BOTANICAL TEXT-BOOK. THE BOTANICAL TEXT-BOOK, AN INTRODUCTION TO SCIENTIFIC BOTANY, BOTH STRUCTURAL AND SYSTEMATIC. FOR COLLEGES, SCHOOLS, AND PRIVATE STUDENTS. POURTH EDITION, ILLUSTRATED WITH TWELVE HUNDRED ENGRAVINGS ON WOOD. BY ASA GRAY, M. D. FISIIER PROFESSOR OF NATURAL HISTORY IN IIARVARD UNIVERSITY. NEW YORK: GEORGE P. PUTNAM & CO. 1 85 3. Entered according to Act of Congress, in the year 1853, by GEORGE P. PUTNAM & CO., in the Clerk's Office of the District Court of the Southern District of New York. CAMHBRIDGE: METCALF AND COMPANY, PRINTERS TO' THE UNIVERSITY. PREFACE TO THE THIRD EDITION. THIS compendious treatise is designed to furnish classes in our schools and colleges with a suitable text-book of Structural and Physiological Botany, as well as private students with a convenient introductory manual, adapted to the present condition of the science. The favor with which the former editions have been received, while it has satisfied the author that the plan of the work is well adapted to the end in view, has made him the more desirous to improve its execution, and to render it a better exponent of the present state of Physiological Botany. To this end the structural and physiological part of the work has been again almost entirely rewritten for this Third Edition, and much enlarged. The chapter on the Elementary Structure of Plants, or Vegetable Anatomly, the sections on the Internal Structure of the Stem, on Phyllotaxis and its relations to floral structure, and on the Symmetry and Morphology of the Flower, may be particularly adverted to, as having been altogether recast and greatly extended. The want of space and time has prevented a similar extension of the systematic part of the work, especially of the 1 * Vi PREFACE. Illustrations of the Natural Orders. This portion, however amplified, could never take the place of a Flora, or System of Plants, but is designed merely to give a general idea of the distribution of the vegetable kingdom into families, &c., withl a cursory notice of their structure, distribution, properties, and principal useful products. The student who desires to become acquainted, as he should, with the plants that grow spontaneously around him, will necessarily use some local Flora, such, for example, as the author's Manual of the Botany of the Northern United States. For particular illustrations the botanist may advantageously consult the.. Genera of the Plants of the United States, illustrated by Figures and Analyses from Nature, of which two volumes have been published. By permission of the Secretary of the Smithsonian Institution, the figures No. 20-22, 33, 37, 105-110, 130133, 135, 136, 159, 160, and 161-164, are copied from original sketches made for the Introduction to a Report on the Trees of the United States, now in preparation by the author, for that Institution. The changes in this Fourth Edition are comparatively small; consisting of corrections and minor alterations, especially in the parts which relate to Vegetable Anatomy and Physiology, and in the addition of a short chapter on the Fecundation of Cryptogamous or Flowerless Plants. HARVARD UNIVERSITY, CAMBRIDGE, March, 1853. CONTENTS. PAGE INTRODUCTION. - GENERAL SURVEY OF THE SCIENCE.. 13 PART I. STRUCTURAL AND PHYSIOLOGICAL BOTANY. CHAPTER I. OF THE ELEMENTARY STRUCTURE OF PLANTS....17 SECT. I. OF ORGANIZATION IN GENERAL. 17 The Elementary Constitution of Plants... 17 Their Organic Constitution..... 18 Distinctions between Minerals and Organized Beings 19 Individuals and Species..20 Life... 21 Difference between Vegetables and Animals.... 22 SECT. I.. OF THE CELLS AND CELLULAR TISSUE OF PLANTS IN GENERAL... 23 Cellular Structure.2. Formation and Development of Cells.26 Multiplication of Cells.29 Gemmation or Budding of Cells.32 Elongating and Ramifying Cells.. 33 Circulation in Young Cells.33 Permeability and Imbibition (Endosmosis) 34 Growth of Cell-Membrane interstitially.. 35 Thickening by Deposition.. 36 Markings of the Walls of Cells.... 38 Free Gelatinous Coils in Cells..... 42 VIii CONTENTS. SECT. III. OF THE KINDS OR TRANSFORMATIONS OF CELLULAR TISSUE...... 42 Parenchyma... 43 Prosenchyma, Woody Tissue...... 44 Bast Tissue..... 46 Vascular Tissue or Vessels...... 48 Interlaced Fibrilliform Tissue...... 52 Laticiferous Tissue......52 Intercellular System........ 54 Epidermal System......55 SECT. IV. OF THE CONTENTS OF THE TISSUES... 56 Sap......56 Proper Juices...... 57 Starch....... 57 Vegetable Jelly......59 Sugar, Wax, Chlorophyll.. 60 Alkaloids....... 61 Vegetable Acids.... 61 Crystals or ]aphides...... 62 Silex...... 63 CHAPTER II. OF THE GENERAL MORPHOLOGY OF THE PLANT.64 The Individual Plant. i..... 64 Plants of a Single Cell........ 65 Plants of a Single Row of Cells....... 68 Spores, Conjugation...... 69 Plants of a Tissue of Cells...... 70 Plants with a Distinct Axis and Foliage... 72 Thallophytes and Cormophytes...... 73 Cellular and Vascular Plants...... 73 Cryptogamous or Flowerless Plants...... 75 Phmnogamous or Flowering Plants.... 76 Development of the Plant from the Embryo 77 Organs of Vegetation.. 79 CHAPTER III. OF THE ROOT OR DESCENDING AXIS so The Primary Root.... 80 Annuals, Biennials, and Perennials 85 Secondary Roots......87 Aerial Roots....... 87 Epiphytes....... 89 Parasites....... g90 CONTENTS. ix CHAPTER IV. OF THE STEM OR ASCENDING AXIS 93 SECT. I. ITS GENERAL CHARACTERISTICS AND MODE OF GROWTH.. 93 Nodes and Internodes. 94 Buds... 95 SECT. II. RAMIFICATION. 98 Branches. 98 Adventitious and Accessory Buds. 100 Propagation from Buds. 103 SECT. III. THE KINDS OF STEM AND BRANCHES... 103 Herbs, Shrubs, and Trees.103 Stolons, Runners, Tendrils, Thorns, &c. 104 Subterranean Modifications.106 Rhizoma or Rootstock.108 Tuber, Corm. 109 Bulbs and Bulblets.. 110 SECT. IV. THE INTERNAL STRUCTURE OF THE STEM.. 112 SECT. V. THE EXOGENOUS OR DICOTYLEDONOUS STEM. 115 The First Year's Growth.. 116 The Pith and Medullary Sheath.. 116 The Wood.. 117 The Bark......... 119 The Second Year's Growth in Diameter 121 Annual Increase of the Wood.. 122 Sap-wood and Heart-wood.. 124 SECT. VI. THE ENDOGENOUS OR MONOCOTYLEDONOUS STEM 129 SECT. VII. OF THE THEORETICAL STRUCTURE OF THE STEM 132 Origin of the Wood.132 The Plant a Composite Being. 137 Phytons. 139 CHAPTER V. OF THE LEAVES.141 SECT. I. THEIR ARRANGEMENT.... 141 Phyllotaxis... 141 Vernation or Preefoliation.151 SECT. II. THEIR STRUCTURE AND CONFOR.MATION 152 Anatomy of the Leaf.. 152 Stomata... 157 Development of the Leaf.... 160 X CONTENTS. The Forms and Venation of Leaves... 161 Compound Leaves.168 The Petiole or Leafstalk. 172 Phyllodia.. 172 Ascidia, or Pitchers. 174 Stipules..175 SECT. III. THEIR DEATH AND FALL; EXHALATION, ETC.. 175 Duration of Leaves.175 Fall of the Leaf......... 176 Death of the Leaf... 177 Exhalation from the Leaves.179 Rise of the Sap.. 179 CHAPTER VI. OF THE FOOD AND NUTRITION OF PLANTS..... 181 SECT. I. THE GENERAL PHYSIOLOGY OF VEGETATION. 181 SECT. II. THE FOOD AND ELEMENTARY COMPOSITION OF PLANTS 1 83 SECT. III. ASSIMILATION, OR VEGETABLE D[GESTION, AND \ ITS\ RESULTS.194 CHAPTER VII. OF FLOWERING AND ITS CONSEQUENCES.. 209 Flowering an Exhaustive Process...... 209 Evolution of Heat.211 Plants need a Season of Rest.213 CHAPTER VIII. OF THE INFLORESCENCE... 215 Indefinite or Indeterminate Inflorescence.... —.. 216 Definite or Determinate Inflorescence.. 222 CHAPTER IX. OF THE FLOWER.... 227 SECT. I. ITS ORGANS, OR COMPONENT PARTS.. 227 SECT. II. ITS THEORETICAL STRUCTURE OR GENERAL MORPHOLOGY.230 SECT. III. ITS SYMMETRY.238 Alternation of the Floral Organs...... 241 Position as Respects the Axis and Bract..... 243 SECT. IV. THE VARIOUS MODIFICATIONS OF THE FLOWER 244 Augmentation of the Floral Circles. 248 Chorisis or Deduplication. 249 CONTENTS. Xl Coalescence of Parts.256 Adnation.......... 258 Irregularity. 260 Suppression or Abortion. 263 Abnormal States of the Receptacle. 276 SECT. V. TIlE FLORAL ENVELOPES.277 Their Development..277 XAstivation or Prsefloration..278 The Calyx..285 The Corolla. 286 SECY. VI. THE STAMENS 2..289 The Filament and Anther.291 The Pollen..........295 SECT. VII. THE PISTILS.. 297 The Placenta.300 The Carpel or Carpidium. 300 The Compound Pistil. 301 Modes of Placentation. 302 Gynxcium of Gymnospermous Plants.. 306 SECT. VIII. THE OVULE.. 09 SECT. IX. FERTILIZATION. 313 Action of the Pollen.... 313 Formation of the Embryo. 315 CHAPTER X. OF THE FRUIT.... 320 SECT. I. ITS STRUCTURE, TRANSFORMATIONS, AND DEHISCENCE.320 SECT. II. ITS KINDS.. 325 CHAPTER. XI. OF THE SEED.330 SECT. I. ITS STRUCTURE AND PARTS.330 The Nucleus and Albumen. 332 The Embryo..334 SECT. II. GERMINATION.336 CHAPTER XII. OF REPRODUCTION IN CRYPTOGAMOUS PLANTS.339 CHAPTER XIII. OF THE SPONTANEOUS MOVEMENTS WHICH PLANTS EXHIBIT. 346 Special Directions.346 The Sleep of Plants.. 350 Xii CONTENTS. Movements from Irritation. 351 Automatic Movements.. 353 Free Movements of Spores.354 PART II. SYSTEMATIC BOTANY. CHAPTER I. OF CLASSIFICATION AND ITS PRINCIPLES.357 Individuals......357 Species.358 Varieties and Races.. 359 Hybrids or Cross-breeds.. 360 Genera.360 Orders or Families.. 361 Suborders, Tribes, &c.. 362 Classes...... 362 Characters...........362 CHAPTER IL OF THE ARTIFICIAL SYSTEM OF LINNIEUS.364 CHAPTER III. OF THE NATURAL SYSTEM... 369 CHIAPTER IV. ILLUSTRATIONS OF THE NATURAL ORDERS.......379 APPENDIX. SIGNS AND ABRREVIATIONS. 513 DIRECTIONS FOR COLLECTING AND PRESERVING PLANTS, &C. 514 INDEX AND GENERAL GLOSSARY OF BOTANICAL TERMS.. 516 THE BOTANICAL TEXT-BOOK. INTROD UCT ION. GENERAL SURVEY OF THE SCIENCE. 1. BOTANY is the Natural History of the Vegetable Kingdom. The vegetable kingdom consists of those beings (called plants) which derive their sustenance from the mineral kingdom, that is from the earth and air, and create the food upon which animals live. The proof of this proposition will be hereafter afforded, in the chapter upon the food and nutrition of plants. The vegetable kingdom, therefore, occupies a position between the mineral and the animal kingdoms. Comprehensively considered, Botany accordingly embraces every scientific inquiry that can be made respecting plants, - their nature, their kinds, the laws which govern them, and the part they play in the general economy of the world, - their rblations both to the lifeless mineral kingdom below them, from which they draw their sustenance, and to the animal kingdom above them, endowed with higher vitality, to which in turn they render what they have thus derived. 2. There are three aspects under which the vegetable world may be contemplated, and from which the various departments of the science naturally arise. Plants may be considered either as individual beings; or in their relations to each other, as collectively constituting a systematic unity, that is, a vegetable kingdom; or in their relations to other parts of the creation, - to the earth, to animals, to man. 3. Under the first aspect, namely, when our attention is directed to the plant as an individual, we study its nature and structure, 2 14 INTRODUCTION. the kind of life with which it is endowed, the organization through which its life is manifested;- in other words, how the plant lives and grows, and fulfils its destined offices. This is the province of PHYSIOLOGICAL BOTANY. It comprises a knowledge, 1st, of the intimate structure of the plant, the minute machinery through which its forces operate; —this is the special field of VEGETABLE ANATOMY; - and, 2d, of the plant's external conformation, the forms and arrangement of the several organs of which it is composed, the laws of symmetry which fix their position, and the modifications they respectively undergo, whether in different species, under different conditions, or in a single individual during the successive stages of its development. This branch of the science is variously called ORGANOGRAPHY (the study of the organs), or MORPHOLOGY (the study of their various modifications in form, according to the office they are destined to subserve), or STRUCTURAL BOTANY; and nearly corresponds with what is termed Comparative Anatomy in the animal kingdom. Under both these aspects, (whether we study their interior structure, or their external conformation,) the plant is viewed as a piece of machinery, adapted to effect certain ends. The study of this apparatus in action, endowed with life, and fulfilling the purposes for which it was constructed, is the province of VEGETABLE PHYSIOLOGY, strictly so called. 4. The subjects which Physiological Botany embraces, namely, Vegetable Anatomy, Organography, and Physiology, therefore, spring naturally from the study of vegetables as individuals,from the contemplation of an isolated plant throughout the course of its existence, from germination to the flowering state, and the production of a seed like that from which the parent stock originated. These branches would equally exist, and would form a highly interesting study, (analogous to human anatomy and physiology,) even if the vegetable kingdom were restricted to a single species. 5. But the science assumes an immeasurably broader interest and more diversified attractions, when we look upon the vegetable creation as consisting, not of wearisome repetitions of one particular form, in itself however perfect or beautiful, but as composed of thousands of species, all constructed upon one general plan, indeed, but this plan modified in each according to the rank it holds, and the circumstances in which it is placed. This leads to the INTRODUCTION. 15 second great department of the science, namely, SYSTEMATIC BOTANY, or the study of plants in their relations to one another; as forming a vegetable kingdom, which embraces an immense number of species, more or less like each other, and therefore capable of being grouped into kinds or genera, into orders, classes, &c. 6. Thus arises CLASSIFICATION, or the arrangement of plants in systematic order, so as to show their relationships; also SPECIAL DESCRIPTIVE BOTANY, embracing a scientific account of all known plants, designated by proper names, and distinguished by clear and exact descriptions. Necessarily connected with these departments is TERMINOLOGY or GLOSSOLOGY, which relates to the application of distinctive names or terms to the several organs of plants, and to their numberless modifications of form, &c. The accomplishment of this object renders necessary a copious vocabulary of technical terms; for the current words of ordinary language are not sufficiently numerous or precise for this purpose. New terms are therefore introduced, for accurately expressing the great variety of new ideas to which the exact comparison of plants gives rise; and thus a technical language has gradually been formed, in this as in every other science, by which the botanist is able to describe the objects of his study with a perspicuity and brevity not otherwise attainable. 7. These several departments include the whole natural history of the vegetable kingdom, considered independently. But, under a third point of view, plants may be contemplated in respect to their relations to other parts of the creation; whence arises a series of interesting inquiries, which variously connect the science of Botany with Chemistry, Geology, Physical Geography, &c. Thus, the relations of vegetables with the mineral kingdom, considered as to their influence upon the soil and the air, —as to what vegetation draws from the soil and what it imparts to it, what it takes from and what it renders to the air we breathe; and, again, the relations of the vegetable to the animal kingdom, considered as furnishing sustenance to the latter, and the mutual subservience of plants and animals in the general economy of the world, - all these inquiries belong partly to Chemistry, and partly to Vegetable Physiology; while the practical deductions from them lay the foundation of scientific Agriculture, &c. The relations of plants to the earth, considered in reference to their natural distribution 16 INTRODUCTION. over its surface and the laws that regulate it, especially as connected with the actual distribution of those natural agents which chiefly influence vegetation, such as heat, light, water, &c., (in other words, with climate,) give rise to GEOGRAPHICAL BOTANY, a subject which connects Botany with Physical Geography. Under the same general department naturally falls the consideration of the changes which the vegetable kingdom has undergone in times anterior to the present state of things, as studied in their fossil re. mains, (a contribution which Botany offers to Geology,) as well as of those changes which man has effected in the natural distribution of plants, and the alterations in their properties or products which have been developed by culture. 8. Of these three great departments of the science, that of Physiological Botany, forming as it does the basis of all the rest, first demands the student's attention. PART I. STRUCTURAL AND PHYSIOLOGICAL BOTANY. 9. THE principal subjects which belong to this department of Botany may be considered in the most simple and natural order by tracing, as it were, the biography of the vegetable through the successive stages of its existence, - the development of its essential organs, root, stem, and foliage, the various forms they assume, the offices they severally perform, and their combined action in carrying on the processes of vegetable life and growth. Then the ultimate development of the plant in flowering and fructification may be contemplated, -the structure and office of the flower, of the fruit, the seed, and the embryo plant it contains, which, after remaining dormant for a time, is at length aroused by the influence of common physical agents, (warmth, air, and moisture conjoined,) and in germination developes into a plant like the parent; thus completing the cycle of vegetable life. A preliminary question, however, presents itself. To understand how the plant grows and forms its various parts, we must first ascertain what plants are made of. CHAPTER I. OF THE ELEMENTARY STRUCTURE OF PLANTS. SECT. I. OF ORGANIZATION IN GENERAL. 10. The Elementary Constitution of Plants. In considering the materials of which vegetables are made, it is not necessary at the outset to inquire particularly into their chemical or ultimate composition, that which they have in common with the mineral world. 2* 18 THE ELEMENTARY STRUCTURE OF PLANTS. The chemistry of vegetation may be more advantageously treated of hereafter. As they derive all the materials of their fabric from the earth and air, plants can possess no simple element which these do not supply. They may take in, to some extent, almost every element which is thus supplied. Suffice it for the present to say, however, that, of the about sixty simple substances now recognized by chemists, only four are essential to vegetation and are necessary constituents of the vegetable structure. These are Carbon, Hydrogen, Oxygen, and Nitrogen. Besides these, a few earthy bodies are regularly found in plants, in small and varying proportions. The most important of them are Sulphur and Phosphorus, which are thought to take an essential part in the formation of certain vegetable products, Potassium and Sodium, Calcium and Magnesium, Silicon and Aluminum, Iron and Manganese, Chlorine, Iodine, and Bromine. None of these elements, however, are of universal occurrence, orare actual components of any vegetable tissue; they occur either among the materials which are deposited on the walls of the cells or collected within them. 11. Their Organic Constitution. Although plants and animals have no peculiar elements, though the materials from which their bodies spring, and to which they return, are common earth and air, yet in them these elements are wrought into something widely different from any form of lifeless mineral matter. Under the influence of the principle of life, in connection with which alone such phenomena are manifested, the three or four simple constituents effect peculiar combinations, giving rise to a few organizable elements (27), as they may be termed; because of them the organized fabric of the vegetable or animal is directly built up. This fabric is in a good degree similar in all living bodies; the solid parts or tissues in all assuming the form of thin membranes or filaments, arranged so as to surround cavities, or form the walls of tubes, in which the fluids are contained. It is called organized structure, and the bodies so composed are called organized bodies, because such fabric consists of parts co6perating with each other as instruments or organs adapted to certain ends, and through which alone the living principle, under whose influence the structure itself was built up, is manifested in phenomena which the plant and animal exhibit. There is in every organic fabric a necessary connection between its conformation and the actions it is destined to perform. This is equally true of ORGANIZATION. 19 the minute structure, or tissues, themselves, as revealed by the microscope, and of the larger organs which the tissues form in all plants and animals of the higher grades, such as a leaf, a petal, or a tendril, a hand, an eye, or a muscle. The term organization formerly referred to the possession of organs in this larger sense. It is now recognized to apply quite as well to the intimate structure of these larger parts, themselves made up of smaller organs through which the vital forces directly act. 12. Distinctions between Minerals and Organized Beings. In no sense can mineral bodies be said to have organs, or parts subordinate to a whole, and together making up an individual, or an organized structure in any respect like that which has just been spoken of, and is soon (in respect to plants) to be particularly described. Without attempting to contrast mineral or unorganized with organized bodies in all respects, we may briefly state that the latter are distinguished from the former, - 1. By parentage: plants and animals are always produced under the influence of a living body similar to themselves, or to what they will become, in whose life the offspring for a time participates; while in minerals there is no relation like that of parent and offspring, but they are formed directly, either by the aggregation of similar particles, or by the union of unlike elements combined by chemical affinity, in. dependent of the influence, and utterly irrespective of the previous existence, of a similar thing. 2. By their development: plants and animals develope from a germ or rudiment, and run through a course of changes to a state of maturity; the mineral exhibits no phases in its existence answering to the states of germ, adolescence, and maturity, - has no course to run. 3. By their mode of growth: the former increasing by processes through which foreign materials are taken in, made to permeate their interior, and deposited interstitially among the particles of the previously ex-'isting substance; that is, they are nourished by food;- while the latter are not nourished, nor can they properly be said to grow in any way; if they increase at all, it is merely by juxtaposition, and because fresh matter happens to be deposited on their external surface. 4. By the power of assimilation, or the faculty that plants and animals alone possess of converting the proper foreign materials they receive into their own peculiar substance. 5. Connected with assimilation, as a part of the function of nutrition, which can in no sense be predicated of minerals, is the state of 20 THE ELEMENTARY STRUCTURE OF PLANTS. internal activity and unceasing change in living bodies; these constantly undergoing decomposition and recomposition, particles which have served their turn being continually thrown out of the system as new ones are brought in. This is true both of plants and animals, but more fully of the latter. The mineral, on the contrary, is in a state of permanent internal repose: whatever changes it undergoes are owing to the action of some extraneous force, not to any inherent power. This holds true even in respect to the chemical combinations which occur in the mineral and in the organic kingdoms. In the former they are stable; in the latter they are less so in proportion as they are the more under the influence of the vital principle; as if in the state of unstable equilibrium, a comparatively slight force induces retrograde changes, through which they tend to reassume the permanent mineral state. 6. Consequently the duration of living beings is limited. They are developed, they reach maturity, they support themselves for a time, and then perish by death sooner or later. Mineral bodies,have no life to lose, and contain no internal principle of destruc-tion. Once formed, they exist until destroyed by some external power; they lie passive under the control of physical forces. As they were formed irrespective of the existence of a similar body, and have no self-determining power while they exist, so they have no power to determine the production of like bodies in turn. The organized being perishes, indeed, from inherent causes; but not until it has produced new individuals like itself, to take its place. The faculty of reproduction is, therefore, an essential characteristic of organized beings. d3. Individuals. The mass of a mineral body has no necessary limits; a piece of marble, or even a crystal of calcareous spar, ~may be mechanically divided into an indefinite number of parts, each one of which exhibits all the properties of the mass. It is only figuratively that we speak of a mineral individual. Plants and animals, on the contrary, exist only as individuals; that is, as beings composed of parts together constituting an independent whole, which can be divided only by mutilation. Each may have the faculty of self-division, or of making offshoots, which become new and complete individuals. It is in this faculty, indeed, comprehensively considered, that reproduction consists. The individuality is no less real in those animals of lower grades, and in plants, where successive generations of individuals remain more ORGANIZATION. 21 or less united with the parent, instead of separating while the offspring is in the embryo or infantile state. 14. Species. This succession of individuals, each deriving its existence with all its peculiarities from a similar antecedent living body, and transmitting it with its peculiarities essentially unchanged from generation to generation, gives the idea of species; a term which essentially belongs to organic nature, and which is applicable only by a figure of speech to inorganic things. By species we mean, abstractly, the type or original of each sort of plant, or animal, thus represented in time by a perennial succession of like individuals: or, concretely, the species is the sum of such individuals. 15. Life. All these peculiarities of organized, as contrasted with inorganic bodies, will be seen to depend upon this; that the former are living beings or their products. The great characteristic of plants and animals is life, which these beings enjoy, but minerals do not. Of the essential nature of the vitality which so controls the matter it becomes connected with, and of the nature of the connection between the living principle and the organized structure, we are wholly ignorant. We know nothing of life except by the phenomena it manifests in organized structures. We have adverted only to some of the most universal of these phenomena, those which are common to every kind of organized being. But these are so essentially different from the manifestations of any recognized physical force, that we are compelled to attribute them to a special, superphysical principle. As we rise in the scale of organized structure through the different grades of the animal creation, the superadded vital manifestations become more and more striking and peculiar. But the fundamental characteristics of living beings, those which all enjoy in common, and which necessarily give rise to all the peculiarities above enumerated (12), are reducible to two; namely, — 1. the power of se~:fsupport, or assimilation, that of nourishing themselves by involving surrounding mineral matter and converting it into their own proper substance; by which individuals increase in bulk, or grow, and maintain their life: 2. the power of self-dicision or reproduction, by which they increase in numbers and perpetuate the species.* * A single striking illustration may set both points in a strong light. The larva of the flesh-fly possesses such power of assimilation, that it will increase 22 THE ELEMENTARY STRUCTURE OF PLANTS. 16. Difference between Vegetables and Animals. The distinction between vegetables and minerals is therefore well defined. But the line of demarcation between plants and animals — the two kingdoms of organized beings subject to the same general laws - is by no means so readily drawn. Ordinarily, there can be no difficulty in distinguishing a vegetable from an animal. But the questionable cases occur on the lower confines of the two kingdoms, which descend to forms of the greatest possible simplicity of structure, and to a minuteness of size that baffles observation. Even here the uncertainty is probably attributable rather to the imperfection of our knowledge, than to any confusion of the essential characteristics of the two kinds of beings. It may therefore be less difficult to define them, than to apply the definitions to the actual discrimination of the lowest plants from the lowest animals. The essential characteristics of vegetables are doubtless to be sought in the position which the vegetable kingdom occupies between the mineral and the animal, and in the general office it fulfils. Plants, according to the definition given at the outset (1), are those organized beings that live directly upon the mineral kingdom, that grow at the immediate expense of the surrounding earth and air. They alone convert inorganic, or mineral, into organic matter; while animals produce none, but draw their whole sustenance from the organized matter which plants have thus elaborated. Plants, having the most intimate relations with the mineral world, are generally fixed to the earth, or other substance upon which they grow, and the mineral matter on which they feed is taken directly into their system by absorption from without, and assimilated under the influence of light in organs exposed to the air; while animals, endowed with volition and capable of receiving external impressions, have the power of selecting the food ready prepared for their nourishment, which is received into an internal reservoir or stomach.* The proper tissue its own weight two hundred times in twenty-four hours; and such consequent power of reproduction, that Linnaeus perhaps did not exaggerate, when he affirmed that " three flesh-flies would devour the carcass of a horse as quickly as would a lion." "The faculty of locomotion, and even that of "making movements tending to a determinate end," cannot be denied to many plants. Doubtless the sensibility to external impressions, which some plants so strikingly manifest, does not amount to perception: on the other hand, that the lowest animals possess CELLULAR TISSUE. 23 of plants, moreover, is composed of three elements only; namely, Carbon, Hydrogen, and Oxygen. The tissue of animals comprises a fourth element, Nitrogen. Plants, as a necessary result of assimilating their inorganic food, decompose carbonic acid and restore its oxygen to the atmosphere. Animals in respiration continually recompose carbonic acid, at the expense of the oxygen of the atmosphere and the carbon of plants. These definitions will be verified, extended, and illustrated in the progress of this work. SECT. II. OF TIIE CELLS AND CELLULAR TISSUE OF PLANTS IN GENERAL. 17. THE question recurs, What is the organized fabric or tissue of plants, and how is vegetable growth effected? The stem, leaves, and fruit appear to ordinary inspection to be formed of smaller parts, which are themselves capable of division into still smaller portions. Of what are these composed? 18. Cellular Structure. To obtain an answer to this question, we examine, by the aid of a microscope, thin slices or sections of any of these parts, such, for example, as the young rootlet of a seedling plant. A magnified view of such a rootlet, as in Fig. 1, presents on the cross-section the appearance of a network, the meshes of which divide the whole space into more or less regular cavities. A part of the transverse slice more highly magnified (Fig. 2) shows the structure with greater distinctness. A perpendicular slice (Fig. 3) exhibits somewhat similar meshes, showing that the cavities do not run lengthwise through the whole root without interruption. In whatever direction the sections are made, the cavities are seen to be equally circumscribed, although the outlines may vary in shape. Hence, fwe arrive at the conclusion, that the fabric, or tissue, consists of a multitude of separate cavities, with consciousness is not certainly made out. But it is becoming more and more apparent, that the absolute distinctions between plants and animals are not to be drawn from this class of characters. Dr. Lindley's definition, that " a plant is a cellular body, possessing vitality, living by absorption through its outer surface, and secreting starch," is so far good, that it indirectly recognizes the essential function of vegetation, starch being one of its organic products; yet it is only one special form under which the nutritive matter created by the plant occurs. It is much as if animals were characterized by the faculty of secreting fat. 24 THE ELEMENTARY STRUCTURE OF PLANTS. closed partitions; forming a structure not unlike a honeycomb. This is also shown by the fact, that the liquid contained in a juicy fruit, such as a grape or currant, does not escape when it is cut in two. The cavities being called CELLS, the tissue thus constructed is termed CELLULAR TISSUE. When the body is sufficiently translucent to be examined under the microscope by transmitted light, this structure may usually be discerned without making a section. We may often look directly upon a delicate rootlet (as in Fig. 1), or the petal of a flower, or a piece of thin and transparent sea-weed, and observe the closed cavities, entirely circumscribed by nearly transparent membranous walls. 1 2 4 3 5 6 19. Does this cellular tissue consist of an originally homogeneous mass, filled in some way with innumerable cavities? Or is it composed of an aggregation of little bladders, or sacs, which, by their accumulation and mutual cohesion, make up the root or other organ? Several circumstances prove that the latter is the correct view. 1. The partition between two adjacent cells is often seen to be double; showing that each cavity is bounded by its own special walls. 2. There are vacant spaces often to be seen between contiguous cells, where the walls do not entirely fit together. These intercellular spaces are sometimes so large and numerous, that many of the cells touch each other at a few points only; as in the lower stratum of the green pulp of leaves (Fig. 7). FIG. 1. Portion of a young root, magnified. 2. A transverse slice of the same, more magnified. 3. A smaller vertical slice, magnified. FIG 4. Cellular tissue from the apple, as seen in a section. 5. Some of the detached cells from the ripe fruit; magnified. FIG. 6. Portion of a hair from the filament of the Spider Lily (Tradescantia), magnified: a, vestige of the nucleus or cytoblast. CELLULAR TISSUE. 25 3. When a portion of any young and tender vegetable tissue, such as an Asparagus shoot, is boiled, the elementary cells separate, or may readily be separated by the aid of fine needles, and examined by the microscope. 4. In pulpy fruits, as in the Apple, the walls of the cells, which at first cohere together, spontaneously separate as the 7 fruit ripens (Fig. 4, 5). 20. The vegetable, then, is constructed of these cells or vesicles, much as a wall is built up of bricks. When the cells are separate, or do not impress each other, they are generally rounded or spherical. By mutual compression they become polyhedral. As in a mass of spheres each one is touched by twelve others, if equally impressed in every direction, the yielding cells become twelve-sided; and in a section, whether transverse (as in Fig. 2) or longitudinal (as in Fig. 3), the meshes consequently appear sixsided. If the organ is growing in one direction more than another, the cells commonly lengthen more or less in that direction, and thus become oblong, cylindrical, or tubular when nearly free, or prismatic when laterally impressed. If the force of extension, compression, or nutrition be greater in one direction than another, or unequal on corresponding sides, a corresponding variety of form is produced. It is not necessary to detach a cell in order to ascertain its shape; that may usually be inferred from the outlines of their section in two or three directions. Nor have the forms precise geometrical regularity; they merely approach more or less closely the figures to which they are likened. 21. The walls of the cells are transparent, at least in their early state, and almost always colorless. In a few cases the membrane itself is said to have a tinge of green, and in the stems of Ferns it is often brown. The various colors which the parts of the plant present, the green of the foliage, or the vivid hues of the corolla, FIG. 7. A magnified section through the thickness of a leaf of Illicium Floridallum, showing the irregtular spaces or passages between the cells, which are small in the ulpper layer of the green pulp, the cells of which (placed vertically) are well compacted, so as to leave only minute vacuities at their rounded ends; but they are large and copious in the rest of the leaf, where the cells are very loosely arranged. a, The epidermis or skin of the upper. b: of the lower surface of the leaf, composed of perfectly combined thick-walled cells. 3 26 THE ELEMENTARY STRUCTURE OF PLANTS. do not belong to the tissues themselves, but to the matters of different colors which the cells contain (87). 22. The cells vary greatly in size, not only in different plants, but in different parts of the same plant. The largest are found in aquatics, and in such plants as the Gourd, where some of them are as much as one thirtieth of an inch in diameter. Their ordinary diameter is about 5 or 5~ of an inch. In the common Pink, it has been computed that more than 5,000 cells are contained in the space of half a cubic line, which is equivalent to almost 3,000,000 in a cubic inch. 23. Cells are sometimes drawn out into tubes of a considerable length, as in hairs, and the fibres of cotton, which are long and attenuated cells. The hairs, or hair-like prolongations from the surface of rootlets, are good examples of the kind. Two short ones are seen in Fig. 1. In Fig. 13, 14, they are more fully illustrated. 24. Some idea may be formed respecting the rate of their production, by comparing their average size in a given case with the known amount of growth. Upon a fine day in the spring, many stems shoot up at the rate of three or four inches in twenty-four hours. When the Agave or Century-plant blooms in our conservatories, its flower-stalk often grows at the rate of a foot a day; it is even said to grow with twice that rapidity in the sultry climes to which it is indigenous. In such cases, new cells must be formed at the rate of several millions a day. The rapid growth of Mushrooms has become proverbial. A gigantic Puff-ball has been known to grow from an insignificant size to that of a large gourd during a single night; when the cells of which it is entirely composed are computed to have been developed at the rate of three or four hundred millions per hour. But this rapid increase in size is owing, in great part, to the expansion of cells already formed. 