained.

MYRICEA,

Myrica, Sweet-gale. Dicecious ; four to eight stamens, two
stigmas.

CUPULIFERE.

Carpinus, Hornbeam. Stamens twelve to each scale ;
pistillate catkins slender and loose; a three-lobed scale
(perianth ?) to each pistil, which enlarges with the fruit (fig.
313). Used for timber.

Corylus, Hazel. Stamens eight to each scale ; two pink
stigmas to each ovary; fruit a nut inaleafyinvolucre. Filberts,

Cobs, and Barcelona nuts are varieties of Hazel.
N 2
180 Elementary Botany

Fagus, Beech. Staminate flowers in a globose catkin ;
stamens five to fifteen; fruit two three-cornered nuts in a
prickly involucre. The wood yields
good charcoal.

Quercus, Oak. Stamens five to
ten; staminate flowers in a long
drooping catkin ; fruit surrounded
with a cup-shaped involucre. The
timber is most valuable for many
purposes. Cork is the outer bark of
Q. suber. Oak-galls and Oak-apples
are also obtained from various spe-
cies, whilst the bark is often used for
tanning.

Fic. 313.—Fruit of the Hom- Exotic plants of interest belonging

Re three hea sees) with to this order are—Carya, Hickory ;

Castanea, Sweet Chestnut ; /uglans,

Walnut ; Ziguidambar, species of which yield resins known as
“ storax and liquidambar ; and Osérya, Ironwood,

 

MONOCOTYLEDONS.
PETALOIDA.
ORCHIDACEZ.

Typical plant, Spotted Orchis.(Orchis maculata).

Note, the plant is herbaceous ; flowers very irregular (fig.
314) ; perianth superior (note, the twisted ovary may be mis-
taken for a stalk), six-lobed ; there are three outer and three
inner segments, all petaloid ; one of the inner lobes is flattened
out, forming a lip or labellum, and is also prolonged below
into a spur. Behind the labellum there is a short column
terminating in a knob, the rostellum (fig. 314, 11, R), anda
single stamen with two anther lobes (fig. 314, IL, L, P), con-
taining not free pollen, but a mass united together and stalked,
a pollinium (fig. 314, 1v.). Below the rostellum and stamen is
the stigma (fig. 314, IL, st), so that the arrangement is
gynandrous. Below is the one-celled ovary with three parietal
placentas.
Orchidacee 181

Taking a flower which has but recently expanded, push
gently a sharpened pencil into the spur. It is found that on
touching the rostellum its pouch-like membrane is pushed down,

 

Fic. 314.—I. Aceras anthropophora (Man Orchis), whole plant. II. Flower of an
Orchid looked at in front, the ovary being concealed : L, Pp, anther lobes, each contain-
ing a pollinium ; st, stigma; R, rostellum. III. Gynostegium of Cypripedium, seen
laterally ; above to the right the anther, to the left the stigma. IV. Pollinia of an
Orchid, with their pedicels united by the rostellum. V. Burst capsule. VI. Trans-
verse section of an ovary.
182 Elementary Botany

and the pencil comes in contact with the viscid substance at
the base of the pollinia. On removing the pencil one or both
of the’ pollinia are removed attached to it. It will be found
after removal they gradually bend over towards the point of the
pencil.

If an insect, such as a bee, visits the plant for the honey
contained in the spur, it presses its head against the rostellum,
and flies away with the two pollinia attached; on visiting a
second flower these have bent forward, so that instead of re-
turning to the same place from which they were taken in the
previous flower, they strike against the viscid stigma, and some
of the pollen remains attached.

The exact method of fertilisation varies in the different
plants of this order. It is very widely distributed, especially
in tropical regions. Many of the plants are epiphytes, or air
plants : clinging to the trunks of trees, their roots are green
with stomata, and never reach the soil ; they absorb all their
nourishment from the air. Many of the plants are remarkable
for the singular shapes of their flowers, which simulate various
natural objects, insects, birds, reptiles, &c. So much so that
Dr. Lindley says, ‘So various are they in form, there is scarcely
a common reptile or insect to which some of them have not
been likened.’ Amongst our British genera we have the Fly
Orchis (Ophrys muscifera), which presents the appearance of
several flies growing up the stem ; Bee Orchis (Ophrys apifera)
and Spider Orchis (Oprys aranifera), each with the flowers
like the insectsnamed. There are various species of the genus
Orchis, all of which have spurred flowers: Aceras, or Man
Orchis (fig. 314, 1.) ; Zéstera, or Twayblade ; Habenaria, or
Butterfly Orchis, and others. Though so numerous a family,
the plants are not economically useful. Salep is a starchy
esculent substance obtained from the roots of several species
of Orchis ; and vanilla is a flavouring material obtained from the
fruit of an exotic plant, Van7l/a aromatica. The marvellous
forms of the flowers cause them to be much cultivated in our
greenhouses.
Lihaceé 183

LILIACEZ.

Typical plant, Bluebell (Scilla nutans, or Agraphis nutans).

Note, the plant is herbaceous (the Butcher’s-broom is the
only British plant which is shrubby, but exotics may be shrubs
or trees) ; perianth inferior, polyphyllous (it may be gamo-
Phyllous), six divisions (in Herb Paris there are eight) ; stamens
six (eight in Herb Paris); pistil syncarpous, three-celled,
with axile placente and numerous ovules (four-celled in Herb
Paris).

This large and important order is widely distributed through-
out the world. It is divided into several sub-orders, some of
which are sometimes raised to the dignity of orders.

The British genera may be grouped into the five following
sub-orders :—

TRILLIDEZ. Leaves net-veined ; styles distinct ; fruit a
berry.
(All the other sub-orders have parallel-veined leaves.)

CoNnVALLARIEZ. Fruit a berry; styles united; testa of
seed membranous.

ASPARAGER. Fruit a berry; styles united ; testa of seed
hard and black.

Liniez. Fruit a capsule ; styles united.

Cotcuice#. Fruit a capsule ; styles distinct.

Principal British Plants.
TRILLIDEE.

Paris, Herb Paris. A remarkable plant with four net-
veined leaves upon a short stem, and the parts of the flower
arranged in fours, thus resembling Dicotyledons ; but otherwise
a monocotyledonous plant.

CONVALLARIE.

Polygonatum, Solomon’s Seal. Flowers axillary, drooping ;
perianth gamophyllous, shortly six-cleft, tubular.

Convallaria, Lily of the Valley. Differs from last in flower-
stalk being leafless ; perianth campanulate.
184 Elementary Botany

ASPARAGE,

Asparagus. Leaves small, subulate, surrounded by short
scarious scales; flowers small, polyphyllous; two ovules in each
of three cells of ovary ; style single, and three-lobed stigma.
The young succulent shoots are eaten.

’ Ruscus, Butcher’s-broom. Shrubby plant. The b:anches

 

Fic. 315.—Leaf-like branch or phylloclade of Ruscus aculeatus: a, flower.

are leaf-like (fig. 315), and known as phy/oclades, the true leaves
being scales upon them. The flowers are small, sessile upon
the phylloclades.

LILIEZ.

Allium, Garlic, Chives, &c. Flowers in an umbel, with two
or three thin bracts at base; flower-stalk leafy. Amongst culti-
vated species of this genus are the Onion (4. Cega), Garlic
(A. sativa), and Leek (4. Porrum).

Fritillaria, Fritillary. Flowers generally single on the
stalk, polyphyllous ; the three inner segments have each a
nectary at the base ; anthers attached above their bases ; style
three-cleft.

Ornithogalum, Star of Bethlehem. Flowers in racemes or
corymbs ; perianth persistent ; a scarious bract at base of each
flower-stalk.

Scilla, Squill, Bluebell, &c. Flowers blue or pink, in
racemes or panicles ; perianth not persistent. The medicinal
Squill is an exotic species of this genus.

Tulipa, Tulip. Flowers solitary on leafy stalk; petals with-
out a nectary ; anthers innate ; style absent.
Liliacee 185

COLCHICE#.

Colchicum, Meadow Saffron. Flowers with long tube, so
that the ovary is underground, but superior ; styles three, very
long and thread-like.

Amongst exotic plants of this order which are grown for
ornamental purposes, or are variously employed, are several
species of the genus Li/um, also Hyacinthus. The genus Aloé
yields several species, some of which are used medicinally :
Dracena Draco is the famous Dragon-tree of Teneriffe ; Phor-
mium yields New Zealand flax ; Sanseviera yields African
hemp ; the buds of the Xanthorrhaa, or Grass-tree of Aus-
tralia, are eaten like Asparagus; and Yuca is the Adam’s

Needle.
AMARYLLIDACEA.,

Typical plant, Lent Lily or Daffodil (Warcissus pseudo-
Narcissus). Note the bulbous underground stem; membranous
bract; perianth with six divisions, superior ; corona (not always
present in the order); six stamens, epiphyllous; ovary inferior,
three-celled.

The plants of this order differ from the Liliacee in possess-
ing an inferior ovary.

Principal British Genera.

Galanthus, Snowdrop. No corona; three outer segments
of perianth larger than three inner ; flowers solitary.

Leucojum, Snowflake. No corona; all perianth divisions
equal ; flowers two to six together.

Narcissus. Flowers with corona (fig. 197).

GLUMACEZ.
CYPERACE#.

Typical plant, Common Cotton Sedge (Eriophorum poly-
stachyum, see fig. 83).

Note, the stem is herbaceous, solid; leaves sheathing ;
the sheaths are entire, not split down the side of the stem,
opposite to the free lamina ; flowers arranged in a spike with
numerous scaly bracts (g/emes), the outer of which are empty,
186 Elementary Botany

and the inner ones contain the bisexual flowers ; perianth
consists of numerous hypogynous bristles, which elongate on
fruiting (in some plants of the order no perianth is present) ;
stamens three; anthers zznate; ovary one-celled, with three
simple stigmas. This order contains numerous grass-like plants.
In the large genus of Carex (Sedges) there are unisexual flowers

(fig. 316).

 

Fic.316.—Flower of Cyperus Fic. 317.—I. Male flower, II. Female flower of
Zongus, with the parts sepa- Carex.
rated,

The Sand Sedge (Carex arenaria) is very useful for binding
together the loose sand by means of its creeping stems. The
Lake Scirpus (Scizpus lacustris) is used for chair bottoms,
baskets, mats, &c. Papyrus was obtained from the stems of
an Egyptian Cyperus.

GRAMINACEA,

Typical plant, Common Wheat (Z7riticum vulgare).

Note, plant is herbaceous (some exotics are shrubby) ;
leaves sheathing, sheath split in front ; an appendage on the
leaf where it separates from the sheath known as the ligule
(fig. 318, 2) ; stem hollow, except at nodes.

Flowers arranged in a spike with glumes, as in Cyperacez.
If we remove one of the spikelets from the centre of the spike
Graminacee 187

(fig. 319, I.) we find there are two outer bracts (g/umes), G, G,
containing several flowers, some fertile and others barren, Fs.
Each fertile flower is enveloped by two scales, one with a pro-
longation or azwz, a, the flowering glume, or outer pale; the
other, Pz, more delicate, the zaner pale. Within these there
are two minute scales, feathery above, the Jodicules. These re-
present all there is of the perianth (see fig. 319, 11.) ; then three
stamens with versatile anthers, and lastly a single ovary with
two feathery stigmas.