25. Development of Cells. The whole potentiality of the plant exists in the individual cells of which it is made up. In them its products are elaborated, and all the vital operations carried on. Growth consists in their production, multiplication, and enlargement. A knowledge of these processes is therefore requisite in almost every inquiry that arises in physiological botany. Systematic botany and zoology, moreover, as Xwell as anatomy and physiology, both animal and vegetable, have advanced to the point at which investigations into the development of organs are of the CELLULAR TISSUE. 27 utmost consequence. The formation, propagation, and growth of cells, forming, as they do, the groundwork of anatomy and physiology, are subjects which for the last few years have tasked the powers of the ablest investigators. Such, however, are the intrinsic difficulties of these investigations, that the subject is still involved in much obscurity, especially in regard to the formation of cells; and great differences of opinion prevail upon many other essential points. At present, it is hardly possible to separate what is known or reasonably well settled from. what is conjectural, unproved, or untrue; nor can the more or less conflicting views of the most experienced observers be presented and explained in such an elementary treatise as this.* In respect to cellular development in plants, however, now that Schleiden has greatly modified his views,e the highest authorities, namely, Mohl, Schleiden, and Niigeli, have arrived at substantially similar conclusions. These, in their general outlines, may be here presented. 26. We must distinguish between the original formation of cells and their multiplication. We must also distinguish between the young, vitally active cell, and the completed cell, no longer capable of multiplication or of having new cells formed within it. 27. Formation of Cells, Cells originate within other cells, or at least within living tissues.4 They are formed from organizable * The best authorities for the student to consult upon the subject are, - 1. The memoirs of Mohl in the Lilncea, the Botanische Zeitung, &c., the most important of which are translated in the Anrnales des Sciences Naturelles, the Annals and Magazine of N/ttural History, and in Taylor's Scientific Memoirs. 2. Those of Nageli in the Zeitsclhrift fitr Wissensch. Botanik, whose principal memoir has been translated by Henfrey for the Ray Society. 3. Schleiden's Principles of Scientific Botany, translated into English by Dr. Lankester. 4. Lindley's Introduction to Botany, 4th edition. 5. Henfrey's Outlines of Structural and Physiological Botany; a compendious work, of which the chapters on elementary structure, and all of this author's writings upon the subject, are especially excellent. t Grunditze der Wissenschaftl. Botanilc, ed. 3, reproduced in the Appendix to the English translation, cited above. t The Yeast-plant, developed in fermenting fluids, if that be a true vegetation, is an exception to the rule. According to Schleiden, this is a case of " the formation of cells without the influence of another cell previously existing." The material has of course been elaborated in former vegetable cells; and, according to Karsten, the ferment-cells, with which the development commences, already exist in the juice of the fruit, and pass through the filter into the solution; which makes this a case of cell-multiplication, rather than of cell-formation. 28 THE ELEMENTARY STRUCTURE OF PLANTS. matter (11, vegetable mucilage, protoplasm, &c.) assimilated in previously existing cells, and dissolved in the water which the tissue of growing parts contains.* This organizable material always and necessarily consists of a mixture of two classes of assimilated matter, one of which is azotized, the other is not. That is, one is composed of three elements, carbon, hydrogen, and oxygen, and exists in the liquid form in the state of vegetable mucilage, dextrine, sugar, &c., or collects in a peculiar solid form in the cells,' as starch, or finally constitutes the proper and permanent wall of the cell, under the name of CELLULOSE. The other is composed of nitrogen in addition to these three elements, and exists in growing parts in solution, as some state of what is called proteine, and is known among vegetable products in the forms of diastase, albumen, gluten, fibrine, &c. The latter makes no portion of the permanent fabric, indeed; but it plays an indispensable part in the production of cells, and always exists in young and vitally active cells, as a mucilaginous lining. A weak solution of iodine causes it to turn brown, and detaches it from the proper wall of the cell. According to Mohl, it appears earlier than the proper cell-wall, which is formed under its influence, and is, as it were, moulded upon it. Mohl has therefore given the appropriate name of protoplasm to this azotized mucilaginous matter. 28. Fromt a Nucleus or Cytoblast. When new cells are produced by original formation within the cavity of a parent cell, the following processes appear to take place. Portions of "' the protoplasm collect into a more or less perfectly spherical body, at length sharply defined, the nucleus of the cell (cytoblast); upon this is deposited a layer of protoplasm, which expands as a vesicle, and forms the subsequent lining of the cell; at a very early period the whole becomes inclosed by a wall of cellulose, and the cell is completed."t This plan, under a more restricted form, was propounded, and until recently maintained, by Schleiden, as the universal mode of cell-development. It is now maintained as one principal mode only, and in a form essentially agreeing with * "Cells can be formed only in a fluid which contains sugar, dextrine, and proteine compounds." - Schleiden, 1. c. t Schleiden, 1. c., ed. 3; from the Appendix to the English translation. "This appears to occur especially in the embryo-sac and the embryonal vesicle." CELLULAR TISSUE. 29 Mohl's view." The gelatinous nucleus of the cell often remains adherent to some part of the wall, where its vestiges frequently appear as a dark spot after the cell is full grown. Otherwise it lies free in the cavity, the forming cell-wall being disengaged from it on every side; and sooner or later it is dissolved or absorbed. 29. Without an antecedent N\Tucleus. Some observers do not admit that the nucleus plays an essential part in cell-formation, or that it exists in the first instance. Nor does it have a place in Schleiden's account of the formation of free cells in fermenting fluids, viz.:t "A globule of nitrogeneous substance originates; in this a cavity is formed, it grows, and the complete cell has a delicate coat of cellulose, without our being able to determine the epoch of its production.": 30. Multiplicationl of Cells. It is not by original cell-formation, however, but by the multiplication of cells already existing, that the fabric of the vegetable is built up. A cell once originated, in * In Botanische Zeitngq, Vol. 2, 1844. The abstract of Mohl's view is thus rendered, in the Appendix, 1. c. p. 571, translated from Schleiden's 3d ed.: — "In all vitally active cells a living membrane occurs, consisting of a nitrogeneous layer; this membrane exists earlier than the cell-wall formed of cellulose, and therefore Mohl calls it the'primordial utricle.' The new cells probably originate by the solution of the old primordial utricle, and the formation of several new ones effected through a nucleus, which always precedes the cell-formation." t Schleiden, in App'x to Engl. Trans., 1. c. And Nageli, as rendered in an abstract by Schleiden, 1. c. p. 572. " 1. There is a free cell-formation without a nucleus in certain of the lower Algoe, and in the formation of the spores of Lichens and Fungi. Sometimes a nucleus is subsequently produced in the completed cell. 2. Perfectly homogeneous globules of mucilage are formed, the'nucleoli; around these a perfectly homogeneous nucleus, on which a proper membrane is soon to be distinguished. A homogeneous layer of mucilage is deposited around the nucleus; this gradually becomes thick, especially at one side; then granular in the interior; next it is enveloped by a membrane, and the cell with a parietal nucleus is complete." On the other hand, " Hoffmneister holds that, in the formation of a nucleus, a spherical drop of mucilaginous fluid becomes coated by a membrane, and thus individualized, without the presence of a corpuscle of denser substance (a nucleolus) inside the spherical mass of mucilage either being essential or contributing to the process." Henfiey, Bot. Gazette, 1. p. 128. t There seems to be little real discrepancy between this view and those of Grew, Bauer, Mirbel, Unger, and Endlicher, which agree in this: that cells originate as cavities in a mucilaginous matrix, and at length acquire independent walls. 3" 30 THE ELEMENTARY STRUCTURE OF PLANTS. whatever manner, has the power of propagating itself by division into parts, each of which forms a new cell. The modes by which cells are thus multiplied, diverse as they appear to be in the various processes of vegetable growth, are evidently reducible to two; and even these, if they are now rightly understood, are only two modifications of one and the same process of division, or merismatic multiplication. Taking the most distinct cases for examples, we may say that, in the first mode, 31. The cell is propagated by the division of its living contents into two, four, or sometimes a greater number of free new cells; the wall of the original cell perishing or losing its vitality in the process. This can occur only in cells whose walls have not been thickened by internal deposition (39), and while yet lined with the vitally active layer of protoplasm * (26, 27). This mucilaginous lining becomes constricted or infolded around the middle, and the fold extends inward until it is divided, with the whole contents, into two parts (Fig. 64); at the same time, or immediately following the division, a wall of cellulose is deposited around each portion. The two new cells thus produced may at once divide again in the ~same way, giving rise to four cells in a parent cell (as in Fig. 65); ~or the division may be again and again repeated. The delicate -wall of the parent cell is either absorbed or obliterated as the,new ones, it incloses enlarge, or it remains, for a while at least, although no longer in a living state. By this method the cells,of pollen formed in the anther of all Flowering plants (110), and * This layer, according to Mohl, is a delicate and soft membrane of proto-plasm (called by him the primordial utricle), formed earlier than the cellulose cell-wall which is soon deposited around it. Schleiden has not been able to satisfy himself that this matter is organized into a membrane, or that it precedes the proper wall of cellulose. By terming it, without reference to these points, the mucilaginous lining, or vitally active layer of protoplasm, inter-posed between the proper wall of the cell and its contents (nucleus, gelatinous mass, endochrome, or whatever they may be called), their views are brought into agreement with each other. Those of Mr. Thwaites do not essentially differ, except in his pushing too far, as I should suppose, the inference, " that cell-membrane is quite a subordinate part of living structure; that its ftinctions are of a purely physical' character; that its principal office is to protect, locate, or isolate the matter it contains, and that any vitality it possesses is derived from the presence within it of its endochrome." Ann. 4- Mag. Nat.:ist., Vol. 18. - The movement of the cilia on the surface of the cell-wall, seen in so many spores; surely shows that this possesses for a time a vitality of its own. CELLULAR TISSUE. 31 the spores of most FloWverless plants (101, 109), originate.* It is subservient to reproduction, as these examples show, rather than to vegetation. On the one hand, it might be ranked as a mode of original cell-formation; on the other, it passes by insensible gradations into the next mode, - where 32. The cell is multiplied by the formation of a partition which divides its cavity into two; the original wall remaining. In this way, a single cell gives rise to a row of connected cells, when the division takes place in one direction only, or a plane or solid mass of such cells, when it takes place in two or more directions; thus producing a tissue. It is in this way that all ordinary vegetating or growing parts are produced and increased. The division is effected, as before, by the annular constriction and infolding of the mucilaginous lining of the cell (the primordial utricle of Mohl); the circular fold meeting at the centre divides the contents into two portions, and a layer of permanent cell-membrane, which is somewhat later deposited upon each lamella of the fold, forms a complete double partition; thus converting one cell into two, and so on.t 33. Although connected in their origin, such cells may break * Some spores are produced by the condensation of the whole contents of the parent cell and the acquisition of an investing cell-membrane, without any division, as in Conferva glomerata, &c., or of the undivided contents of one end of a cell, as in Vaucheria, Fig. 71. t This mode of cell-multiplication was first shown and most.ably maintained by Mohl, as the universal mode of increase in growing parts. It has been illustrated from independent observations by Henfrey, in a paper read before the British Association at Cambridge, in 1846; and has recently received new confirmation from Mitscherlich's researches upon the development of Conferva ylomerata, the plant upon which Mohl's observations upon celldivisions were principally made. Henfrey has given an abstract of Mitscherlich's paper in Ann. 8 Mag. Nat. Hist., Vol. 1, new ser., 1848, p. 436. Schleiden's statement of the process, as rendered by his English translator (p. 572), is: "This fold of the primordial utricle is followed somewhat later by a fold of the cell-membrane itself, which, finally arriving at the axis of the cell, blends, and from the nature of its origin forms a complete double septurn." But Mohl, Henfrey, and Mitscherlich appear to agree that the proper wall of the parent cell is not constricted, only its lining or primordial utricle; and that " the septum is certainly a new structure, a double layer of membrane formed in the fold," yet deposited, according to Mohl and Henfrey, " gradually from the circumference to the centre." " The layers of the partition are therefore continuous with the layers of thickening in the interior of the lateral walls," as Henfrey states. 32 THE ELEMENTARY STRUCTURE OF PLANTS. apart at an early period into separate individuals. In that case, the result is the same as in the preceding (31); especially when the cells are globular and divide first in one direction and next in the opposite direction; except that here the parent cell is, as it were, broken up into two or four, each invested with its portion of the original cell-membrane. While in the former, the old cell-wall is destroyed or remains distinct, and the new cells formed in it acquire each its own independent coating of cell-membrane. This is the more apparent where the cell is elongated and goes on to form a chain of cells, as in the green Confervas of streams and pools. Fig. 8 represents a portion of a Conferva, magnified, so as plainly to exhibit the formation of the par-,0OQ/ titions. Here the process of division goes on pari passu with that of (7/x/;%~/ 34. Gemmation or Budding; namely, with continuous growth from their free extremity, or 8 the shooting forth of a protrusion or branch from some part of the surface of a cell, which grows onward from its apex in the same way. A cell thus prolonged into a tube is divided by a transverse partition; the upper joint, 9 10 after elongating from its apex, has its cavity like. wise divided into two by a transverse partition; the lowest of these remaining stationary, the upper elongates and continues the same process; which may thus go on indefinitely. Fig. 9-12 show modifications of this gemmiparous (or budding) mode of growth, as seen in some of the microscopic plants of doubtful nature which develope in fermenting infusions. as, 1i1 12 FIG. 8. Branching summit of a plantlet of Conferva glomerata, magnified; after Mohl showing, at a, a, the partitions forming by the infolding process. FIG. 9- 12. The minute infusory plant which developes in yeast and fluids which are in vinous fermentation. 9. The original vesicle or cell, which is forming a second by a kind of budding. 10. The same, farther advanced. 12. The plant fully developed by the successive production of new cells in this manner. 11. The same, or a similar plant, developing in a slightly different mode, nearly as in Fig. 8. All the figures are magnified. CELLULAR TISSUE. 33' 35. Elongating and Ramifying Cells, This onward growth may take place, moreover, without the formation of partitions at all; when elongated, vegetating cells 13 are produced, whether simple or branched. The hair-like bodies that copiously appear on the surface of young rootlets furnish examples of the kind, as is shown in Fig. 13, 14. More conspicuous examples are furnished by certain Alga3 of the simplest structure, where the cell grows out into a tube of uninterrupted calibre, or branches as it grows into a series of such tubes with the cavity perfectly continuous throughout; as 14 in Botrydium (Fig. 67- 70), where an originally spherical cell is extended and ramified below in the fashion of a root; in Vaucheria (Fig 71), where a slender tube forks or branches sparingly; and in Bryopsis (Fig. 73), where numerous branches are very regularly produced. In these ~k\ (h\ V I.cases, the fully developed plant, with all its branches, is only one proliferous cell, extended from various points by this faculty of continuous budding growth. iAD ( " \[ii \x=y/j~ The mycelium or spawn of 15 NMushrooms, and the intricate threads of Moulds (Fig. 74- 76) are formed of very attenuated branching cells. And in Lichens, cells of the same kind are densely interwoven into a filamentous tissue (Fig. 15). 36. Circulation in young Cells, A kind of circulation or movement of rotation has been observed in numerous cells, particularly in those that form the hairs of many plants, which are well situated for observation; and it probably takes place in most cells at an early period, while yet filled with fluid. The string of bead-like FIG 13. Magnified cellular tissue from the rootlet of a seedling Maple; some of the external cells growing out into root-hairs. 14. A few of the cells more highly magnified. FIG. 15. Entangled, filamentous, branching cells from the fibrous tissue of the Reindeer Lichen (Cladonia rangiferina), magnified. 34 THE ELEMENTARY STRUCTURE OF PLANTS. cells which compose the jointed hairs of the common Spider Lily (Tradescantia, Fig. 6) show this circulation well, under a magnifying power of about four hundred diameters. With this power, a network of anastomosing currents, rendered visible by the little globules they carry with them, will be seen to move between the transparent and glassy cell-membrane and the inclosed colored contents, traversing the cell in various directions, without much regularity, except that the streamlets appear to radiate from, and return to, the parietal cytoblast (28). In this instance, it is easy to see that the currents belong to the layer of mucilaginous fluid, or protoplasm, interposed between the cell-membrane and the colored aqueous contents. The same is the case, according to Mohl's thorough observations, in the tubular cells of Chara, where they may be observed with an ordinary lens; and in our Vallisneria, where a moderate magnifying power shows, in the cells of the leaves, a continuous rotation round the whole wall of the cell, the stream rising on one side and descending on the other. The current is powerful enough to carry along, not only minute granules, but small grains of chlorophyll or green coloring matter (87), which renders it abundantly visible; and sometimes, where the green granular contents cohere in a mass filling the centre of the cell, it throws this whole mass into slow revolution on its axis. In these instances, the whole layer of mucilaginous fluid takes part in the movement. The cause of this motion is wholly unknown, as also the office it subserves. We shall' have occasion to refer to it in another chapter, in connection with other vegetable movements. At present, we may merely remark that it is not like a true circulation, through vessels, which is characteristic of animals. 37. Permeability and Imbibition. The wall of the cells, at least in their living or vitally active state, is a perfectly closed sac, destitute of openings or visible pores (although perforations sometimes appear in old or effete cells, as in those of Peat-Moss); but, like all organic membranes, it is permeable to fluids. The cell constantly contains a fluid thicker than water, and therefore tends to imbibe water by endosmosis,* as well as to yield by exosmosis * a * Endosmosis and exosmosis are names given by Dutrochet (who first illustrated them in liquids) to a physical process of permeation and interchange which takes place in fluids, according to the following law, briefly stated. When two liquids of unequal density are separated by a permeable membrane, the lighter liquid or the weaker solution will flow into the denser or CELLULAR TISSUE. 35 portion of its liquid contents to a contiguous cell, which may be charged with contents of greater density than its own. From the nature of the process of assimilation and other operations carried on in the interior of cells, they must always contain a denser fluid than the water in which aquatic plants live, or which is presented to the roots or other parts of the surface of terrestrial plants. This, with the gaseous and other matters it holds in solution, the vegetable must constantly tend to imbibe by endosmosis. In virtue of the same law, as will hereafter be explained, not only is the crude food imbibed by the roots, but transferred from cell to cell to the place where assimilation is principally effected or growth is going on. In addition to the simpler process, animals, even of the lowest grades, have a proper circulation through vessels. There is no such circulation in plants. 38. Growth of Cell-Membrane interstitially. By appropriating the - assimilated matter it contains or imbibes, the young cell increases rapidly in size; its wall is extended equally on every side (unless something interferes with its expansion in particular directions), so that a larger space is surrounded. Meanwhile, instead of becomstronger, with a force proportioned to the difference in density (endosmosis); but at the same time, a smaller portion of the denser liquid will flow out into the weaker (exosmosis). Thus, if the lower end of an open tube, closed with a thin membrane, such as a piece of moistened bladder, be introduced into a vessel of pure water, and a solution of sugar in water be poured into the tube, the water from the vessel will shortly be found to pass into the tube, so that the column of liquid it contains will increase in height to an extent proportionate to the strength of the solution. At the same time, the water in the vessel will become slightly sweet; showing that a small quantity of syrup has passed through the pores of the membrane into the water without, while a much larger portion of water has entered the tube. The water will, continue to enter the tube, and a small portion of syrup to leave it, until the solution is reduced to the same strength as the liquid without. If a solution of gum, salt, or any other substance, be employed instead of sugar, the same result will take place. If the same solution be employed both in the vessel-and the tube, no transference or change will be observed. But if either be rendered stronger than the other, a circulation will be established, and the stronger solution will increase in quantity until the two attain the same density. If two different solutions be employed, as, for instance, sugar or gum within the tube, and potash or soda without, a circulation will in like manner take place, the preponderance being towards the denser fluid, and in a degree exactly proportionate to the difference in density. Instead of animal membrane, any vegetable matter with fine pores, such as a thin piece of wood, or even a porous mineral substance, may be substituted with the same result. 36 THE ELEMENTARY STRUCTURE OF PLANTS. ing thinner as it expands, it grows thicker; although the increase of surface at this time is much greater than that of thickness. Therefore it not merely enlarges, but grows. That is, it incorporates new assimilated matter, which penetrates the membrane and is deposited in it, not as a new layer, lining and strengthening the old, but interstitial1ly; so that the enlarging cell-wall is still as homogeneous and simple as before. After attaining, for the most part rapidly, a definite size, the cell ceases to enlarge, and its wall no longer incorporates new materials. Some cells remain in this condition, with walls of great tenuity, as do the parent cells in which grains of pollen or other new cells are produced (31); in which case they seldom endure, but are soon destroyed or absorbed. The assimilated matters they contained were wholly diverted to the new product to which they give rise. 39. Thickening by Deposition. In most cells that make part of a permanent structure, however, the membrane continues to thicken after it has ceased, or nearly ceased, to enlarge, no longer interstitially, but by a deposit on its inner surface. The nature of the contained assimilated matter is such, that, by the mere abstraction of water, it readily passes into a solid state (81). As it organizes (doubtless under the influence of tlhe living lining of protoplasm), it solidifies on the surrounding cell-wall, which is thus strengthened by a new layer of cellulose, or by a succession of such layers. Every degree of this secondary deposition occurs, from a slight increase in the thickness of the membrane to the filling up of the greater part of the cavity of the cell. The older wood-cells of any hard wood furnish good illustrations of such solidification. Indeed, the difference between sap-wood and heart-wood of trees is principally owing to the increase of this secondary deposit, which con. verts the former into the latter; as may be seen by comparing, under the microscope, the tissue of the older with that of the newest rings of wood, taken from the same tree. In an ensuing chapter (on the internal structure of the stem), this is shown in a piece of oak wood. Fig. 18 represents a highly magnified cross-section of some wood-cells from the bark of a Birch, with their calibre almost obliterated in this way. It is by the same process that the tissue of the stone of the peach, cherry, and other stone-fruits acquires its extreme hardness. Indurated cells of the same kind are met with even in the pulp of some fruits, as in the gritty grains, which every one has noticed, scattered through the flesh of many pears, espe. CELLULAR TISSUE. 37 cially of the poorer sorts. A section of a few cells of the kind is represented in Fig. 16, with their cavity much reduced and rendered very irregular in outline by such in- - crustation. Similar cells are readily seen, with a moderate magnifying power, to form a part of the tissue 16 17 even of such juicy fruits as the cranberry and the blueberry (Fig. 17). 40. This deposited matter can rarely consist of pure cellulose, but may include all the various matters capable of solidification, of whatever nature, which are introduced into the cells from without, or are elaborated there. As, for example, mineral matters, small quantities of which must needs be dissolved in the water, which the plant imbibes by its roots, and be deposited in the cells of the wood through which it passes, and especially in those of the leaves where it is concentrated by evaporation (311 - 313); also, coloring matters, such as give the different tints to heart-wood, and other special solidified products formed in the cells themselves. The cells fill up, therefore, partly by organic deposition, and partly by incrustation. 41. Even when purified as much as possible from all admixture of foreign materials, the secondary deposit is found to differ a little from cellulose, or original cell-membrane, in chemical composition. It contains a somewhat larger proportion of carbon and hydrogen; and is therefore richer in combustible matter. Forming as it does the principal part of the weight of wood (lignum), it has received the name of LIGNINE (also that of Sclerogen); but it is probably only cellulose a little modified or altered. This difference in chemical composition, however, shows why the hard woods, such as hickory and oak-wood, which abound in this lignified deposit, should be more valuable for fuel, weight for weight, than the soft woods, which have little of it (such as basswood, &c.); at least, when the latter are not charged with resinous mattedr. 42. The secondary deposit often forms an even and continuous increase in the thickness of the walls (as is shown in the White Oak, in the section on the Internal Structure of the Stem): but it is FIG. 16. Magnified section of the gritty cells of the pear; the cavity almost filled with inacrusting matter. 17. Similar cells from the pulp of the blueberry (Vaccinium corymbosum). 4 38 THE ELEMENTARY STRUCTURE OF PLANTS. not unfrequently distinguishable, when highly magnified, into more or less defined concentric layers; as shown in Fig. 18, from the inner bark of the Birch, and in Fig. 19, in some cells of ~ ~ ~ proper wood. Whether the 17._ thickening deposit is distin. guishable into layers or not, it is more commonly interrupted at certain points and in a definite way, so as to next p e g n a p lgive the diminished cavity very irregular outlines; as we see in Fig. 16 and Fig. 17. This occurs in wood-cells as well as in ordinary rounded cells, and is partly shown in Fig. 19. The earliest layers of thickening fail to be deposited at certain points, consequently leaving thinner spots; the succeeding layers are exactly applied to the next preceding, and leave precisely the same intervals: consequently, these unthickened spots become grooves or canals running from the cavity of the cell to the original wall, or in that direction. And it is noticeable that the pits or canals of contiguous cells usually correspond: an obvious effect or use of this adaptation is to maintain a lateral communication between contiguous cells of the kind, notwithstanding the thickening of their walls. No tissue which we have seen shows these lateral passages and their nature more clearly than the wood of the American Plane-tree, or Buttonwood (Fig. 22), which at the same time demonstrates the true character of one large class of the 43. Mlarkings of the Walls of Cells. These, whether in the form of bands, spiral lines, dots, or apparent pores, all arise from the unequal distribution of the secondary deposit. They are portions of the walls which are either thinner or thicker than the rest. These markings display the greatest variety of forms, many of them of surpassing elegance. The principal kinds occur with perfect uniformity in each species or family, and in definite parts of the plant; so that, in a multitude of cases, a given species or genus FIG. 18. Highly magnified cross-section of a bit of the old liber of the bark of the Birch; the tubes nearly filled with a deposit of solid matter in concentric layers. (From Link.) FIG. 19. Highly magnified wood-cells (seen in transverse and longitudinal section), from the root of the Date Palm; showing the internal deposit in layers, and some connecting canals or pits. (From Jussieu, after Mirbel.) CELLULAR TISSUE. 39 may be as certainly identified by the minute sculpture of its cells alone, as by more conspicuous external characters. They are preserved even when the tissue is fossilized, and the external form, with every outward appearance. of organization, is obliterated. Through thin slices and other contrivances, the hidden structure is revealed under the microscope, and thus the true nature of our earth's earliest vegetation may be often satisfactorily made out.* The simplest cases of these markings are those of 44. Dots or Pits, often 22. 20 taken for pores, such,. as those on the cells of the pith of Elder (Fig. -4I''25), and upon those... that are called dotted ducts; as in Fig. 39,, c and Fig. 21, b. All markings of this kind, are thin spots, which, o 1 c lo, for some reason, have W o~ not partaken in the general thickening of the wall. It has 1 o o been explained by supposing that a slight enlargement of the original wall takes place, which stretches the l oo 7 - nascent lining, so as to break or fray it into slits or holes here and there. o1 O the uniformity with which each suc- cessive layer is moulded on the pre- i ceding, with exactly corresponding 2a interruptions (42), forbid our adopt* In this way, and by taking advantage of the fact, that the secondary deposits in the cells consist in part of mineral matter, which is left behind in the FIG. 20. Magnified cross-section of a small portion of heart-wood of the Plane-tree or Buttonwood (Platanus occidentalis). 21. A corresponding longitudinal section, parallel with the circumference. a, The dotted woody tissue; the lower ends of the two cells to which the letters are appended are divided lengthwise, so as to show the irregularly thickened calibre; the others are mostly entire, showing the dots: in the cross-section the secondary deposit is seen to form indistinct layers, and some of the dots to form canals of lateral communication. b, Dotted ducts: the middle one in the longitudinal section is obliquely jointed. c, Medullary ray. FIG. 22. Portion of four cells of the woody tissue, with both transverse and longitudinal section, highly magnified, showing the canals or deep pits.in the thickened walls, and their apposition in adjoining cells: on the cross-section the layers of deposit are more plainly visible. 40 THE ELEMENTARY STRUCTURE OF PLANTS. ing this mechanical explanation. Although they are not primarily pores or real perforations of the wall, as has been thought by some, yet they often become so with age, by the breaking away of the thin primary membrane, after the cell has lost its vitality. The subjoined dissections of the wood of the American Plane-tree, already referred to, clearly show the true nature of these dots, which here abound on the proper wood-cells as well as the larger ducts. Except in their lesser size and greater depth, arising from the more extensive thickening of the tubes, they do not essentially differ from the well-known 45. Discs, or large circular dots, which mark nearly all the wood-cells of the Pine Family (Fig. 23, 24). These are thinner spaces, which consequently appear more transparent than the rest of the tube (except when filled with a film of air), when viewed by transmitted light. The discs of contiguous tubes are applied directly to each other, face to face (just as the o canals or thin places of other cells thickened,G by secondary deposits correspond, 42), and 0 each is a little depressed, so that a lenticular 0D O l s @ space is left between them, as between two e 0 watch-glasses put together by their circumfer\o ~@ ences. They are seldom found on the sides 10 l eof the wood-cells that look towards the bark 0O' 3 \) or towards the pith; while they abound in a section made in the direction of the lines of 23 24 silver-grain. The dots on the wood-cells of the Plane-tree, on the contrary, are most abundant on the sides that look towards the centre and the circumference of the trunk. Although of universal occurrence in the Pine Family and the related order Cycadaceme, these discs are not restricted to them, as was once supposed. Mr. Brown long since showed that the wood of the Winter's-bark tree was similarly marked; and our Fig. 33 represents them as they appear in the Star-Anise of Florida, which belongs to the same natural group of plants. They are said to be ashes, Prof. Bailey, of West Point, has enabled us to detect and distinguish vegetable tissues in anthracite coal. See Silliman's Journal, Vol. I., New Series. FIG 23. Piece of a Pine shaving, magnified, to show the dots or discs which appear on the cells of all Coniferous wood. 24. A separate cell of the above, more strongly magnified. CELLULAR TISSUE. 41 " common in aromatic trees "; probably under forms scarcely if at all distinct from ordinary dotted wood-cells. 46. Bands, Rings, or Spiral Markings. These are, in most cases at least, definite portions of the wall more thickened than the rest; as is shown by the spiral vessel, where the secondary formation is restricted to a delicate thread, capable of being unwound (60); and particularly by the thick plate which winds around in the cells of certain Cacti, like a spiral staircase (Fig. 29). Markings of this kind (which are rarely thick and projecting as in the last example) occur as rings (Fig. 43), or fragments of rings (Fig. 44), but more frequently as spiral threads or bands (Fig. 26), sometimes as branching threads (Fig. 27); all of which, however, exhibit a spiral tendency. The elongated cells which form the hairs on the seeds of many Acanthaceous plants exhibit these markings in great variety. Two such cells from the same seed, one with a series of rings, the other with a continuous spiral thread, are represented in Fig. 31. Sometimes a band of fibres appears to ascend in the same direction: occasionally two spiral threads seem to wind in opposite directions; and sometimes branching threads inosculate and form a kind of network on the membrane, as in Fig. 26 25 27 28 32 31 29 30 28. Often the rings or turns of the spiral thread are nearly in contact (Fig. 45); while as frequently they are separated more or FIG. 25. Cell of the pith of Elder, marked with oblong dots. FIG. 26. Cells of the leaf of Sphagnum, or Peat Moss, marked with a spiral fibre. FIG. 27 -30. Spirally banded cells from species of Cactus, after Schleiden. FIG. 31. Hairs from the seed-coat of Ruellia strepens; one with a spiral band, the other with a set of rings developed on the inner surface of the tube. FIG. 32. Tissue from the lining of the anther of Cobmea scandens; where, the delicate walls of the cells being soon obliterated, the fibrous bands with which they were marked remain. 4* 42 THE ELEMENTARY STRUCTURE OF PLANTS. less; as if the cell-membrane had extended after the thread was deposited, which is probably the case. 47. The delicate walls of some such cells are torn or obliterated at maturity, while the firmer bands or fibrous markings remain in the form of separate threads; as in the tissue that lines the walls of the anther (Fig. 32). In a similar manner the spirally-marked tubes that are mingled with the seeds of the Hepatic Mosses are converted into elastic spiral threads (Fig. 85). So, also, the delicate cells or hairs that invest the coat of some seeds, which contain a spirally-coiled thread, give way when moistened, or are torn asunder by the force with Which the thread uncoils. 48. Free Gelatinous Coils in Cells. In many cases, however, the spiral deposit in the cells which form the hairs on the surface of seeds, and of some seed-like fruits, remains of a gelatinous consistence, and lies loose in the cell. When moistened, water is absorbed by endosmosis, the gelatinous contents swell, burst the cell-membrane (at the same time frequently forcing it away from its attachment), and gush out in the form of uncoiling. mucilaginous threads. Examples of the kind are furnished by the seeds of Collomia and Gilia; and very striking ones by hairs or papillae on the seed-like fruits of numerous species of Senecio and the allied genera. Those of Crocidium project a thick, mucilaginous twisted band, in place of a thread. This structure is known to be common on the surface of seeds and seed-like fruits; one purpose which it subserves will be pointed out in a future chapter. 