   

Fic. 318.—a, split leaf- Fic. 319.—I. Expanded spikelet of the Oat, with a fertile

sheath of a Grass ; 4, and a barren flower, rs; G, glumes; Pe, outer pale, with
ligule ; d@, part of the awn, A; PZ, inner pale; within are the feathery stigmas.
lamina of the leaf; c, II. Fertile lower with the outer pale removed.

node of the culm.

This is the general structure of the plants of the order ; here
are, however, minor points of deviation. Thus, in the Sweet-
smelling Vernal-grass there are four outer glumes to each
spikelet, in the Rye-grass one, and in the Mat-grass none.
Sometimes the pale is absent, as in the Foxtail ; or the lodicules,
as in the Vernal-grass, Mat-grass, and Foxtail. In the Rice
there are six stamens, and in the Mat-grass only one stigma.
The Indian Corn has moncecious flowers ; the staminate flowers
have two lodicules and three stamens ; the pistillate flowers no
lodicules and but one stigma.

This large and wide-spread order is one of the most import-
188 Elementary Botany

ant to man, yielding, as it does, the various cereals that he
employs as food, and the Grasses used as food for cattle.
Amongst the cereals the first place must be given to Wheat
(Triticum vulgare). The origin of this important plant is
entirely lost in the past. We are not acquainted with the wild
stock from which it has been produced. Numerous varieties
of Wheat are cultivated, some with awns to the flowering glumes
and some without. Interesting experiments have been tried
by Major Hallett in Sussex. By choosing the best ears and
grains, and using these for sowing, and by repeating this pro-
cess several times, the Wheat is greatly improved in character.
By this process of artificial selection what is known as ‘ Pedigree
Wheat’ is obtained. The seeds in the case of all the plants of
the Graminacee are albuminous, and flour is obtained from the
crushed albumen.

Barley (Hordeum vulgare) is another important cereal, pro-
bably one of the first cultivated. Malt is prepared from Barley
by allowing it to begin to germinate, and then heating it to 160°
or 180° ; by this means the starch of the grain is converted into
sugar, which is capable of fermentation.

Oats (Avena sativa), Rye (Secale cereale), and Millet, which
is obtained from several genera, are also cultivated. Indian
Corn is obtained from Zea Mais, which is a native of the
New World. Rice is obtained from Oryza sativa, a tropical
plant.

Besides these food plants we have the important Sugar-
cane (Saccharum officinarum), the clarified juice of which yields
us sugar, whilst the residue produces molasses and treacle.

Numerous Grasses are grown for fodder purposes, whilst
from some sweet essences are obtained. Lemon-grass oil
is extracted from <Azdropogon citratum, citronelle oil from
Andropogon Nardus, and some suppose that the spikenard oil
of Scripture was obtained from Andropogon Lwarancusa.

The Bamboo is an arborescent genus of this order, used
for many important purposes.

It will be well in conclusion to point out the differences
between the two allied orders Cyperaceze and Graminacez in
a tabular form.
Description of Plant 189

Cyperacee. Graminacee.
Stem solid. Stem hollow.
Leaf-sheaths entire. Leaf-sheaths split.
No ligule present. Ligule present.
No lodicules, Lodicules generally present.
Anthers innate. Anthers versatile.
Stigmas three, simple. Stigmas two, feathery.

PLAN FOR DESCRIBING A PLANT.

foot.— kind.

Stem.—a. Kind (herbaceous, shrubby, or woody).
6. Shape (rounded, angular, square, ribbed, &c.).
c. Direction (upright, spreading, creeping, climbing,
&c.).
@. Surface (smooth, hairy, rough, &c.).

Leaves.—t. Insertion (opposite, alternate, radical, &c.).
2. Petiole (presence or absence, peculiarities).
3. Lamina.

a. Composition (simple or compound).
8. Venation.
c. Margin.
@. Incision.
e. Apex.
Ff. General outline.
g. Surface (smooth, hairy, &c.).
4. Stipules (present or absent, shape if present;
also note if sheath).

LInflorescence.—Kind of inflorescence and bracts.

Flower.—1. Calyx.

a. Cohesion (gamosepalous or polysepalous).
4. Number of sepals or divisions.

¢. Adhesion (inferior or superior).

@. Specialities (colour, shape, &c.).
190

Elementary Botany

2. Corolla.
a. Cohesion.
6. Number.
c. Adhesion.
d. Specialities.
Note. If perianth is present, describe it in
same manner.

As above.

3. Corona or other appendages between corolla
and androecium should be described here.

4. Androecium.
a. Cohesion (free, monadelphous, &c.).
&. Number.
c. Adhesion.
d. Specialities (if tetradynamous or didy-
namous; also peculiarities of filament
and anther).

5. Gynoecium.

a. Cohesion (syn- or apo-carpous).

&. Number of carpels.

c. Adhesion (inferior or superior).

@. Peculiarities of ovary, including—
a. Number of cells.
6. Placentation.
y. Number of ovules.

e. Peculiarities of style and stigma.

Fruit and Seed.

EXAMPLE.

Sweet Vioxet (Viola odorata).
Root.—Fibrous.
Stem.—Slightly shrubby, rounded, short, underground,

forming a rhizome ; surface scarred.

Leaves.—Apparently radical, but really growing in a tuft at

apex of stem. efiole evident, covered with
short scattered hairs. Zamna simple, net-veined,
unicostate, curve-veined, crenate margin, apex
either rounded or somewhat acute, cordate or
Description of Plant IQI

reniform, surface hairy, especially upon the
margins and veins. S#pudes present, slightly
membranous, undivided, lanceolate.

Lnflorescence.—Single-flowered, the flower-stalks growing

Flower-—

from the axils of the leaves and bearing two

small nearly opposite linear bracts about the
centre.

Calyx.—Polysepalous ; five sepals, inferior,
irregular, each sepal broad in centre and pointed
towards the two extremities, green, hairy.

Corolla.—Polypetalous ; five petals, hypo-
gynous. Irregular, either purple or white; in the
former case the lower petal has several darker
lines converging towards interior of flower ; the
lateral petals have a hairy tuft near mouth of
tube; the inferior petal is prolonged into a short
blunt spur.

Andrecium.—Stamens free, five in number,
hypogynous, almost sessile, the filament being
very short ; connective prolonged beyond the
anthers as an orange-coloured mass ; two of the
stamens spurred, the spurs passing into the spur
of corolla.

Gynecium.—Syncarpous, three carpels, supe-
rior ; ovary one-celled, with three parietal pla-
centas and numerous ovules; surface of ovary
hairy ; style curved ; stigma hooked.
193

QUESTIONS FOR EXAMINATION.

[Those followed by a date are questions which have been set at previous exami-
nations held in connection with the Science and Art Department, South
Kensington. |

1. How can you distinguish a plant rom an animal ?

2. Into what two great sub-kingdoms may plants be divided ?

3. Describe fully the seed of a Bean. (1875 and 1878.)

4. Compare the seed of the Oat with that of the Bean.

5. Explain the terms ‘albuminous’ and ‘ exalbuminous,’ and mention
some albuminous seeds.

6. Describe the structure of a living parenchymatous plant-cell. What
chemical elements enter into the composition (a) of the cell-wall, (4) of the
protoplasm? (1887.)

7. What are the composition and properties of cellulose ?

8. Enumerate and describe briefly the most important substances
which are formed w2thin the protoplasm of plant-cells.

g. Give an account of the general properties of chlorophyll, and of the
conditions which are necessary to its formation.

10. What remarkable change do plants show when they are grown in
the dark? (1876.)

11. Why does heaping earth round Celery cause the stalks to be
white? (1877.)

12, What is the nature of starch? How is it formed, and what is its
use? (1879.)

13. Explain the structure of a cell and the changes it undergoes in the
growth of a plant. (1878.)

14. What conditions modify the shape of cells?

15. How are thickened cells produced ?

16, In what respects does the wood of the stem of a Conifer (Fir Tree)
differ from that of a dicotyledonous plant? Describe the development_of
‘ bordered pits.’

17, What is meant by a vessel? How is it formed, and what is its
use? (1878.)

18. How are the cells, sayin the leaf of a plant, increased in number?

19. Give an account of ‘parenchyma.’ Explain how it is formed.

1875.)
o
194 Elementary Botany

20. Describe what happens in the germination of a Beanseed. (1878.)

21. What requisites are needed for germination ?

22. Compare the germination of the following seeds :—Broad Bean,
Acorn, Cress, Mustard, Pine, Date, and Wheat.

23. Compare the modes of germination of seeds of the Oak and of the
Beech. In what important respects do they differ? (1884.)

24. Describe the way in which roots grow. (1877.)

_ 25» The seeds of Mustard and Cress will germinate on flannel soaked
with rain-water. Will they go on growing under these circumstances? and
if not, why not? (1879.)

26. When any vegetable material is burned, what constituents go off
as gas? What are left behind? (1877.)

27. What are the principal substances which form the food of plants?
(1875.)

28. What part of the food of a plant is taken up by the roots ? (1878.)

29. Explain how the food is absorbed by the roots.

30. Of what substances in the plant is nitrogen an essential ingredient ?
How does the plant obtain the nitrogen? (1876.)

31. Why do plants require nitrogen, and in what form do they take it
in? (1880.)

32. Explain the ‘ rotation of crops.’

33. Explain why the root of a turnip first grows aster than the stem,
and then stops while the stem grows rapidly. (1877.)

34. What are the chief differences between a root and a stem?
(1876.)

35. Suppose a piece of the axis of some flowering plant were shown to
you, what appearances would enable you to decide whether it was part of
a root or ofastem? (1882.)

36. Compare the appearance of a monocotyledonous and dicotyle-
donous stem as seen in transverse section.

37. What is the cause of the ring-like markings seen in the cross-
section of a tree-trunk ? (1876 and 1881.)

38. Describe and explain as much of the texture of a deal plank as can
be made out with the naked eye. (1879.)

39. Explain the difference in the growth of the bark of a tree and that
of the wood. (1880.)

40. What is the structure and use of cambium ?

41. State generally what is the composition of a vascular bundle.
Describe the longitudinal course of the vascular bundles in the stem of
any Dicotyledon. (1887.) F

42. Describe a ‘runner,’ a ‘ rhizome,’ an ‘ offset,’ and give examples.

43. Give a full account of a Potato, and explain as much as you can

structure. (1875.)
44. Explain why a Potato is considered to be a stem. (1878.)
45. Describe and explain the structure of an Onion, (1876 and 1880,)
Questions 195

46. Give a botanical description of the part, in each of the following
plants, which is commonly used as food:--the Potato, the Onion, the
Turnip,and the Carrot. (1887. )

47. What are the essential differences between a node and an inter-
node? Illustrate your answer by examples. (1884.)

48. Describe a bud. To what structures do the outer coverings corre-
spond? What is the origin and use of the resinous secretion with which
they are often covered? (1877 and 1881.)