49. Similar in their formation, probably, are the loose, spirally. coiled bodies, which are found in the antheridia of Mosses and Liverworts, in seedling Ferns, &c.; which, on account of their exhibiting a vermicular motion in water when first extricated from the cell, were denominated Phytozoa by Grisebach. The functions which these bodies are supposed to perform, in reproduction, will be explained hereafter. SECT. III. OF THE KINDS OR TRANSFORMATIONS OF CELLULAR TISSUE; VIZ. WOODY TISSUE, DUCTS, ETC. 50. THE statements of the preceding section apply in general to the cells of which all plants are composed, irrespective of the manifold forms they may assume, and of some peculiar transform mations they may undergo. Some of these should now be speci PARENCHYMA. 43 fled; as they give rise to kinds of tissue so unlike the ordinary cellular, in outward appearance at least, that they have always been distinguished by special names. We allude particularly to what is called Woody Tissue or Woody Fibre, and Vascular Tissue or Vessels, of vafrious forms. These have been considered as essentially different kinds of tissue, of independent origin. But it is now known that they are modifications of one common type, the cell, and are produced in the same mode as ordinary cells; so all the statements of the foregoing section, in respect to the formation, multiplication, and growth of cells, are equally applicable to these also. Some kinds differ from ordinary cells in shape alone; others result from their combination or confluence. This is shown in two ways: first, by noting the intermediate gradations which may be found between every particular sort; and second, by watching their development and tracing them directly from their earliest condition, as ordinary cells, to the peculiar forms they soon assume. The first of the kinds enumerated below is typical cellular tissue; the second, through a slight change in the development, introduces the special forms. 51. Parenchyma is the substantive name applied to ordinary membranous cellular tissue in general, such as that which forms the pith of stems, the outer bark, &c. In the most restricted application, it belongs to such tissue when composed of angular or polyhedral cells (as in Fig. 1- 3, 13, &c.); the distinctive name of Merenchyma having been proposed for the looser tissues (as in Fig. 7, and in the pulp of leaves and fruits generally), formed of rounded or ellipsoidal cells, that is, where they do not mutually impress each other into plane faces. But this distinction vanishes in the numberless intermediate states; and the name of Parenchyma is applied to both. That in which the walls barely touch each other, more or less extensively, and leave intervening spaces where the ends or sides are rounded off, is termed by Schleiden incomplete parenchyma. The principal forms of complete parenchyma, where the cells are in perfect contact on every side, and the sections are consequently several-sided, are designated by adjective terms; as the regular, when the cells are dodecahedral or cubical; the elongated or prismatic, when extended longitudinally; and the tabular, when cubical cells are much flattened; one kind of which, called the muriform, because the laterally compressed cells appear in the magnified section like 44 THE ELEMENTARY STRUCTURE OF PLANTS. courses of bricks in a wall, is seen in the silver-grain of wood (Fig. 20, c). 52. Prosenchyma is the general name to designate tissues formed of elongated cells, with pointed or conical extremities; their narrowed ends overlapping and thus filling up the intervening spaces which must otherwise exist. Every gradation may be traced between this and incomplete parenchyma. As to length, such cells vary from fusiform, or spindle-shaped, only three or four times longer than broad, to tubular, and to tubes so long and narrow that they are commonly called fibres. As to their extremities, they are often so blunt, and applied to each other with such moderate obliquity, that they are more properly said to be placed end to end than side by side; while, again, precisely similar cells, sometimes even in the same bundle, exhibit flattened ends resting directly one over the other.* Nor can we draw any fixed line of distinction from the thickness of the walls. Indeed, no one can diligently examine the tissues of two or three of the commonest plants, without perceiving that there is no essential difference between cellular and 53. Woody Tissue, (Pleurenchyma of Meyer and Lindley. Woody Fibre of the older authors.) Wood, which makes up so large a part of trees and shrubs, and a distinguishable portion in all Phaenogamous (110) herbaceous plants, is wanting in Mosses and plants of still lower grades, such as Lichens, Sea-weeds, and Fungi. That is, in the latter there is no formation corresponding to the wood of higher plants, although many of them exhibit, at least in certain parts, prosenchymatous cells, and others drawn out into tubes or hollow fibres of greater length and tenuity than are those of ordinary wood; such, for instance, as the interlaced fibrous tissue of Lichens (Fig. 15). Nor, on the other hand, does the proper woody system of trees (except in the Pine Family) consist entirely of that form which has received the special name of woody tissue, but three or four other sorts are variously intermingled with it. Indeed, there are some trees whose wood is almost entirely composed of true parenchyma, or of large dotted (58) cells; while in stone-fruits, and many like cases, common parenchymatous * The forming woody tissue, as seen in a germinating plant or young rootlet, consists of prismatic cells, with square ends; as these lengthen, their ends push by each other, and so become oblique and wedged together, or converted into prosenchyma. WOODY TISSUE. 45 cells acquire by incrustation a ligneous consistence and even greater density than wood (39). Nevertheless, the principal and characteristic component of wood in general is thick-walled..prosenchyma. So that this takes the name of woody tissue even in the bark, leaves, &c. Fig. 21 represents some pleurenchyma along with the other usual elements of the wood, and shows the manner in which these woody tubes are spliced together, as it were, by their overlapping, pointed ends. Their diameter, in this instance, is about.yA- of an inch. Those of our Linden or Bass-wood (a few of which are shown in Fig. 36, 37) are rather larger, but not more than T-uI of an inch in diameter.* Their size varies in different plants almost as much as ordinary cells do, but they are usually much smaller than parenchyma, especially in herbaceous plants. Perhaps the largest are found in the Pine Family, where they are of a peculiar sort, and are often as much as -,I- or a of an inch in diameter. The density or closeness of grain in wood, however, does not depend so much on the fineness of the wood-cells as upon the intermixture of other kinds of tissue, and the thickness of their walls. This is much greater in proportion to their diameter than in ordinary parenchyma, and, with their slenderness and their very compact arrangement into threads or masses which run lengthwise through the stem, conspires to give the toughness and strength which characterize those parts in which this tissue abounds. A transverse section under the microscope shows that woody tissue is composed of lengthened cells, that is, of hollow tubes and not of solid fibres (Fig. 20, 36, &c.). But as their walls thicken by the secondary or incrusting deposit to which they are especially liable (39 - 41), the calibre diminishes, and in old wood sometimes becomes nearly obliterated. This thickening usually occurs evenly in woody tissue; at least, bands or spiral lines are seldom seen in it; but small dots or pores, the nature of which has already been explained (44), are not uncommon. They are well shown in the wood of the Plane-tree (Fig. 20 - 22). Of similar character, only more conspicuously marked, is the 54. Disc-bearing Woody Tissue (Glandular Woody Tissue of Lindley), which forms the wood in the Pine Family. The nature *Lindley states that the woody tubes of the Linden are as much as _L of an inch in diameter; but I find none of any thing like this size. 46 THE ELEMENTARY STRUCTURE OF PLANTS. of the discs, or thin spots, has just been explained (45). On account of their markings and unusually large size, and because in the Pine Family they make up the wood without any admixture of ducts, these peculiar wood-cells ~0 $ 1\ llI2, have been thought to be rathera 0 form of vascular tissue. But in the ~~ioh be Star-Anise the same kihd of mark~o~ $ ings is found on undoubtedly genu-'o 0 ine woody tissue (Fig. 33). In the 0o 1 o ^ } X ]$;z 0" " Yew, on the other hand, where the discs are few, delicate spiral markings appear (Fig. 34), showing a O1 < _ 03 t- perfect transition between the prop0 o t Wer woody and the vascular tissues; as is seen by comparing the figure 33~ n WU ~,"34 with that of a spirally marked duct of Bass-wood, Fig. 36, a. 55. Bast Tissue, or Woody Tissue of the Liber. The bast or bass, fibrous inner bark, or liber, as it is variously termed, of those plants that have a true bark separable from the wood of the stem, is principally pleurenchyma, consisting, of much longer, very thick-sided, and usually tougher, but more soft and flexible cells, than those of the wood itself. These properties are " probably given them that they may possess the strength, combined with flexibility, which their position near the circumference of a branch renders necessary." These especially adapt them to the useful purposes they so largely subserve for clothing and cordage. The textile fibres of flax, hemp, &c. are all derived from this woody tissue of the bark, separated from the brittle cells of the wood itself, and freed from the surrounding thin-sided parenchyma by maceration (which soon decomposes the latter) and mrechanical means. Cotton differs from linen in many respects; it consisting of hairs, or long tubular cells, growing on the seeds, with very thin walls, that collapse so that they twist variously, which gives them a peculiar adaptation to be spun, or drawn out together by torsion into a thread. But the walls have none of the FIG. 33. Magnified woody tissue of Illicium Floridanum (longitudinal view), marked with large dots, like the discs on the wood-cells of the Pine Family. FIG. 34. Magnified woody tissue from the American Yew (longitudinal view), showing delicate spiral markings; some of the cells also showing the disc-like markings or dots of ordinary Coniferme. Across the base is seen a portion of a medullary ray. WOODY TISSUE. 47 thickness and toughness which characterize the liber-cells. Fig. 35 represents one of the bast-cells of our Bass-wood 35 36 or Linden, with a portion of another; while Fig. 36, 37, represent a few of the cells of the wood from the same stem, and equally magnified; showing the great difference in the length of the fibre-shaped cells. Being a soft wood, the cells of the latter have X thin walls, as is seen on the cross-section of two of them at the top; while the section of one of the bast-cells shows a thick wall and very small calibre. The disproportion in length is still greater in our Leather-wood, which has a bark of extraordinary toughness, used for thongs, while the wood itself is very brittle and tender. Its capillary bastcells measure from an eighth to a sixth of an inch in length, with an average diameter of 2f of an inch (so that, if the whole length'of a cell, magnified as in Fig. 38, were given, the figure would be from a foot to a foot and a half in length), while those of the wood itself are only the Tno of an inch long. Among the bast-cells are found the longest cells which occur in any tissue. Schleiden says that he has measured those which were four or five inches long. They are of great length in the Milk. 37 weed Family, and in the Dogbane, or Indian Hemp, the tough bark of which accordingly furnishes the aborigines a sort of ready-made cordage. In these families they are said by Schleiden frequently to exhibit " very delicate spiral fibres, crossing'each other. In some spots their cavity becomes entirely obliterated; whilst in others they are swollen and vesicular, and contain a true milky juice." So that they are the milk.vessels in these plants; at least in part. The ribs, with the veins and veinlets, that form the fibrous 38 framework of leaves, giving to them the requisite firmness, are chiefly of the same kind of woody tissue as those of the bark. FIG. 35. Two bast-cells from the bark of the American Bass-wood, magnified. FIG. 36. Some woody tissue from the wood of the same; a, upper end of a spirally-marked duct. 37. A separate cell from the wood. All magnified to the same degree as Fig. 35. FIG. 38. Ends of some bast-cells from the bark of the Leather-wood (Dirca palustris), highly magnified. 48 THE ELEMENTARY STRUCTURE OF PLANTS. 56. The woody tissue runs lengthwise through the stem, root, or other organ (except in reticulated leaves, and there its ramifications all spread in one plane); for this reason, it is sometimes designated as Longitudinal Tissue, the Vertical or Longitudinal System of the stem, &c. It shares this name, however, with some other forms of tissue which accompany it, particularly in the wood. These all agree in exhibiting markings of some kind on their walls, and in being larger than woody tissue: they are all more or less tubular, or conspire to form tubes of considerable length, and hence they have all been combined, in a general way, under the name of 57. Vascular Tissue or Vessels. This is an unfortunate name, however, and apt to mislead, like most of those in botany that are based on loose analogies with the animal kingdom. To avoid the erroneous impressions that are so prevalent, it should be remembered that these so-called vessels are mere modifications of cellular tissue, and are wholly unlike the veins and arteries of animals. It is much better to call them ducts, a name appropriate to their nature and office, and leading to no false inferences. Their true nature is most readily shown in the largest and most conspicuous form, which often exhibits unequivocal indications of its cellular origin, namely, 58. Dotted Ducts, called also Pitted or Vasiform Tissue, Bothren. chyma, &c. (Fig. 39, 40). They have likewise been termed Porous Cells or Porous Vessels; but the round or m-c~ oblong dots that characterize them are thin places where the wall has not been thickened by an internal incrusting deposit, as has already been explained (44), and not perforations, except in old cells where the primary membrane is obliterated at these points. Some. di -1 times they are continuous tubes of considerable length (Fig. 40); but commonly, the circular lines which they exhibit at short intervals (as in 39 40 Fig. 39), and the imperfect transverse partition which is often found at these points, plainly indicate their composition; showing that they are made up of a row of cells, with the intervening partitions more or less obliterated. In Fig. 21, some FIG. 39 Portion of a dotted duct from the Vine, evidently made up of a series of short cells. FIG. 40. Part of a smaller dotted duct, showing no appearance of such composition. VASCULAR TISSUE. 49 of these ducts, shown in place among the woody tissue, are seen to have oblique partitions of the same kind. An examination in Mhe forming state confirms this view; and, in the young stems of herbaceous plants, they may often be separated artificially into their primitive elements. These jointed ducts are occasionally branched, giving further proof that they are aggregations of confluent cells. Dotted ducts are usually met with inthe wood alone, where they commonly abound. Being of greater calibre than any other cells or vessels found there, they form the pores so conspicuous to the naked eye on the cross-section of many kinds of wood, such as of Oak, Chestnut, and Mahogany, as well as the lines or channels seen on the longitudinal section. Their size, compared with that of the wood-cells in the wood of the Plane-tree, is shown both in longitudinal and transverse section, in Fig. 20, 21. 59. Reticulated, Banded, and Scalariform Ducts are the modifications of what is more strictly called vascular tissue (Trachenchyma of Morren and Lindley) which most resemble dotted ducts; and which usually take their place, or occur with them, in the stems of herbaceous and small woody plants. There is no essential difference between them: indeed, they are often distinguishable 45 46 47 44 43 41 42 FIG. 41. Scalariform ducts of a Fern, rendered prismatic by mutual pressure. FIG. 42. Similar duct of a Fern, torn into a spiral band. FIG. 43. Duct from the Wild Balsam or Jewel-weed; the coils of the thread distant; a portion forming separate rings. FIG. 44. A portion of a ductfrom the leafstalk of Celery; the lower part annular; the middle reticulated, and the thread at the upper part broken up into short pieces. FIG. 45. A simple spiral vessel, torn across, with the thread uncoiling. 46. Two such ves. sels joined at their pointed extremities. FIG. 47. A compound spiral vessel, partly uncoiled, from the Banana. 5 50 THE ELEMENTARY STRUCTURE OF PLANTS. only by the form of the markings; and these vary so greatly in the same tissue, and even in the very same duct (Fig. 44), that it would be an endless and useless task to describe all their varieties. A continuous dotted duct with oblong spots is nearly the same as the large ducts with rather larger markings, disposed so as to form a series of regular bands, which abound in Ferns (Fig. 42). When the markings are a little longer, and the walls are rendered prismatic by mutual pressure (as in parenchyma) we have the Scalariform Ducts of Ferns (Fig. 41), so named because the lines (or slits as they become in old tissue) form transverse bars resembling the rounds of a ladder. In many cases, it is uncertain whether the lines or narrow bands are spots thinner than the rest of the wall, as they certainly are in dotted ducts, and probably in. the scalariform vessels; or whether they are places where the secondary deposit is thickened. Probably there are Reticulated Ducts (those where the lines branch and run together here and there, forming a network) of both sorts; — certainly of the latter; for we occasionally meet with such markings (as in the middle of Fig. 44) on a part of the walls of true 60. Annular and Spiral Duets (Tracheae). The nature of their markings is explained in Paragr. 46. They are elongated cells (or ducts formed by the confluence of several cells), with their delicate membranous walls strengthened by the deposition of fibres within. Sometimes the fibre is deposited in unbroken rings (as in the middle of Fig. 43, and in Fig. 48, d), which forms the Annular Duct. More commonly it is deposited as a continuous spiral coil, producing the Spiral Duct or Spiral Vessel (Fig. 45- 47); which is taken as the typical or pattern form of vascular tissue, because of its universal occurrence in Flowering Plants, and because of the general tendency of such definite secondary deposits to assume a spiral form. That these markings are thickened, and not thinner lines, is well shown in those remarkable cells from Cacti, already described (Fig. 29, 30), in which the fibre thickens into a band, with its edge, as it were, applied to the wall: also in those cells which have a loose spiral fibre generated within (48). Moreover, in what is called the true Spiral Vessel (Fig. 45-47), the fibre is so strong and tough, in comparison with the delicate cell-wall on which it is deposited, that it may be torn "Out and uncoiled when the vessel is pulled asunder, the membrane being destroyed in the operation. This is seen by breaking almost any young shoot or VASCULAR TISSUE. 51 leafstalk, or the leaf of an Amaryllis, and gently separating the broken ends; when the uncoiled threads appear to the naked eye like a fine cobweb. In stems furnished with pith, the spiral vessels usually occupy a circle immediately around it. They occur also in the veins of the leaves, and in all parts which are modifi-. cations of leaves. More commonly the spire is formed of a single fibre, as in Fig. 45, 46: it rarely consists of two fibres; but not uncommonly of a considerable number, forming a band, as in Fig. 47. Such Compound Spiral Vessels are to be found in an Asparagus shoot; and are finely seen in the sterns of the Banana, from which the fibres may be extracted in large quantities. From the Musa textilis of Manilla, of the same genus as the Banana, these cobwebby fibres are procured and used in the production of the most delicate of textile fabrics. By comparing Fig. 47 with Fig. 42, we may readily perceive that the wall of those ducts in Ferns which tear into a band when pulled asunder, may have an indistinct spiral deposit, composed as it were of a band of fibres that are confluent into a lining, but are individually separated at certain points, so' as to leave. interstices in the form of bars, &c. 61. These ducts or vessels usually have tapering extremities (Fig. 45- 47), as in prosenchyma. Like prosenchyma, they vary greatly in length; some of them are barely oblong or cylindrical, and are manifestly only simple cells, of the same character as the fibrous-walled cells formerly mentioned (46, Fig. 26, 29), which no one would think of calling vessels. Others, though still nothing but single cells, are more,. prolonged. But those which form tubes of much greater length usually consist (as their development shows), like dotted ducts, of a row of cells formed by multiplication (32-34, and therefore produced from one cell), with the intervening walls obliterated, so as to give a continuous calibre. This origin is well shown in some of the spiral ducts in Fig. 48 (a., b, c), which are conspicuously jointed, or composed of a series of cells directly confluent by their FIG. 48. A bundle of spiral ducts from the stem of'Polygonum orientale, magnified: a, one composed of short cells and with the fibre closely coiled: the next, b, is composed of much longer joints and has a very loose coil: c is short-jointed, and the fibre of the loose coil is oc. casionally forked: d and e show no appearance of joints or partitions, and the turns of the spiral fibre are still more remote. 52 THE ELEMENTARY STRUCTURE OF PLANTS. abrupt extremities. Even the pointed overlapping ends of two contiguous ducts frequently communicate at maturity, by the obliteration of the membrane between the coils of the fibre. The turns of the spiral fibre are more commonly close, as in Fig. 48, a; but they are often separated, even widely, as if the thread had been extended by the elongation of the cell after the spiral deposition had been formed. Fig. 48 exhibits several degrees of this, in different vessels of the very same bundle. 62. Interlaced Fibrilliform Tissue, This is quite as distinct from ordinary cellular tissue, and as worthy of a special name, as is any sort of the so-called vascular tissue of plants. It is the more worthy of notice from its near resemblance to ordinary forms of animal tissue. It consists of very long and much attenuated, simple or branching, fibre-like cells, or strings of cells, inextricably entangled or interwoven without order, so as to make up a loose, fibrous tissue., It is principally met with in Fungi, Moulds, &c., where the cells are extremely soft and destructible; and in Lichens (Fig. 15), where it is dry and much firmer. 63. Laticiferous Tissue. (Vessels of the Latex or Milky Jutice. Cinenchyma of Morren and Lindley.) This, the only remaining kind of vegetable tissue, is of an ambiguous character. It consists of long and irregularly branching tubes or passages, lying in no definite position with respect to other tissue, and when young of such extreme tenuity (their average diameter being less than the fourteen-hundredth of an inch) and transparency that i i t @ |( 0 they are hardly visible, even under powerful microscopes, except by particular manipulation. But their older trunks are much larger than this, when gorged with the milky or other special juices which it is their office to 49 -' 50 contain, and when their sides are thickened by the deposition of such matters. Another peculiarity is, that they anastomose or inosculate, forming a sort of network by the union of their branches, so that there is a free FIG. 49. Vessels of the latex, ramifying among cellular tissue, in the Dandelion; and 50, older and larger vessels from the same plant; all highly magnified. LATICIFEROUS TISSUE. 53 communication throughout the whole system. In this respect, as well probably as in the mode of their formation, they resemble the veins of animals. But their branches do not proceed from larger trunks, and in turn divide into smaller branchlets. They merely fork and inosculate here and there, the branches being commonly as large as the trunk before division. The articulations which they often present (as in the upper part of Fig. 50) would seem to prove that they are formed by the confluence of cylindrical cells. It appears altogether most probable, however, that they are not composed of cells at all; but are, at first, mere passages in the intercellular spaces, which in time acquire a proper membrane by deposition from the contained fluid. The regular circulation which Schultz, the discoverer of this tissue, so elaborately described, has been shown to have no real existence. There is merely a mechanical flow from a part subject to pressure, or towards a place where the latex is escaping, as from a wound. These vessels are found in the bark, especially in the liber, in the leafstalks, and in the leaves. They are most numerous or conspicuots in those plants in which the fluid they contain becomes white or colored, that is, in those which have a milky juice. 64. All the different kinds of tissue that enter into the composition of the plant have now been described, and referred to the cell as their original. Every plant or each organ consists at first of one or more cells of proper cellular tissue; each doubtless commencing with a single specialized cell. In mapy of the simpler vegetables, the cells multiply in this primitive form solely; and the fully developed plant consists of parenchyma alone. But in all plants of the higher grades, some of them early assume the forms, or undergo the transformations, by which they give rise to woody tissue, ducts, or vessels. All these various sorts of modified cells lie vertically in, or conspire to form bundles or cords that run lengthwise through, the stem or other organ they occur in; so that they may be collectively called the Vertical System or Longitudinal System (56). They accompany each other, and together make up the woody parts, as in the wood proper, in the liber or inner bark, and in the fibrous framework of the leaves. Although the various kinds run into each other through every manner of intermediate forms (as in the wood of the Yew, for instance~ 54), the whole, taken together, compose tissues which are almost always manifestly different from the parenchyma in which they are imbedded. It 5* 54 THE ELEMENTARY STRUCTURE OF PLANTS. is convenient, therefore, to give to these the collective name of Fibro-vascular Tissues, or the FIBRO-VASCULAR SYSTEM, aS distinguished from the Horizontal, PARENCHYMATOUS, or common CELLULAR SYSTEM of the plant. 65. Intercellular System. The only exception, if such it be, to the statement that all the vegetable tissues are formed of cells, is that of the so-called vessels of the latex, which, according to the view now best supported' (63), do not so originate, but are a secondary formation, resulting from the transudation of peculiar assimilated matters into the interspaces between the cells; and are therefore rather to be classed with other receptacles, canals, or intervals that are found among or between the cells. Some of these are due to imperfect contact or cohesion, and are in some sort accidental, or at least are irregular and indefinite: such are the INTERCELLULAR SPACES or PASSAGES, left when the angles in parenchyma do not accurately fit throughout. Such are the larger and irregular winding passages in the looser tissues called merenchyma (51), as in the lower'stratum of the leaf (Fig. 7), or those formed by the lobed or branching shape of the cells' themselves, so disposed as to join each other only by their extremities, as is seen in many water-plants. These spaces are soon filled with air. There are besides, in the stems and foliage of aquatic and marsh plants, an abundance of much larger AIR-CELLS or AIR-PASSAGES, usually of many times greater diameter than the cells of the tissue, and produced by their particular arrangement. These are as elaborately built up as any proper organ can be, are constructed upon a uniform plan in each species, and are evidently essential to its existence, such plants requiring a full supply of air in their interior. Other air-spaces or empty intervals, apparently less essential to the life of the plant, arise from the destruction of a part of the parenchyma, either by absorption, or by distention, from the more rapid enlargement of the outer part. In this way, the stem or the pith of many plants becomes hollow. 66. Receptacles of Special Secretions, These arise from the exudation of the proper juices of the cells into the intercellular passages, which are distended by the accumulation; or from the obliteration of contiguous cells, so as to form cavities of considerable size. Such are the turpentine canals of the Pines, &c.; the oil-cells of the fruit of the Umbelliferua, and in the rind of the orange and lemon; the latex-canals in Sumach, &c; EPIDERMAL SYSTEM. 55 67. Internal Glands, such as those which form the translucent dots in the leaves of the Orange and -Myrtle, are compact little clusters of cells filled with essential oil. 68. Epidermal System. In most plants, except of the lowest grades, the superficial layer or layers of cells are different from those they envelope. Also certain appendages grow from the surface, which may be briefly noticed here. 69. The Epidermis, or skin of the plant, is formed of one or more layers of empty cells, with thick walls, cohering so as to form a firm and close membrane, which may be torn off from the subja. cent tissue. It covers all parts of the plant that are'directly ex.,-posed to the air, e t the stjgma, Its structure and office will be more particularly described, (and the nature of what has been specially termed the Cuticle explained,) in the chapter on the Leaves. 70. Stomates (Stomata), or Breathing-pores, are orifices connected with a peculiar structure in the epidermis of leaves and other green parts: -their structure and office will likewise be described in the chapter on the Leaves, to.which organ they more particularly belong. 71. iHairs are exterior.prolongations of cells of the epidermis, consisting either of single elongated cells, or of several cells placed end to end, or of various combinations of such cells. They are simple or branched, single or clustered (stellate, &c.), and exhibit the greatest variety of forms. They are called Glandular Hairs, or Stalked Glands, when the upper cell or cluster of cells elaborates peculiar (usually odorous) products, such as the fragrant volatile oil'of the Sweet Brier. 72. Glands. This' name is applied to any secreting apparatus, and also to superficial appendages of diverse kinds. 73. Bristles (SetTa) are rigid-, thick-walled hairs, usually of a single cell. But the name is likewise given to any setiform body, of whatever nature. 74. Prickles are larger and indurated, sharp-pointed processes of the epidermis or bark; such as those of the Rose and Blackberry. 75. Stings, or Stinging Hairs, such as those of the Nettle, geher. ally consist of, a rigid and pointed cell, terminating in an expanded, globular base, which secretes an irritating fluid. 76. Scurf, or Lepidote, Scale-like Hairs, are flattened, star-like clusters of cells, united more or less into a flat scale, which is fixed 56 THE ELEMENTARY STRUCTURE OF PLANTS. by its centre to the epidermis. They are well shown in the Oleaster, Shepherdia, and most silvery leaves like theirs. Our species of Vesicaria exhibit beautiful gradations between these and stellate hairs. SECT. IV. OF THE CONTENTS OF THE TISSUES. 77. THESE comprise all the products of plants, and the materials they take in from which these products are elaborated. To treat of them fully would anticipate the topics which belong to the chapter on'Nutrition. Some of the contents of cells, however, have already been mentioned, in the account of their production and growth (27 - 39): others require a brief notice here, especially two solid products which are of nearly universal occurrence and great importance in the vegetable economy, namely, Chlorophyll and Starch; and a third, which, however constant, may be regarded as a kind of accidental deposit, namely, Raphides or Crystals. 78. The same cells contain liquids, solids, and air, at different ages. Growing and vitally active cells are filled with liquid (at least while vital operations are carried on), namely, with water charged more or less with nutritive assimilated matters, the prepared materials of growth (11, 27). Any gaseous matter they may contain at this period is, for the most part, held in solution. Completed cells may still be filled with liquid, or with air, or with solid matter only. The liquid contents of the vegetable tissues, of whatever nature or complexity, are often spoken of under the common name of 79. Sap, In employing this name we must distinguish, first, CRUDE SAP; the liquid which is imbibed by the roots and carried upwards through the stem. This is water, impregnated with certain gaseous matters derived from the air, and with a minute portion of earthy matter dissolved from the soil. It is therefore inorganic (12). But as it enters the roots and traverses the cells in its ascent, it mingles and necessarily becomes impregnated with the liquid or soluble assimilated matters which these contain (37). On reaching the leaves, the inorganic materials are transformed, under the influence of light, into organizable or assimilated matter; and the liquid, thus charged with the ready prepared materials of growth, is now ELABORATED SAP. The two classes of CONTENTS OF THE TISSUES. 57 nutritive matter thus produced, and which all forming and vitally active cells necessarily contain, namely the ternary (of which sugar and dextrine are representatives), and the quaternary (proteine, protoplasm, &c.), have already been mentioned (27). 80. Proper Juices, Caoutchouc, Essential Oils, Turpentines, &c. Of the peculiar products of plants, which occur under an infinite variety of forms in different species, it is only needful to say here, that they doubtless arise from one or the other of the two classes of assimilated matter just mentioned, by chemical transformations which throw them out of the ranks of nutritive bodies. They seem to be turned to no account in vegetable growth; they undergo changes on exposure to the air, by which they become resins, gums, wax, &c.; they incline to extravasate into intercellular spa. ces or into cavities of dead or effete tissues, or to be directly excreted from the surface. So that we may regard them all, perhaps, as of the nature of excretions, even where they are stored up in the interior of the plant. For we must remember that the vegetable has no organs or apparatus for eliminating and casting out excreted matters, except to a very limited extent by a few superficial glands, which are found in some plants and in some organs only. Caoutchouc exists in the form of minute globules, diffused as an emulsion in the milky juice of plants, most abundantly in Urticaceme, Euphorbiacen, and Apocynaceue. Gutta percha is a similar product of the milky juice of a Sapotaceous plant. 81. Starl'ch (Farina, Fecula) is one of the most important and universal of the contents of cells, in which it is often accumulated in great quantity, so as to fill them completely (Fig. 52), as in farinaceous roots, seeds, &c. It occurs in the parenchyma of al- j most every part of the plant, excepting the epi- 5i 52 dermis: but while chlorophyll is nearly restricted to the superficial parts, directly exposed to the light, starch is most abundant FIG. 51. Two cells of a potato, with some contained starch-grains, highly magnified; one of the cells contains a few cubical crystals also. FIG. 52. A minute portion of Indian meal, strongly magnified; the cells absolutely filled with grains of starch. 58 THE ELEMENTARY STRUCTURE OF PLANTS. in internal or subterranean parts, most concealed from the light, as in roots and tubers, the pith of stems, and seeds. Starch consists of oval or rounded grains, usually somewhat irregular in outline, and sometimes becoming polyhedral by mutual pressure, as in rice. The size of the, grains varies extremely in different plants, and even in the same cell; as in the potato, where the larger grains measure from am to,-6 of an inch in their larger diameter, but the smallest only J{f of an inch. In wheat-flour the larger grains are Ag to w- of an inch in diameter. And the largest starch-grains known are y2w of an inch long. Indeed, from their manner of growth, we might expect that their bulk would be somewhat indefinite. The mode of their formation is indicated by the peculiar markings, by which starch-grains may almost always be recognized; namely, by the dot or darker point which is seen commonly at one end of the grain, and the fine concentric lines drawn around it, which present the appearance of a succession of irregular circles over the whole surface, in whatever direction the grain is turned. These appearances are best seen in starch from the potato, one of the most characteristic forms and easiest to be examined, under a magnifying power of from 250 to 500 diameters (Fig. 51). The chemical composition of starch is exactly the same as that of cellulose (27); and the grains are solid throughout, but their interior usually softer or more gelatinous. The lines, therefore, it is evident, mark the concen. tric layers, or hollowed scales, of different density, which are successively deposited on an original nucleus. The dot (or hilum, as it has been called) that indicates the position of the nucleus, becomes a concavity, from its not receiving a part of the successive deposits, which are greatest on the opposite side, or very eccentric. The grains lie loose in the cell, and are probably formed so; although it is thought by some that the nucleus or hilum was in contact with the cell-wall, so that the increase by deposition must necessarily have taken place on the other sides. On the whole, there is reason to conclude that starch-grains are formed on nuclei or cytoblasts, that is, on minute solidified portions of protoplasm, like those from which cells primarily originate, by the deposition of layer over layer of ternary assimilated matter (dextrine, &c.), essentially like that which constitutes the secondary deposit that thickens the cell-membrane (39). Their origin, therefore, would be closely analogous to that of cells formed directly from a cy CONTENTS OF THE TISSUES. 59 toblast in the manner propounded by Schleiden; only that the deposit in the case of starch is exogenous, by layer over layer upon a solid nucleus; while in the cell it is endogenous, or by layer within layer, lining the walls. In both, the solidified matter is insoluble in cold water; but in starch it dissolves (or rather swells up into a jelly) and is diffused in boiling water. The deposit on the walls of the cell is of various degrees of density, and sometimes exhibits the chemical peculiarity of starch. Though usually permanent, probably it is sometimes redissolved, to be appropriated elsewhere. But starch is a temporary formation, for future use; in which respect it may be compared with the fat of animals. When required for nutrition, the grains are restored to a liquid state in the plant, at the natural temperature; that is, they are reconverted into Dextrine, — a modification of the same substance which is soluble in cold water,- and this passes, in part, at least, into Sugar, which is still more soluble; and thus a syrup is formed, which the sap dilutes and conveys to the adjacent parts wherever the process of growth is going on. Physiologically considered, therefore, starch is unappropriated' cellulose, stored up in a particular form, as the ready-prepared material of new tissues: while dextrine and sugar are forms in which the same unazotized' assimilated matters are prepared for the immediate purposes of nutrition. The part which these substances play in the vegetable economy will be more fully explained elsewhere. 