49. Why are some of our fruit-trees thorny in the wild state, but not
when cultivated? (1879.)

50. Mention, with examples, the different members of the plant which
may be modified into tendrils.

51. Explain precisely how a tendril acts. (1881.)

52. Explain the process of grafling. (1876.)

53. What is the structural difference between a prickle (as in the Rose,
and a spine (as in the Blackthorn), (1881.)

54. What is a leaf? What is its use to the plant? (1877.)

55. Describe the general structure of a leaf.

56. What are stomata? Where are they found in the plant and
what is their use? (1880.)

57. What is the general plan of arrangement of leaves on a stem?
Why is it the most advantageous to the plant? (1881.)

58. What components of the atmosphere are taken from it by plants,
and for what purpose? (1881.)

59. What is the cause of the green colour of plants? What is its use?
(1875-)

60. State why absence of light is injurious to plants. (1881.)

61. Plants are said to ‘starve in the absence of light.’ Explain this
statement. (1883.)

62. Why will a plant grown in a dwelling-room be less vigorous than
one grown in the open air? (1879.)

63. What is meant by respiration? Describe an experiment for show-
ing that plants respire. (1878.)

64. What is meant by transpiration? Under what circumstances do
plants transpire most? (1879.)

65. What are the conditions, external and structural, which regulate
the amount of evaporation from leaves?

66. Explain the action of the leaves of carnivorous plants.

67. Give instances in which leaves are only imperfectly developed.
What useful purposes may they serve in such cases? (1882.)

68. Excluding the leaves forming the flower, we have three kinds
occupying different positions on the stem in the higher plants. Briefly
describe these.

69. What are bracts? Give some o  eir modifications,

02
196 Elementary: Botany

70, ‘What is meant by definite and indefinite inflorescence? Give ex-
amples and draw diagrams to explain your answer. (1875.)

71. If an inflorescence appears at the end of a branch of a tree, what
is the effect on the future growth of the branch? (1879.)

72. Tabulate the principal indefinite inflorescances.

73. What is meant by ‘ mixed inflorescence ’?

74. What is a flower? What structures compose it, and what are
their use? (1877.)

+ 75. Give the names and brief descriptions of the enveloping and essen-
tial organs of a flower. (1875.)

. 76, Some English plants have one, others have two, and even three
kinds of flowers. Explain how this is possible. (1879.)

77. Explain the terms ‘ polygamous,’ ‘ dicecious,’ ‘ gynandrous,’
‘ syngenesious,’ ‘ hypogynous,’ ‘ perigynous,’ ‘ inferior,’ ‘ epigynous.’

78. Explain fully the various respects in which a petal differs from a
leaf. (1880.)

79. How do you explain the fact that while the leaves of most plants
are green their flowers are of some other colour? (1878.)

80, What is pollen? What is its use? (1875 and 1878.)

81. What is meant by an inferior ovary? Give examples, (1875.)

82, What is meant by placentation? Describe the various forms.

83. What is a placenta? Describe the placentation in the Cruci-
feree, the Leguminosze, and the Liliacez.

84. Explain the terms ‘ monadelphous,’ ‘ diadelphous,’ ‘ adnate,
*jnnate,’ ‘ versatile,’ ‘introrse,’ ‘ extrorse.’

85. Mention plants whose flowers contain nectar. What is its use?
(1877.)

86, Describe the general structure of an ovule.

87. Explain the terms ‘orthotropous,’ ‘ anatropous,’ ‘ raphe,’ ‘ hilum,
 micropyle,’

88. Draw a diagram showing the arrangement of the parts of the
flower of a leguminous plant as seen in transverse section. Point out in
what respects it differs from the arrangement typical of flowers generally.
(1883.)

89. Draw a diagram showing the arrangement of the different parts of
the flower of any Crucifer, (1882.)

go. Explain what is meant by an irregular flower. What is the ad-
vantage to a plant of having such flowers? (1878 and 1881.)

gi. What provisions are made for cross-fertilisation ?

92. What is a fruit ?

93. Explain the terms ‘syncarp,’ ‘ pseudocarp,’ ‘drupe,’ ‘achene,’
* pome.’

94. Classify the dehiscent fruits.

95. What is.a berry? What is the advantage to a plant to have this
kind of fruit? (1877.)
Questions 197

96. Explain the essential differences of structure in the fruits of the
Strawberry and Blackberry. (1881.)

97. How do the fleshy parts of the Strawberry, Blackberry, Apple,
and Plum originate? (1876.)

98. Describe as fully as you can the structure of an Apple, and explain
the origin of the different parts. (1879.)

99. Explain the terms ‘ epicarp,’ ‘ mesocarp,’ ‘ endocarp,’ ‘ loculicidal,’
‘ septifragal,’ ‘circumscissile.’

100. Describe the fruits of a Buttercup and of a Pink. In what re-
spects do they agree and in what respects do they differ? (1883.)

101. Describe, with sketches, the structures seen in transverse sections
of the fruit of an Apple and of an Orange respectively. Point out, as far as
you can, the parts in each case of which the structural value is the same.
(1884. )

102. In what points of structure does an ovule differ from u seed?
(1880. )

103. What are ‘endosperm’ and ‘perisperm’? Also give the struc-
ture of the arillus.

104. There are three distinct modes in which water moves in the
plant. State what they are, and describe the experiments by which you~
would prove their existence. (1884.)

105. What is the channel by which the leaves of a plant make up for
the loss of water by transpiration? Where does the water come from ?

106, Why can a tree be transplanted more safely in the winter than in
the summer? (1877.)

107. When a branch of a tree is cut off, why do the leaves of the branch
fade, while those of the tree remain fresh? (1876 and 1880.)

108. What constituents of sunlight are most effective in producing the
chemical changes on which the nutrition of plants depends?

109. What is a hybrid? (1876.)

110. What are the characters of the two groups of flowering plants ?

111. Describe the typical structure of a stamen. State the peculi-
arities characteristic of those of a Crucifer, a Composite, a Labiate, and a
Grass. (1880.)

112. In what important respects does the fruit of a cruciferous plant
(such as Shepherd’s-purse) differ from that of a leguminous plant (such as
a Pea)? How can the differences be accounted for? (1880.)

113. Describe the general structure of the ovary and of the fruit in
Rosaceze and Leguminosze.

114. Compare the natural orders Labiatee and Scrophulariacez.

115. Give an account of the structure of the head of a Daisy. (1880.)

116. What is the difference between an annual and a perennial plant ?

(1875.-)
INDEX AND GLOSSARY.

ABS

ABSORPTION of food by roots, 34;
by leaves, 85

Accrescent calyx (Lat. accresco, to in-
crease). ‘Term used when the calyx
forms a bladdery expansion round
the fruit, 104

Accretion (Lat. accresco). Term ap-
plied to growth by a series of layers,
16

Aceras, 181

Acerose (Lat. acer, sharp). Term ap-
plied to leaves when sharp and
pointed, 79

Achene (Gr. a, not ; chaino, toopen). A
dry fruit which does not open, 142

Achlamydeous(Gr. a, without; chlamus,
acloak). Flowers destitute of both
calyx and corolla, 100

Aconitum, 105, 111, 157

Acorn, germination of, 26

Action of chlorophyll, 86

Action of heat, 148

Action of light, 149

Acuminate (Lat. acuminatus, made
pointed). Term applied to the gra-
dually pointed apex of leaves, 7

Acute (Lat. acutus, sharpened). ‘Term
applied to the pointed apex of
leaves, 77

Adam's Needle, 185

Adnate (Lat. ad, to ; ascor, natis, to
grow). Where one part grows
against another, applied to stamens
where the filament grows up against
the anther, 115

Adonis, 157 : i

Adventitious (Lat. adventicius, foreign
or extraneous). Applied to anything
growing out of its ordinary oe as
buds, 61, 62; and roots which are not
direct prolongations of the radicle,

2
Aerial stems (Lat. aev, air) Stems
growing above ground, 55 |
stivation (Lat. estivus, relating to the
summer) Term applied to the

 

ANA

arrangement of the parts of the
flower in the flower bud, 113

AE thusa, 168

Agraphis, 183

A grimonia, 165

Alz (Lat. wings). Term used to de
scribe two of the petals in the papilio-
naceous corolla, 109

Albumen (Lat. aléus, white). Food
material found in many seeds, 4

Albuminous seeds. Those containing
albumen, 5

Alburnum (Lat. a@/éxs, white). The
outer wood of a dicotyledonous stem
usually light in colour, 46

Alchemilla, 166

Aleurone (Gr. aleuvon, fine meal).
Oily grains often found in cells, 14

Alkanet, 175

Allium, 184

Almond, 165

Alnus, 179

Albe, 185

Alternate leaves, 84

Amaryllidacee, 105

Amentacee, 178

Amentum (Lat. a strap). A form o
spike bearing unisexual flowers, 96

Ammonia. Acompoundof nitrogen and
hydrogen, which forms a source of
nitrogenous food to the plant, 35

Ameebiform movements (Gr. aszoibe,
change). Changes of form of proto-
plasm such as are seen in the Amoeba
or Proteus animalcule, 8

Amplexicaul (Lat. amfplexus, encircling ;
caulis, stem). Applied to leaves
which encircle the stem at their

base, 85

Amygdalee (Lat. amygdalum, an
almond). A division of the order
Rosacez, 165

Amygdalus, 165

Anagallis, 176

Anatropous (Gr. axa, backwards; /vopos,
a turn). An ovule which is turned
200

ANC

over so that the micropyle is near
the placenta, 123
Anchusa, 175
Andreecium (Gr. andreigs, male; otkos,
a house). Term applied to the col-
lected stamens of the flower, 113
Andropogon, 188
Anemone, 158
Anemophilous (Gr. a@nemos, wind).
Plants which are fertilised by the
wind, 130
Anethum, 170
Angelica, 167
Angiosperms (Gr. augos, vessel; sperma,
seed), Plants whose seeds ‘are en-
closed in vessels or ovaries, 128
Annular cells (Lat. annularis, ringed).
Cells with the secondary deposit
arranged in rings, 19
Annulated roots. Roots with several
ring-like constrictions, 33
Anthemis, 170
Anther (Gr. antheros, flowery). The
hollow box at the summit of the
stamen and which contains the pollen,
I14, 115, 117
Anthriscus, 170
Antipodal cells (Gr. azti, opposite ; ous,
podos, foot). Cells developed in the
embryo-sac at the opposite end to the
embryo-cell, 126
Antirrhinum, 108, 174
Apex of leaves, 76, 77
Apium, 168
Apocarpous (Gr. ago, from; harpfos, a
fruit). Pistils with separate carpels,

TIQ

Apple, 135, 141, 164, 166

Apricot, 165
quilegia, 158

Arachis, 164

Arctium, 7%

Arillus (Lat. avco, to be dried up). A
peculiar coat growing up around the
ovule of some plants and remaining
attached round the seed, 144

Arnica, 172

Artemisia, 171

Artichoke, 172

Asparagee. A group of the order Lilia-
ceze, 183-184

Asparagus, 184

Assimilation of food, 86

Astragalus, 162

Atmosphere, composition of, 86

Atriplex, 177

Avena, 188

Axillary buds (Lat. axilla, the arm-pit).
Buds which grow in the angle formed
between the leaf and stem, 59

BALM, 174
Balsam of Tolu, 164
Bark, 42, 48
Barley, 188
Basifixed, 115
Basil, 174

 

Elementary Botany

CAL

Basil Thyme, 173

Bast. The inner bark, 48

Bastard Saffron, 172

Bast fibres, 21, 48

Bast tubes, 22

Bast vessels, 21, 48

Bean seed, 3

Beech, 180

Beet, 177

Bellis, 171 2

Berry. A fleshy fruit which does not
open, and which contains several seeds,
141

Beta, 177

Betula, 179

Betulinee. A group of the order Amen-
tacez, 179

Bicrenate (Lat. dzs, twice; cvena, a
notch). Term applied to leaves having
their edges doubly notched, 77

Birch, 179

Bird’s foot Trefoil, 163

Biserrate (Lat. zs, twice ; serra, a saw).
Term applied to leaves when their
edges are doubly toothed, 77

Blackthorn, 164

Bluebell, 183, 184

Bluebottle, 107, 171

Borage, 175

Boraginace@, 175

Borago, 175

Bostrychoid (Gr. dostruchos, a curl).
A term applied in branching when the
successive branches come off on the
same side, ‘66, 67, 68

Botany, definition of, 1 ; divisions of, 2

Bracts (Lat. dractea, a thin plate of
metal). Organs, generally leaf-like,
growing between the leaves and the
flowers, 92

Bramble, 164

Branching, 59, 66

Brassica, 160

Broad Bean, 164; seed of, 3 ; germina-
tion of, 27

Broom, 163

Budding, 63

Buds, 40

Bulbs, 57

Bunium, 168

Burdock, 93, 94, 171

Burnet Saxifrage, 169

Butchers Broom, 50, 183, 184
Buttercup, 102, 103, 111, 114, 119, 142

ABBAGE, 160
Caducous (Lat. caducus, falling |
An organ which falls off early, especi-
ally applied to the calyx which falls off
before the buds open, 104
Calamintha, 173
Calendula, 172
Callus (Lat. a hard skin), A growth of
cambium which is formed when the
stem is wounded, 63 .
Caltha, 15
Ludex and Glossary

CAL

Calyciflore, a group of plants, the sepa-
rate petals of whose flowers are ar-
ranged either around or upon the
ovary, 162

Calyx (Gr. haluzx, from halupto, to
cover). The outer covering of the
flower, 100 :

Cambium (Lat. cambio, to change).
The formative layer between the wood
and the liber out of which new wood
and new liber are formed, 42, 44, 45,

47

Campanulate (Ital. caszpana, a bell).’
Bell-shaped corolla, 107

Campion, 161

Campylotropous (Gr. kasmpzlos, bent ;
tropos, direction), An ovute which is:
bent over, 123

Candytuft, 160

Capitulum (Lat. diminutive from caput,
a little head). An indefinite inflores-
cence with shortened axis and sessile
flowers, 95

Capsella, 160

Capsule (Lat. capsuZa, a small box).
A form of fruit which opens to allow
the seeds to fall out, 136

Caraway, 168

caper of plants, whence obtained, 34,

Carbonic acid or Carbon dioxide, 34, 86

Carcerulus (Lat. carcer, a_ prison).
A fruit breaking up into four one-
seeded nucules, 139

Carduus, 171

Carina (Lat. keel). Term applied to
the innermost petals of the papiliona-
ceous corolla, 109

Carnation, 161

Carnivorous plants (Lat. caro, carnis,
flesh ; voro, to eat), Plants which feed
upon flesh, 89

Carpels (Gr. “argos, a fruit) The
innermost parts of the flower which
when ripened form the fruit, 100, 118

Carpinus, 179

Carpophore (Gr. Aar$os, fruit; phero,
tobear). A prolongation of the flower
stalk growing between the carpels of
the pistil or fruit, 124, 139

Carrot, 169

Carthamus, 172

Carum, t

Carya, 180

Caryophyllacece, 161

Cassia, 164

Castanea, 180 Scat

Castor-oil seed, germination of, 27

Catkin (diminutive of cat), see Amentum.

Cauline (Lat. cazdis, a stem). Leaves
growing upon the stem, 85

Caulis (Lat. stem) A herbaceous.
annual stem, 54

Celery, 9, 168 7

Cells, 6; contents, 6, 7; changes in
wall, 7; division, 23; formation, 23,
117; growth, 15 ; sap, 12; shape, 16; °
size, 23; thickening, 17; tissues, 24,

 

201

_ COL

Cells with bordered pits, 20

Cellulose. The substance of which the
cell wall is built up, 6

Centaurea, 171

Centrifugal inflorescence (Lat. centri,
centre ; /ug7o, to flee from). Inflo-
rescence where the oldest flowers are
towards the centre, 94, 97

Centripetal inflorescence (Lat. cen-
trum, centre ; eto, to seek). Inflo-
rescence where the youngest flowers
are in the centre, 93, 94

Cerastium, 161

Chalaza (Gr. a tubercle), The point by
which the nucleus of the seed is
attached to the integuments, 122

Cheiranthus, 159, 160

Chenopodiaceae, 177

Chenopodiunz, 177

Cherry, 165

Chervil, 170

Chickweed, 161

Chicory, 172

Chlorine of plant, whence obtained, 35

Chlorophyll (Gr.  chloros, green;
Pphullon, leaf). The green colouring
matter of plants, 8

Christmas Rose, 158

Chrysanthemum, 171

Cicinnal (Gr. Aikinnos, Lat. cicinnus, a
curled lock of hair), A term used in
branching when the _ successive
branches come off on opposite sides,

7

Cicuta, 168

Cilia (Lat. e722, an eye-lash), Hair-
like prolongations of cells, 1, 8, 77

Ciliate. A term applied to the margins
of leaves when they have a hairy
fringe, 77

Circinate (Lat. civc7mo, to make round),
Term applied to the arrangement of
the leaves in the bud when the apex is
rolled towards the base, 64

Circulation of sap, 245

Cirrhi (Lat. cirrus, a curl).
61

Clary, 173

Classification, 153

Cleistogamous (Gr. fleistos, closed;
gamos, marriage). Flowers where the
ovule is fertilised without the flower-
bud opening, 134

Climbing stems, 54

Closed bundles. Woody bundles con-
taining no cambium, 44

Clover, 163

Cloves (Lat. clavus, a nail), The young
bulbs developed by the side of the old
ones, 58 .

Cochlearia, 160

Colchicee, a group of the Liliacez, 183,

Tendrils,

185

Colchicum, 185

Coleorhiza (Gr. foleon, a_ sheath ;
rhiza, a root). The sheath around
the base of the root in many monoco-
tyledons, 29
202

coL

Coltsfoot, 171

Columbine, 158

Comfrey, 176

Complete flowers. Those flowers which

~ possess all four of the floral whorls,
I00, 154

Composite, 155, 170

Composition of air, 86

Compound flowers, 155 ; leaves, 76, 80

Conduplicate (Lat. conduplico, to

* double), When in the leaf bud the
two edges of the leaf are doubled
on leaving the midrib in the centre,

4.

Cone (Lat. conus). A unisexual spike
with woody bracts, 96

Conical root, 32

Conium, 168

Connate (Lat. con, together; sascor,
natus, to grow). When the bases of
opposite leaves are united so that they
appear to be one, 84

Connective (Lat. con, together ; necto,
to bind). The portion of the filament
which unites the anther lobes, 116

Convallaria, 183

Convallariee, a group of the Liliacez,

183

Convolute (Lat. convolutus, rolled up).
When in the leaf bud the two edges of
the leaf are rolled the one over the
other, 65

Copaiba, 164

Copal, 164

Coriander, 168

Cork cambium (see Cambium). The
formative tissue below the cork cells,

43, 48

Cork cells. The outermost cells of the
bark, 42, 48

Corm (Gr. korutos, a stem or trunk). An
underground stem resembling a bulb
but more solid, 58

Corn Cockle, 161

Corolla (Lat. a small wreath) The
second of the floral envelopes, 100,

106

Corolliflore. A group of dicotyledonous
plants with gamopetalous corollas, 148,
154, 170

Corona (Lat. a crown). An extra organ
sometimes present within the corolla
of flowers, 110

Corpuscula (Lat. siege set a little
body). Certain cells produced within
the embryo-sac of conifers, 129

para ear bark), 42
orylus, 178, 179

Corymb (Gr. sorumbos, a cluster of
fruit or flowers). An indefinite in-
florescence where the flowers form a
flattopped head, 96, 97

Cotyledons (Gr. otuledon, a hollow
vessel), The lobes within the embryo
of the seed, 4, 5, 26, 153

Cow Parsnip, 167, 169

Cow Wheat, 175

Crambe, 160

 

Elementary Botany

DEF

Crategus, 166

Cremocarp (Gr. kremnao, to hang down ;
karpos, a fruit). A fruit which breaks
up into two halves hanging upon a
central stalk, 139, 167

Cress, 160, germination of, 27

Crithmum, 168

Cross fertilisation. The arrangement by
which the pollen of one flower fertilises
the ovule of another, 130

Crowfoot, 159

Cructfer@, 154, 159

Cruciform (Lat. craa, a cross ; forma,
a shape). Cross-shaped. Applied to
the corolla when the petals are ar-
ranged in the form of a Maltese cross,
109, 154) 159

Cryptogams (Gr. ruftos, hidden;
gamos, marriage). Flowerless plants, 3

Crystalloids (Gr. Arustallos, ice ; eidos,
form). Nitrogenous materials in many
cells presenting a crystalline appear-
ance, 13

Crystals, 13

Culm (Lat. czdweus, a stalk) The
hollow jointed stem of grasses, 54, 186

Cumin, 170

Cupule (Lat. cupula, a little cup) A
peculiar growth of bracts forming a
cup around the fruit, 141, 179

Cupulifere (Lat. cupula, a little cup;
‘ero, Lbear). A group of the Amen-
taceae, 179

Cuticle (Lat. cvticula, the skin). The
outer structureless layer of plants,
especially of leaves, 72

Cyclamen, 176

Cydonia, 167

Cyme (Gr. £uma, a wave). Definite
inflorescence, 97

Cynara, 172

Cynarrhodum (Gr. Avon, kunos, a dog
rhodon, arose). The fruit of the rose.
An assemblage of achenes within a
hollow receptacle, 142, 165

Cyperacee, 155, 185, 189

Daisy, 109, 170, 171
Dandelion, 93, 109, 170, 172

Date, germination of, 28

Daucus, 16:

Dead Nettle, 99, 109, 115, 154, 172, T

Deciduous (Lat. de, off ; cado, to fal i.
Falling off, especially applied to parts
of the flower, leaves, etc., which fall
early, 104

Decurrent (Lat. de, down; curro, to
run). Leaves with base running along
the stem, 85

Decussate (Lat. decuzssis, the intersection
of two lines crosswise). When two
pairs of opposite leaves are arranged
at right angles, 84

Definite inflorescence. Inflorescence

where the oldest flowers are above or

in the centre, 94, 97

Definition of botany, 1 ; of plant, z
Index and Glossary

DEH

Dehiscent fruits (Lat. de, apart ; hzsco,
to gape). Fruits which break when
ripe, 136

Delphinium, 158

Development, of buds, 60 ; of plumule,
40; of root, 25

Dextrine (Lat. dexter, to the right).
British gum ; analtered form of starch,
so called because it turns the rays of
polarised light to the right, 7, 10

Diadelphous (Gr. dis, twice ; adelphos,
a brotherhood). Stamens arranged in
two bundles, 114

Dianthus, 161 ,

Diastase (Gr. diastasis, a division). A
ferment produced in germinating seeds
and which acts upon starch, 12