82. A distinguishing character of starch is that it is turned blue or deep violet by iodine, even in the most dilute solution. Starchgrains are usually simple and separate; but occasionally two or more young grains join, and are enwrapped by new layers into one. In some plants the grains regularly cohere in united clusters. Compound grains of the kind are seen in West Indian Arrow-root, the corms of Colchicum, Arum,* &c. The starch-grains are nearly uniform in the same plant or organ, and of very different appearance in different plants: so that the smallest quantity of starch from the potato, wheat, rice, maize, &c. may at once be distinguished under the microscope. 83. Vegetable Jelly (Bassorin, Salep, Pectine, rVegetable Mucilage The rootstocks of Brasenia and Nymphrea exhibit oblong or club-shaped compouncl starch-grains of great size, very much like those fiom Arum, represented by Schleiden, on page 17, Engl. translation. 60 THE ELEMENTARY STRUCTURE OF PLANTS. in part) has the chemical composition and nearly the properties of starch after it has been diffused in hot water. It is not only one of the contents of cells, as in the tubers of Orchises, in many fruits, &c., and largely in those of Algm, but it also forms in great part the cell-wall of Alga, as in the Carragheen AMoss (Chondrus crispus), from which vegetable jelly is obtained for culinary purposes. WVhen dry, it is horny or cartilaginous; when moist, it swells up, becomes gelatinous, and is capable of being diffused perfectly through cold water, It passes by various modifications, on the one hand into cellulose, and on the other into starch and dextrine. We have it as an excretion in Gum Tragacanth. True gums, such as Gum Arabic, &c., are altered states of the same substance, or of dextrine, and are likewise formed only as excretions. 84. Sugar (of which there are two distinct kinds, Cane and Grape Sugar) is the most soluble of the many forms of ternary organizable matter, as already stated. Though sometimes crystallized as an excretion in the nectaries of flowers, yet in the plant it exists only in solution. It abounds in growing parts, in many stems just before flowering, as those of the Sugar-cane, Maize, Maple, &c. and in pulpy fruits. 85. Fixed Oils belong to the class of ternary assimilated products, but they contain little or no oxygen. The fatty oils take the place of starch (from which they are probably formed) in the seeds of many plants (as in flax-seed, walnuts, &c.), and of sugar in some fruits, such as the olive. They also exist in the herbage, and in some smaller proportion in the cells, perhaps, of almost all plants. 86. Wax is a product of nearly the same nature as the fixed oils (only it is solid at the ordinary temperature), which is extensively found in plants as an excretion, particularly on the surface of leaves and fruits, forming the bloom or glaucous surface which repels water, and so prevents such surfaces from being wetted. It forms a thick coating on some fruits, as the bayberry. As bees convert sugar into wax, and as the sugar-cane yields a kind of wax which " sometimes passes into sugar," we may infer that wax in the vegetable is formed of sugar or its kindred products. Wax also exists as one of the contents of cells, of leaves especially; where a substance allied to it in composition abounds, namely, 87. Chlorophyll, the substance which gives the universal green color to the leaves and herbage. It is formed principally in parts exposed to the light, such as the green bark, and especially the CONTENTS OF THE TISSUES. 61 leaves; not, however, in the external layer of cells, or epidermis (69), but in the parenchyma, especially in the superficial strata. It consists of minute soft granules, of no particular form, either separate or in clusters, forming grains of considerable size, which lie free in the cells (Fig. 53, 180), or loosely adhere to their sides. In some Confervre they collect in the form of spiral lines or bands (as in Fig. 81, the lower part). They often adhere to the surface of starch-grains. Indeed, Mr. Henfrey plausibly considers chlorophyll to arise from altered starch (with the evolution of oxygen); which is the more likely, as it is said to appear in the cells later than starch.* It belongs to the class of waxy bodies; and is soluble in alcohol or ether, but not in water. Chlorophyll undergoes certain changes, in autumn foliage especially, by which it turns to red or yellow. CHROIULE is a name applied to coloring matters not green, and m6stly in a liquid form, as in the cells of petals, giving to them their peculiar tints. These coloring matters are probably a mixture of very various products. 88. Alkaloids (such as Morphine, Strychnine, and Quinine) are quaternary products of plants, principally formed in the cells or interspaces of the bark. Unlike the proteine compounds (27, 79, gluten, fibrine, &c.), they appear to bear no part in vegetation, but to be completed results of vegetation, and of excretory nature. In these substances reside the most energetic properties of the vegetable, considered as to its action on the animal economy, the most powerful medicines, and the most virulent poisons. That they are of the nature of excretions may be inferred from the fact, that a plant may be poisoned by its own products. 89. Tannin or Tannic Acid, which most abounds in older bark, is probably a product of the oxidation or commencing decomposition of the tissues. So, also, Humus, Humic Acid, Ulmine, Ulmic Acid, and the numerous related substances distinguished by the chemists, are products of further decomposition of vegetable tissue, and not products of vegetation. * In that case, the nitrogen obtained in Mulder's incomplete analysis (which gave C'5, HI', N2, Os, with some nitrogeneous matter not determined) must belong to the mucous matter, or protoplasm, which invests the green granules. According to M. Verdeil (in Comptes Rendus, Dec. 22, 1851), the green grains consist of a mixture of a colorless, fatty matter, and a coloring matter anralogous to the red coloring matter of the blood in composition, and like it containing a Considerable proportion of iron! 6 62 THE ELEMENTARY STRUCTURE OF PLANTS. 90. legetable Acids. Tartaric, Citric, and Malic acids are the principal kinds, which occur in leaves and those succulent stems which have a sour juice, and in all acidulated fruits. They are ternary products, with an excess of oxygen. Oxalic Acid, which is an almost universal vegetable product, is a binary body, differing from carbonic acid in ultimate composition only in having a small proportion more of oxygen. (Hydrocyanic or Prussic Acid is one of the special products peculiar to certain plants, and of very different composition, containing a large proportion of nitrogen.) These vegetable acids do not appear to play any leading part in vegetation. They seldom exist in a free state, but are combined with the alkaloids, and with the inorganic or earthy alkalies (Potash, Soda, Lime, and Magnesia) which are introduced into plants from the soil with the water imbibed by the roots. The more soluble salts thus produced are found dissolved in plants; the more insoluble are frequently deposited in the cells in the form of 91. Crystals or Rlaphides, These exist in more or less abundance in almost every plant, especially in the cells of the bark and leaves, as well as in the wood and pith of herbaceous plants. Far the most common, and the principal kind formed with a vegetable acid, are those of oxalate of lime. In an old stem of the Old-man Cactus (Cereus senilis), the enormous quantity of 80 per cent. of the solid matter left after the water was driven off was found to consist of these crystals. In the thin inner layers of the bark of the Locust, for example, each cell contains a single crystal, as is seen in Fig. 57. And Professor Bailey, who has devoted particular attention to this subject, computed that, in a square inch of a piece of Locust-bark, no thicker than ordinary writing-paper, there are more than a million and a half of these crystals. There is frequently a group of separate crystals in the same cell; or a conglomerate cluster, as in Fig. 58. In the leaves of the Fig, and many other Urticaceous plants, a globular crystalline mass is suspended in the cell by a kind of stalk. Oxalate of lime crystallizes in octahedra (as in Fig. 56, the crystal in the lower righthand cell), and in right-angled four-sided prisms (as in Fig. 59, 60), with variously modified terminations. The crystals are frequently acicular, or needle-shaped, either scattered or packed in bundles of from twenty to some hundreds (as in Fig. 53- 55). It is to this form that the name of Raphides (which is the Greek CONTENTS OF THE TISSUES. 63 word for needles) was originally applied, and to which it properly belongs; although it has been indiscriminately extended to all kinds of crystals which occur in the cells of plants. In the common Arum or Indian Turnip, as well as in the Calla /Ethiopica and other plants of that family, the crystal-bearing cells (Fig. 54) may readily be detached from the rest of the tissue; and when moistened and distended by endosmosis, they forcibly discharge their contents, in a curious manner, from an orifice at each end, as is shown in Fig. 55. These acicular crystals are generally thought 53 55 56 57 I ti.-I 54 58 59 60 to consist of oxalate of lime; according to Quekett, they are phosphate of lime. Of other crystals composed of inorganic acids and an earthy base, the more usual are rhombic crystals of carbonate of lime, found in Cacti; and tabular, often twin crystals of sulphate of lime, which are "found in the Musacee and many Scitaminee." Such are wholly formed of inorganic materials, derived from the soil. 92. Silex, likewise derived from the soil, very generally occurs FIG. 53. Raphides, or acicular crystals, from the stalk of the Rhubarb: three of the cells contain chlorophyll, and two of them raphides. FIG. 54. Raphides of an Arum, contained in a large cell; and 55, the same, detached from the surrounding tissue, and discharging its contents upon the application of water. FIG. 56. Crystals from the Onion; one of them a hemitrope. FIG. 57. Crystals of the inner bark of the Locust. FIG. 58. A glomnerate mass of crystals from the Beet-root. FIG. 59, 60. Crystals from the bark of Hickory. Figures 55-60, and also 51, are from sketches kindly supplied by Professor Bailey of West Point. 64 THE GENERAL MORPHOLOGY OF THE PLANT. as a part of the deposit or incrustation on the walls of cells; * but it is not found in the form of crystals in their interior. In the Diatomaceae nearly the whole cell-wall is composed of this indestructible material; consequently, the remains of these minute organisms accumulate at the bottom of the water in which they live, so as to form immense strata in many places. CHAPTER II. OF THE GENERAL MORPHOLOGY OF THE PLANT. 93. The Individual Plant, The organic elements, or cells in their various forms, which have been treated of in the preceding chapter, make up the individual plant. Looking now upon plants as individual beings, we observe that they present themselves under the greatest variety of forms; some of them are of the utmost simplicity, and many of these are so minute, that they are individually undistinguishable or invisible to the naked eye, and only become conspicuous by their aggregation in great numbers: others are highly complex in structure, and attain to a vast size, such as gigantic trees, some of which have flourished for a thousand years or more. All the larger vegetables are formed of a countless number of cells; which, as they increase, arrange themselves so as to shape the fabric into definite parts, such as stem, leaves, and roots, each having, distinct offices to fulfil, while all are subservient to the nutrition and perfection of the individual whole. These parts are called the Organs of the plant; or, more technically, the Compound Organs, since it is the cells of which they are composed that are the real instruments, and carry on the operations of the vegetable economy. These organs are most distinct, and at the same time most diversified, in the highest grade of plants; in the lower, they are successively less and less evolved, until all such distinction of parts vanishes, and the plant is reduced to a rounded or flattened mass of cells, to a row of cells strung end * This may be shown by carefully burning off the organized matter of the tissue, and examining the undisturbed ashes by the microscope (311, 312). PLANTS OF A SINGLE CELL. 65 to end, or even to a single cell. Since these last are the simplest plants, and the higher acquire their more complex structure (as will hereafter be shown) from an equally simple beginning, the most natural order for exhibiting the principal grades of vegetation is to commence with the lowest and simplest possible kinds, namely with 94. Plants of a Single Cell. There are several kinds of such plants among the Algte (Sea-weeds, &c.), which rank as the lowest order of the vegetable kingdom. They are especially interest. ing here, because they furnish the readiest illustrations of the various methods of cell-formation which have been described in the preceding chapter (26- 35). For in them vegetation is reduced to its simplest terms: the plant and the cell are here identical. The cell constitutes an entire vegetable without organs, imbibing its food by endosmosis (37) through its permeable walls, assimilating this food in its interior, and converting the organizable products at first into the materials of its ownS enlargement or growth, or finally into new cells, which constitute its progeny. Thus we have an epitome of all that is essential in vegetation, even on the largest scale, namely, the imbibition of inorganic materials; their assimilation; their application to the growth of the individual, or nutrition, and'the formation of new individuals, or reproduction. But even while thus organically simple, the plant is not restricted to one monotonous pattern. On the contrary, different species, each in its own uniform manner, develope the cell and give rise to their progeny in all the various ways that have been mentioned when describing the forms and the development of cells. The simplest case is that of 95. 1st, Plants of a Single Globular 61 63 64 Cell; that is, of a cell which grows equal-. ly in every direction, and therefore is 0 neither elongated nor branched. Of this, 0 the microscopic plant known as giving rise to the phenomenon of red snow (but which also occurs on damp earth, &c.) furnishes a good illustration. Each indi- 62 65 FIG. 61. Several individuals of the Red-snow Plant (Protococcus nivalis) magnified. 62. An individual highly magnified, showing more distinctly the new cells or spores formed within it. FIG. 63. An individual of Chroococcus rufescens, after NUgeli, much magnified. 64. A more advanced individual, with the contents forming two new cells by division. 65. Another, with the contents divided into four new cells. 6* 66 THE GENERAL MORPHOLOGY OF THE PLANT. vidual is a single cell (Fig. 61), which quickly attains its growth, and produces (by original cell-formation, it is thought) a considerable number of minute firee cells in its interior. The mature mother-cell now decays; and the new generation it contained enlarge into similar cells or plants, which give rise to their progeny and perish in their turn. Some other globular one-celled plants (like Chroococcus, Fig. 63), are very similar, except that they propagate by division of the whole contents, and finely illustrate that general process of free cell-multiplication (37). The layer of protoplasm which lines the cell-wall forms a constriction in the middle, and soon separates the whole inclosed contents into two parts; a layer of cellulose is at the same time deposited on the surface, and thus two new cells are produced (Fig. 64), which usually subdivide each into two (Fig. 65). Four new cells are thus formed within a mother-cell; and the latter is destroyed in the process, all its living contents having been employed in the formation of the progeny, and its effete wall is obliterated by softening or decay, or by the enlargement of the contained cells. Thus the simplest vegetation goes on, from generation to generation. The softened remains or products of the older cells often accumulate and form a gelatinous stratum or nidus, in which the succeeding generations are developed, and from which they doubtless derive a part of their sustenance, -just as a tufted Moss is nourished in part from the underlying bed of vegetable mould which is formed of the decayed remains of its earlier growth. One step in advance brings us to 96. 2d, Plants of a Single Elongated Cell; that is, of a cell which grows on in one direction, but without branching. Such plants answer to cells of prosenchyma, or to vessels,/ Adr,9 (52, 57). For an example we may take any species of Oscillaria (Fig. 66); a,! A d =form of aquatic vegetation of microscopic minuteness, 66 considered as to the size of the individuals, but which rapidly multiply in such inconceivable numbers, that, at certain seasons, they sometimes color the surface FIG. 66. Two individuals pf Oscillaria spiralis, magnified; one of them with one extremity cut off. PLANTS OF A SINGLE CELL. 67 of whole lakes of a green hue, as suddenly as broad tracts of alpine or arctic snow are reddened by the Protococcus.* 97. 3d, Plants of an Elongated and Branching Cell. Some elongated cells in vegetable tissue fork as they elongate, and become branched; as seen in Fig. 15. Several plants consist of individual cells of this kind; as, for example, the species of Vaucheria, which form one kind of the delicate and flossy green threads which abound in fresh waters, and are known in some places by the name of Brook-silk. These, under the magnifyingglass, are seen to be single cells, of unbroken calibre, furnished with branches here and there (Fig. 71). The branches are protrusions, or new growing points, which shoot forth, and have the power of continuous growth from the apex. In Bryopsis (Fig. 73), 67 a 72 70 71 73 a beautiful small Sea-weed, the branches are much more numerous and regular: they are often constricted where they join the main stem, if we may so call it, but the cavity continues from stem to * If the transverse markings of Oscillaria arise fiom imperfect partitions, then the plant corresponds to the duct (58). FIG. 67-69. Botrydium Wallrothii in its development, and with new cells forming within; after Kiitzing: 67, the cell still spherical: 68, pointing into a tube below: 69, the tube prolonged and branched: all much magnified. F1G. 70. Botrydium argillaceum, after Endlicher; the full-grown plant, magnified. FIG. 71. Vaucheria clavata, enlarged: a, a spore formed in the enlarged apex of that branch. 72. End of the branch, more magnified, with the spore escaped from the burst apex. FIG. 73. Bryopsis plumosa; summit of a stem with its brarichlets, much enlarged. 68 THE GENERAL MORPHOLOGY OF THE PLANT. branch; or, in other words, the whole plant consists of a single vegetating cell. 98. While in these cases the ramifications of the cell imitate, or as it were foreshadow, the stem and branches of higher organized plants, we have in Botrydium (Fig. 70) a cell whose ramifications resemble and perform the functions of a root. This is a terrestrial Alga, with a rounded body composed of an enlarged cell, which elongates and ramifies downwards, the slender branches penetrating the loose, damp soil on which the plant grows, exactly in the manner of a subdivided root. Meanwhile, a crop of rudimentary new cells is produced, by original free cell-formation (28), in the liquid which fills the body of the mother-cell: these, escaping when that decays or bursts, grow into similar plants, in the manner shown by Fig. 67- 69. 99. The new cells by which Vaucheria is propagated are produced in a different way; as is shown in V. clavata (Fig. 71, 72). The apex of a branch enlarges; its green contents thicken, separate from those below, and a membrane of cellulose is formed around it, just as it forms around the contents of the whole cell in the microscopic Chroococcus (Fig. 63), but no further division takes place; the wall of the mother-cell bursts open, and the new-born cell escapes into the water. When it grows, it elongates a little from one end, and by this fastens itself to any solid body it rests on, and then grows from the opposite end into a prolonged tube, with occasional branches, like its parent. In this way, a plant composed of a single cell imitates not obscurely the downward and upward growth (the root and stem) of the more perfect plants. In the foregoing cases we noticed that the production of new cells insured the death of the parent; the whole living contents being appropriated to the new formation. In this case, the progeny originates from the living contents of a part of the cell only, and the walls of that portion alone perish. 100. Plants of a Single Row of Cells. To these there is but a single step from plants formed of a single cell (whether branching or unbranched) which has the power of continuous growth from the apex; and that step consists in the formation of transverse partitions. The manner in which these are produced has been already described (Fig. 8), as observed in a species of Conferva. Most of these simple, thread-like Algae are composed of a single row of cells, produced in this way. The three kinds of Moulds or Mil PLANTS OF A SINGLE ROW OF CELLS. 69 dew Fungi here represented (Fig. 74- 76) consist, as to the creeping part at the base (which spreads widely through the substance they live Pf~, g Aon) of long, threadqi~, like, and usualQ 0Q5 O ~ ly branching cells (much like those of Fig. 15), for the most part destitute of partitions; while the upright portions are composed of a 74 -75 76 row of short cells, like those of a Conferva. These are terminated in the Breadmould (Fig 74) by a much larger cell, which developes numerous and very minute rudimentary ones in its interior. In Fig. 75, we have a different arrangement, namely, a cluster of branches, made up of a series of bead-like, easily separable cells, which are evidently formed by the process of division just illustrated, and which serve as seeds to reproduce the species. 101. Spores. When the cells remain connected as they multiply, they increase the size or complexity of the individual vegetable. When they separate, each becomes the initial cell of a new plant. Any cell is capable of originating a new individual. No sooner, however, does the plant acquire such slight complexity as to consist even of a single series of cells, than a distinction begins to appear between cells adapted for vegetations, and those for reproduction. Both may propagate the species: the threadlike, vegetating cells which form the base of the Moulds, in Fig. 75, for example, grow with the same readiness as the minute specialized cells which terminate this simple vegetation. But the first appear to do so after the manner in which the higher grades of plants multiply by offshoots or division of the root; while the second are analogous in this respect to the seeds or embryos of such higher plants. These cells specialized for propagation, however they may originate, are accordingly distinguished by a special name, that of SPORES or SPORULES. We have to rise still higher in the scale, however, before a well-marked distinction can be FIG. 74. The Bread.nmould (Mucor) magnified. 75. Another Mould (Penicillum glaucum). 76, Botrytis Bassiana, a parasitic Mould. All magnified. 70 THE GENERAL MORPHOLOGY OF THE PLANT. drawn in all cases between cells for reproduction and cells for vegetation. 102. Conjugation, At this stage of vegetation, however, and even in a large tribe of plants composed of single and simple cells, a process of great physiological importance is first observed — the evident equivalent of bisexuality in the higher orders, - by which the reproductive cells or spores are still further specialized and potentiated. They are formed by conjugation; that is, by the mingling of the contents of two cells, both of which take part in the formation of the resulting spore. Fig. 77 - 80 exhibit this 77 78 79 80 conjugation in a minute silicious-coated, one-celled plant, of the family Desmidiaceae; where the recent discovery of this process, by Mr. Ralfs, has confirmed the vegetable character of these ambiguous microscopic bodies beyond all doubt. Also Figure 81 shows the conjugation of two individuals of Zygnema (Spirogyra), a common plant of our pools, composed of single rows of cells, nearly all of which, in the figure, are represented as taking part in the conjugation. 103. Plants of a Tissue of Cells combined in one Plane, The next step in complexity is seen in those Algae which consist of a few jointed tubes laterally cohering with each other; or of numerous cells united in a single plane, as in the little Sea-weed, Fig. 82. FiG. 77. Magnified individual of Closterium acutum, after Ralfs. 78. Two individuals more magnified, in conjugation; their cells opening one into the other, and the contents mingled; in 79, condensing; in 80, collected and formed into a spore. FIG. 81. Magnified view of two conjugating filaments of Zygnema, showing all the stages of the process by which the cells from different approximated filaments form each a corresponding protuberance, these come into contact, the intervening walls are absorbed, and the green contents pass from one cell into the other, condense, acquire an investing memrbrane, and so form a spore: the several stages are shown from below upwards. PLANTS OF A TISSUE OF CELLS. 71 This gives rise to frondose or leaf-like forms. The name of FROND is applied A4+n 0 ~0 O Q0~ to such expanded I) oOQCp bodies, which are 82 83 fice of both. Only the simplest forms, however, consist of a single layer of cells. Most frondose Sea-weeds, as well as Lichens, Liverworts, &c., are made up of several such layers. This is not the place to illustrate the almost endless diversity of forms under which the frond, or, as it is called in Lichens and Fungi, the Titallus, appears in these lower grades of plants; nor to notice their particular modes of propagation; except to say, in general, that the spores are still nothing but specialized cells, developed in some one of the ways already explained. But we now begin to meet with special organs or peculiar apparatus in which the reproductive cells are formed, instead of occurring indifferently in any part. b a 84 85 8a 104. Plants of a Tissue of Cells combined into a solid Axis, or with FIG. 82. A branch of elsesseria s LePrieurei (fromt th e lae towice the natural size. 83. A small portion more magnified, to show the cellular structure. The cells have thick gelatinous walls; those in the middle are elongated, those Towards the margins rounded. FIG. 81. Fruit-stalk, with a portion of the foliage, of a Jungermannia, magnified, to show its entire cellultar structure. FIll.. One of the tubular spirally-mariz ed cells from the fruit of a Jungermannia ( of; and (way) the spiral threads which resxplt from its disruption. Some of he spres stick to th spectuiale. FIG. 86. Jungerannia Lyof elii, less than the natural sizece FIG. 86. Jungennannia Lyelilt, less than the natural size. 72 THE GENERAL MORPHOLOGY OF THE PLANT. stem and branches. Stem-like solid forms occur, perhaps as abundantly as the leaf-like or frondose, in the higher representatives of the lowest orders of plants, in Algae, Fungi, and Lichens; and occasionally the two are somewhat vaguely presented in the same individual. Thus, many of the larger Sea-weeds display a leaflike frond on the summit of a solid stalk; this stem, however, has once formed a part of the leaf. But in the Liverwort Family the distinction is first clearly exhibited, and in the true Mosses the higher type of vegetation is fully realized, namely in 105. Plants with a Distinct Axis and Foliage; that is, with a stem which shoots upward from the soil, or whatever it is fixed to, or creeps on its surface; which grows onward from its apex, and is symmetrically clothed with distinct leaves as it advances. All these lower vegetables which have now been mentioned, of whatever form, imbibe their food through any or every part of their surface, at least of the freshly formed parts. Their roots, when they have any, are usually intended to fix the plant to the rock or soil, and not to draw nourishment from it. The strong roots of the Oar-weed, Devil's Apron (Laminaria), and some other large Sea-weeds of our coast, are merely holdfasts, or cords expanding into a disc-like surface at their extremity, which by their adhesion bind these large marine vegetables so firmly to the rock that the force of the waves can seldom carry them away. Mosses f,': t! also take in their nourishment through ~___, their whole expanded surface, princi[)t rr 7t ~pally therefore by their leaves: but the stems also shoot forth from time to time delicate rootlets, composed of slender cells or tubes, which grow in a downward direction and doubtless perform their part in FIG. 87. An individual of a Moss (Physcomitrium pyriforme), enlarged to about 12 times the natural size. 8S. Tip of a leaf, cut across, much magnified, to show that it is made up (except the midrib) of a single layer of cells. CELLULAR AND VASCULAR PLANTS. 73 absorption. Although sometimes of scarcely higher organization than the root-hairs which grow from the under side of a Liverwort (Fig. 86), yet they distinctly introduce the root. A Moss, therefore, as respects its vegetation, is an ordinary herb in miniature: it presents an epitome of the three universal ORGANS OF VEGETATION, namely Root, Stem, and Leaves; although its roots are of a secondary and subordinate character. In the apparatus of reproduction there is more complexity, but no essential change of plan. The spores of Mosses are formed by division of the contents of mother-cells into fours (31); and are contained in Spore-cases (or Sporangia) of peculiar structure, which are accompanied with some apparatus too elaborate to be described here, and are commonly elevated, before maturity, on a naked and slender stalk. The reproductive apparatus no longer forms a part of the general tissue, nor is imbedded in it, but special and altogether distinct organs are assigned to this office. 106. Thallophytes and Cormoplhtes. It is convenient to mention here, that these plants of the lower grades, Algoe, Fungi, and Lichens, which exhibit no proper distinction of stem and foliage, are by some botanists collectively called THALLOPHYTES, that is, plants formed of a thallus (103), or bed, as the compound word imports. And the name is appropriate for the greater part of these rootless, stemless, and leafless forms of vegetation, which compose flat crusts or plates, like the common Lichens on rocks, walls, and bark; or spreading Mushrooms; or the broad, membranous Seaweeds, such as the Dulse and Laver: and even the plants of single cells or single rows of cells are more commonly aggregated so as to make up a stratum, or bed of interlaced threads, more or less compact or definite. Such general names are seldom characteristic of every form they are meant to comprise. The contradistinguishing name of CORMOPHYTES (meaning stem-growing plants) is given to the higher forms of vegetation, from Mosses upwards, because they develope a proper stem, usually adorned with distinct foliage. 107. Cellular and Vascular Plants. While the Mosses emulate ordinary herbs and trees in vegetation and external appearance, they agree with the lower plants in the simplicity of their internal structure. They are entirely composed of cellular tissue strictly so called, chiefly in the form of parenchyma (51), at least they 7 74 THE GENERAL MORPHOLOGY OF THE PLANT. have no vessels or ducts * (57) and form no wood. They, with all the plants below them, were therefore denominated CELLULAR PLANTS by De Candolle. Those above, inasmuch as vascular and woody tissues enter into their composition, when they are herbs as well as when they form shrubs or trees, he distinguished by the general name of VASCULAR PLANTS. 108. The strength which these tissues impart - owing to their toughness and the close bundles or masses they form running lengthwise through the stem (53, 56) — enables these vascular and woody plants to attain a great size and height; while Mosses and all other Cellular plants are of humble size, except when they 90 float in water, in which a few of the coarser Sea-weeds do indeed attain a prodigious length and bulk. The lowest forms of Vascular plants, such as the Club-Mosses,. —-_,1~~~o (Fig. 89), are of humble size, as the name indicates, although the stems are often of a woody texture. Most Ferns, or Brakes, are 9 91 also herbaceous, or their persistent and more or less woody stems remain underground, in the form of rootstocks, or creep on its sur. f ~face (as in Fig. 95). A few of them, however, in the warmer parts of the world, rise into trunks, ~~~...igand form palm-like trees (Fig. 94), of graceful port, and sometimes of great altitude. Thus far, the roots 89 are still of a secondary character; that is, they spring from the stem, wherever it is in contact with or covered by the soil. From the mode of development it will hereafter appear that Ferns and Club-Mosses, like true Mosses, can * The spirally marked tubes which are found in the spore-cases of Liverworts (Fig. 85, a) offer an exception. FIG. 89. Lycopodium Carolinianum, of the natural size. 90. A leaf from the spike of fructification, with the spore-case in its axil, and spores faliing out. 91. A group of four spores, magnified. 92. The same separated. 93. A burst spor;-case of Selagineila apus, with its four large spores. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 75 have no primary root. The axis, therefore, grows from the apex only, and it has no provision for increase in diameter as it increases in age. They have accordingly received the name of ACROGENS or ACROGENOUS PLANTS, -terms of Greek derivation, signifying that they grow from the apex alone. As to their fructification, all these families belong to the great lower series of 109. Cryptogamous or Flowerless Plants. Such are all plants which are reproduced by spores in place of seeds. Spores, as has been already shown, are single specialized cells, which originate in some one of the ordinary modes of cell-production, and without the agency of proper flowers. Cryptogamous and Flowerless are therefore equivalent terms; the former denoting, metaphorically, that the flowers or organs of reproduction are concealed or obscure.* The great advance 94 made by Club-Mosses and Ferns in their organs of vegetation is not attended by any corresponding complexity in their mode of reproduction. The spores of Club-Mosses and Ferns are as simple as those of true Mosses themselves, and the apparatus concerned is scarcely more elaborate. Even the tall Tree Ferns spring from spores of,y the same simple character, -. and of size so small that they are separately invisible to the naked eye. It is worthy of'' note, however, that their simple spore-cases are borne on the leaves, either on leaves in 95 their natural state as organs of vegetation, or on those more or * Most Cryptogamous plants, however, are now known to have organs analogous to those of the flower, at least in function. These will be described in another place. FIG. 94. Sketch of a Tree Fern, Dicksonia arborescens, of St. Helena; after Dr. J. D. Hooker. 95. Polypodium vulgare, with its creeping stern or rootstock. 76 THE GENERAL MORPHOLOGY OF THE PLANT. eless altered to subserve the special purpose. For in like manner, on leaves more or less altered or specialized, the seeds are manifestly borne in the simplest form of 110. Phenogamous * or Flowering Plants, In these we reach at length the perfected type, the highest grade of vegetation. They are the only flower-bearing plants, as their name indicates. Their reproduction is effected through an apparatus essentially different from that of Cryptogamous plants, namely, by Stamens and Pistils (the essential organs of the flower); the stamen producing Pollen, or free fertilizing cells; the pistil producing bodies to be fertilized, called Ovules, and which after fertilization become SEEDS. While Cryptogamous plants are propagated from spores, or specialized cells, which in germination multiply into other cells, and at length form a young plant, Phsenogamous plants are propagated from seeds, which are more complex bodies, essentially characterized by having already formed within them, before they separate from the mother plant, an EMBRYO, that is an organized plantlet, which is only further developed in germination. 111. In the lowest grade of Phoenogamous plants (viz. in the Cycadaceoe, and in the Coniferae or Pine Family), the flowers are of such extreme simplicity that they consist, some of a stamen only, others of one or more naked ovules borne on the margins of an evident leaf, as in Cycas, or on the base or inside of an altered, scale-like leaf, as in the Pine Family. In the former, the ovules answer to the spore-cases of Ferns; in the latter, to the sporecases of Club-Mosses; thus confirming an analogy which is indicated by general aspect between two of the higher families of Cryptogamous, and the lowest two of Phmnogamous plants. These are Gymnospermous (that is, naked-seeded) Phtenogamous plants. In all the rest, the ovules are perfectly inclosed in the pistil, which forms a pod or closed covering of some sort for the seeds; they are accordingly distinguished by the name of Angiospermous (that is, covered-seeded) Phsenogamous plants. Their flowers in the simplest cases consist, one sort of a stamen only, the other of a pistil only. But as we rise in the scale, these organs tend to multiply; to be combined so as to have both kinds in the same flower; * Sometimes written Plhanerogamous. Both terms are made from the same Greek words, and signify, by a metaphorical expression, the counterpart of Cryptogamous; that is, that the essential organs of the flower are manifest or conspicuous. PHAMNOGAMOUS OR FLOWERING PLANTS. 77 to be protected or adorned with a circle of peculiar leaves (the CALYX), or with two such circles (CALYX and COROLLA), of which the inner is commonly more delicate in texture and of brighter color. This, the completed flower, exhibits the ORGANS OF REPRODUCTION in their most perfect form. 112. The Organs of Vegetation also exhibit their most perfect development in Phvenogamous plants. The three kinds, root, stem, and leaves, are almost always well defined. In a few exceptional cases, however, we have frondose forms; as in the Duck-weed (Fig. 96), where stem and leaf are fused together into a green flat body which floats on the water, emitting roots from the' lower surface and exposing the upper like a leaf to the light. So, true leaves seldom appear in the Cactus Family, where the green bark of the whole surface takes their place, although the points from which they should arise are distinctly indicated; nor are they developed at all in the Dodder (135, Fig. 122), and some other parasitic Flowering plants. In all Cryptogamous plants furnished with a distinct axis, or stem, and leaves, this whole structure has to be formed after germination (110, 0i, in a manner to be hereafter shown); and when formed, the axis grows from its apex only (108), so that there is no primary root. Phwenogamous plants, on the contrary, are developed directly from an embryo plantlet, namely, from an axis with its appendages, which already exists in the seed, and which grows both ways in germination; from one end to produce the stem, and from the other to form the root, thus exhibiting a regular opposition of growth from the first. To understand this, and to obtain the clearest conception of the plant as a 96 whole and of its mode of growth, we should at the outset attentively consider the 113. Development of the Embryo. The Phmnogamous plant, then, in the early stage at which we begin its biography, is an EMBRYO (Fig. 100) contained in the seed (Fig. 99). The form of this initial plantlet varies greatly in different species. It is often an oblong or cylindrical body, simple at one extremity, and nicked or lobed at the other, as in the case we have chosen for illustration. The undivided or stem part is called the RADICLE; it is the rudimentary FIG. 96. A Duck-weed (Lemna minor, the whole plant), in flower; magnified. 7 78 THE GENERAL MORPHOLOGY OF THE PLANT. axis, the initial stem. The two lobes into which the upper end is split are the COTYLEDONS, or the undeveloped first pair of leaves, often named the Seed-leaves. These are often so large as to make up nearly the whole bulk of the seed, as in the pea and bean, or the Apple and Almond (Fig. 97), where the radicle is very short in proportion; and on nute rudiments of one or more additional leaves may often be detected within (Fig. 98, a). The embryo, therefore, consists of a short axis or stem, crowned with two or 97 98 more undeveloped leaves, or, in other words, with a Bud. In germination the axis or radicle elongates throughout, so as usually to elevate the budding apex above the surface of the soil, and its cotyledons expand in the air into the first pair of leaves; and at the same time from the opposite extremity is formed the root, which grows in a downward direction, so as to penetrate more and more into the soil. The two extremities of the embryo are therefore differently affected by the same external in100 101 102 103 104 fluences, by light especially, and exhibit exactly opposite tendencies. The budding end invariably rises upwards, as if it sought FIG. 97. Embryo (the whole kernel) of an Almond, the cotyledons slightly separated. 98. The same, with one cotyledon taken off, to show the plumule, or minute undeveloped leaves, a, between the two. FIG. 99. A longitudinal section of a seed, showing the embryo or rudimentary plant it contains. 100. The embryo taken from the seed, and its rudimentary leaves, or cotyledons, a little separated. 101. The same in germination, the cotyledons expanding into the first pair of leaves. 102-104. The seedling plant more advanced. (The radicle, or first joint of stem, should have been drawn more elongated.) DEVELOPMENT OF THE EMBRYO. 79 the light and air; the root-end turns constantly from the light, and buries itself in the dark and moist soil. These tendencies are absolute and irreversible. If obstacles intervene, the root will take as nearly a downward, and the stem as nearly an upward direction, as possible. They are only the first manifestation of an inherent property which continues, with only incidental modifications, throughout the whole growth of the plant, although, like instinct in the higher animals, it is strongest at the commencement: and it insures that each part of the plant shall be developed in the medium in which it is designed to live and act, - the root in the earth, and the stem and leaves in the air. The axis, therefore, especially in plants of the highest grade, possesses a kind of polarity; it is composed of two counterpart systems, namely, a Descending Axis or root, and an Ascending Axis or stem. The point of union or base of the two is termed the crown, neck, or collar. Both the root and stem branch; but the branches are repetitions of the axis from which they spring, and obey its laws. The branches of the root tend to descend; those of the stem tend to ascend. 114. Organs of Vegetation, These three organs, Stem, Root, and Leaves, either preexist rudimentarily in the seed, or appear at the first development of the embryo in germination. Of them, vegetables essentially consist; for they are all that are requisite to, and actually concerned in, their life and growth. Indeed, the whole ulterior evolution of the plant exhibits only repetitions of these essential parts, under more or less varied forms. They are, therefore, properly termed the FUNDAMENTAL ORGANS of plants, or the ORGANS OF VEGETATION. The root absorbs the crude food of the plant from the soil; this is conducted through the stem into the leaves, is in them digested, under the agency of solar light and heat; and the nourishment thus assimilated is returned into the stem and root, to be expended in the formation of new rootlets, new branches, and new leaves. The more the plant grows, therefore, the more it multiplies its instruments and means of growth; and its evolution would seem to be limited only by the failure of food, of a fit temperature, or other external circumstances. 115. Sooner or later, however, the plant changes its mode of development, and bears Flowers, or ORGANS OF REPRODUCTION. But even in these, the philosophical botanist recognizes the stem and leaves, under peculiar forms, adapted to special purposes. And the object or consummation of the flower is the production 80 THE ROOT. of seeds, containing an embryo plant which is composed of these same fundamental organs, and which in its development repeats these successive steps, to attain the same ultimate result. 116. Having briefly traced the plan and progress of vegetation from the simplest or lowest through to the highest or most elaborately perfect grade of plants, we may, in the following chapters, leave the Cryptogamous or Flowerless plants entirely out of view (reverting to them only to explain separately their principal peculiarities at the close), and explain the phenomena, first of vegetation, and then of reproduction, as manifested in the higher series of Phoenogamous or Flowering plants. The simpler kinds of the lower series doubtless afford peculiar facilities for investigating questions of anatomical structure, and for ascertaining what is really essential to vegetation. But the general scheme of the vegetable kingdom, and the unity of plan which runs through the manifold diversities it displays, enabling us to refer an almost infinite variety of details to a few general laws, must be studied in the higher series of Phuenogamous plants, which exhibit, in manifold variety of form, the completed type of vegetation. CH A P T E R III. OF THE ROOT OR DESCENDING AXIS. 117. THE Organs of Vegetation (114) in Pharnogamous plants, namely, the root, stem, and leaves, are to be considered in succession; and it is on some accounts most convenient to begin with the root, charged as it is with the earliest office in the nutrition of the vegetable, that of absorbing its food. According to our view of the matter, however (113), its formation does not precede, but follows, that of the stem. 118. The Primary Root, as already defined (112-114), is the descending axis, or that portion of the trunk which, avoiding the light, grows downwards, fixing the plant to the soil, and absorbing nourishment from it. The examination of any ordinary embryo during germination, such as that of the Sugar Maple (Fig. 105 - 107), will give a good idea of the formation and entire peculiar THE PRIMARY ROOT. 81 ities of the root. Its radicle (a), or preexisting axis, first of all grows in such a way as to elon. gate throughout its whole exb tent (thus showing that it is not - t \ i itself root, but the first joint of. -.-........... stem); this lengthening, while ea5,o6 it thrusts the root-end down. wards (113) a little deeper into the soil, at the same time raises the 107 cotyledons (b) to the surface, and at length elevates them above it, where b they expand in the light and air, and begin to perform the office of leaves (Fig. 107). Contemporaneous with this elongation of the radicle. a new and different growth takes place from its lowver extremity in a downward direction, which forms the ROOT (Fig. 107, r). The root is therefore a new formation from the root-end of the radicle. It begins by the production of a quantity of j new cells (by division) at the extremity of the radicle; not on its' surface, however, but beneath its thin epidermis and the superficial cells. The multiplication of cells at this point proceeds from below onwards;... a those behind quickly expanding to - —.-. their full size, and then remaining unaltered, while those next the apex 108 continue to multiply by division. In this way the root grows onward by continual additions of new material to its advancing exFIG. 105. An embryo of Sugar Maple, just unfolding in germination. 106. Same, a little more advanced; the radicle, a, considerably elongated. FIG. 107. A germinating embryo of Sugar Maple, still more advanced: a, the radicle elongated into the first joint of stem, bearing the unfolded cotyledons or seed-leaves, b, and between them the rudiments of the next pair of leaves; while from its lower extremity the root, r, is formed. FIG. 103. The lower end of the same root, magnified: a, the place where growth, through the multiplication of cells by division, is principally taking place: b, the original apex of the radicle, which has been carried onward by the growth that has taken place just behind it.. 82 THE ROOT. tremity; lengthening from the lower end entirely or chiefly, so that this part of a growing root always consists of the most newly formed and vitally active tissue. 119. The new cells, however, do not occupy the very point, as is commonly, but incorrectly, stated. This is capped, as it were, by an obtusely conical mass of older cells, consisting of the superficial tissue of the end of the radicle, pushed forward by the cellmultiplication that commenced behind it, as already mentioned (Fig. 108). As the original cells of this apex wear away or perish, they are replaced by the layer beneath; and so the advancing point of the root consists, as inspection plainly shows, of older and denser tissue than that behind it.* The point of every branch of the root is capped in the same way. It follows that the so-called spongioles or spongelets of the roots have no existence. Not only are there no such special organs as are commonly spoken of, but absorption evidently does not take place, to any considerable extent, through the older tissue of the point itself. 120. As to absorption by roots, the inspection of the root of a germinating plantlet, or of any growing rootlet, even under a low magnifying power, shows that they must imbibe the moisture that bathes them, by endosmosis (37), through the whole recently formed surface, and especially by the hair-like prolongations of the exterior 109 layer of cells, or J.fibrils, as they may be termed, which are copiously borne by all young roots (Fig. 108). Fig. 109, 110, show some of these root-hairs, and the tissue that bears them, more magJy nified. These capillary tubes, of 5- great tenuity and with extremely delicate walls, immensely increase the surface which the rootlet exl poses, and play a more important part in absorption than is gener2-== —— = | |ally supposed; for they appear 110 to have attracted little attention. These fibrils perish when the growing season is over, or when the * It is a similar tissue that exfoliates from the point of some aquatic (as in Lemna, Fig. 96), and many aerial roots (as in Pandanus), in the form of a loose cup or sheath. THE PRIMIARY ROOT. 83 root gets a little older; at the same time, the external layer of cells that bears them, at first undistinguishable from the parenchyma beneath, except perhaps in the size of the cells, hardens and thickens into a sort of epidermis, or firmer skin; so as to arrest or greatly restrain the imbibition. This epidermis (69) of the root consists of less compressed cells than in parts exposed to the light, and is destitute of stornates or breathing-pores (70). 121. The growth of the root and its branches keeps pace with the development of the stem. As the latter shoots upward and expands its leaves, from which water is copiously exhaled during vigorous vegetation, the former grow onward and continually renew the tender, hygrometric tissue through which the absorption, required to restore what is lost by evaporation or consumed in growth, is principally effected. Hence the danger of disturbing the active roots during the season of growth. In early summer, when the sap is rapidly consumed by the fresh leaves, the rootlets are also in rapid action. The growth of the branches and roots being simultaneous, while new branchlets and leaves are developing, the rootlets are extending at a corresponding rate, and their tender absorbing points are most frequently renewed. They cannot now be removed from the soil without destroying them, at the very time when their action is essential to restore the liquid which is exhaled from the leaves. But towards the close of summer, as the leaves grow languid and the growth of the season is attained, the rootlets also cease to grow, the loose tissue of their extremities, not being renewed, gradually solidifies, and absorption at length ceases. This indicates the proper period for transplanting, namely, in the autumn after vegetation is suspended, or in early spring before it recommences. 122. This elongation of roots by their advancing points alone is admirably adapted to the conditions in which they are placed. Growing as they do in a medium of such unequal resistance as the soil, if roots increased like growing stems, by the elongation of the whole body, they would be thrown, whenever the elongating force was insufficient to overcome the resistance, into knotted or contorted shapes, very ill adapted for the free transmission of fluid. But, lengthening only at their farthest extremity, they insinuate themselves with great facility into the crevices or yielding parts of the soil, and afterwards by their expansion in diameter enlarge the cavity; or, when arrested by insuperable obstacles, their advan. 84 THE ROOT. cing points follow the surface of the opposing body until they reach a softer medium. In this manner, too, they readily extend from place to place, as the nourishment in their immediate vicinity is consumed. Hence, also, may be derived a simple explanation of the fact, that roots extend most rapidly and widely in the direction of the most favorable soil, without supposing any prescience on the part of the vegetable, as some have imagined. 123. The advancing extremity of the root consists of parenchyma alone; but bundles of vessels and woody tissue appear in the forming root, soon after their appearance in the primordial stem above: these form a central woody or fibrous portion, which continues to descend (by the transformation of a portion of the nascent tissue) as the growing apex advances; sometimes, although not usually, inclosing a distinct pith, as the wood of the stem does. The surrounding parenchymatous portion becomes the bark of the root. Increase in diameter takes place in the same way as in the stem. (Chap. IV. Sect. IV., V.) 124. We have taken the root of the seedling as an example and epitome of that of the whole herb or tree; as we rightly may; for in its whole development the root produces no other parts; it bears nothing but naked branches, which spring from different portions of the surface of the main root, nearly as this sprung from the radicle, and exactly imitate its growth. They and their ramifications are mere repetitions of the original descending axis, serv-. ing to multiply the amount of absorbing surface. The branches of the root, moreover, shoot forth without apparent order; or at least in no order like that of the branches of the stem, which have a symmetrical arrangement, dependent, as we shall see, upon the arrangement of the leaves. 125. To the general statement that roots give birth to no other organs, there is this abnormal, but by no means unusual exception, that of producing buds and therefore sending up leafy branches. Although not naturally furnished with buds, like the stem, yet, under certain circumstances, the roots of many trees and shrubs, and of some herbs, have the power of producing them abundantly. Thus, when the trunk of a young Apple-tree or Poplar is cut off near the ground, while the roots are vigorous and full of sap, those which spread just beneath the surface produce buds, and give rise to a multitude of young shoots. The roots of the Maclura, or Osage Orange, habitually give rise to buds and branches. ANNUAL ROOTS. 85 Such buds are said to be irregular, or adventitious. This power, however, roots share with every part of the vegetable that abounds with parenchyma: even leaves are known to produce adventitious buds. 126. The root has been illustrated from the highest class of Phbenogamous plants; in which the original root, or downward prolongation of the axis, continues to grow, at least for a considerable time, and becomes a tap-root, or main trunk, from which branches of larger or smaller size emanate. Often, however, this main root early perishes or ceases to grow, and the branches take its place. In some plants of the highest class (in the Gourd Family, for example), and in nearly the whole great class to which Grasses, Lilies, and Palms belong, there is no one main trunk or primary root from which the rest proceed; but several roots spring forth almost simultaneously from the radicle in germination, and form a cluster of fibres, of nearly equal size (Fig. 111). Such plants scarcely exhibit that distinct opposition of growth in the first instance, already mentioned as one characteristic of Phanogamous vegetation. Most Phaonogamous plants likewise shoot forth secondary roots from the stem itself, the only kind produced by Cryptogamous plants. To these we must revert, after having considered some diversities connected with the duration and form of' roots, and an important subsidiary purpose which they often subserve. 127. Alnnual Roots are those of a plant which springs from the seed, flowers, and dies the same year or season. Such plants always have fibrous roots, composed of numerous slender branches, fibres, or rootlets, proceeding laterally from the main or tap-root, which is very little enlarged, as in Mustard, &c.; or else the whole root divides at once into such fibrous branches, as in Barley (Fig. 111) and all annual Grasses. These multiplied rootlets are well adapted for absorption from the soil, but for that alone. The food which the roots of such a plant absorbs, after being digested and elaborated in its leaves, is all expended in the production of new leafy branches, and at length of flowers. The flowering process and the maturing of the fruit exhaust the vegetable greatly (in a manner hereafter to be explained), consuming all the nourishing material which it contains, or storing it up in the fiuit or seed for its offspring; and having no stock accumulated in the root or elsewhere to sustain this draught, the plant perishes at the close of the season, or whenever it has fully gone to seed. 8 86 THE ROOT. 128. Biennial Roots are those of plants which do not blossom until the second season, after which they perish like annuals. In these the root serves as a reservoir of nourishing, assimilated matter (27, 79); its cells therefore become gorged with starch (81), vegetable jelly (83), sugar (84), &c. Such thickened roots are said to be fleshy, and receive different names according to the shapes they assume. When the accumulation takes place in the main trunk or tap-root, it becomes conical, as in the Carrot, Fig. 112, when it tapers regularly from the base or crown to the apex; it is fisifornm or spindle-shcaped when it tapers upwards as well as downwards, as in the Radish, Fig. 113; or napiform or turnipshaped, when much swollen at the base, so as to become broader than long. If some of the branches or fibres are thickened, instead of the main axis, the root is said to be fasciculated or clustered, as in Fig. 114; or tuberiferous or tuberous, when they assume the form of rounded knobs, as in Fig. 115; or palmnate, when the knobs are branched, as in Fig. 116. These must not be confounded with tubers, such as potatoes, which are forms of stems. Most of these are biennial. Such plants (of which the Radish, Carrot, Beet, and Turnip, among our esculents, are familiar exam111 112 116 1n-v 113 115 ples) neither flower the first season, nor even expend in the production of stems and branches much of the nourishment they generate; but, forming a large tuft of leaves at the very surface of the ground, they accumulate in the root nearly the whole sumFIG. 111-ll11G. Different kinds of roots. BIENNIAL AND PERENNIAL ROOTS. 87 mer's supply of nourishment. When vegetation is resumed, the following spring, they make a strong and rapid growth, shooting forth a large stem, and bearing flowers, fruit, and seed, almost wholly at the expense of the accumulation of the previous year; this store is soon consumed, therefore; and the plant, meanwhile neglecting to form new roots, perishes from exhaustion. 129. Perennial Roots. A third class of herbs, and all woody plants, do not so absolutely depend upon the stock of the previous season, but annually produce new roots and form new accumulations; sometimes in separate portions of the root, as in the Dahlia or the Orchis (Fig. 115), where, while one or more of such reservoirs is exhausted each year, others are providently formed for the next year's sustenance; and so on from year to year; a portion annually perishing, but the individual plant surviving indefinitely. More commonly, the whole body and main branches of the root are somewhat thickened; or portions of the stem may subserve this purpose, as in all tuberous herbs; or the nourishing matter may be widely distributed through the trunk, as in shrubs and trees. These are some of the modifications in this respect of perennial plants, which survive, or at least their roots, and blossom from year to year indefinitely. 130. Secondary Roots. (Also called Adventitious Roots.) Thus far, the primitive root, that which originated from the base of the embryo in germination, with its ramifications, has alone been considered. But roots habitually spring from any part of a growing stem that lies on the ground, or is buried beneath its surface, so as to provide the moisture and darkness they require; for such roots obey the ordinary tendency of the organ, avoiding the light, and seeking to bury themselves in the soil. Most creeping plants produce them at every joint; and most branches, when bent to the ground and covered with earth, will strike root. So, often, will separate pieces of young sterns, if due care be taken; as when plants are propagated by cuttings. Stems commonly do not strike root, except when in contact with the ground. To this, however, there are various exceptions; as in the case of 131. Aerial Roots. Some woody vines climb by such rootlets; as the Ivy, our own Poison Ivy (Rhus Toxicodendron), and the Bignonia or Trumpet-Creeper, which in this way reach the summit of high trees. Such plants derive their nourishment from their ordinary roots imbedded in the soil; their copious aerial rootlets 88 THE ROOT. merely serving for mechanical support. Other plants produce true aerial roots, which, emitted from the stem in the open air, descend to the ground and establish themselves in the soil. This may be observed, on a small scale, in the stems of Indian Corn, where the lower joints often produce roots which grow to the length of several inches before they reach the soil. More striking cases of the kind abound in those tropical regions where the sultry air, saturated with moisture for a large part of the year, favors the utmost luxuriance of vegetation. The Pandanus or Screw-Pine (a Palm-like tree, often cultivated in our conservatories) affords a well-known instance. The strong roots, emitted in the open air from the lower part of the trunk, soon reach the soil, as is shown in Fig. 117, giving the tree the appearance of having been partially raised out of the ground. The famous Banyan-tree ~ ~Z ~(Fig. 119) affords a still more striking illustration. Here /ii' ~ ~' ~~the aerial rootlets strike from the horizontal branches of the tree, often at a great height, and swing free in the air like pendent _______~~L ____'" ":: cords; but they finally reach and establish themselves in 117'~-~:,~-~~~~,.the ground, where ~117 118 ~ they increase in diameter and form numerous accessory trunks, surrounding the original boll and supporting the wide-spread canopy of branches and foliage. Very similar is the economy of the Mangrove (Fig. 118), which inhabits muddy sea-shores throughout the tropics, and even occurs sparingly on the coast of Florida and Louisiana. Its aerial roots spring both from the main trunk, as in the Pandanus, FIG. 117. The Pandanus, or Screw-Pine; with, 118, a MIangrove-tree (Rhizophora IMangle). AERIAL ROOTS. -EPIPHYTES. 89 and from the branchlets, as in the Banyan. Moreover, this tendency to shoot in the air is shown even in the embryo, which be119 gins to germinate while the pod is yet attached to the parent branch; the radicle, or root-end of the embryo, elongating into a slender thread, which may even reach the ground, from the height of many yards, before the pod is detached. In this manner the Mangrove forms those impenetrable maritime thickets which abound on low, muddy shores, within the tropics. 132. Epiphytes, or Air-plants, exhibit a further peculiarity. Their roots not only strike in the free air, but throughout their life have no connection with the soil. They generally grow upon the trunks and branches of trees; their roots merely adhering to the bark to fix the plant in its position, or else hanging loose in the air, from which such plants draw all their nourishment. Of this kind are a large portion of the gorgeous Orchidaceous plants of very warm and humid climes, which are so much prized in hot-houses, and which, in their flowers as well as their general aspect, exhibit such fantastic and infinitely varied forms. Some of the flowers resemble butterflies, or strange insects, in shape as well as in gaudy coloring; such, for example, as the Oncidium Papilio (Fig. 120), which we have selected for one of our illustrations. To another family of Epiphytic plants belongs the Tillandsia, or Long Moss, which, pendent in long and gray tangled clusters or festoons from the branches of the Live-Oak or Long-leaved Pine, gives such a FIG. 119. The Banyan-tree, or Indian Fig (Ficus Indica). 8* 90 THE ROOT. peculiar and sombre aspect to the forests of the warmer portions of our Southern States. They are called Air-plants, in allusion to 120 121 the source of their nourishment; and Epiphytes, from their growing upon other plants, and in contradistinction to 133. Parasites, that not only grow upon other vegetables, but live at their expense; which Epiphytes do not. Parasitic plants may be divided into two sorts, viz.:- 1st, those that have green foliage, and 2d, those that are destitute of green foliage. They may vary also in the degree of parasitism; the greater number being absolutely dependent upon the foster plant for nourishment, while a few, such as the Cursed Fig (Clusia rosea) of tropical America, often take root in the soil, and thence derive a part, or sometimes the whole, of their support. This occurs only in 134. Green Parasites, or those furnished with green foliage, or proper digestive organs of their own. These strike their roots through the bark and directly into the new wood of the foster FIG. 120. Oncidium Papilio, and, 121, Comparettia rosea; two epiphytes of the Orchis Family; showing the mode in which these Air-plants grow. PARASITIC PLANTS. 91 plant; whence they can draw little except the ascending, mostly crude sap (79), which they have to assimilate in their own green leaves. The Mistletoe is the most familiar example of this class. It is always completely parasitic, being at no period connected with the earth; but the seed germinates upon the trunk or branch of the tree where it happens to fall, and its nascent root, or rather the woody mass that it produces in place of the root, penetrates the bark of the foster stem, and forms as close a junction, apparently, with its young wood as that of a natural branch. Some species of Mistletoe, or of the same family, however, display no proper green foliage, but are of a yellow or brown hue. On the other hand, imperfect root-parasites with green foliage have recently been detected in more than one tribe of plants; * thus exhibiting intermediate states between the Green and the 135. Pale or Colored Parasites, that is, of other colors than green; such as Beech-drops, Orobanche, &c. These strike their roots, or sucker-shaped discs, into the bark, mostly that of the root, of other plants, and thence draw their food from the sap already elaborated (79). They have accordingly no occasion for digestive organs of their own, and are in fact always destitute of green foliage. In some cases of the kind, as in the Dodder (Fig. 122 - 124), the seeds germinate in the earth, from which the primitive root derives its nourishment in the ordinary manner; but when the slender twining stem reaches the surrounding herbage, it gives out aerial roots, which attach themselves 1 122 123 124 firmly to the surface of the supporting plant, penetrate its epidermis, and feed upon its juices; while' In England a Thcsium was discovered by Mr. Mitten to attach its roots FIG. 122. The common Dodder of the Northern States (Cuscuta Gronovii), of the natural size, parasitic upon the stem of an herb: the uncoiled portion at the lower end shows the mode of its attachment. 123. The coiled embryo taken from the seed, moderately mtagnified. 12-. Tile same in germination; the lower end elongating into a root; the upper into a thread-like leafless stem. 92 THE ROOT. the original root and base of the stem perish, and the plant has no longer any connection with the soil. Thus stealing its nourishment ready prepared, it requires no proper digestive organs of its own, and, consequently, does not produce leaves. This economy is, as it were, foreshadowed in the embryo of the Dodder, which is a slender thread spirally coiled in the seed (Fig. 123, 124), and which presents no vestige of cotyledons or seed-leaves. A species of Dodder infests and greatly injures flax in Europe, and sometimes makes its appearance in our own flax-fields, having been introduced with the imported seed. Some species make great havoc in the clover-fields of the Old World. 136. Such parasites do not live upon all plants indiscriminately, but only upon those whose elaborate juices furnish a propitious nourishment. Some of them are restricted, or nearly so, to a particular species; others show little preference, or are found indifferently upon several species of different families. Their seeds, in some cases, it is said, will germinate only when in contact with vat_ the stem or root of the species upon which they are destined to live. - Having no seed or foliage, such plants may be reduced to a parasitically, by suckers, to the roots of adjacent herbs. (It would be interesting to know if this is the case with our Comandra.) Then Decaisne, recollecting that Rhinanthaceous plants generally, all of which blacken more or less in drying, were known to be uncultivable, and have the reputation, in France and elsewhere, of being injurious to cereal and other plants in their vicinity, was led to the discovery that plants of Rhinanthus, Melampyrum, and of the allied genera, attach themselves by numerous suckers on their roots to the roots of Grasses, shrubby plants, and even of trees, among which they grow. Our handsome species of Gerardia are equally uncultivable, doubtless on account of this partial parasitism. FIG. 12-5. Rafflesia Arnoldi; an expanded flower, and a bud; directly parasitic on the stem of a vine: reduced to the scale of half an inch to a foot. THE STE3M. 93 stalk with a single flower or cluster of flowers, as in the different kinds of Beech-drops,* the Cytinus, which is parasitic on the Cistus of the South-of Europe, &c. They may even be reduced to a single flower directly parasitic on the bark of the foster plant, without the intervention of any manifest stem. A truly wonderful instance of this kind is furnished by that vegetable Titan, the Rafflesia Arnoldi of Sumatra (Fig. 125). The flower which was first discovered grew upon the stem of a kind of grape-vine; it meas. ured nine feet in circumference, and weighed fifteen pounds! Its color is light orange, mottled with yellowish-white. 137. Among Cryptogamous plants, numerous Fungi are para. sitic upon living, especially upon languishing vegetables; others infest living animals; the rest feed on dead or decaying vegetable or animal matters: all are destitute of chlorophyll (87), or any thing like green foliage. It is not improbable that our Monotropa, or Indian Pipe, a pallid and fungus-like Phornogamous plant, draws its nourishment, at least in great part, from the decaying leaves among w hich it grows. CHAPTER IV. OF THE STEM, OR ASCENDING AXIS. SECT. I. ITS GENERAL CHARACTERISTICS AND ]MODE OF GROWTH. 138. BESIDES the direction of its growth, the descending axis or root we have found to be characterized by producing nothing except naked branches or subdivisions, and these in no definite order; by their continued extension through new formation at the extremity only, and in an uninterrupted manner, so as to give rise to no joints or nodes, and consequently to bear no leaves (141); by the absence of stomates in its epidermis (which, however, is the case in all parts developed under ground); and commonly by having no pith in the centre, or only a minute pith at the base, where it joins the stem. The latter organ differs in nearly all these particulars. * See family Orobanclaccecc, in the second part of this work. 94 THE STEI. 139. Tilhe Stemll is the ascending axis, or that portion of the trunk which in the embryo grows in an opposite direction from the root, seeking the light, and exposing itself as much as possible to the air. All Phanogamous plants (110) possess stems. In those which are said to be acaulescenzt, or stenmless, it is either very short, or concealed beneath the ground. Although the stem always takes an ascending direction at the commencement of its growth, it does not uniformly retain it; but sometimes trails along the surface of the ground, or burrows beneath it, sending up branches, flowerstalks, or leaves into the air. The common idea, therefore, that all the subterranean portion of a plant belongs to the root, is by no means correct. 140. The root gives birth to no other organs, but itself directly performs those functions which pertain to the relations of the vegetable with the soil;- its branches bind the plant to the earth; its newly formed extremities, or fresh rootlets, with the capillary fibrils they bear, imbibe nourishment from it. But the aerial functions of vegetation are chiefly carried on, not so much by the stern itself as by a distinct set of organs which it bears, namely, the leaves. Hence, the production of leaves is one of the characteristics of the stem. These are produced only at certain definite and symmetrically arranged points, called 141. Nodes, literally knots, so named because the tissues are here condensed, interlaced, or interrupted, more or less; as is conspicuously seen in the Bamboo, in a stalk of Indian Corn, or of any other Grass. Here each node forms a complete indurated ring, because the leaf arises from the whole circumference of the stemn at that place. When the base of the leaf or leaf-stalk occupies only a part of the circumference, the nodes are not so distinctly marked, except by the leaves they bear, or by the scars left by their fall (Fig. 127, 130). When distinct they are often called joints, and sometimes, indeed, the stem is actually jointed, or arliculated, at these points; but commonly there is no tendency to separate there. Each node bears either a single leaf, or two placed on opposite sides of the stem (Fig. 104), or three or more, placed in a ring (in botanical language, a whorl or rerticil) around the stem. The naked portions or spaces that intervene between the nodes are termed 142. Internodes. The undeveloped stem is, in fact, made up of a certain number of these leaf-bearing points, separated by short NODES AND INTERNODES.- BUDS. 95 intervals; and its growth consists, primarily, in the elongation of these internodes (much after the mode in which the joints of a pocket-telescope are drawn out, one after the other), so as to separate the nodes to a greater or less distance from each other, and allow the leaves to expand. 143. This brings to view the leading peculiarity of the stem, namely, that it is formed of a succession of similar parts, developed one upon the summit of another, each with its own independent growth: each developing internode, moreover, lengthens throughout its whole body, unlike the root, which elongates continuously from its extremity alone. The nodes or the leaves they bear are first formed, in close contiguity with the preceding; then the internodes appear, and by their elongation separate them, and so carry upward the stem. To have a good idea of this, we have only to observe the gradual evolution of a germinating plant, where each internode developes nearly to its full length, and expands the leaf or pair of leaves it bears, before the elongation of the succeeding one commences. The radicle, or internode which preexists in the embryo (118), elongates, and raises the seed-leaves into the air (Fig. 107); they expand and elaborate the material for the next joint, the leaves of which in turn prepare the material for the third (Fig. 102- 104), and so on. The internode lengthens principally by the elongation of its already formed cells, particularly in its lower part, which continues to grow after the upper portion has finished. 144. Buids. The apex of the stem, accordingly, at least of every stem capable of further terminal growth, is always crowned with an undeveloped portion, the rudiments of parts similar to those already unfolded, that is, with a BUD (113). The embryo itself may be rightly viewed as the fundamental bud borne on the apex of the radicle or original internode, from which the whole plant is developed; just as an ordinary bud of a tree or shrub developes to form a year's growth. Except that, in the latter case, the different steps follow each other more closely; for the bud usually has a considerable number of parts ready formed in miniature before it begins to grow, and has a full store of assimilated sap accumulated in the parent stem to feed upon. Such buds, which appear at the apex of a stem when it has completed its growth for the season, often exhibit the whole plan and amount of the next year's growth; the nodes, and even the leaves they bear, being 96 THE STEM. already formed, and only requiring the elongation of the internodes for their full expansion. The structure is shown in the annexed diagram (Fig. 126), which represents the vertical section of a bud (like that which crowns the stem in Fig. 127), as it appears in early spring. As the bud is supplied by the stem on which it rests with nourishment sufficient for its whole develop~fl --- }ment, it elongates rapidly and - — f).(f T / / although the growthcommcnces,29 with the lowest internode, and follows the same course as in the seedling, yet the second, third, and fourth internodes, &c., have begun to lengthen long before the first has attained its full growth; as is attempted to be shown by the diagram,, Fig. 128. The stern thus continued from a tcrat~ial bud is, if it survive, again terminated 127 1289 12 with a similar bud at the close of the season, which in its development repeats the same process. 