Dichlamydeous (Gr. dis, _ twice;
chlamus, a cloak). Flowers with both
calyx and curolla, 100

Dichogamy (Gr. dicha, in two ; gamos,a
marriage). Plants where the pistil and
stamens are ripened at different times,
so that there must be cross fertilisation,

131

Dichotomous (Gr. dicha, in two ; temno,
to cut), When branches divide con-
tinually into two, 66, 98

Dicotyledons (Gr. dis, twice ; kotuledon,
a hollow vessel). Plants with two co-
tyledons in the embryo, 5, 153

Dicotyledonous stem, 44, 153; leaves,
75, 153; root, 29, 153

Didynamous (Gr. dis, twicé ; dunamts,
power). Flowers with two long and
two short stamens, 115

Digitalis, 174

Dill, 170

Dimorphic (Gr. dis, twice; morphe,
shape). Plants where the flowers
differ, some having short pistil and
long stamens, and others long pistil
and short stamens, 132

Dicecious (Gr. dis, twice; ozkos, a
house). Stamens and pistils upon se-
parate plants, 102 7

Discoid (Cr. diskos, around plate ; eidos,
form). A term applied to pith when
it is broken up into a number of flat
plates, 45

Distinguishing characters of roots and
stems, 40

Dorema, 170

~ Dorsifixed, 115

Dotted cells, 18

Double flowers. Flowers in which sta-
mens and pistils are converted into
petals, 134

Dracaena, 185

Dragon-tree, 53, 185

Drupacee, a group of the Rosacez, 165

Drupe (Lat. dvupa, an over-ripe olive).
Stone fruit, where the inner layer is
hard and stony, 140, 164, 165 |

Duramen (Lat. dzrus, hard). The inner,
generally hard, layers of wood, 46

Dyer's-weed, 162 '

Dyer's Woad, 160

 

203

ETA

ARTH-NUT, 168
Echium, 176
LElecampane, 17%
Elements in plants, 34
Elliptical cells, 16; leaves, 79
Embryo (Gr. em for ex, in; brio, to
swell). The young plant in the seed, 4
Embryo-cell. The cell of the ovule
which forms the embryo, 126
Embryo-sac. The cell of the ovule in
which the embryo-cell is formed, 122,

125
Embrgone vesicles, see above, Embryo-
cells
Endocarp (Gr. endon, within ; karfos,
fruit). The inner layer of the fruit,

135
Endogenous growth. Growth from
within, seen in roots, 4o ; in stems, 52
Endogens (Gr. endo, within ; gennao,
to produce). Plants where the new
wood bundles are first of all produced
within the older ones; monocotyle-

dons, 52 :

Endophloeum (Gr. endo, within; phloios,
inner bark) The internal bark or
liber of dicotyledons, 43

Endorhizal (Gr. exdon, within ; rhiza,
root)., Applied to roots of monocoty-
ledons which branch before leaving the
seed, 29

Endosmose (Gr. endon, within ; osmos,
an impulse), The passage inwards ot
fluids through a membrane, 36

Endosperm (Gr. endon, within; ser-
ma,aseed). Thecells formed within
the embryo-sac around the embryo, 5,

127
Entomophilous (Gr. extoma, insects).
Flowers fertilised by insects, 130
Epicarp (Gr. ez, upon; arZos, fruit).
The outer layer of the fruit, 135
Epidermis (Gr. efi, upon; dermis, the
skin). The outer skin of the plant, 29,

40, 71
Epigeal (Gr. efz, upon; ge, the earth),
Seeds where, on germinating, the coty-
ledons rise above the soil, 29
Epigynous (Gr. efz, upon; gune, wo-
man). Attachment of petals and sta-
mens above the pistil, 107, 115, 154
Epipetalous (Gr. efz, upon). A.ttach-
ment of stamens to petals, 115
Epiphloeum (Gr. pe upon; phioios,
bark). The outer bark of dicotyledons,

43
Epiphyllous (Gr. ¢47, upon; phudlon,
leaf). Attachinent of stamens upon
the divisions of the perianth, 115
Equitant (Lat. egztans, riding). Term
used in vernation when two condupli-
Ge leaves are bent round one another,

Ervumy, 164

Eryngium, 167, 169

Etzrio (Gr. hetaivos, a companion).
Fruits formed by the aggregation of
several distinct ovaries, 142
204

ETI

Etiolation (Fr. é¢doler, to make slender).
Parts of plants blanched by being
grown in the dark, 9

Luphrasia, 174

Evening Campion, 16%

Exalbuminous seeds.
albumen, §, 27 :

Excretion (Lat. ex, from ; cerno, cretus,
to separate), The separation of ma-.
terials from the plant by the roots,’
38

Exogenous growth (Gr. exo, outside ;
gennao, to grow). Growth on the
outside. Seen in stems, 40; charac-
teristic of dicotyledons, 46, 1533 seen
in monocotyledons, 54

Exogens. Dicotyledons with exogenous
growth, 46

Exorhizal (Gr. exo, without; rhiza,
root). Roots which commence to
branch outside the seed, 29, 153

Exosmose (Gr. exo, without ; dsmos,
an impulse), The passage outwards
of fluids through a membrane, 36

Seeds destitute of

Exstipulate (Lat. ex, without ; stzpaZa, |
Leaves destitute of stipules, |

astalk).

70

External forms of stems, 53

Extine. The outer coat of the pollen
grain, 117, 125

Extrorse (Lat. extra, externally ; orsus,
originating). The opening of the

anthers outwards towards the exterior .

of the flower, 116
Eyebright, 174,

FARINOSE (Lat. far, a kind of

grain). One of the components of’

starch, 17

Fascicle (Lat. fascicula, a little bundle).

cyme witha number of flowers on

short stalks, 98

Fasciculated root. The swellings of the
root arranged in a bundle, 33

Fennel, 169

Fertilisation, 125; by insects, 130; by
the wind, 130; of conifers, 128

Ferula, 170

Fibres (Lat. 7bra, a filament). More.

or less lengthened, generally thickened,
cells, 22, 42, 46, 48

Fibro-vascular bundles. Bundles, con-

sisting principally of fibres and ves-

sels, found in the stems of plants, 42, |

51

Figwort, 175

Filament (Lat. #Z«m, a thread). The
stalk which supports the anther of the
stamen, 114, 116

Floral diagram, 125

Flow of sap, 36, 46, 48, 50, 53, 72, 88,

145
Flowering plants, 3, 153
Flowerless plants, 3

Flowers, general structure of, 100; re-

lation of parts of, 134°
Follicle (Lat. foldiculus, asmall leathern

 

Elementary Botany

GYM

bag). A capsule opening along only
one of its edges, 138, 157

Food of plants, 3

Fool's Parsley, 168

Fool's Watercress, 169

Forget me-not, 175, 176

Forms, of calyx, 104; of cells, 16 ; of
corolla, 107 ; of fruit, 137 ; of inflores-
cence, 93; of leaves, 78; of roots, 32
ot stems, 55

Fovilla (Lat. foveo, to support, assist).
The protoplasmic contents of pollen
grains, 117, 126

Foxtatl, 187

Fragaria, 165

Free cell formation, 117

Free central placentation, 121, 154, 155,
161, 170

French Beans, 164

Fritillary, 184

Fruit, 135

Functions, of leaves, 85; of roots, 343
of stems, 44, 46, 48, 50, 53

Fundamental tissue, 412

Funiculus (Lat. alittle rope). The stalk
by which many ovules are attached
to the placenta, 122

Furze, 164

Fusiform (Lat. /usus, a spindle).
Spindle-shaped, ze. pointed at each
end. Applied , to cells, 16; and to
roots, 32

G4ALANTHUS, 385
Galeate, Lat. (galeatus, a helmed

warrior). Helmet-shaped, 105

Gamopetale (Gr. gamos, a marriage).
A group of dicotyledons with the
petals united, 154

Gamopetalous. Union of the petals of
the corolla, 107, 154

Gamosepalous. Union of the sepals of
the calyx, 104

Garlic, 184

Genera, 156

Genista, 162

Germination, 25

Glans (Lat. an acorn).
hardened walls, 142

Glomerulus (Lat. a little ball). A
cyme arranged in a compact head, 98

Glumace@, 154, 155, 185

Glumes (Lat. glwma, husk). The
scaly bracts in grasses and sedges,
93, 154, 185, 186

Good King Harry, 177

Goosefoot, 177

Grafting, 62

Graminacee, 186

Granulose (Lat. granum, a grain ot
corn). One of the constituents of
starch, 11

Guard cells. The cells around the
stomata of the epidermis, 41

Gymnosperms (Gr. mnos, naked ;
sperma, aseed). Plants whose seeds
are not contained in ovaries, 128

An achene with
Index and Glossary

GYN

Gynandrous (Gr. gzne,a woman ; aner,
aman). Applied to flowers where the
pistil and stamens are united together
in a central column, 114, 180 :

Gyncecium (Gr. ge, a woman ; otkos,
ahouse). The pistil or female organ
of the flower, 100, 113

Gynophore (Gr. gue, woman ; phero,
to carry). A prolongation of the
flower stalk beyond the calyx, bear-
ing the ovary, 124

ABENARIA, 182 :
Hairs, prolongation of the epi-

dermis of plants, 31, 72

Hawthorn, 166

Hazel, 101, 178, 179

Heartwood. ‘The inner wood of dicoty-
ledons, 46

Helianthus, 172 :

Helicoid (Gr. helix, helicos, coiled), The
same as bostrychoid, which see

Heliotropism (Gr. Helios, sun; trope, a
turn). The bending of plants towards
the light, 149

Helleborus, 158 ‘

Helosciadium, 169

Hemlock, 168

Heracleum, 167, 169

Herb Paris, 116, 183 2

Hermaphrodite (Lat. hermaphroditus).
Plants where stamens and pistil grow
in the same flower, 101 i

Hesperidium (from the Lat. Hesperides).
A multilocular berry, as seen in the
orange, 141 ;

Heterostylism (Gr. eteros, different
from). Plants where the styles differ
in length in the various flowers,

132

Hilum (Lat. a very little thing). The
scar by which the ovule or seed is
attached to the raphe or placenta, 3,
122

Hordeum, 188

Horse-radish, 160

poe re
acinthus, i

Fiybrid (Lat. igirida, amongrel). The
common offspring of two distinct
species, 156

Hydrocotyle, 169 .

Hydrogen of plant, whence obtained,

4

Hypocrateriform (Gr. Aupo, under;
krater, a goblet). Salve -shaped
corolla; that is, a long tube with
spreading lobes above, 109

Hypogeal (Gr. Augo, under; ge, the
Sn. Seeds whose cotyledons re-
main below the soil, 29

Hypogynous (Gr. Azo, under ; grne,
a woman). Attachment of petals and
stamens below the pistil, 107, 115,

154
lyssop, 174

 

205

INV

BERIS, 160

Imbricate (Lat. zwebricatus, over-
lapping). Arrangement of leaves in
a bud where they overlap like tiles of
a house, 65

\Imparipinnate (Lat. dwar, odd ; pin-

natus, winged), Leaves where the
leaflets are arranged on each side of
the central stalk like barbs of a
feather, and an odd leaflet terminates
the whole, 80

Imperfect flowers. Those where the
pistil and stamens are on separate
flowers, 100

. Incomplete, 154, 177
. Incomplete flowers.