145. These yearly growths, in trees with well-formed Scaly Buds, such as the Magnolia (Fig. 130), the I-orsechesnut (Fig. 127), &c., are plainly marked by the assemblage of scars or rings on the bark (a), which mark the places where the bud-scales were attached. The reason why these, and the leaf-scars, are obliterated afteiP a few years, will appear when the increase of the stem in diameter is considered. The bud-scales themselves, which so closely overlie each other and protect the tender parts within against injury from moisture and sudden changes of temperature during the dormant state,* are only a special modification of * The more effectually to iward off moisture, they are commonly covereld with a waxy, resinous, or balsamic exudation (as in the Poplar especially), FIG. 126. DiaPlram of a longitudinal section of a bud. such as th t of the Horsechlestiut. FIG 127. A year's growth of a IHorsechestlut branch, crowned with a termitlal buld: a, scars left by the bud-scales of the previous year: b, scars left by the fallen leafstalks: c, axillary buds. FIG. 12S. Diagram to illustrate the developmeat of the bud in Fig. 12G, 127. FIG. 129. Branch and buds (all axillary) of the Lilac. NODES AND INTERNODES. - BUDS. 97 130 JII leaves, developed in this shape at a iii / time when the internodes have ceased, i to elongate; so that the space between ~' x1:{ each ring in the figure just referred to / t - \ | d represents an undeveloped internode. / Such a stem displays alternately two. I,~tI /'i \,''( 0 modes of growth. First, the internodes i;elongate and interspace a succession \ of leaves, making the proper vegetation!X'/ / of the season. Then a series of leaves form as bud-scales, with internodes in-?~:!?i':lZ..I <,: capable of extension, and within them the rudiments of the next year's vege\Q 61l: tation are prepared, to be developed as before, after a season of repose. As might be expected, therefore, such scaly (or perulate) buds belong to trees and shrubs of countries which have a winter; and are not met with, at least so distinctly, in those of the tropics;',' where, as there is no danger of injury from cold, the first parts that appear in the bud are ordinary leaves. On the other hand, many trees and shrubs of cold climates bear naked buds, as the'<.>< Locust, Honey Locust, Ailanthus, &c.,,../.'../ or buds with little scaly covering, as in the Kentucky Coffee-tree, the Papaw, " f< A &c. But in these cases the bud scarcely'\'~~7% projects so as to be visible externally until it begins to develope in the spring. In Viburnum, some species, such as V. impervious to rain, but which is melted by the heat of the sun when it stimulates the bud into growth. To guard against sudden changes of temperature, they are often lined, or the rudimentary leaves within are invested, with nonconducting down or wool. FIG. 13). Branch of MIagnolia Umbrella, of the natural size, crowned with the terminal bud; and below exhibiting the large, rounded leaf-scars, and the annular scars left by the fall of the budscales, of the previous season. 131. A detached scale from a similar bud; its thickened axis is the base of a leafstalk; the membranous sides consist of the pair of stipules. 9 98 THE STErM. Opulus, &c., have proper scaly buds, while in V. lantanoides, V. nudum, &c., they are entirely naked. 146. The bud, it is evident, is nothing more than the first stage in the development of a stem (or branch), the axis still so short that the scales without and the rudimentary leaves within cover or overlap one another. The various ways in which these parts are packed in the bud will be considered under another head (Vernation, 257). That the scales of the bud are of the same general nature as leaves is evident, not only from their position, but from their gradual transition into ordinary leaves in many cases. This is well seen in the expanding buds of the Lilac, Hickory, Horsechestnut, and especially of the Buckeye. The scales represent, sometimes the blade of the leaf, as in the Lilac; but more commonly the dilated base of the leafstalk, as is evident in the Balsam, Poplar, Butternut, and Hickory; or their stipules (259), either combined with this base, as in the Magnolia (Fig. 131), or alone, as in the Tulip-tree. Scales passing into ordinary leaves are abundantly obvious on the turions, or subterranean budding shoots, of numerous perennial herbs. 147. By the development of the preexisting bud in the embryo, the original stem is produced; and it may be continued from year to year by the continued evolution of a temiinal bud. Growing in this way only, the stem would of course remain simple or unbranched; as is the case with many during the first year, and with others, such as most Palms (Fig. 166) and Reeds, throughout their whole existence. But more commonly branches appear, even during the first yeatr's growth. SECT. II. RAMIIFICATION. 148. Branches spring from lateral or axillary buids. These are new undeveloped axes or growing points, which habitually appear, or at least may appear, one (or occasionally twvo or three) in the axil of each leaf, that is, in the upper angle which the leaf forms with the stem. (See Fig. 127, c, where the point at which the fallen leaves were attached is marked by the broad scar, b, just below the bud.) The axillary bud is at first a little cellular nucleus on the surface of the wood, at the end of one of the cellular lines that form the silver-grain (196), and underneath the bark, through which it pushes as it grows, and shapes itself into a rudimentary RAMIFICATION. 99 axis, covered with the little appendages which become scales or leaves. When these buds grow, they give rise to BRANCHES; which are repetitions, as it were, of the main stem, growing just as that did from the seed; excepting merely, that, while that was implanted in the ground, these proceed from the parent stem. The branches thus produced are in turn provided with similar buds in the axils of their leaves, which have the same relation to the primary branch that it has to the main stem, and are capable of developing into branches of a third order, and so on indefinitely, producing the whole ramification of the plant. The whole is merely a series of repetitions, from new starting-points, of what took place in the evolution of the first axis, preexistent in the seed. In the seed, therefore, or rather in the embryo it contains, we have the expression, in a condensed form, of the whole being of the plant. The latest ramifications, or twigs, are termed BRANCHLETS. 149. The arrangement of axillary buds depends upon that of the leaves. When the leaves are opposite (that is, two on each node, placed on opposite sides of the stem), the buds in their axils are consequently opposite; as in the Maple, Horsechestnut (Fig. 127), Lilac (Fig. 129), &c. W~hen the leaves are alternate, or one upon each node, as in the Apple, Poplar, Oak, Magnolia (Fig. 130), &c., the buds implicitly follow the same arrangement. Branches, therefore, being developed buds, their arrangement is not left to chance, but is predetermined, symmetrical, and governed by fixed laws. When the leaves are alternate, the branches will be alternate: when the leaves are opposite, and the buds develope regularly, the branches will be opposite. In other words, if a bud in the axil of each leaf is developed into a branch, the relative situation of the branches will be the same as that of the leaves. 150. But the regular symmetry of the ramification is often accidentally interfered with by various causes, especially by the nondevelopment of a part of the buds. As the original embryo plant remains for a time latent in the seed, growing only when a conjunction of favorable circumstances calls its life into action, so also many of the buds of a shrub or tree may remain latent for an indefinite time, without losing their power of growth. In our trees, most of the lateral buds generally remain dormant for the first season: they appear in the axils of the leaves early in summer, but do not grow into branches until the following spring; and 100 THE STEM. even then only a part of them usually grow. Sometimes the nondevelopment or suppression occurs without appreciable order; but it often follows a nearly uniform rule in each species. Thus, when the leaves are opposite, there are usually three buds at the apex of a branch; namely, the terminal, and one in the axil of each leaf; but it seldom happens that all three grow at the same time. Sometimes the terminal bud continues the branch, the two lateral generally remaining latent, as in the Horsechestnut; sometimes the terminal one is regularly suppressed, and the lateral grow, when the stem annually becomes forked, as happens in the Lilac (Fig. 129). 151. The undeveloped buds do not necessarily perish, but are ready to be called into action in case the others are checked. When the terminal buds are destroyed, some of the lateral, that would else remain dormant, develope in their stead, incited by the abundance of nourishment, which the former would have monopolized. In this manner our trees are soon reclothed with verdure, after their tender foliage and branches have been killed by a late vernal frost, or other injury. The buds may remain latent even for years, and become covered with wood. The trunk of a tree, therefore, always contains an immense number; some of which, after a long period, may force their way through the wood to the surface, and break forth into branches; especially when the tree is pollarded, or its leading branches injured. 152. Adventitious Buds. But many such branches have an abnormal origin, from irregular or adventitious buds, like those produced by roots under similar circumstances (125). Such buds are still more readily produced on woody stems, when surcharged with sap, as we constantly observe on pollard Willows and Lombardy Poplars. Indeed, in several instances, buds are known to arise even from the surface or margins of leaves, as in Bryophyllum, which derives its name from this unusual circumstance; and the gardener produces them from root-cuttings or leaf-cuttings of certain plants, which he propagates in this way. Adventitious buds originate in the parenchyma, some cells of which are incited to take an independent development. In trees, they form on the surface of the wood, at the ends of the lines of the silver-grain (medullary rays, 191, 196). They are especially liable to spring from the new cellular tissue that forms at the growing season between the wood and bark when the trunk is wounded or cut off. ADVENTITIOUS AND ACCESSORY BUDS. 101 Thus the predestined symmetry of the branches is obscured or interfered with in two distinct ways; first, by the failure of a part of the regular buds to develope; and secondly, by the irregular or casual development of buds from other parts than the axils of the leaves: to which we may add, that great numbers of branches perish and fall away after they have begun to grow, or have attained considerable size. There is still another source of irregularity, namely, in the production of 153. Accessory Buds. These are, as it were, multiplications of the regular axillary bud, giving rise to two, three, or more, instead of one; in some cases situated one above another, in others side by side. In the latter case, which occurs occasionally in the Hawthorn, in certain Willows, in the Maples (Fig. 132), i &c., the axillary bud seems to divide into three, or itself give rise to a lateral bud on each side, as soon as or before it penetrates the bark. On some shoots 7 of the Tartarean Honeysuckle as many as half a dozen buds are developed independently in each axil, one above another, the lower being successively the stronger and earlier produced, and 1, iii the one immediately in the axil, therefore, grows in preference; but when two or more grow, superposed accessory branches result. It is much the H same in Aristolochia Sipho, except that 4 the uppermost bud is there strongest. So it is in the Butternut (Fig. 133), where the true axillary bud is minute and usually remains latent, while the accessory ones are considerably remote, and the uppermost, which is much the 132 133 strongest, is far out of the axil; usually this alone developes, and gives rise to an extra-axillary branch. 154. The stems of those Cryptogamous plants that possess a FIG. 132. Branch of Red Maple, with triple axillary buls, placed side by side. FIG. 133. Piece of a branch of the Butternut, with accessory buds placed one above another: a, the leaf-scar: b, proper axillary bud: c, d, accessory buds. 9* 102 THE STEM. proper trunk (the Horsetails or Scouring Rushes excepted) do not branch, by the development of axillary or any kind of lateral buds implanted on its surface; but they often fork at the apex, by the division of the terminal bud. Their ramification, like their whole growth, is merely acrogenous, or from the apex (108). 155. Excurrent and Deliquescent Stems. Sometimes the primary axis is prolonged without interruption, by the continued evolution of the terminal bud, even through the whole life of a tree (unless accidentally destroyed), forming an undivided main trunk, from which lateral branches proceed; as in most Fir-trees. Such a trunk is said to be excurrent. In other cases the main stem is arrested, sooner or later, either by flowering, by the failure of the terminal bud, or the more vigorous development of some of the lateral buds, and thus the trunk is lost in the branches, or is deli-. quescent, as in most of our deciduous-leaved trees. The first naturally gives rise to conical or spire-shaped trees; the second, to rounded or spreading forms. As stems extend upward and evolve new branches, those near the base, being overshadowed, are apt to perish, and thus the trunk becomes naked below. This is well seen in the excurrent trunks of Firs and Pines, which, when grown in forest, seem to have been branchless for a great height. But the knots in the centre of the trunk are the bases of branches, which have long since perished, and have been covered with a great number of annual layers of wood, forming the clear-stlff of the trunk. 156. Definite and Indefinite Annual Growth of Branches. In the larger number of our trees and shrubs, especially those with scaly buds, the whole year's growth is either already laid down rudimentally in the bud (144), or else is early formed; and the development is completed long before the end of summer, and crowned with a vigorous terminal bud (as in the Hlorsechestnut, Fig. 127, Magnolia, Fig. 130, &c.), or with the uppermost axillary, as in the Lilac (Fig. 129). Such definite shoots do not lie down at all the following winter, but grow on directly, the next spring, from the terminal or some of the upper axillary buds, which are generally more vigorous than those lower down. In others, on the contrary, the branches grow onward indefinitely through the whole summer, or until arrested by the cold of autumn: they mature no terminal or upper axillary buds; or at least the lower and older axillary buds are more vigorous, and alone develope into KINDS OF STEM AND BRANCHES. 103 branches the next spring; the later-formed upper portion most commonly perishing from the apex downward for a certain length in the winter. The Rose and Raspberry, and among trees the Sumac and Honey Locust, are good illustrations of this sort; which, however, runs into the other mode through various gradations. Perennial herbs grow after the latter mode, their stems dying down to or beneath the surface of the ground, where the persistent base is charged with vigorous buds, well protected by the ground, for the next year's vegetation. 157. Propagation from Buds. Buds, being, as it were, new individuals springing from the original stem, may be removed and attached to other parts of the parent trunk, or to that of another individual of the same, or even of a different, but nearly related species, where they will grow equally well. This is directly accomplished in the operation of budding. In ingrafting, the bud is transferred, along with a portion of the shoot on which it grew. Moreover, as the cut end of such shoots, when buried in moist and warm soil, will commonly, under due care, send out adventitious roots, they may be made to grow independently, drawing their nourishment immediately from the soil, instead of indirectly through the parent trunk. This is done in the propagation of plants by cuttings. The great importance of these horticultural operations rests chiefly on the well-known fact, that buds propagate individual peculiarities, or varieties (668), which are commonly lost in raising plants from the seed. SECT. III. THE KINDS OF STEnM AND BRANCHES. 158. ON the size and duration of the stem the oldest and most obvious division of plants is founded, namely, into Herbs, Shrubs, and Trees. 159. ielrbs are plants in which the stem does not become woody and persistent, but dies annually or after flowering, down to the ground at least. The difference between annual, biennial, and perennial herbs has already been pointed out (127- 130). The same species is so often either annual or biennial, according to cir.curnstances or the mode of management, that it is convenient to have a common name for plants that flower and fruit but once, at whatever period, and then perish: such De Candolle accordingly designated as MoNOCARPIC plants; while to perennials, whether 104 THE STEM, herbaceous or woody, large or small, he applied the counterpart name of POLYCARPIC plants, signifying that they bear fruit more than once, or an indefinite number of times. Between herbs and shrubs there are the intermediate gradations of 160. Undershrubs, or siffruticose plants, which are woody plants of humble stature, their stems rising little above the surface. If less decidedly woody, they are su/ffrutescent. 161. Shrubs are woody plants, with stems branched from or near the ground, and less than five times the height of a man. Between shrubs and trees there is every intermediate gradation. A shrub which approaches a tree in size, or imitates it in port, is said to be arborescent. 162. Trees are woody plants with single trunks, which attain at least five times the human stature. 163. A Culm is a name applied to the peculiar jointed stem of Grasses and Sedges, whether herbaceous, as in most Grasses, or woody or arborescent, as in the Bamboo. 164. A Caudex is a name usually applied to a Palm-stem (Fig. 166), to that of a Tree Fern (Fig. 94), and to any persistent, erect, or ascending, root-like forms of main stems. It is sometimes nearly synonymous with the rhizoma (174). 165. Those stems which are too weak to stand upright, but recline on the ground, rising, however, towards the extremity, are said to be decumbent: if they rise obliquely from near the base, they are said to be ascending. When they trail flat on the ground, they are procumbent, prostrate, or running; and when such stems strike root from their lower surface, as they are apt to do, they are said to be creeping, or repent. 166. They are called Climbers, when they cling to neighboring objects for support; whether by tendrils, as the Vine and Passionflower, by their leafstalks, as the Virgin's Bower (Clematis), or by aerial rootlets, as the Poison Oak (Rhus); and Tiviners, or twining plants, when they rise, like the Convolvulus, by coiling spirally around stems or other bodies within their reach. Other modifications of the stem or branches have received particular names, some of which merit notice from having undoubtedly suggested several important operations in horticulture. 167. A Stolon is a form of branch which curves or falls down to the ground, where, favored by shade and moisture, it strikes root, and then forms an ascending stem, which is thus capable of draw KINDS OF STEM AND BRANCHES. 105 ing its nourishment directly from the soil. The portion which connects it with the parent stem at length perishing, the new individual acquires an entirely separate existence. The Currant, Gooseberry, &c., multiply in this way, and doubtless suggested to the gardener the operation of layering; in which he not only takes advantage of and accelerates the attempts of nature, but incites their production in species which do not ordinarily multiply in this manner. Plants which spread or multiply by this natural layering are said to be stoloniferous. 168. A Sucker is a branch of subterranean origin, which, after running horizontally and emitting roots in its course, at length, following its natural tendency, rises out of the ground and forms an erect stem, which soon becomes an independent plant. The Rose, the Raspberry, and the Mint afford familiar illustrations, as well as many other species which shoot up stems " from the root," as is generally thought, but really from subterranean branches. Cutting off the connection with the original root, the gardener propagates such plants by division. Plants which produce suckers are said to be surculose. 169. A Runner, of which the Strawberry furnishes the most familiar example, is a prostrate, slender branch, sent off from the base of the parent stem, which strikes root at its apex, and produces a tuft of leaves; thus giving rise to / an independent plant capable of extending itself in the same manner. Branches of this sort are termed // flagelliform. 170. All Offset is a similar, but short, prostrate branch, with a tuft of leaves at the end, which, resting% on the ground, there takes root, and E ) ) at length becomes independent; as in the Houseleek. 134 171. A Tendril is commonly a thread-like, leafless branch, capaFIG. 134. End of a shoot of the Grape-vine, showing the tendrils. 106 THE STEM. ble of coiling spirally, by which climbing plants attach themselves to surrounding bodies; as in the Grape-vine (Fig. 134). But sometimes tendrils belong to the leaves, as in the Pea; when they are slender prolongations of the leafstalk. Stems or stalks which bear tendrils are cirrhose or cirrhliferous. 172. A Spine or Thorn is an imperfectly developed, indurated, leafless branch of a woody plant, attenuated to a point. Their nature is manifest in the Hawthorn (Fig. 136), not only by their position in the axil of a leaf, but often by their bearing imperfect 135 leaves themselves. In the Sloe, Pear, &c., many of the v> cium (418) of five stamens alternating with the // -~g ~ petals, and a gynecium (419) of five pistils, which are alternate with the stamens; and all K C~p-oi~ 2 the parts are regular and symmetrical, and also ~ )j// distinct and free from each other; except that the sepals are somewhat united at the base, and the petals and stamens slightly connected with the inside of the calyx, instead of manifestly arising from the receptacle or axis, just beneath the pistils. Five is the prevailing or normal number in this family. Nevertheless, FIG. 283. Flower of a Crassula. 284. Cross-section of the bud. ITS VARIOUS MIODIFICATIONS. 247 in the related genus Tillkea, most of the species, like ours of the United States, have their parts in fours, but are otherwise similar, and one common European species has its parts in threes (Fig. 277): that is, one or two members are left out of each circle, which of course does not interfere with the symmetry of the blossom. So in the more conspicuous genus Sedum (the Stonecrop, Live-for-ever, Orpine, &c.) some species are 5-merous, others 4-merous, and several, like our S. ternatum, have the first blossom 5-merous, but all the rest on the same plant 4-merous. But Sedum also illustrates the case of regular augmentation (447, lst) in its andrcecium, which consists of twice as many stamens as there are members in the other parts; that is, an additional circle of stamens is introduced (Fig., 285, 286), the members of which may be distin- 285 guished by being shorter or a little later than those of the primary circle, l and also more definitely by their alternation with the primary, which brings them directly opposite the petals. A third genus (Rochea) exhibits the same 5-merous and normal flower as Crassula, except that the contigu- o ous edges of the petals slightly cohere o about half their length, although a little force suffices to separate them: in another (Grammanthes, Fig. 287), 286 the petals are firmly united into a tube for more than half their length, and so are the sepals likewise; presenting, therefore, the third of the deviations above enumerated (447). Next, the allied genus Cotyledon (Fig. 288) exhibits in the same flower both this last case of the coalescence of similar parts in its floral envelopes, and an additional circle of stamens, as in Sedum. It likewise presents the next order of deviations, in the adnation of the base of its stamens to the base of the corolla, out of which they apparently arise, as is seen in Fig. 289, where the corolla is laid open and displayed. The pistils, although ordinarily exhibiting a strong tendency to unite, are perfectly distinct in all these cases, and indeed throughout the order, with two exceptions; one of which is seen in Penthorum, where the five ovaries (Fig. FIG. 285. Flower of a Sedum. 2S6. Cross-section of the bud. 248 THE FLOWER. 290) are united below into a solid body, while their summits, as well as the styles, are separate. The same plant also furnishes an example of the non-production (or suppression) of one whorl of organs, that of the petals; which, although said to exist in some specimens, are ordinarily wanting altogether. Another instance of increase in the number of parts occurs in the Houseleek (Semper. vivum), in which the sepals, petals, and pistils vary in different species from six to twenty, and the stamens from twelve to forty. 287 288 289 291 490 450. Some illustrations of the principal diversities of the flower, as classified above (447), may be drawn at random from different families of plants; and most of the technical terms necessarily employed in describing these modifications may be introduced, and concisely defined, as we proceed. The multiplication of parts is usually in consequence of the 451. Augmentation of the Floral Circles, An increased number of circles or parts of all the floral organs occurs in the Magnolia Family; where the floral envelopes occupy three or four rows, of three leaves in each, to be divided between the calyx and corolla, while the stamens and pistils are very numerous, and compactly arranged on the elongated receptacle. The Custard-Apple Family, which is much like the last, has also two circles in the corolla, three petals in each, a great increase in the number of stamens, and, in our Papaw (Fig. 493), sometimes only one circle of pistils, viz. 3, sometimes twice, thrice, or as many as five times that FIG. 287. Flower of Grarmnanthes. FIG. 288. Flower of a Cotyledon. 289. The corolla laid open, showing the two rows of stamens inserted into it. FIG. 290. The five pistils of Penthorum, united, so as to form a compound ovary. 291. A cross-section of the same. AUGMENTATION, OR REGULAR MULTIPLICATION. 249 number. The Water-Lily, likewise, has all its parts increased (Fig. 265), the floral envelopes and the stamens especially occupying a great number of rows; and the pistils are likewise numerous;'although their number is disguised by a combination, to be hereafter explained. When the sepals, petals, or other parts of the flower are too numerous to be readily counted, or are even more than twelve, especially when the number is inconstant, as it commonly is in such cases, they are said to be indefinite; and a flower with numerous stamens is also termed polyandrous. 452. When such multiplication of the floral circles is perfectly regular, the number of the organs so increased is a multiple of that which forms the basis of the flower; but this could scarcely be determined when the numbers are large, as in the stamens of a Buttercup, for example, nor is there much constancy when the whorls of any organ exceed three or four. In such cases, the circles usually appear to run into a continuous spiral, as is plainly seen in the cone of a Magnolia or of a Tulip-tree. The doubling or trebling of any or all the floral circles does not interfere with the symmetry of the flower; but it may obscure it (in the stamens and pistils especially), by the crowding of two or more circles of five members, for example, into what appears like one of ten, or two trimerous circles into what appears like one of six. The latter case occurs in most Endogenous plants. 453. The production of additional floral circles may account for most cases of increase of the normal number of organs, but not for all of them; unless through the aid of hypotheses that have rio intrinsic probability, and are unsupported by any clear analogies drawn from the organs of vegetation, which, it is evident, must give the rule in all questions involving the morphology, or at least the position, of the floral organs. It must, we think, be admitted that certain parts of the blossom are sometimes multiplied by the production of a pair or a group of organs which occupy the place of one; namely, by what has been termed 454. Chorisis or Deduplication. The name dedoublement of Dunal, which has been translated deduplication, literally means unlining; the original hypothesis being, that the organs in question unline, or tend to separate into two or more layers, each having the same structure. We may employ the word deduplication, in the sense of the doubling or multiplication of the number of parts, without receiving this gratuitous hypothesis as to the nature of the process, 250 THE FLOWER. which at best can well apply only to some special cases. The word chorisis (xpto-ras, the act or state of separation or rnultiplication), also proposed by Dunal, does not involve any such assumption, and is accordingly to be preferred. By regular multiplication, therefore, we mean the augmentation of the number of organs through the development of additional circles; which does not alter the symmetry of the flower. By chorisis we denote the production of two or more organs in the place of one, through the multiplication of the leaf part of an individual phyton; —a case which may be compared with the multiplication of cells by division (30), and more directly with the division of the blade of a leaf into a number of separate blades or leaflets. Chorisis may take place in two different ways, which are perhaps to be differently explained: in one case, the increased parts stand side by side; in the other, they are situated one before the other. Both cases must evidently disturb or disguise the normal symmetry of the flower. 455. Of the first case, which may be termed collateral chorisis, we have a good example in the tetradynamous 292 stamens (519) of the whole natural family Cruciferae. Here, in a flower with symmetrical tetramerous calyx and corolla,we have six stamens; of which the two lateral or shorter ones are alternate with the adjacent petals, as they normally should be, while the four are in two pairs, one pair before each remaining interval of the petals; as is shown in the annexed diagram (Fig. 292). That is, on the anterior and on the posterior side of the flower we have two stamens where there normally should be but a single one, and where, indeed, there is but one in some species of Cruciferoe. Now it occasionally happens that the doubling of this stamen is, as it were, arrested before completion, so that in place of two stamens we see a forked filament bearing a pair of 2s3 anthers; as is usually the case in several species of Streptanthus (Fig. 293). Here the two stamens which stand in the place of one may be compared with a FIG. 292. Diagram of a (tetradynamous) flower of the order Cruciferme. FIG. 293. Flower of Streptanthus hyacirthoides, from Texas (the sepals and stamens removed), showing a forked or double stamen in place of the anterior pair. CHORISIS OR DEDUPLICATION. 251 sessile compound leaf of two leaflets. In the related order Fumariaceoe, each phyton of the andrcecium is trebled in the same manner. The circles of the flower in that order are in twos throughout, or dimerous. There is, first, a pair 29 of small scale-like sepals; alternate with / &c. (Fig. 294-296), are saccate or spurred below: alternate and within these there is a second pair of petals (Fig. 297): alternate A with these are two clusters of three more or less united stamens, 295 294 which plainly stand in the place of two single stamens. The arrangement of parts is shown in the annexed diagram (Fig. 298); where the lowest line indicates the subtending bract, and therefore the anterior side of the blossom; the two short lines in the same plane represent the sepals; the two next within, the lateral and exterior petals; those alpp~q n~r ternate and within these, the inner circle of petals; and alternate with these are the anthers of the two stamen-clusters. The centre is occupied by a section of the pistil, which, as will hereafter be shown, con298 299 sists of two united. The three stamens are lightly connected in Dicentra (Fig. 296); but in Corydalis and FIG. 294. Dicentra Cucullaria (Dutchman's-breeches), with its kind of bulb, a leaf, and a scape in flower; reduced in size. 295. A flower of the natural size. 296. The same with the parts separated, except the sepals, one of which is seen at the base of the pistil. 297. The inner pair of petals, with their tips coherent. FIG. 298. Diagram (cross-section) of the similar flower of Adlumia. 299. One of the stamens increased into three by chorisis (the lower part of the cornmon filament is cut away). 252 THE FLOWER. Adlumia there is only one strap-shaped filament on each side, which is three-forked at the tip, each fork bearing an anther. One of these trebled stamens is shown in Fig. 299. 456. We have a similar case in some Hypericums and in Elodea (Fig. 300), except that in these, while the floral envelopes are 5-merous, the circles within them are commonly 3-merous. The three @//>\z~ T members of the andrcecium are normally placed, alternating with the three members of the gynecium within, and without with three glands, which probably replace an exterior o00 I circle of stamens; but each member as it developed has divided above into three stamens (Fig. 301); each anther of which'may be viewed as homologous with a leaflet of a trifoliolate leaf (289). In the same way are the false filaments placed between the petals and the real stamens of Parnassia, partly divided into three in our P. Caroliniana (Fig. 305), or into from 9 to 15 shorter glandular lobes in P. palustris. So each cluster of numerous stamens of the polyandrous species of Hypericum (Fig. 553) doubtless arises from the repeated chorisis of a single phyton, and is therefore analogous to a decompound leaf. The actual development of such a cluster from a small protuberance, which in the forming flower-bud stands in the place of a single stamen, and its repeated forkings as it grows, have been traced by Duchatre, particularly in Malvaceous plants. 457. Thus far we are sustained by a clear analogy in the organs of vegetation. As the leaf frequently developes in the form of a lobed, divided, or compound leaf, that is, as a cluster of partially or completely distinct organs from a common base, so may the stamen, or even the pistil, become compound as it grows, and give rise to a cluster, instead of completing its growth as a solitary organ: and it appears that the organogeny is strikingly similar in the two cases. Nor is it very unusual for petals to become divided or deeply lobed in the same manner; as, for example, those of Mignonette. In many cases, however, the multiplication takes place in the opposite plane, so that the parts are situated one beFIG. 300. Diagram (cross-section) of a flower of Elodea Virginicao 301. One of the three stamen-clusters, consisting of a trebled stamen. CHORISIS OR DEDUPLICATION. 253 fore the other; — an arrangement which is not known to occur in the leaflets of any compound leaf. 458. Some examples of this vertical or transverse chorisis may be adduced before we essay to explain them. A common case is that of the crown, or small and mostly two-lobed appendage on the inside of the blade of the petals of Silene (Fig. 302) and of many other Caryophyllaceous plants. This is more like a case of real dedoublement or unlining, a partial separation of an inner lamella from the outer, and perhaps may be so viewed. The stamens sometimes bear a similar and more striking appendage, as in Larrea, for example (Fig. 303), 802 and most other plants of the Guaiacum Familyl; also in the Dodder (Fig. 930). Let it be noted that in these cases the appendage occupies the inner side of the petal or stakJ) men, and that it is often two-lobed. Again, before each petal of Parnassia (Fig. 305), although slightly if at all united with it, is found a body which in P. palustris is somewhat petal-like, with a considerable number ii?4 of lobes, and in P. Caroliniana is divided almost to the 303 base into three lobes, which look much like abortive stamens. The true stamirieal circle, however, occupies its proper place within these ambiguous bodies, alternate with the petals. We cannot doubt that the former are of the same nature as the scale of the stamens in / a Larrea, and the crown of the petals of Silene.'Wi C 459. It may also be noticed, that, while in collat- 305 304 eral chorisis the increased parts are usually all of the same nature, like so many similar leaflets of a compound leaf, in what is called transverse chorisis FIG. 302. A petal of Silele Pennsylvanica, with its crown or appendae. FIG. 303. A stamen of Larrea Mexicana, with a scale-like appendage cohering with its base on the inner side, FIG. 304. Diagram (cross-section) of the flower of Parnassia Caroliniana. 305. A petal, with the appendage that stands before it. 22 254 THE FLOWER. there is seldom if ever such a division or ramification into homogeneous parts; but the original organ remains, as it were, intact and unmodified, while it bears an appendage of some different appearance or function on its inner face, or at its base on that side. Thus the stamens of Larrea, &c. bear a scale-like appendage; the petals of Sapindus, Cardiospermum, &c., a petaloid scale quite unlike the original petal; the petals of Parnassia, a cluster of bodies resembling sterile filaments united below. In a still greater number of instances, the accession to the petal consists of a real stamen placed -before it, and often more or less united with its base, as in the whole 00~o~, Buckthorn Family (Fig. 315), and in the 00g, X ) )) "/ o Byttneriacea3; or of a cluster of stamens, h\\o''"'~" o// / as in the Mallow Family, and indistinctly in most European Lindens; or of such a cluster with a petal-like scale in the midst, as in the 306 American Lindens (Fig. 622, 623, 306). In the first-named cases, the accessory organ developes entire and simple; in the latter, it is multiplied by collateral chorisis.* 460. A most able writer in a recent number of the Journal of Botany, (with whom we entirely accord as to the nature of collateral chorisis,) " being totally at a loss to find any thing analogous in the ordinary stem-leaves" to this transverse or vertical multiplication of parts, inclines to consider such appendages as those of the petals of Silene, Sapindus, Ranunculus, &c., as deformed glands, and the stamens thus situated, whether singly or in clusters, as developments of new parts in the axil of the petals, &c.t It appears to us, however, that the leaves do furnish the proper analogue of these appendages (especially those of Fig. 302, 303, 305, and the * For illustrations, and more detailed explanation of these points, the student is referred to the figures and text of The Genera of the United States F;lora Illustrated, especially to Vol. 2. The opposition of the exterior circle of stamens to the petals in Geranium, &c., we explain in a different way (477). t Namely, in Hooker's Journal qf Botany and KIew Garden Miscellany, Dec., 1849, p. 360.- The morphology of true glands is still obscure, notwithstanding the interesting light that is thrown upon them in the article here referred to; and stipules often tend to assume the glandular character, or are reduced to glands, as in Linum. FIG. 306. Diagram (cross-section) of the unopened flower of the American Linden, to show the scale and the cluster of stamens before each petal. CHORISIS OR DEDUPLICATION. 255 petaloid scales of Sapindacea) in the ligule of Grasses (298), and the stipules (304). The former occupies exactly the same position. The latter form an essential part of the leaf (259), and usually develope in a plane parallel with that of the blade, but between it and the axis, particularly when they are of considerable size, and serve as teguments of the bud, as, for example, in Magnolia (Fig. 130) and Liriodendron. The combined intrapetiolar stipules of Melianthus, &c. furnish a case in point, to be compared with the two-lobed internal scale of the stamens in Larrea, the twocleft adnate appendage of the petals in Caryophyllem, Sapindus, &c.; and instances of cleft or appendaged stipules may readily be adduced to show that such bodies are as prone to multiplication by division as other foliar parts. The supposition of a true axillary origin of the organs in question, therefore, appears to be gratuitous, and it would certainly introduce needless complexity into the theory of the structure of the flower. Still, as the axillary branch must begin with a single phyton, its development may in the flower be restricted to one phyton (as in the pistillary leaf in the axil of a bract in Coniferme); thus giving a single axillary organ, which, if it multiply at all as it developes, may do so by collateral chorisis. And, reduced to the simplest case, between the transverse division of a nascent phyton, and the axillar production of a second phyton at an extremely early period in the development of that which subtends it, there is'little assignable difference. At present, ac cordingly, we think that the same generic name may properly enough be employed both for the collateral and the vertical multiplication of organs, where two or more bodies occupy the place of one, carefully distinguishing, however, the two different cases; and also, that a special term is needful for discriminating between such multiplication and that by the regular augmentation of floral organs through the development of additional circles. Nor is a special term the less requisite, at least in systematic botany, because we recognize, in one or both kinds of chorisis, processes or modes of division which are common to the floral organs and to the foliage.* * We are aware that Dr. Lindley summarily rejects the whole doctrine of chorisis, or any evolution of two or more bodies in the normal place of one, however explained; and for three reasons, which may be cited from Introd. to Botany, 1. p. 333, with a word of comment. "1. There is no instance of 256 THE FLOWER. 461. The Coalescence or union of the parts of the same whorl or set of organs is so frequent, that few cases are to be found in which it does not occur, to a greater or less extent, in some portion of the flower. When the sepals are thus united into a cup or tube, the calyx is said to be monosepalous, or, more correctly, gamosepalous: when the petals are united, the corolla is said to be monopetalous, or gamopetalous; the latter being the appropriate term, as it denotes that the petals are combined; but the former is in common use, although strictly incorrect, as it implies that the corolla consists of a single petal. The inappropriate names, in these cases, twere given long before the structure was rightly understood. So, also, such a calyx or corolla is said to be entire, when the sepals or petals are united to their very summits; as the corolla of Convolvulus (Fig. unlining [read chorisis, which Dunal, as quoted by Lindley, proposes to substitute] which may not be as well explained by the theory of alternation." — Not to mention other instances, how is the andricecium of Fumariacex to be explained upon the theory of alternation? If by the hypothesis still reproduced in the Vegetable Kingdom, p. 436, we inquire, What analogy warrants the supposition that a stamen or a leaf may split into halves, and the halves unite each with a different filament which has an angular distance of 90 degrees?-" 2. It is highly improbable and inconsistent with the simplicity of vegetable structure, that in the same flower the multiplication of organs should arise from two wholly different causes, viz. alternation at one time, and unlining at another. 3. As it is known that in some flowers, where the law of alternation usually obtains, the organs are occasionally placed opposite each other, it is necessary for the supporters of the unlining theory to assume that in such a flower a part of the organs must be alternate and a part unlined, or at one time be all alternate and at another time be all unlined, which is entirely opposed to probability and sound philosophy. See the Camellias figured in the Elements of Botany, p. 76, fig. 156, 157, 158." —In double Camellias the numerous petals of the rosette are in some cases spirally alternatein others placed opposite each other in five or more ranks. Now, when in the very same species two such different modes of arrangement occur, is it not a priori more probable that the two arrangements result firom different causes and are governed by essentially different laws? —" 4. The examination of the gradual development of flowers, the only irrefiagable proof of the real nature of final structure, does not in any degree show that the supposed process of unlining has a real existence." Compare with this the well-stated abstract of Duchatre's memoir on the Morphology and Organogeny of Malvacere, which is given in the same work (Vol. 2, p. 70, et seq.), and which asserts that the stamens of the Malvaceous flower appear and multiply in a manner wholly conformable to the doctrine of chorisis, as here maintained, and hardly explicable upon any other theory. See, also, several diagrams of the testivation of flowers of Malpighiacee, where the petals extend within the outer row of stamens. COALESCENCE OF ITS ORGANS. 257 92i), which thus appears to be one simple organ; or to be toothed, lobed, cleft, or parted, according to the degree in which the union is incomplete; this language being employed just as in the case of the division of leaves (281). When the sepals are not united, the calyx is said to be polysepalous; and when the petals are distinct, the corolla is said to be polypetalous; that is, composed of several petals. Examples of this union of the parts of the same circle have already been shown, as respects the calyx and corolla (Fig. 287), and in the account of what is called the monopetalous divis. ion of the exogenous natural orders further illustrations are given, exhibiting this union in very different degrees. 462. The union of the stamens occurs in various ways. Sometimes the filaments are combined, while the anthers are distinct. When thus united by their filaments into one set, they are said to be monadelphous; as in the Lupine, &c. (Fig. 307). When united by their filaments into two sets, they are diadelphous (Fig. 308), as in most plants of the Pea tribe (Leguminosae),where nine stamens form one set and the tenth is solitary; and in Dicentra (Fig. 296, 308 307 309 310 299), where the six stamens are equally combined in two sets. When united or arranged in three sets or parcels, they are said to be triadelphous, as in the common St. John's-wort (Fig. 553); or if in several, polyadelphous; as in other Hypericums, in Tilia, &c. In some of these instances, indeed, the stamens of each group have a common origin, as we suppose (456); still, the same terms are employed in botanical description, under whatever theoretical views. In other cases, the filaments are distinct, or nearly so, and the anthers united into a ring; as in the vast order Compositne, or class Syngenesia of the Linnaan artificial system; when the stamens are said to be syngenesious (Fig. 309, 310). Again, in Lobelia, not only are the anthers syngenesious, but the filaments FIG. 307. Monadelphous stamens of a Lupine. 303. Diadelphous stamens (9 and 1) from a papilionaceous flower. Compare with the diagram, Fig. 282. FIG. 309. Syngenesious stamens of a flower of a Composita. 310. The tube of anthers laid open. 22* 258 THE FLOWER. are also combined in a tube for the greater part of their length (Fig. 786). The same thing is seen in the Gourd tribe, where the anthers are sometimes long and sinuous or rei markably contorted, as well as coherent into a mass (Fig. 311-313). 463. The union of the pistils is still more common than that of the stamens. It occurs in every degree, from the partial combination of the ovaries, as in Penthorum (Fig. 290), &c., to their complete union while the styles remain distinct, as in the St. John's-wort (Fig. 313 554), to the partial union of the latter, as in the Mallow, or to the perfect union of the styles also into a single body, as in Convolvulus (Fig. 922). In some cases, the styles are wholly combined, while the ovaries are only partially so; and in the Milk-weed and Dogbane (Fig. 953), the stigmas are united, while the ovaries are distinct. But the structure of the compound or syncarpous pistils will require particular illustration farther on. When there is no such union, but the several organs of the same circle are separate or unconnected, they are said to be distinct. 464. The terms union, cohesion, and the like, must not be understood to imply that the organs in question were first formed as distinct parts, and subsequently cohered. This is-seldom the case. The union is congenital; the members of a gamosepalous calyx, a gamopetalous corolla, a monadelphous circle of stamens, or a compound pistil, were connate, and showed their union from the earliest period. The language we use has reference to our idea of these parts, as answering each to a single leaf. We might more correctly say that the several leaves of the same circle have failed to isolate themselves as they grew. The same remark applies to the case of 465. Adnation, or the union of different circles of floral organs with one another. This may take. place in various degrees. It presents the appearance of one circle or set of parts growing out FIG. 311. Column of stamens, at once triadelphous and syngenesious, of the Gourd: the floral envelopes cut away. 312. A cross-section of the united anthers, nearly the natural size. 313. A sinuous anther of the Melon. ADNATION OF ITS ORGANS. 259 of another, as the corolla out of the calyx, the stamens out of the corolla, or all of them out of the pistil; and therefore disguises the real origin of the floral organs from the receptacle or axis, in successive series, one within or above the other (42). In the numerous cases where the real origin, or insertion, of the floral organs is not obscured by these cohesions, but where they are in appearance as well as in theory inserted on the receptacle, the calyx, corolla, and stamens are said to be hypogynous, that is, inserted below the pistils; as in the Buttercup, the Magnolia, in Cruciferous flowers (Fig. 297), &c. The floral organs in such cases are also said to be free; which is the term opposed to the adhesion of one organ to another, as that of distinct is to the cohesion of the parts of the same whorl or set of organs. Thus, the stamens are said to be distinct, when not united with each other, and to be free, when they contract no adhesion to the petals, sepals, or pistils; and the same language is equally applied to all the floral organs. The word connate (born united) is applied either to the congenital union of homogeneous parts (as when we say that the two leaves of the upper pairs of the Honeysuckle are connate, the sepals or stamens are connate into a tube, or the pistils into a compound pistil), or to the coalescence of heterogeneous parts (as that of the petals with the calyx, or of both with the pistil). But the word adnate belongs to the latter case only. 466. When heterogeneous parts are adnate, that is, congenitally adherent to each other, some additional technical terms are rendered necessary. Thus two words are used as counterparts of hypogynous (under the pistil), and accord with different degrees of adnation, viz. perigynous and epigynous. The petals and stamens, which almost always accompany each other, are said to be perigynous (literally placed around the pistil) when they adhere to the base of the calyx, or ] in botanical language are inserted on it, either directly, or perhaps more commonly by means of a 314 315 disc or sort of common fleshy base, from the upper surface or edge of which they grow; as in FIG. 314. A flower of Rhamnus alnifolius, showing the perigynous disc, into the margin of which the petals and stamens are inserted. 315. Vertical section through the calyx and the fleshy disc which lines it. 260 THE FLOWER. the Cherry, the Buckthorn (Fig. 314, 315), &c. The same term is often applied to the calyx when it is adnate to the base of the ovary, in which case it necessarily carries the petals and stamens with it. Very frequently the calyx invests and coheres with the whole surface of the ovary, so that all the parts of the flower seem to grow out of its summit; as in the Honeysuckle, the Dogwood, (Fig. 240, a), the Valerian, &c. The organs which thus apparently arise from the top of the ovary are said to be epigynous (literally on the pistil); a case of which is shown in Fig. 316. The earlier botanists called the flower, or calyx, in such cases, superior, and the ovary and fruit inferior; and when no such combination occurs, the ~'.II! flower, or calyx, &c. was said to be inferior, and the ovary superior. But these terms' are nearly, and should be altogether, 316 superseded by the equivalent and more appropriate expressions of calyx adherent in the one case, and calyx free in the other; or that of ovary coherent with the calyx, and ovaryfreefrom the calyx, which is the same thing in other words. 467. The various parts of the flower, thus consolidated, may separate into their integral elements at the point where they become free from the ovary, as in Cornus (Fig. 240); or else remain variously combined; the calyx being frequently prolonged into a tube with which the petals and stamens cohere, as in the Evening Primrose (Ord. Onagraceae), where the united sepals form a long and slender tube, bearing the petals and stamens onr its summit. In most cases, where the corolla is gamopetalous, the stamens continue their adhesion to it; while in the Orchis Family they are free from the corolla, but adherent to the pistil, or gynandrous. 468. Irregularity, from unequal development or unequal union. The Pea tribe affords a familiar illustration of irregular flowers arising from the unequal size and dissimilar form of the floral en. velopes; especially of the corolla, which, from a fancied resemblance to a butterfly in the flower of the Pea, &c., has been called papilionaceous. The petals of such a corolla are distinguished by FIG. 316. Vertical section through a flower of Aralia nudicaulis, showing the calyx adnate to the whole surface of the compound pistil, on the summit of which the petals and stamens are accordingly inserted. ITS IRREGULARITY. 261 separate names; the upper one, which is usually most conspicuous, being termed the vexillum, standard, or banner (Fig. 318, a); the two lateral (b) are called wings (ale), and the two lower (c), which are usually somewhat united along their anterior edges, and 317 318 319 320 more or less boat-shaped (Fig. 319), together form the keel (carina). The sepals, which are coalescent below into a cup, are also of unequal size or somewhat unequally united. But here are all.the parts of a symmetrical pentamerous calyx and corolla, only they are irregular on account of their unequal size, shape, or union. There is a tendency to become regular, however, in some flowers of the same tribe; this is slightly observable in Baptisia (Fig. 321), but is more manifest in Cercis (the Red-bud or Judastree), and most of all in Cassia;where the five petals are separate, spreading, and almost alike in size and form. The irregularity of papilionaceous flowers likewise affects the stamens, which, although of symmetrical number, viz. ten, or two circles, are in most cases unequally diadelphous (462), nine of them being united by the cohesion of their filaments for the greater part of their length, while the FIG. 317. A flowering branch of Lathyrus myrtifolius. 318. The corolla displayed: a, the vexillum or standard; b, the ali or wings; c, the two petals of the carina or keel. 319. The keel-petals in their natural situation. 320. The stamens and pistil, enlarged; the sheath of filaments partly turned back. 262 THE FLOWER. tenth (the posterior) stamen is distinct or nearly so (Fig. 320). But in Amorpha (Fig. 323, ~~321~~~~ ~324), which belongs to the same family, an approach to regularity is seen in this respect, the ten stamens / 7 / being united barely at their base; and there is a complete return to regularity in those of Baptisia (Fig. - 322), which are perfectly distinct or separate. An example of a different sort of irregular blossom 322 323 is afforded by the Fumitory Family, the structure of which has already been explained, especially as to the stamens (455, Fig. 296). The floral envelopes of Dicentra are in one view regular, inasmuch as the two members of each circle are alike: but the exterior pair of petals is very unlike the interior pair; and in Corydalis and Fumaria itself one of the exterior petals is unlike the other, rendering the blossom more conspicuously and truly irregular. Here the irregularity is combined with more or less cohesion of the petals; although this union, like that of the two keel-petals of a papilionaceous flower, is not congenital, but occurs subsequently to the development of the organs. 469. There are many other forms of irregular polypetalous blossoms, which we cannot here separately explain, such as that of Polygala, and that of the Larkspur and Monkshood, both of which are farther complicated by the suppression of some organs, as well as by the irregular development of others. 470. Among gamopetalous flowers the most common case of irregularity is that of what are called bilabiate (or two-lipped) corollas, which prevail in the' Mint Family, and to some extent in several related families. Here the irregularity of form does not arise from the suppression of some of the petals, as might at first FIG. 321. Papilionaceous flower of Baptisia. 322. The same, with the petals removed, showing the ten distinct stamens. FIG. 323. Flower of Amorpha. 324. The same, with the solitary petal removed, showing the slightly monadelphous stamens. SUPPRESSION OR ABORTION. 263 sight be supposed, but from their unequal union: the upper lip being formed by the more extensive cohesion of the two upper petals with each other than with the lateral ones; which in like manner unite with the lower petal to form the lower lip (Fig. 367). But, in some such cases, the two upper petals do not cohere with each other as far as they do with the lateral ones, and, being smaller in size, the corolla has the appearance of wanting the upper lip, and shows a deep cleft in its place; as in Teucrium Canadense (Fig. 881). The flowers of Lobelia (Fig. 785) exhibit a striking instance of a similar kind; the two upper petals being united with the lateral (which are still further combined with the lower, to form the lower lip), but wholly unconnected with each other; so that the corolla appears to be split down to the base on the upper side. The ligulate or strap-shaped corollas of Compositae are evidently formed in the same way, as if by the splitting down of a tubular corolla on one side. In the bilabiate corolla of most Honeysuckles, the upper lip consists of four united petals; the lower of only one (Fig. 743). 471. Suppression or Abortion,. A complete flower, as already remarked (416), comprises four whorls or sets of organs; namely, calyx, corolla, stamens, and pistils: when any of these are wanting, the flower is said to be incomplete. Deviations resulting from/ the non-production of one or more of the whorls are not uncommon, and may affect. any of the floral organs. The calyx, however, is never wanting when the corolla is present, or rather, when the floral envelopes consist of only one whorl of leaves, they are called calyx, whatever be their appearance, texture, or color. For since the calyx is frequently delicate and petal-like (in botanical language petaloid or colored), and the corolla sometimes greenish or leaf-like, the only real difference between the two is, that the calyx represents the outer, and the corolla the inner series; and even this distinction becomes more or less arbitrary when either, or both, of these organs consist of more than one circle. The apparent obliteration of the calyx in some cases is owing to the entire cohesion of the tube with the ovary, and the reduction of the free portion, or limb, to an obscure ring or border, either slightly toothed or entire, as in Aralia (Fig. 316), Fedia (Fig. 764), &c. In Compositm, the partially obliterated limb of the calyx, when present at all, consists of scales, bristles, or a ring of slender hairs (as in the Thistle), and receives the name of pappus. 264 THE FLOWER. 472. The petals, however, are frequently absent; when the flower is said to be apetalous, as in the Anemone (Fig. 325), Clematis, Caltha, &c., in the Crowfoot Family, other genera of which are furnished with both calyx and corolla; as in some species of Buckthorn, IgW Vod while others bear petals; as in our C5\ ~Northern Prickly Ash I (Fig. 641, 642), while the petals are present in the Southern species. They are constantly wanting in a large num325/ ber of families of Exogenous plants, which on this account form the division Apetalae. When the calyx is present while the corolla is wanting, the flower is said to be monochlaznydeous, that is with a perianth (417) or floral envelope of only one kind; as in the cases above mentioned. But sometimes both the calyx and the corolla are entirely wanting, as in the Lizard's-tail (Fig. 1021), when the flowers, being destitute of floral envelopes, are termed achlanzydeous. The essential organs (418) are nevertheless present in these cases, so that the flower is perfect (or bisexual), although in, complete. 473. A still further reduction, however, occurs in many plants; where even these essential organs are not both present in the same flower, but the stamens disappear in some flowers, and the pistils in others. Such flowers are said to be diclinous, unisexual, or separated; that which bears stamens only is termed sterile or staminate, and that provided with pistils only, fertile, or pistillate. This separation of the essential organs is very frequently met with where one or both of the floral envelopes are present, as in Menispermum (Fig. 495, 497) and Prickly Ash (Fig. 641, 642); but when these are absent, it presents instances of the\ greatest possible reduction of which the flower is suscepti* In our Northern Zanthoxylum the monochlamydeous perianth which is present may, however, be justly held to be the corolla, and not the calyx, because the five stamens alternate with it, just as they do with the undoubted petals of Z. Carolinianum: in this case, therefore, we may say that the calyx, and not the corolla, is suppressed. See Gen. lllustr, 2, p. 148, tab. 156. FIG. 325. Flower of Anemone Pennsylvanica (apetalous or monochlamydeous). SUPPRESSION OR ABORTION. 265 ble.* An example of the kind is furnished by Ceratiola (Fig. 1036- 1039), the sterile flowers of which consist merely of a couple of stamens situated in the axil of a bract; and the fertile, of a pistil surrounded by similar bracts. 326 327 In the Willow (Fig. 326-329), which presents a more familiar illustration, Xl/! the sterile flowers Os likewise consist of two or three stamens in the axil of bracts, / which form a catkin (391); and the fertile, of solitary pistils also subtended by bracts, and disposed likewise in a catkin. That is, the 329 flowers are not only wholly destitute of floral envelopes (unless a little glandular scale on the upper side should be a rudimentary perianth of a single piece), but in one set of blossoms the stamens are also suppressed, and in another, the pistils. The pistillate flowers are reduced to a single pistil. The stamens vary in number in different species, from two to five. If there,were only one of the latter, an instance would be afforded of flowers reduced, not merely to one kind of organ, but to a single organ. Now there is one species of Willow, which appears to have a solitary stamen in its staminate flowers, * Except, perhaps, in what are called neutral flowers, such as those which occupy the margin of the cymes of several Viburnums and Hydrangeas, or even the whole cluster in monstrous states, as in the Snowball or Guelder Rose of the gardens (Viburnum Opulus), and the cultivated Hydrangea, which consist of floral envelopes only, with sometimes mere rudiments of stamens or pistils. Of the same kind are the neutral florets of Compositre, such as the marginal flowers, or rays, of the Sunflower. FIG. 326. A catkin of staminate flowers of Salix alba. 327. A single staminate flower detached and enlarged (the bract turned from the eye). 328. A pistillate catkin of the same species. 329. A detached pistillate flower, magnified. 23 266 THE FLOWER. and has therefore been named Salix monandra. But on inspection this seemingly single stamen is found to consist of two united quite to the top (Fig. 330). Here, as in many other cases, the normal condition of the flower is not only much altered by the suppression of some organs, i but disguised by the coalescence of those that remain. The blossoms of the Birch are very similar, except that three pistils, the sole representatives of as many flowers, 330 are found under each bract of the fertile catkin. 474. When the stamens and pistils are thus separated, the two kinds of blossoms may be borne, either upon different points or branches of the same individual, or upon entirely different individual plants. The flowers are said to be moncecious when both kinds are produced by the same individual plants; as in Indian Corn, the Birch, the Oak, Beech, Hazel, Hickory, &c.: and they are called dicecious when borne by different individuals; as in the Willow and Poplar, the Sassafras, the Prickly Ash, the Hemp, Hop, &c. In many cases, while some of the flowers are staminate only, and others pistillate only, a portion are perfect, the different kinds occurring either on the same or different individuals; as in most Palms, in many species of Maple, &c.: plants with such flowers are said to be polygamous. 475. The term ssuppression in all such cases merely denotes that the parts in question are wholly left out. It is the non.production of some organ or set of organs which forms a component part of our pattern plan of the flower, and which is realized in the complete flower. The term abortion, which is often used with exactly the same meaning, is more properly applied to those cases where the organ is deformed or imperfect (where a sterile filament, for example, occupies the position of a stamen), or where a mere rudiment marks the place of a non-developed organ. 476. The suppression or abortion of a whole circle of organs in a symmetrical flower does not destroy its symmetry, if we count the absent members. Thus a monochlamydeous flower, with a single full circle of stamens, usually has the latter placed opposite the leaves of the perianth, that is, of the calyx, the corolla or intervening circle, with the members of which it normally alternates, having failed to appear; -as in Comandra (Fig. 1004), ChenopoFIG. 330. A staminate flower ofSalix purpuirea (or monandra), with the stamens coalescent (monadelphous and syngenesious), so as to appear like a single one. SUPPRESSION OR ABORTION. 267 dium, and the Elm (whenever its blossoms have only one set of stamens, Fig. 338). 477. But when, with the abortion of the primary circle, say of the stamens, we have an augmentation of one or more additional circles of the same kind of organ, the law of alternation appears to be violated; the stamens that are present, or the outer circle of them, standing opposite the petals, instead of alternate with them. It is customary to assume this explanation for all cases of the opposition of the stamens to the petals, whether in the Primrose Family, in Claytonia, in the Vine (Fig. 334) and Buckthorn (Fig. 314), or in Byttneriacete, &c.: but considerations which have already been adduced indicate a different explanation for many of them (459). It can no longer be deemed sufficient to assume the obliteration of a normal floral circle, and the production of another one, when no traces of the former are to be detected and no clear analogy shown with some strictly parallel instance. But we may confidently apply this view when we find traces of the obliterated or abortive organs, as in the Geranium Family, for example. The pentamerous flower of- Geranium (Fig. 633) exhibits ten stamens in two rows, distinguished by their different length, the five of the exterior circle being shorter than the others. One set of these stamens alternates with the petals, the other is opposed to them; which would appear to conform to the law of alternation. But, on'closer examination, we see that it is the inner circle of stamens that alternates with the petals; those of the outer circle stand directly before them. This is a not uncommon case in diplostemonous flowers (viz. in those which have twice as many stamens as there are petals or sepals). In this instance the explanation of the anomaly is furnished by the five little bodies, called by the vague and convenient name of glands, which stand on D the receptacle between the petals and the sta- 0 0 mens, and regularly alternate with the for- QJ mer. They accordingly occupy the exact position of the original stamineal circle: wherefore, as situation is the safest guide in deter- 331 mining the nature of organs, we may regard them as the abortive FIG. 331. Diagram (cross-section) of the flower of Geranium maculatum, exhibiting the relative position of parts, especially the glands alternate with the petals, and the two rows of stamens within them. 268 THE FLOWER. rudiments of the five proper stamens, which here remain undeveloped. In the annexed diagram (Fig. 331) these are accordingly laid down in the third circle, as five small oval spots, slightly shaded. The actual stamens consequently belong to two augmented circles, those of the exterior and shortor set of which (represented by the larger, unshaded figures), normally alternating with the glands, are of course opposed to the petals, and those of the inner and larger set, normally alternating with the preceding, necessarily alternate with the petals. This view is further eluci. dated by the closely allied genus Erodium, where all the parts are just the same, except that the five exterior actual stamens are shorter still, and are destitute of anthers; that is, the disposition to suppression which has caused the obliteration of the primary circle of stamens, and somewhat reduced the second in Geranium, has in Erodium rendered the latter abortive also, leaving those of the third row alone to fulfil their proper office. It is just the same in the Flax Family, except that the glands which answer to the primary suppressed stamens are still less conspicuous, and those of the next circle are reduced to very small abortive 3d2 333 filaments, or to minute teeth in the ring formed by the union of all the filaments into a cup at the base, leaving five perfect stamens, which, though they alternate with the petals indeed, belong to a third circle (Fig. 332, 333). In a' few species of Flax, the second circle. of stamens is perfectly obliterated, so that no vestige is to be seen. 478. The case is different in the Buckthorn Family and in Byttneriaceoe, where we cannot but consider the stamens which alone appear, and stand singly before the petals (with which they are frequently connected at the base), as belonging to the corolline circle (459). Here the symmetrical alternation is interfered with first by chorisis, and then, that process having given an abnormal set of stamens, by the total suppression of the real stamineal circle,'as in the Buckthorn Family, &c., or their abortion, and reduction to sterile rudiments, as in many Byttneriacee; while in others the genuine circle of stamens appears as an inner FIG. 332. Flower of Linum perenne. 333. Its stamens and pistils separated: the glands are not represented: the next circle is reduced to minute sterile filaments alternating with the actual stamens. SUPPRESSION OR ABORTION. 269 series. In the same way we incline to explain the opposition of the stamens to the petals in the Grape-vine also (Fig. 334- 336); in- 331 335 asmuch as the five glands (represent. ed by the small shaded figures in the / diagram, Fig. 336) which alternate with the petals clearly belong to a / circle within the actual stamens, while there are no vestiges outside of them. The glands, therefore, would seem to represent the proper stamineal 0 circle, in an undeveloped state, reduced to these rudiments or to a lobed disc. 479. The stamens of the Barberry 336 (Fig. 505) are in appearance only, but not really, opposed to the petals, and the petals to the sepals. Here the appearance is caused, not by the suppression, but by the symmetrical augmentation of the floral envelopes and of the stamens. The calyx consists of two alternating circles of sepals, three in each; the corolla of two circles of petals, three in each; the three exterior petals alternating as they should with the inner circle of sepals, and the three interior ones alternating with these. But when the flower opens, the six petals, spreading apparently as one whorl, are necessarily opposed to the six sepals; and the six stamens in two circles, which are still more confluent into one whorl, are equally opposed to these, taken six and six; but they really alternate in circles of threes. In other words, decussating verticils of threes necessarily form six vertical ranks (251, 441). It is just the same in the Lily, Crocus, and most Monocotyledonous plants; where the perianth is composed of six leaves in two circles, and the andrcecium of six stamens in two circles, giving a regular alternation in threes; although, taken as two 6-merous circles, we have a stamen before each leaf of the perianth. 480. The symmetry of the flower is more frequently and seriously obscured by the suppression of a part of the members of the FIG. 334. Flower of the Grape, casting its petals without expanding them. 335. The same, without the petals:' both show the glands distinctly, within the stamens. 336. Diagram of the flower. 23 270 THE FLOWER. same circle, than from any other kind of deviation. The tendency to such obliteration increases as we advance towards the centre of the blossom, owing, doubtless, to the greater pressure exerted on the central parts of the bud, and the progressively diminished space the organs have to occupy on the conical receptacle. So, while the corolla, when present at all, almost always consists of as many leaves as the calyx, the members of the stamineal circle or circles are frequently fewer in number (although from their form they occupy much less room than the petals), and the pistils are still more commonly fewer, excepting where the axis is prolonged for the reception of numerous spiral cycles. Thus, the pistils, which present their typical number in Sedum, and all Crassulaceous plants (Fig. 256, 277, 283-290), are reduced to two, or rarely three, in the allied Saxifragaceous Family, while the other floral circles are in fives. So, in Aralia (the Wild Sarsaparilla and Spikenard), the flowers are pentamerous throughout, although the ovaries of the five pistils are united into one (Fig. 316); but in Panax, our other genus of the same family, they are reduced to three in the Ground-nut, and to two in the Ginseng, as also in all Umbelliferous plants. Although the pistils are indefinitely augmented in the Rose, Strawberry, and the greater part of Rosaceous plants, or of the normal number five in Spiraea, yet there are only two in Agrimonia, one or rarely two in Sanguisorba, and uniformly one in the Plum and Cherry, although the flowers of the whole order are formed on the pentamerous or sometimes the tetramerous plan, with a strong tendency to augmentation of all the organs. And the Pulse Family has, almost without exception, five members in its floral envelopes, and ten, or two circles, in its stamens, but only a single pistil (Fig. 282). A flower, it may here be added, is isomerous (that is, of equal members) when it presents the same number in all its floral circles, - a term therefore equivalent with symmetrical, - and anisonmerous when the number of parts is different in some of the circles. 481. As to the stamens, it may be remarked that they are usually symmetrical and regular when the floral envelopes are regular (although the'common Chickweed and the Maple are exceptions to this rule); while they strongly tend to become unsymmetrical by abortion or irregular (that is, of unequal size or shape) when the calyx and corolla are irregular, or the whole is oblique in the bud; the different stamens at the time of their development SUPPRESSION OR ABORTION. 271 being therefore placed in unlike conditions in such cases, so as to favor the growth of some of them, and to arrest or restrain others, either by pressure or by the abstraction of nourishment. Compare in this respect the more or less irregular corolla of Scrophulariaceous plants (Fig. 854-861) with their stamens. The Mullein (Verbascum) is one of the few genera of that family which has as many stamens as there are petals in the composition of its corolla, and sepals in its calyx: but even here they are unequal, and the posterior ones usually bear imperfect or deformed anthers. In other instances, where the five stamens are all present, indeed, the posterior one is either changed into a bearded sterile filament, as in Pentstemon and Chelone, or reduced to a mere rudiment, as in some Snapdragons; or to a deformed filament adherent to the corolla, and bearing a scale-like body in place of the anther, as in Scrophularia. The four remaining perfect stamens, in these cases, and nearly throughout the order, are unequally developed; two of them being longer than the remaining pair; as in Chelone, above cited, in Gerardia, &c.: the same thing is observed in most plants of the related orders Acanthacem, Bignoniacem, Orobanchacem (Fig. 850), Verbenaceu (Fig. 863- 865), and Labiatie (Fig. 872884). In such cases, viz. where of four two are long and two are shorter, the stamens are said to be didynamous. Not unfrequently, a further suppression takes place, and the two shorter of these stamens either entirely disappear; as in the Sage, Monarda, Lycopus Virginicus, &c. among Labiatee, and Gratiola Virginica, &c. among the Scrophulariaceme; or else are reduced to mere sterile filaments, such as those which may commonly be observed in Gratiola aurea, in the Wild Pennyroyal (Hedeoma), and in many other Labiate plants. 482. The obliteration of one or more members of the corolla follows the same laws. The loss of a petal from the circle is a case of irregularity from unequal growth carried to the greatest possible extent, or an arrest of the development of an organ from an early period, and we may sometimes trace the gradation in related plants from the diminution or dwarfing of certain organs to their total suppression. Thus, the papilionaceous corolla (468) of Erythrina herbacea has its five petals, but four of them (all except the posterior or vexillum) are small and inconspicuous: in Amorpha (Fig. 323), these same four disappear altogether, and the papilionaceous corolla is reduced to its vexillum alone. In some 272 THE FLOWER. cases, the obliteration or diminution may be attributed to local pressure or obstruction of the light, acting uniformly in all instances, from some constant cause. Thus the marginal or ray flowers of the dense head in Composite (as in the Aster, Sunflower, Centaurea, &c.) are not only much larger than those of the central or disc flowers, which are much pressed together, but their principal development is external. It is the same in the similar head of the Scabious; where the marginal corollas are not only the larger, but their exterior lobes or petals are much larger than the inner, which are dwarfed, as it were, by the pressure on that side. In other cases, however, we cannot give any such mechanical explanation. In our Buckeyes, for example, the whole five petals are occasionally present, as they.are uniformly in the Horsechestnut (another species of the same genus): but more commonly a vacant space marks the place from which the anterior petal has disappeared (Fig. 658). There is also a suppression of two or tlree stamens out of the two circles of those organs. 