Those where any

of the floral whorls are absent,
rI00

Indefinite inflorescence. Inflorescence
where the youngest flowers are above
or in the centre, 94

Indehiscent fruits (Lat. 7, not ; dehisco,
to gape). Fruits which do not break
when ripe, 136, 140

Indian Corn, 188

Indigo, 164

Induplicate (Lat. zz, in; duplicatus,
doubled). When in the leaf bud in-
volute leaves touch by their edges
without overlapping, 66

Inferior. Applied to the calyx when it
is attached beneath the ovary, 108 ;
and to the ovary when the calyx is
above it, 103

Inflorescence (Lat. 2/Zoresco, I flourish).
The general arrangement of the
flowers upon the stem, 93

Influence of plants on climate, 88

Infundibuliform (Lat. cz/fundibulunz,
a funnel). Funnel shaped: applied
to the calyx or corolla, 109 -

Innate (Lat. zzmatus, inbred). When
the anther lobes are attached imme-
diately on top of the filament, 115

Inner bark, 48

Integument of seed. (Lat. ztegummen-
tum, a covering) The outer coat of
seeds,

Interfascicular cambium (Lat. zzzer,
between ; fasciculus, a little bundle).
Cambium growing between the fibro-
vascular bundles, 47

Internodes (Lat. izter, between 3 xodis,
a knot). The portions of the stem
between the nodes, 60

Intine. The inner coat of the pollen
grains, 117

Intussusception (Lat. zz¢zs, from within;
suscifio, to beget). The peculiar
method of growth seen in organic
bodies, 15

Inula, 171

Inuline. A peculiar compound found in
the roots of Composite, 14

Involucel. A partial or secondary in-
volucre, 95

Involucre (Lat. ‘zvolucrum, a covering).
A whorl of bracts forming a covering
206

INV

around a single flower or a head of
flowers, 92, 95

Involute dae involutus, wrapped up).
Arrangement in the leaf bud when the
margins of the leaves are rolled towards
the upper surface, 65

Trregular. Applied to the calyx and
corolla when the various parts are
wanting in symmetry, 104, 107

/satis, 160

Gone 180

EEL. The innermost petals of a
papilionaceous flower, 109
Kino, 164
Knapweed, 171

[_ABELLUM (Lat. Zadbinm, a lip).
‘ The lower lip or petal of orchids,

160

Labiate, 155, 172

Labiate (Lat. dadium, a lip). Applied
to the calyx or corolla when arranged
in atwo-lipped manner, 104, 109, 172

Laburnum, 164

Laciniate (Lat. dacinia, a fringe). Ap-
plied toa leaf when it is very much
cut up, 83

Lactuca, 172

Lamina (Lat. a blade). The blade of a
leaf, 69

Lamiunt, 172, 173

Lanceolate (Lat. dancea, alance). Ap-
plied to leaves which are narrow and
pointed or lance-shaped, 79

Larkspur, 158

Latex (Lat. a liquid). A peculiar milky
juice in the stems and leaves of many
plants, 2

Lathyrus, 162, 163

Laticiferous vessels (Lat. datex, and fero,
I bear), The vessels containing the
latex, 23

Lavender, 174

Leaves, 69 ; forms of, 78; functions of,
85; margin of, 76; structure of, 71

Legume (Lat. degumex, pulse). A one-
celled monocarpellary capsule opening
by both edges, 138%, 162

Leguminos@, 155, 162

Lemon Grass, 188

Lepidium, 160

Leucojum, 185

Liber (Lat. inner bark). Theinner bark
of dicotyledons, 44, 48

Lignin (Lat. dignus, wood). The
changed condition of cellulose as seen
in woody cells, 7

Ligulate (Lat. Zigzda, a strap). Amem-
branous appendage at the top of the
sheath of the leaves of grasses, 186,

189
Liguliflora, 170, 17%

 

Elementary Botany

MES

Ligusticum, 169

Liliacee, 155, 183

Liliew, 183, 184

Lilium, 184

Linaria, 175

Linear (Lat. Zizea, a line). Applied to
leaves which are long and narrow with
parallel edges, 79

Liguidambar, 180

Liquorice, 164

Listera, 182

Loculicidal (Lat. Zoculus, a cell; czeo, I
move). Applied to those capsules
which, on dehiscing, open into the
loculi or cells, 13

Loculus (Lat. a cell). The cell or inter-
nal cavity in the various organs of the
plant, as the anther, 116; fruit, 137;
or ovary, 120

Locust-tree, 61, 164

Logwood, 164

Lomentum (Lat. bean meal) A fruit
which breaks up transversely into
several portions, 139, 159

poe 163
ovage, 169

Lychnis, 161

Lyrate (Lat. ra, aharp). A leaf with
the terminal lobe rounded and several
smaller lobes below, 82

Lysimachia, 176

M48scin of leaves, 76
Marjoram, 173

Marrubium, 173

Marsh Marigold, 157, 158

Mat Grass, 187

Matthiola, 160

May, 166

Meadow Saffron, 185

Meadow Sweet, 166

Medicago, 163

Medulla (Lat. the interior part). The
pith of dicotyledonous stems, 42-44

Medullary rays. The rays of parenchy-
matous tissue extending from the pith
to the bark, 44, 50

Medullary sheath. The layer of vessels
surrounding the pith, 45

Melampyrum, 175

Melilotus, 163

Melissa, 174

Mentha, 1

Mericarp (a. meris, a part; karpos, a
fruit). When a fruit breaks up into
pieces without the seeds falling out,
each piece is called a mericarp, 138

Meristem (Gr. szeristes, a divider).
Growing tissue, the cells of which are
continually dividing so as to produce
fresh tissue, 24

Mesocarp (Gr. sesos, middle; kargos,
fruit). The middle layer of the fruit, 135

Mesophleum (Gr. esos, middle;
phloios, bark), The middle or green

‘ ayes of the bark of dicotyledons, 43,
4
Index and Glossary

MES
Mespilus, 166
Micropyle (Gr. mikros, small; pzle, a
gate), The opening which leads into
the seeds and ovules, 3, 122
Midrib. The central vein which runs
from the base to the apex of the leaf,

75

Millet, 188

Mimosea, 162

Mint, 173

Mistletoe, growth of, 34, 90

Mixed inflorescence. Inflorescence where
there isa mixture of definite and in-
definite, 99

Molecular hypothesis, 15

Monadelphous (Gr. zzoxos, one; adel-
phos, a brother). Union of stamens
into one bundle by means of their fila-
ments, 114

Moniliform (Gr. monile, a necklace).
Applied to that form of root which has
several contractions, making it look
like beads on a necklace, 33

Monkshood, 157

Monochlamydeous (Gr. monos, one;
chlamus, a cloak), Flowers which
have only one floral envelope, 100

Monocotyledonous (Gr. zoos, one; hotz-
Zedon). Possessing but one cotyledon
in the embryo: characteristic of the
leaves, 74 5 root, 29; stem, 44 .

Monocotyledons, 5, 153, 155, 180

Moneecious (Gr. zones, one; otkos, a
house). Plants which have the sta-
mens and pistil on different flowers
but on the same plant, 102

Monopodium (Gr. monos, one; ors,
podos, a foot), In branching, where
several branches grow from a common
axis, 67

Mouse-ear Chickweed, 161

Mousetail, 158

Movements of plants, 151

Movements of protoplasm, 8

Movements of water in plants, 145

Mucilage, 7 ,

Mucronate (Lat. mucronatus, pointed).
Applied to the leaf when the apex is
flattened, with a sharp point growing
out, 78

Mullein, 175

Multicostate (Lat. #ultus, many 3 costa,
arib). A leaf with several principal
veins, 75

Multifoliate (Lat. mulius, many;
folium, a leaf). A leaf with many
leaflets springing from a common
point, 80

Multilocular (Lat. wadtus, many ; Zocu-
lus, a cell). A cavity divided into
several cells, as in several ovaries, 120;
and fruits, 147

Mustard, 160

Myosotis, 175, 176

Myosurus, 158

Myrica, 179

Myricee, 179

Myrrhis, 169

 

207

OST

N42PIFORM (Lat. zagus, a turnip).
Aroot which is swollen ina turnip-

like manner, 32

Narcissus, 185

Nasturtium, 160

Natural system, 153

Nectary (Lat. zectar, honey), Recepta-
cles in the flower containing honey, 111

Nitric acid and nitrates, 35

Nitrogen of plant, whence obtained, 35
ode (Lat. zodus, a knot). The points
on the stem from which the leaves are
given off, 60

Nodulose (Lat. xodus, aknot). Applied
to roots which have knot-like swell-
ings, 33

Normal root. The root which is formed
by the direct prolongation of the
radicle, 29

Nucleus (Lat. a kernel) A mass of proto-
plasm aggregated at a certain point in
the cell, 117; also the internal portion
of the ovule in which the embryo is
formed, 122; and therefore the portion
of the seed within the seed coats, 4

Nut (Lat. zx). Anachene with har-
dened walls 42

AK, 180
Oats, 188

Obcordate (Lat. od, inversely ; cov, a
heart). Inversely heart-shaped. Ap-
plied to the outline of leaves, 79

Oblong. Applied to leaves, 79

Obovate (Lat. 04, inversely ;, ovatus,
egg-shaped). Applied to the outline
of leaves,

Obvolute (Lat. obvolutus, covered over),
When the leaves inthe bud are partly
covered over one another, 66

Ocymeunt, 174

Gnanthe, 16

Offset. A short thick branch whose
terminal bud takes root, 55

Old Man’s Beard, 158

Onobrychis, 163

Oosphere (Gr. coz, an egg ; sphaira, a
globe). Cells formed within the em-
bryo-sac of conifers, 129

Open bundles. Fibro-vascular bundles
which contain cambium, 44

Ophrys, 182

Opoponax, 170

Opposite leaves, 84

Orache, 177

Orchidacee, 155, 180

Orchis, 180, 182 ; fertilisation in, 181

Organic elements, 34

Ornithogalum, 184

Orthotropous (Gr. orthos, straight; repo,
Iturn). When the ovuleis straight, 123

Oster, 179

Osmosis (Gr. dszos=dsts, an impulse).
The passage of liquids through a per-
meable membrane, 36

Ostrya, 180
208

OUT

Outline of leaves, 78
Oval leaf, 79
Ovary (Lat. ovam, anegg). The lowest
part of the pistil, which, on ripening,
forms the fruit, 118
Ovate (Lat. ovatus, egg-shaped). Ap-
lied to leaves which are rounded and
road at the base and tapering at the
apex, 79
Ovule (at. diminutive of ovz, an
egg). The unripened seed, 118, 122
Oxygen of plant, whence obtained, 35

PALES (Lat. falea, chaff). The
membranous bracts surrounding the
flowers of grasses, 187

Palmate (Lat. Jadmatus, palm-shaped).
A leaf with divisions spreading out so
as roughly to appear like an outspread
hand, 83; root, 33

Panicle (Lat. panzcula, the down upon
reeds). A compound raceme, 96

Papilionacee, 162.

Papilionaceous (Lat. Aagsilio, a butter-
fly). A special form of irregular co-
mols as seen in the sweet pea, 109,
162

Pappus (Lat. thistledown). The divided
and hairy calyx as seen in Compo-
site, which often grows into long
hairs crowning the fruit, 105

Paracorolla (Gr. fara, besides, and
corolla). An organ which sometimes
grows between the corolla and sta-
mens, 110

Parallel venation. Venation of leaves
of monocotyledons where there are no
cross veins forming a network, 74

Parasite (Lat. Jarasitus, a guest). A
plant which obtains its nourishment
by growing upon another, go

Parenchyma (Gr. paregcheo, to pour
in besides). Cellular tissue where the
cells are no longer than they are broad,

2

Parietal (Lat. Jaries, a wall). Attach-
ment of ovules upon the wall of the
ovary, 121 7

Paripinnate (Lat. par, equal ; Ainna, a
feather). Pinnate leaves without an
odd leaflet at the end, 8z

Paris, 183

Parsley, 169

Parsnip, 169

Pastinacea, 169

Patchouly, 174

Pea, 163, 164

Peach, 165 : P

Pedate (Lat. jedatus, furnished with
feet). A palmate leaf with the side
lobes divided so as to roughly re-
semble a bird’s foot, 83 -

Peony, 159 7 :

Pepo (Lat. a gourd), A fruit resembling
a berry, but with the outer walls
firmer and harder, 141

 

Elementary Botany

PHY

Perfect. Applied to flowers when both
stamens and pistil are present, 100

Perfoliate (Lat. fer, through ; folium, a
leaf). Applied to the real or apparent
growth of the stem through the leaf,

5

Perianth (Gr. geri, around; axthos,

‘a flower), Term applied to the calyx
and corolla, especially amongst mono-
cotyledons, when they are alike in
appearance, 111

Pericambium (Gr. feri and cambium).
The cambium in roots from which the
branches are produced, 31

Perigynous (Gr. peri, and gune, woman).
Applied to petals and stamens when
attached around the ovary, 107, 115,
154, 164

Perisperm (Gr. evi, around ; sperma, a
seed), The albumen formed within
the ovule outside the embryo-sac, 5,
I2

Permanent tissue. That which is no
longer dividing and increasing in the
number of its cells, 24

Persistent (Lat. Jersistens, remaining).
Applied to any organ which remain
beyond the usual time of such an
organ on other plants, as the calyx
when it remains after fruiting, 104

Personate (Lat. fersona, a mask). A,

* two-lipped corolla with the two lips
closed, 109, 174-175

Petal (Gr. Aetalon, a leaf). One of the
separate parts of the corolla, 100, 107

Petaloide, 155, 180

Petiole (Lat. Aetzodzs, a little foot). The
stalk of the leaf, 69

Petroselinum, 169

Phanerogams (Gr. phaneros, apparent ;
ganws, marriage). Flowering plants, 3

Phaseolus, 164

Pheasant’ s Eye, 157

Phelloderma (Gr. phellos, cork ; derma,
skin). The middle bark of dicotyle-

dons, 43, 48

Phellogen (Gr. phedlos, cork ; gennao, to

. produce). The formative tissue from

' which the cork layer is increased in
thickness, 43

Phloém (Gr. ZAlozos, the inner bark of
trees). The inner bark or liber, 41,
43, 48

Phormium, 185

Phosphorus of plant, whence obtained,

35,

Phylloclade (Gr. phzllon, a leaf;
#lados, a branch). A branch which is
flattened in a leaf-like manner, 184

Phyllocyanin (Gr. phullon, a leaf;
uanos, blue). The blue colour of
chlorophyll, 8

Phyllode (Gr. phdion, a leaf; eidos,
form). A petiole which is flattened
and leaf-like, 70

Phylloxanthin (Gr. phullon, a leaf;
xanthos, yellow). ‘The yellow colour
of chlorophyll, 8
Ludex and Glossary

PIL

Pileorhiza (Gr. Azlos, a cap; rhiza,a
root). The protecting layer of cells
which covers the growing point of
roots, 29

Pimpernel, 176

Pimpinella, 169

Pine, fertilisation of, 128

Pine, germination of, 27

Pink, 161

Pinnate (Lat. siznatus, feathered), A
leaf where the leaflets are arranged on
each side like the barbs of a feather, 80

Pistil (Lat. ae a pestle), The
inner whorl of floral organs, 100, 118

Pistillate flower.
stamens, 101

Pisunt, 163, 164

Pith (Anglo- Saxon Jitha, marrow).
The internal column of parenchyma-
tous cells found in the stems of dicoty-
ledons, 44

Pitted cells. Cells where the secondary
deposit is arranged in little pits or
channels, 18

Placenta (Lat. a cake). The part of the
ovary to which the ovulesare attached,

A flower destitute of

120

Placentation, Attachment of ovules to
the placenta, 120

Placentiform. A flattened form of root,

32

Plant, definition of, z

Plicate (Lat. Alicatus, folded). The
arrangement of the leaf in the bud
when it is folded up like a lady’s fan,

64
Plumule (Lat. Adzsz2a, a little feather).
The undeveloped stem in the embryo,

4
Plumule, development of, 40
Pogostemon, 17.
Pollen (Lat. fine flour). The fine dust
within the anthers of the stamens,

x

Eoibeaton: The act of pollen grains
falling upon the the stigma, 125

Polyadelphous (Gr. Zolus, many ; aded-
os, a brother). Union of stamens
into several bundles, 114

Polygamous (Gr. pods, many ; gavzos,
marriage). Where upon the same
plant there are staminate, pistillate,
and perfect flowers, 102

Polygonatum, 183

Polyhedral (Gr. Jolus, many; hedra, a

side). Applied to cells of many sides |

or faces, 17

Polypetalous (Gr. Jolus, many ; petalon,
a leaf) Applied to the corolla
where the petals are separate, 107

Polysepalous (Gr. folus, many; Low
Lat. sepalum, a sepal). apes tothe
calyx where the sepals are distinct, 104

Pome (Lat. omui, an apple). A berry-
like pseudocarp as seen in the apple,
142, 166

Pome, 166

Poplar, 179

 

209

RAD

Portuguese Laurel, 165

Potato, structure of, 57

Potentilla, 165

Poterium, 166

Preefloration(Lat. Zve, before; os, foris,
a flower). The arrangement of the
parts of the flower in the bud, 113

Przfoliation (Lat. ve, before; /olium,
a leaf). The arrangement of the
leaves in the bud, 63

Primine (Lat. Jrinzus, first), The inner
coat of the ovule, 122

Primrose, 176

Primose, fertilisation of, 132

Primula, 176

Primulacee, 176

Procambium (Gr, Avo, before, and cawz-
bcunz). The formative tissue which
first builds up the fibro-vascular bun-
dles, preceding the true cambium, 42

Prosenchyma (Gr. gros, towards ; egcheo,
to pour in). Cellular tissue where the
cells are long and pointed, 24

Protandrous Gr. protos, first; aner,
man). Flowers where the stamens are
‘ripened before the pistil, 132

Protococcus, 1

Protogynous (Gr. protos, first; gene,
woman). Flowers where the pistil is
ripened before the stamens, 131

Protoplasm (Gr. profos, first; plasma,
anything moulded). The living con-
tents of the cell from which the new
cells are produced, 7; movements of,
8

Prunus, 165

Pseudocarp (Gr. psezdos, false; harpos,
a fruit). Applied when any part of
the plant besides the ovary is united
with the fruit, 135, 142

Purslane, 177

Pyrus, 166

Pyxis (Lat. a box). A capsule which
dehisces transversely, so that the upper
part comes off like a lid, 138

UADRIFOLIATE (Lat. guadrans,
a fourth part ; fodiz, a leaf), A
leaf with four leaflets, 80
Quercus, 180
Quinate (Lat. guéngue, five).
with five leaflets, 80
Quince, 167

A leat

RRACEME (Lat. vacemus, a bunch),
A form of indefinite inflorescence
with lengthened axis and stalked
flowers, 95, 96

Radiating veined (Lat. vadiuvs, a suns
beam), 76 7

Radical (Lat. vadix, a root) Growing
from a point close to the summit of the
root, 85 ane

Radicle (Lat. vadicuda, diminutive of
radix, root). The part of the embryo

a
210
« RAG
which forms the future root of the
plant, 4

Ragged Robin, 161

Ragwort, 171

Ramal (Lat. amus, a branch), Grow-
ing upon the branches, 85

Ranunculacee, 154, 156

Ranunculus, 156, 159

Heplie (Gr. a cord). A cord running up
the side of an anatropous ovule, 123

Raphides (Lat. vaphis, a needle). Crys-
tals, often needle-shaped, contained
within the cells of plants, 13

Rattle, 175

Ray. The outer florets in the flower

heads of Composite plants, 109, 170

Reclinate (Lat. recline, to lean back-
wards), When in the bud the apex of
the leaf is bent towards the base, 64

Regular : calyx, 104 ; corolla, 107

Relation of the flower to the other parts
of the plant, 134

Reniform (Lat. ven, kidney ; forma,
form). Kidney-shaped, that is, a leaf
rounded at the apex and hollowed at
the base, 79

Replum (Lat. part of adoor), The cen-
tral part in the siliquas and siliculas
which remains after the valves have
fallen away, 138

Respiration of plants, 87

Reticulate (Lat. reticzdus, a small net).
Arranged in a net-like manner ; ap-
plied to cells, 19; to the venation of
leaves, 74

Retuse (Lat. ve¢#szs, blunted). A notch
in the apex of a leaf, 77

Revolute (Lat. revolutus, turned back).
When in the bud the two edges are
rolled towards the under side of leaf,

65

Rhinanthus, 175

Rhizome (Gr. vhiza, a root). A creep-
ing underground stem, thick and
swollen, 55

Rice, 188

Rind. The outer coat of monocotyle-

donous stems, 51 ne

Ringent (Lat. +/mgens, grinning). A
bilabiate corolla where the lips are
widely separated, 109, 172

Rings of wood, 45

Roots, 25; branches, 31; forms, 31;
functions, 34 ; growth, 29 ; increase in
thickness, 31; structure, 29

Rosaceae, 164

Rose, 165

pee 165
osemary, 174

Rotate (at. vota, a wheel), Wheel-
shaped ; applied to a rounded corolla,
tog ; and calyx, 104

Rotation of crops, 37

Rowan-tree, 166

Rubus, 164, 165 :

Runcinate (Lat. runcina, a large saw).
A pinnatifid leaf where the terminal
lobe and side lobes are angular, 82

 

Elementary Botany

SEE

Runner. A slender prostrate stem as
seen in the Strawberry, 55

Ruscus, 183, 184

Rye, 188

Rye Grass, 187

SaccaTE (Lat. sacc#s, a sack).
When two of the sepals have a
swelling at their base, 104
Saccharum, 188
Safflower, 172
Sage, 173 ; fertilisation of, 131
Sagittate (Lat. sagitta, an arrow).
Arrow-shaped: applied to leaves
which are pointed at the apex, and
with two pointed lobes like barbs
growing back at the base, 80
Salicinee, 179
Salix, 179
Salver-shaped.
Salvia, 173
Samara (Lat. the fruit of the elm).
A winged fruit, that is, one with
a membranous expansion attached,

See Hypocrateriform

139

Samphire, 168

Sandal-wood, 164

Sander’ s-wood, 164

Sanguisorba, 166

Sanguisorbea, 166

Sanicula, 170

Sap (Lat. saga, sodden wine). A genera
term for the juices of the plant, 12

Sapwood. The outer wood of dicotyle-
dons, 46

Sarothamnus, 163

Satureia, 174

Savory, 174

Scalariform(Lat. scala, a ladder ; forma,
form). Term used when the secondary
thickening of a cell is arranged like
rungs of a ladder, 20

Scarlet Runner, 164

Schizocarp (Gr. schizo, to split ; Aargos,
fruit), A fruit which splits into sepa-
rate pieces each containing one seed,

33

Schultze’s solution, 7

Scilla, 183, 184

Scirpus, 186

Sclerenchyma (Gr. slevos, hard).
Tissue much hardened by formation
of secondary deposit, 24 .

Scorpioid (Gr. skorfios, scorpion ; ezdos,
resemblance). Used in branching as
equivalent to cicinnal, which see, 67 ;
also a peculiar form of inflorescence, 98

Scorpion Grass, 176

Scrophularia, 175

Scrophulariacee, 174

Sea Holly; 169

Sea Kale, 160

Secale, 188 ;

Secundine (Lat. secundus, second). The
inner coat of the ovule, 122

Sedge, 185, 186

Seeds, structure of, 3
Index and Glossary

SEL

Selective poe of roots, 37

Sensitive Tree, 151, 164

Sepal (Fr. sefale; Low Lat. sepalum).

portion of the calyx, the outermost

covering of the flower, 100, 102

Septenate (Lat. septem, seven). A leaf
with seven leaflets, 80

Septicidal’ (Lat. septum, a division;
c@do, 1 cut). A capsule where dehis-
cence takes place along the septa, 137

Septifragal (Lat. septumz, a division ;
frango,1 break). A capsule where,
the carpels opening by their dorsal
sutures, the septa separate from the
valves, 137

Serrate (Lat. serratus, sawed). Applied
to the margin of the leaf when there
are a number of sharp saw-like teeth
Pons towards the apex, 76

Sessile (Lat. sessiis, sitting). When
any organ is destitute of a stalk, 70, 95,

11g

Sieve-tubes. Vessels with the separa-
ting walls perforated in a sieve-like
Manner, 21

Szlene, 161

Silica of plants, whence obtained, 35

Silicula (Lat. a little pod). In structure
like the siliqua, but shorter and
broader, 138

Siliqua (Lat. abean pod). A bicarpellary
capsule with a replum running up the
centre; the two valves break away
and leave the seeds attached upon the
replum. It is long and narrow in
shape, 138

Silver grain, 50

Sinuate (Lat. szzwatus, crooked). Ap-
plied to the margin of the leaf when
there are alternate lobes and depres-
sions of a larger form than in crenate
leaves, 77

sien.
napdragon, 174

Soboles (Lat. a sprout) An under-
ground creeping stem thinner than
the rhizome, 56

Solomon's Seal, 183

Sowbread, 176

Spadix (Lat. a palm branch). A fleshy
unisexual spike surrounded by aspathe,

9 é
Spathe (Lat. sfatha, the flowering

branch of a palm tree). A bract enve-

loping one or a number of flowers, 92,

9! :

Spathulate (Lat. spathula, diminutive
of sfatha). Spoon shaped; when
a leaf is rounded at the apex and
narrower towards the base, 79

Species, 156

Spermoderm (Gr. spernza, seed ; derma,
skin), The term used collectively for
the coats of the seed, 4

Sphere crystals, 14

Spike (Lat. sfica, an ear of corn). An
indefinite inflorescence with prolonged
axis and sessile flowers, 94, 96

SUP

: ee rnecea, 177
pine. A modified branch or leaf which
is hard, stiff, and sharp-pointed, 61
Spiny leaves, Leaves with sharp spines
on their margins, as in the holly, 77
mena cells, 18; vessels, 22; vernation,

Spirea, 166

Spur. A prolongation of the various
parts of the flower, 111

Stamen (Lat, a distaff). One of the
divisions of the andrcecium, the outer-
most whorl of the essential organs of
the flower, 100, 11

Staminate flowers.
but no pistil, ror

Staminode (stamen, and Gr. eidos, re-
semblance). An abortive stamen.

Standard. One of the petals of papilio-
naceous flowers, 109

Star of Bethlehem, 184

Starch, 9

Stellaria, 161

Stellate (Lat. s#ed/a, a star). Term used
in describing cells with several star-
like processes, 16

Stems, 40; forms of, 53 ; growth of, 45,

3
Those with stamens

52

Stigma (Gr. a point). The portion of
the pistil which receives the pollen,
118, 122

Sting, 72

Stipulate. Possessing stipules, 69

Stipule (Lat. s¢ipuda, a blade). ~ Folia-
ceous organs often attached at the base
of the leaf, 69

Stitchwort, 161

Stock, 160

Stolon (Lat. a shoot). A branch given
off above ground and striking into the
soil, 55

Stomata (Gr. stoma, a mouth). The.
openings through the epidermis of
plants, 41, 71

Storehouse of food, 39

Strawberry, 165

Striation of cell wall, 21

Strobilus (Lat.acone). An inflorescence
differing from a cone in possessing
membranous bracts, 96

Style (Lat. styles, a sharp-pointed in-
strument used for writing on waxed
tablets). The stalk which supports
the stigma upon the ovary, 118, r21

Suber(Lat. cork). A changed condition
of cellulose met with in cork, and epi-
dermis cells, 7

Subterranean stems,

Sucker (Lat. suvculus, a branch) A
branch springing below the soil and
growing up into the air, 55

Sulphur of plant, whence obtained, 35

Sunflower, 172

Superior. Applied to calyx when above
ovary, 103; and to ovary when above
calyx, 103

Supervolute (Lat. sper, upon ; volutus,
rolled). When in the leaf bud two

 
212
SUT.

convolute leaves are rolled one around
the other, 66

Suture (Lat. swtzra, a seam). The line
of junction, especially used with re-
gard to the ovaries and fruits, 120, 138

Sweet Cicely, 169

Sweet Pea, 162, 163

Symphytum, 176

Sympodium (Gr. sw, together ; ous,
fodos, a foot) Applied in branching
where the branches become strong so
as to form a false axis, 66, 67

Syncarp (Gr. sum, together ; karfos,
fruit). A compound fruit formed by
the pening. of an inflorescence, 135

Syncarpous (Gr. sux, together ; karfos,
fruit). The union of the several carpels
of one pistil, 119

Syngenesious (Gr. sun, together ;genesis,
origin). Union of stamens by means
of their anthers, 114

“TABULAR (Lat fabula, a table).
Term applied to flattened cells, 17

Tamarind, 164

Taraxacum, 170, 172

Tares, 16.

Tegmen (Lat. tego, I cover), The inner

coat of the seed, 4
Temperature necessary for germination,

148

Tendrils, 6x

Terminal buds, sg

Ternate (Lat. teruus, three each), A
leaf with three leaflets, 80

Testa (Lat. a covering),
coat of the seed, 4

Tetradynamous (Gr. tetra, four ; duna-
mis, power). With four long and
two short stamens, 115

Teucrium, 173

Thalamiflore, 154, 156

Thalamus (Lat. a bed-chamber). The
end of the flower-stalk, to which the
flower is attached, 123

Thistle, 171

Thymus, 173 P

Thyrsus (Lat. a stalk), A panicle with
short stalks, 96

Tonguin Beans, 164 ae

Tracheides (Lat. trachea, windpipe).
Cells with both spiral markings and
pores, 19

Transpiration of plants, 87, 145

Traveller's Foy, 158

Trefoil, 163

Trifolium, 163

Trillidee, 183

Trimorphic (Gr. ¢vezs, three; sorphe,
shape), Plants where there are three
different lengths of pistil and stamens
in various flowers, 133 :

Tripinnate (Lat, ¢ves, three; pinna, a
feather), A pinnate leaf in which the
leaflets are themselves pinnate, and
these secondary divisions are again
divided in a pinnate manner, 82

The outer

Elementary Botany

VER

ft Triticum, 186, 188

Truncate (Lat. ¢v#ncatus, maimed).
When a leaf terminates abruptly, 78

Trunk (Lat. ¢ywucus, the stem of a
tree), 54

Tuber (Lat. a_ swelling).
underground branch, 57

Tuberculated. A root with tuber-like
swellings, 33

Tubular (hae tubus, a pipe). Applied
to the form of the calyx, 104; and
corolla, 107

Tubuliflore, 170

Turbinate (Lat. ¢rbineus, top-shaped).
Applied to the form of the calyx
104

Turnip, 160 ; root of, 39

Twayblade, 182

Twining stems, 54

A swollen

LEX, 164
Umbel (Lat. 2zbella, a sunshade).

An indefinite inflorescence with short-
ened axis and stalked flowers, 95

Umbellifere, 155, 167

Unicostate (Lat. xaus, one; costa, a
rib). Leaves with only one principal
rib or vein, 75

Unilocular (Lat, unus, one; loculus, a
cell). Containing only one cavity
Applied to anthers, 116; to ovaries
120; and to fruits, 138

Urceolate (Lat. xvceolus, alirtle pitcher).
Pitcher-shaped ; applied to the shape
of the calyx, 104 ; and corolla, rog

vs of insects in fertilising flowers, 130,
182

“VACUOLI (Lat. vacuum, an empty
space). The drops in which the

cell sap first appears in the proto-
plasm, 12

Vagina (Lat. a sheath). Applied to the
base of the leaf when it encircles the
stem, 85

\Valvate (Lat. valve, folding doors).
Applied to the bud when the indi-
vidual leaves touch without overlap-
ping, 66

Vanilla, 182

Veins, The fibro-vascular bundles in
the leaves, 72

Venation. The arrangement of the veins
in the leaf, 72

Verbascum, 175

Vernal Grass, 187

Vernation (Lat. ver, spring). Arrange-
ment of leaves in the bud, 63

Veronica, 175

Versatile (Lat. versatilis, revolving).
Applied to an anther which swings on
top of the filament, r1r5

Verticillaster (Lat. vertici@lum, a little
whorl; aster, a star). Cymose bun-
ches which give the appearance of

 

whorled flowers, 99
Lndex and Glossary

VER

Verticillate (Lat. verticilZune). Whorled :
applied to leaves, 84

Vessels. Tubes formed by the fusion of
cells, 21

Vetch, 16.

Vexillum (Lat. astandard), One of the
petals of papilionaceous flowers, 109

Vicia, 164

Violet, 156, 190

Viper’s Bugloss, 176

JV ALLFLOWER, 159, 160
Walnut, 180

Wardian cases, 88

Watercress, 160

Water Dropwort, 169

Water Hemlock, 168

Water Violet, 176

Wheat, 186, 188; germination of, 28

White Rot, 169

Whorl. An arrangement where the or-
gans are placed in a circle round the
central axis. Applied to leaves, 84 ;
and to the parts of the flower, 100

 

213

ZEA

Wild Service-tree, 167

Windflower, 158

Wing. One of the side petals of a
papilionaceous flower, 109

Woad, 160

Wood. The central part of the fibro-
vascular bundles, especially when
hardened by secondary deposit, 41 44

45
Wormwood, 171

X ANTHORRH(UEA, 185
Xylem (Gr. xzlon, wood) The
same as the woo.l, 41, 44, 45

EAST, 6
Yellow Loosestrife, 176
Vellow Pimpernel, 176 ~
Yucca, 185

ZEA; 188

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