483. A few diagrams will exhibit some of the stages of suppression, from the complete and symmetrical to the most reduced con. dition of the flower. The diagram, Fig. 337, well enough exhibits the ground-plan of a 5-merous complete (/U.o 0 cflower, symmetrical in all its parts, exoo'g 0 _,~ g.\...cept that the pistils are reduced from 339 337 338 five to two; as in Sullivantia (Fig. 722). Fig. 338 is a diagram of a similar flower, except that the petals are absent (the place they should occupy is denoted by the five dotted lines): this corresponds with the Elm (when pentandrous), and to Chrysosplenium, which is of the same family as Sullivantia, only that there the sepals and stamens are in fours,- one being left out, perhaps we may say, from each circle. Fig. 339 is a ground-plan of the flower of the common Claytonia, or Spring Beauty (Ord. Portulacacee), the FIG. 337. Ground-plan of the flower of Sullivantia, the united pistils reduced to two. FIG. 338. Ground-plan of a similar flower when apetalous; the five dotted lines indicating the proper position of the suppressed petals. FIG. 339. Ground-plan of the flower of Claytonia; the outer lines representing the calyx of two sepals; the next set the corolla of five petals; next are the five stamens before the petals; and next the ovary, composed of three parts. SUPPRESSION OR ABORTION. 273 ornament of our vernal woods;-a complete and regular, but remarkably unsymmetrical blossom, only two of the four circles having the same number of members, and one of those (the stamens) being abnormal in position. There are only two sepals: within these are five petals: within and opposite these are five stamens; so that the primary stamineal circle is suppressed, and those present belong to a second circle; or, which is more likely, as they cohere at the base with the claws of the petals, they may arise from a chorisis of the petals themselves: and in the centre there are three pistils with their ovaries combined into one. Further examples will illustrate those graver suppressions which render the flower incomplete, and finally reduce it to a minimum. In the Elm (Fig. 1012), the petals entirely disappear, and the pistils are reduced to two, both of which are abortive in a part of the flowers, and one always disappears in the fertile flowers during the formation of the fruit. The occurrence of numerous cases where parts that actually exist in the pistil at the time of flowering are obliterated in the fruit, justifies the use of the term suppression in the case of parts which, though requisite in the ideal plan, are left out in the execution. Our Prickly Ash, as already stated (472), not only wants one circle of floral envelopes altogether (which, however, appears in the species of the Southern States), but, being dicecious (474), the stamens also disappear in all the flowers of one tree, while the pistils are all abortive in those of another individual. In the Blite (Fig. 973, 974), where the plan is trimerous, the petals and two of the stamens are entirely S.. Ai.. O ao 340 341 a 342 b a 343 b i wanting; as the annexed diagram (Fig. 340) shows. In the Callitriche (Fig. 1029-1033), where the plan is tetramerous, the FIG. 340. Diagram of the reduced flower of Blitumn. FIG. 341. Diagram of a perfect flower of Callitriche, which has no floral envelopes, a single stamen, and a four-celled pistil. FIG. 342. Diagram of the moncecious flowers of Euphorbia: a, the pistillate flower reduced to a mere three-celled pistil; and b, one of the staminate flowers reduced to a single stamen. FIG. 343. Diagram of the dioecious flowers of the Willow: a, one of the pistillate flowers reduced to a solitary pistil; b, a staminate flower reduced to a pair of stamens. 274 THE FLOWER. calyx and the corolla wholly disapear, as well as all the stamens but one (Fig. 341); and even this stamen is wanting in some of the flowers on the same stenm, while other flowers consist of a single stamen only. This brings us to a case like that of Euphorbia (Fig. 344- 348, illustrated by the diagram, Fig. 342), the greatly disguised structure of which would be certainly misapprehended, without special study. Nearly the furthest possible reduction, perhaps, is seen in the Willow (Fig. 326-329), where the staminate and pistillate flowers are distributed to different individual trees, the first reduced usually to a pair of stamens, and the second to a single pistil. The plan is represented in the diagram, Fig. 343. 484. A full illustrative series of almost all the kinds of deviation (X p 346 345 344 347 349 we have mentioned, but especially of simplification through sucFIG. 344. Flowering branch of Euphorbia corollata; the lobes of the involucre resembling a corolla. 345. Vertical section of an involucre (somewhat enlarged), showing a portion of the staminate flowers surrounding the pistillate flower (a), which in fruit is raised on a slender pedicel. 346. One of the staminate flowers enlarged, with its bract, a: b, the pedicel, to which the single stamen, c, is attached by a joint; there being no trace of floral envelopes. 347. Cross-section of the 3-pistillate fruit. 348. Vertical section of one of the pistils in fruit (the two others having fallen away from the axis), and of the contained seed; showing the embryo lengthwise. 349. A seed, SUPPRESSION OR ABORTION. 275 cessive suppressions, might be drawn from plants of the Euphorbiaceous Family. Among them are complete and perfect flowers, incomplete and perfect flowers, and achlamydeous and separated flowers, both moncecious and dicecious. Of these, the staminate flowers in some species are reduced to a single stamen, either sessile or on a pedicel, in the axil of a bract; and the pistillate, either to one simple pistil, or to a compound pistil formed of two or three simple ones combined. A cluster of such axillary achlamydeous flowers, each of a single stamen, collected at the base of the pedicel of a terminal achlamydeous pistillate flower of three coalescent pistils, and surrounded by an involucre, -the several leaves of which are coalescent below into a kind of cup, - forms the inJZorescence of Euphorbia, which, until explained by Mr. Brown, was mistaken for a single anomalous blossom (Fig. 344- 349). 485. Abortive or unusually shaped petals were called NECTARIES by the earlier botanists, whether they secreted honey or had a glandular apparatus, or not. This name was applied to the five spur-shaped petals of the Columbine (Fig. 480, 481), where the floral envelopes are symmetrical'and regular, all the petals being alike, although of an extraordinary form; and also to the four reduced and deformed petals of the unsymmetrical and irregular flower of the Larkspur, where two of the petals are spur-shaped and received into the conspicuous spur'of the calyx, while the other pair are of a different and more normal form. In the nearly related Aconite, where three of the five petals are obliterated, the two that remain (the nectaries, as they have been called) have assumed a shape so remarkable (Fig. 350), that their real nature could only be recognized by the position they occupy. Their appearance is rather that of a deformed stamen. A sterile or deformed stamen, destitute of an anther, or a body that occupies the normal place of a stamen, or is intermediate in appearance and situation between a petal and a stamen, is sometimes called a STABIINODIUM (literally a stamen-like body). Staminodia occur naturally and uniformly in many plants. In cultivated semi-double flowers, such transition states are extremely common, as in the Lark- 350 spurs, Columbines, &c. of the gardens. FIG. 350. One of the tvo deformed, stamen-shaped petals of Aconitum uncinatum,. 276 THE FLOWER. 486. Abnormal States of the Receptacle of the flower remain to be mentioned, as obscuring more or less the normal condition, or as giving a singular appearance to the blossom. One of the most remarkable cases of the enlargement of the receptacle is that of.the Nelumbium, where it is dilated into a large top-shaped body, nearly inclosing the pistils in separate cavities (Fig. 351). Sometimes it is hollowed out above, as well as dilated, as in the Rose, where the whole receptacle expands into an urn-shaped disc, invested by the adnate tube of the calyx, and bearing the petals and stamens on its border and the numerous pistils on the concave surface 351 (Fig, 684). It is much the same in Calycanthus (Fig. 690- 695). In Geranium, and many allied plants, the receptacle, which elevates the ovaries more or less, is prolonged between them, and coheres with their styles (Fig. 635). There is nearly a similar prolongation in Euphorbia (Fig. 348). Here there is some development of the axis beyond the proper insertion of the floral organs. Usually the floral internodes remain undeveloped or extremely short, like those of scaly leaf-buds (Fig. 127). But now and then some of them are elongated; as in the Pink and Silene, where the internode between the calyx and the corolla forms a conspicuous stalk, elevating the other parts of the flower in the tube of the calyx; while in many Gentians (Fig. 947) the internode above the circle of stamens is developed, rais- ing the pod on a stalk of its own. This is a common case in the Caper Family; in which the genus Gynandropsis (Fig. 352) exhibits a remarkable develop. ment of the whole receptacle. It is enlarged into a flattened disc where it bears the petals, and is then prolonged 352 into a conspicuous stalk which bears the stamens (or rather, perhaps, FIG. 351. The enlarged receptacle of Nelumbium. FIG. 352. Flower of Gynandropsis, showing an elongated receptacle, which separates the different sets of organs. THE FLORAL ENVELOPES. 277 to which the bases of the stamens are adnate), and then into a shorter and more slender stalk for the pistil; thus separating the four circles or sets of organs, like so many whorls of verticillate leaves. 487. The common name for this kind of stalk, as contradistinguished from the pedicel or stalk of the flower, is the STIPE; and whatever organ or set of organs is thus elevated is said to be stipitate. To particularize the portion of the receptacle which is thus developed, the stipe is termed the Anthophore when it appears just above the calyx, and elevates the petals, stamens, and pistils; the Gonophore, when it supports both the stamens and pistils; and the Gyhop~hore, Gynobase, or Carpophore, when it bears the gynnecium alone. The stalk which sometimes raises each simple pistil of the gynmcium (as in Coptis or the Goldthread) is called a Thecaphore. This, however, does not belong to the receptacle at all, but is homologous with the leaf-stalk.* SECT. V. THE FLORAL ENVELOPES IN PARTICULAR. 488. ALTHOUGH the various organs of the flower have already been connectedly considered under most of their relations, there yet remain some particular points in respect to each of them which require to be separately noticed. It will still be most convenient to treat of the calyx and corolla together, on account of their general accordance in most respects. 489. Their Development, or Organogeny, first requires a brief notice; The flower-bud is formed in the same way as the leaf-bud; and what has been stated as to the formation bf the leaves of the branch (274) equally applies to the leaves, or envelopes, of the flower. The sepals are necessarily the earliest to appear, which they do in the form of so many cellular tumors or nipples, at first distinct, inasmuch as then their tips only are eliminated from the axis. Each one may complete its development separately, in the * A few terms which relate to the combination of different kinds of flowers in the same inflorescence, or their corresponding separation, may here be defined. Thus, a head or spike of flowers is said to be homogamous when all its blossoms are alike, as in Eupatorium; or heterogamous when it includes two or more kinds, as in the Sunflower and Aster. It is androgyznous when it consists of both staminate and pistillate flowers, as the spikes of many Sedges. When the two kinds of flowers occupy different heads, whether on the same or two different individuals, they are hzeterocephalous. 24 278 THE FLOWER. same manner as an ordinary leaf, (only no petiole is interposed between the blade and the axis,*) when the sepals remain distinct (463) or unconnected. Otherwise, the lower and later-eliminated portions of the nascent organs of the circle coalesce as they grow into a ring, which, further developed in union, forms the cup or tube of the gamophyllous calyx: or, in some cases, it would appear that the sepals may at first grow separately, and afterwards, though only at a very early period, coalesce by the cohesion of their contiguous parts. The several parts of an irregular calyx are at first equal and similar; the irregularity is established in their subsequent unequal growth. The petals or parts of the corolla originate in the same way, a little later than the sepals. Their coalescence in the gamopetalous corolla, as far as known, is strictly congenital; the ring which forms its tube appearing nearly as early as the slight projections which become its lobes and answer to the summits of the component petals. The rudiments of the petals are visible earlier than those of the stamens: t but their growth is at first retarded, so that the stamens are earlier completed, and their anthers surpass them, or often finish their growth, while the petals are still minute scales: at length they make a rapid growth, and inclose the organs that belong above or within them. Unlike the sepals in this respect, the base of the petal is frequently narrowed into a portion which corresponds, more or less evidently, to the petiole (the claw), which, like the petiole, does not appear until some time after the blade or expanded part; the summit being always the earliest and the base the latest portion formed. As the envelopes of the flower grow and expand, those of each circle adapt themselves to each other in various ways, and acquire the relative positions which they occupy in the flower-bud. Their arrangement in this state is termed 490. Their Estivation or Pruefloration. The latter would be the preferable term; but the former is in common use; the word ~Estivation (literally the summer state) having been formed for the * At least the case of a petiolate sepal is very rare. The sepals are rather to be compared to bracts, which are mostly sessile, than to ordinary leaves. t When the stamens, or an exterior set of them, originate by chorisis or deduplication of the petals (459), it appears from the observations of Duchatre that the five protuberances which represent the petals at their first appearance divide transversely, or grow double, the inner half developing into a stamen or a cluster of stamens, the outer into the petal itself. JESTIVATION. 279 purpose by Linnmeus; - for no obvious reason except that he had already applied the name of Vernation (the spring state) to express the analogous manner in which leaves are disposed in the leaf-bud. The same terms are employed, and in nearly the same way, in the two cases, but with some peculiarities. As to the disposition of each leaf taken by itself, the corresponding terms of vernation (257) wholly apply to mstivation; and there are no forms of any consequence to be added, perhaps, except the corrugate or crumpZed, where each leaf is irregularly crumpled or wrinkled, longitudinally or transversely, one or both, as happens in the petals of the Poppy and the HIelianthemum, - a case that is not met with in the foliage; the induplicate, where the edges are folded inwards, as those of the sepals of Clematis (Fig. 357), - but this, as compared with vernation, is only a modification of the involute; and the reduplicate, where the margins are bent outwards instead of inwards, as in the corolla of the Potato, — which is a mere modification of the revolute in vernation. 491. The arrangement in the bud of the several members of the same floral circle in respect to each other is of much importance in systematic botany, on account of the nearly constant characters that it furnishes, and still more in structural botany, from the aid it often affords in determining the true relative superposition or succession of parts on the axis of the flower, by observing the order in which they overlie or envelope each other; for every enveloping part is almost necessarily external to, or of lower insertion than, the part enveloped. The various forms of mestivation that have been distinguished by botanists may be reduced to three essential kinds, namely, the imbricative, the contorted or convolutive, and the val'vular.* 492. Imbricative mestivation, in a general sense, comprises all the modes of disposition in which some members of a floral circle are exterior to the others, and therefore overlie or inclose them in the bud. This must almost necessarily occur wherever the parts are inserted at distinguishably different heights, and is the natural result of a spiral arrangement. The name is most significant * We should properly say of the cestivation that it is imbricative, convolutive valvular, &ec., and of the calyx and corolla, or of the sepals, &c., that they are imbricate or inzbricated, convolute, valate, &c. in Tstivation; but such precision of language is seldom attended to. 280 THE FLOWER. when successive leaves are only partially covered by the preceding, as in Fig. 174- 176; here they manifestly break joints, or are disposed like tiles or shingles on a roof, as the term imbricated denotes. It is therefore equivalent to the spiral arrangement, which word is sometimes substituted -for it in mestivation: and, on the other hand, we properly apply the term imbricated to any continuous succession of such partly overlying members, as when we say of oppressed and crowded leaves that they are imbricated on the stern, or thus express the whole arrangement of the scales of a bud (Fig. 127), or a bulb (Fig. 141), or of a catkin or cone (Fig. 175). The alternation of the petals with the sepals, &c. necessarily makes the floral envelopes likewise imbricated in the bud, taken as a whole. But in proper aestivation, what we have to designate is the arrangement of the parts of the same floral circle, say the five sepals or the five petals, in respect to each other. 493. Now where the calyx or the corolla exhibits the character of a complete cycle (439) or of a part of a cycle (442) of leaves with the internodes undeveloped, that is, where we may perceive on close inspection that the several members are inserted on the receptacle at unequal heights, this will be manifested in the bud by the relative position of these members: the lower or outer must overlie or inclose the upper or inner. This is just the case in regular imbricative aestivation; where, of five sepals, for example (as in the diagrams, Fig. 300, 281), two will be wholly exterior in the bud, two wholly interior, and one intermediate, namely, covered at one edge by one of the exterior, while its other edge overlies that of one of the inner sepals'; - which, on comparison with Fig. 172, 173, will be found to correspond exactly with the 2 or quincuncial arrangement of leaves as presented on a similar ground-plan. Leaves No. 1 and No. 2 are external; No. 3 is internal in respect to these, but external in respect to No. 4, which is two fifths of the circumference distant, and more manifestly to No. 5, which, being separated by an interval of two fifths from the preceding, completes the cycle, and is overlapped by No. 3. In this, the normal and the most common arrangement in the 5-merous flower, the parts are said to be spirally, or (with more definiteness as to the numerical kind of spire) quincuncially imbricated in aostivation. 494. We have here the advantage of being able to number the successive sepals, or petals, since the third leaf is not only recognizable by its intermediate position, but also indicates the direction in which the spiral turns, as is shown in Fig. 173. IESTIVATION. 281 495. The same regularly imbricated arrangement in trimerous flowers gives one exterior, one half interior and half exterior, and one interior member in mstivation, after the order of' cycles, as is shown in the diagram, Fig. 353, both for the calyx and corolla;- which compare with Fig. 171, recollecting that the successive cycles are superposed in the foliage, while the floral circles alternate. Regular imbrication in the 4-merous flower gives two outer and two inner 353 members in nestivation (as in the calyx of Cruciferous blossoms, Fig. 280), on the principle of two decussating pairs of leaves (439); or it may sometimes be referable to a modification of some alternate spiral arrangement. 496. The degree of overlapping depends upon the breadth of the parts and the state of the bud; it naturally grows less and less as the bud expands and is ready to open. It is from the fullgrown flower-bud, just before anthesis (or the opening of the blossom), that our diagrams are usually taken; in which the parts are represented as moderately or slightly overlapping. The same overlapping carried to a greater extent will cause the outer leaf to envelope all the rest, and each succeeding one to envelope those within; as shown in Fig. 354 from one circle of petals of a Magnolia taken in an early state of the bud. Here the mode is just the same as that of Fig. 353. To this, however, has not improperly been applied the name of convolute, from its similarity to the convolute verna354 tion of the leaves of the branch (257), similarly rolled up one within the other. But it is practically inconvenient, and wrong in principle, to designate different degrees of the very same mode by distinct names; furthermore, the next general kind of mestivation, when carried to a high degree of overlapping, produces a somewhat similar result; and moreover, it is to this second mode, whatever be its degree, that the name of convolute is more commonly applied, in recent systematic botanical writings. 497. There are numerous cases of imbricative Eestivation, espeFIG. 353. Imbricated wstivation of the calyx and corolla, in a trimerous flower. FIG. 354. The strongly enveloping imbricative aestivation of the three exterior petals of Magnolia grandiflora. 24 282 THE FLOWER. cially in irregular flowers, where the overlapping of parts does not altogether accord with what must needs be their order of succession on the axis. In the 5-merous calyx and corolla of all truly papilionaceous flowers, for example, one edge of the sepal or the petal No. 2 is placed under, instead of over, the adjacent edge of No. 4, in consequence of which three, instead of only one, of the leaves have one edge covered and the other external; as is shown in Fig. 282. Since, in the corolla of this kind of blossom, the exterior petal, here the vexillum (468), is the larger, and at first enmbraces all the rest (as is seen in the separate diagram of the corolla, Fig. 359), this modification of imbricative aestivation has Teceived the name of vexillary. As nearly the same thing occurs in the Violet, it is probably caused by some slight dislocation that takes place during the early growth of organs in the irregular blossom, which the study of their development should explain. It is not restricted to irregular flowers, however, but occurs as a casual variation, or perhaps more frequently than the quincuncial, in the regular corolla of the Linden (as is shown in Fig. 306). A slight obliquity in the position of the petal No. 2, assumed at an early period, would account for the whole anomaly. That this suggests the true explanation is almost demonstrated by the varying mestivation of the corolla of the Linden; in which the same bunch of blossoms often furnishes instances of regular quincuncial imbrication, of the modification here referred to, and of the similar disposition of the fifth petal, throwing one of its edges outwards also. If the first petal were also to partake of this slight obliquity, the imbricative would be completely converted into what is variously named 498. The contorted, twisted, or convolutive mastivation (Fig. 360, the corolla, and 361). In this mode, the leaves of the circle are all, at least apparently, inserted at the same height, and all occupy the same relative position: one edge of each, being directed obliquely inwards, is covered with the adjacent leaf on that side, while the other covers the corresponding margin of the contiguous leaf on the other side. This is owing to a more or less evident torsion or twisting of each member on its axis early in its development; so that the leaves of the floral verticil, instead of forming arcs of a circle, or sides of a polygon having for its centre that of the blossom, severally assume an oblique direction, by which one edge is carried partly inward and the other outward. This con AESTIVATION. 283 torted zestivation, is scarcely ever met with in the calyx, but is very common in the coralla. When this obliquity of position is strong, the petals themselves are usually oblique, or unequal-sided, from the lesser growth of the overlapped side, which is by no means so favorably situated in this respect as is the free external portion, - a case of partial obliteration or dwarfing from pressure. This is well seen in the petals of most Malvaceous plants, to some extent in those of Geranium, Flax, and Wood-Sorrel, and strikingly in those of the St. John's-wort, and in the lobes of the corolla of the Periwinkle (Vinca) and of most other Apocynaceous plants. In the Pink, however, and in many other instances, the petals are symmetrical, although strongly convolute in mestivation. When the petals are broad, this arrangement is frequently conspicuous in the fully expanded flower, as well as in the bud (as in Fig. 365). The convolution in the bud is often so great, that the petals appear as if strongly twisted or rolled up together, each being almost completely overlapped by the preceding, so that they become convolute nearly in the sense in which the term is used in vernation; as in the Wallflower (Fig. 360, 361). Although there is some diversity of usage, the terms convolute and contorted in oestivation are 355 356 357 358 359 360 361 352 363 now for the most part employed interchangeably, or nearly so. In FIG. 355-363. Diagrams of estivation. (When there are two circles, the outer represents the calyx and the inner the corolla.)'355. Valvate. 356. Valvate calyx; the corolla induplicate or nearly conduplicate. 357. Involute, rather than induplicate, sepals of Clematis. 358. Quincuncially imbricated; the first leaf on the upper side. 359. Vexillary imbricated papilionaceous corolla. 360. Imbricated calyx of Wallflower (two outer and two inner sepals), and within the strongly contorted or convolute corolla. 361. Contorted or convolute corolla, with the petals more expanded. 362. Plaited tube of the corolla of Campanula. 363. Plaited and aupervolute corolla of Convolvulus. 284 THE FLOWER. Geranium, and in many other cases (as in Fig. 280), we find the prevailingly contorted or convolute sestivation affecting casual transitions to the imbricative mode, corresponding to those already mentioned in the foregoing paragraph. 499. The valvular or valvate oestivation is that in which the parts of a floral verticil are placed in contact, edge to edge, throughout their whole length, without any overlapping (as in Fig. 355, and the calyx in Fig. 356). Here the members of the circle are strictly verticillate, and stand in an exact circle, no one being in the least degree lower or exterior. The edges of the sepals or petals in this case are generally abrupt, or as thick as the rest of the organ, as is shown in the calyx of the Linden (Fig. 306); by which mark the valvate sestivation may commonly be recognized in the expanded flower. The several parts being all developed under precisely similar conditions in this and the foregoing modes of estivation, these are naturally and almost without exception restricted to regular flowers alone. 500. By the inflexion of the edges, the strictly valvate oestivation passes by insensible gradations into the induplicate (490), as in the calyx of some species of Clematis; a mode which is carried to a maximum in some species of Lysimachia (Fig. 356), where the two edges of the same petal are brought into contact, so as to be condztplicate. When the induplicate margins are inrolled, they become involute (Fig. 357) in oestivation. On the contrary, the valvate calyx of many Malvaceous plants and the corolla of the Potato blossom have the margins projecting outwards into salient ridges, or are reduplicate, in mestivation. 501. The tube of a gamopetalous corolla occasionally exhibits similar ridges or folds, whether salient (as in the bud of some Campanulas, Fig. 362), or reentering (as in Stramonium): this gives rise to the plicalive, plicate, or plaited modification of aestivation. Where the plaits are folded round each other, in a convolutive manner, the mstivation is sometimes termed supervolutive, or supoervolute, as in the Morning-Glory (Fig. 363). 502. The spire in imbricative aestivation, and the order of overlapping in the contorted mode, may turn either from left to right, or from fight to left; and the direction is often uniform through the same genus or family, but sometimes diverse in different blossoms on the same plant. In fixing the direction, we suppose the observer to stand before the flower-bud. De Candolle, THE CALYX. 285 indeed, supposes the observer to occupy the centre of the flower, which would reverse the direction; but the former view is generally adopted. The direction is frequently reversed in passing from the calyx to the corolla, - sometimes with remarkable uniformity; while again the two occur almost indifferently in many cases. 503. The kind of mestivation, although often the same both in the calyx and corolla, as in Parnassia (Fig. 304) and Elodea (Fig. 300), where both are quincuncially imbricated, is as frequently different; and the difference is often characteristic of families or genera. Thus, the calvx is valvate and the corolla convolute in all Malvaceve; the calyx imbricated and the corolla convolute in Hypericurn, in the proper Pink tribe, &c. Solitary exceptions now and then occur in a family. Thus, the corolla in Rosaceme is imbricated, so far as known, except in Gillenia, where it is convolute. In general it may be said, that the estivation of the corolla is more disposed to vary than that of the calyx. 504. The Calyx. In treating of the general structure and diversities of the flower, we have already noticed the principal modifications of the calyx and corolla, as well as the terms employed to designate them; which need not be here repeated. 505. The number of sepals that enter into the composition of a calyx is indicated by adjectives formed from. the corresponding Greek numerals prefixed to the name; as disepalous for a calyx of two sepals; trisepalous, of three sepals; tetrasepalous, of four; pentasepalous, of five; hexasepalous, of six sepals; and so on. Very commonly, however, the Greek word for leaves, phy7la, is used in such composition; and the calyx is said to be diphyllous, triphyllous, tsetraphyllous, pentaphyllous, hexaphyllous, &c., according as it is composed of 2, 3, 4, 5, or 6 leaves or sepals respectively. These terms imply that the leaves of the calyx are distinct, or nearly so. When they are united into a cup or tube, the calyx was by the earlier botanists incorrectly said to be monophyllous (literally one-leaved);-a term which we continue to use, guarding, however, against the erroneous idea which its etymology involves, and bearing in mind that the older technical language in botany expresses external appearance, rather than the real structure, as we now understand it. The correct term, calyx gamophyllous, is now coming into general use; this literally expresses the true state of the case, and is equivalent to the phrase sepals united: the degree of coalescence being indicated by adding " at the base," " to the middle," or " to the summit," as the case may be. 286 THE FLOWER. 506. Still, in botanical descriptions, it is ordinarily more convenient and usual to regard the calyx as a whole, and to express the degree of union or separation by the same terms as those which designate the degree of division of the blade of a leaf (281283): as, for example, Calyx five-toothed, when the sepals of a pentaphyllous calyx are united almost to the top; five-cleft, when united to about the middle; fve-parted, when they are separate almost to the base; and five-lobed, for any degree of division less than five-parted, without reference to its particular extent. The united portion of a gamophyllous calyx is called its tube; the distinct portions of the sepals are termed the teeth, segments, or lobes, according to their length as compared with the tube; and the orifice or summit of the tube is named the throat. The calyx is said to be entire (281), when the leaves of the calyx are so completely confluent that the margin is continuous and even. The terms regular and irregular (446, 468) are applied to the calyx or corolla separately, as well as to the whole flower. The counterpart to calyx monophyllous or monosepalous in the current glossology is polyphyllous or polysepalous (viz. of many leaves or sepals). This is equivalent to the phrase sepals distinct; and does not mean that they are unusually numerous, or of more than one circle. 507. The Corolla has corresponding terms applied to its modifications. When its petals are distinct or unconnected, it is said to be polypetalous; when united, at least at the base, monopetalous, or more properly gamopetalous, as already explained (461). The united portions in the latter case form the tube of the corolla, and the distinct parts, the lobes, segments, &c.; and the orifice is called the throat, just as in the calyx. The number of parts that compose the corolla is designated in the manner already mentioned for the calyx; — viz., a corolla of two petals is dipetalous; of three, tripetalous; of four, tetrapetalous; of five, pentapetalous; of six, hexapetalous; of seven, heptapetalous; of eight, octopetalous; of nine, enneapetalous; of ten, decapetalous. 508. Frequently the petals; and rarely the sepals, taper into a stalk or narrow base, analogous to the petiole of a leaf, which is called the claw (unguis); and hence the petal is said to be unguiculate (as in Cruciferous flowers, the Pink, Fig. 302, and Gynandropsis, Fig. 352, &c.); the expanded portion, like that of the leaf, being distinguished by the name of the lamina, limb, or blade. THE COROLLA. 287 509. Some kinds of polypetalous flowers receive particular names, from the form or arrangement of their floral envelopes, especially of the corolla. Among the regular forms (295) we may mention the rosaceous flower, like that of the Rose, Apple, &c., where the spreading petals have no claws, or very short ones; the liliaceous, of which the Lily is the type, where the claws or base of the petals or sepals are erect, and gradually spread towards their summits; the caryophyliaceous, as in the Pink and Silene, where the five petals have long and narrow claws, which are inclosed in the tube of the calyx; and the cruciate, or cruciform, which gives name to the Mustard Family (Fig. 525), where the four unguiculate petals, diverging equally from one another, are necessarily disposed in the form of a cross, as in the Mustard, &c. Among the irregular polypetalous flowers, which are greatly varied in different families, the papilionaceous or butterfly-shaped corolla of the Pea tribe has already been described (468). 510. Several forms of the gamopetalous corolla, or gamophylious calyx, have been distinguished by particular names. These are likewise divided into the regular, where their parts are equal in size, or equally united; and the irregular, where their size or degree of union is unequal (468). Among the former are the ccampanulate or bell-shaped, as the corolla of the Harebell (Fig. 364), which enlarges gradually and regularly from the base to the 364 365 3,6 367 368 summit; the infundibuliform, or funnel-shaped, where the tube enlarges very gradually below, but expands widely at the summit, FIG. 364. Campanulate corolla of Campanula rotundifolia. 365. Salver-shaped corolla of Phlox. 366. Labiate (ringent) corolla of Lamium; a side view. 367. Personate corolla of Antirrhinurn. 36S. Personate corolla of Linaria, spurred at the base. 288 THE FLOWER. as in the corolla of Morning-Glory (Fig. 921) and the Tobacco (Fig. 935); tubular, where the form is cylindrical throughout: htypocrateriform, or salver-sh1aped, where the limb spreads at right angles with the summit of the more or less elongated tube, as in the corolla of Primula and of Phlox (Fig. 365); and rotate, or wheel-shaped, when a hypocrateriform corolla has a very short tube, as in the Forget-me-not (Fig. 887) and Bittersweet (Fig. 939). 511. The principal irregular gamopetalous or gamophyllous form that has received a separate appellation is the labiate or bi-.labiate, which is produced by the unequal union of the sepals or petals (470), so as to form an upper and a lower part, or two lips, as they are called, from an obviouis resemblance to the open mouth of an animal (Fig. 366). This variety is almost universally exhibited by the corolla of Labiatme, and very frequently by the calyx also, as in the Sage (Ord. Labiattn): it likewise occurs in the corolla of most Honeysuckles (Fig. 742, 743), and in the calyx of many papilionaceous flowers. When the upper lip is arched, as in the corolla of Lamium (Fig. 366), it is sometimes called the galea, or helmet. When the two lips are thus gaping and the throat open, the corolla is said to be ringent. But when the mouth is closed by the approximation of the two lips, and especially by an elevated portion or protuberance of the lower, called the palate, as in the Snapdragon (Fig. 367) and Toadflax (Fig. 368),, the corolla is said to be personate, or masked. 512. In the Snapdragon, the base of the corolla is somewhat protuberant, or saccate, on the anterior side (Fig. 367): in the Toadflax (Fig. 368) the protuberance is extended into a hollow spur. A projection of this kind is not uncommon, in various families of plants. One petal of the Violet is thus spurred or calcarate; so is one of the outer petals in the Fumitory, and each of them in Dicentra (Fig. 295). So, also, one of the sepals is spurred or strongly sac-shaped in the Jewel-weed (Impatiens), the Nasturtium, and the Larkspur; and all five petals take this shape in the Columbine. A monster of the Toadflax is occasionally found, in which the four remaining petals, of the five which enter into its composition, affect the same irregularity, and so bring back the flower to a singular abnormal state of regularity. This was called by Linnreus Peloria; a name which is now used to designate the same sort of monstrosity in different flowers. 513. The petals are sometimes furnished with appendages on THE STAMENS. 289 their inner surface, such as the crown at the summit of the claw in Silene (Fig. 302), and the scales similarly situated on the gamopetalous corolla of Myosotis and Symphytum (Fig. 888, 893). The nature of this crown has already been explained (458). Such appendages are sometimes thought to represent an adherent row of abortive stamens or petals. 514. The bodies termed nectaries (485) by the old botanists are either petals of unusual form, such as the spurs of the Columbine; or petals passing into stamens, such as the fringe of the Passionflower; or a deduplication of the petal, as in Parnassia (Fig. 305); or else abortive and transformed stamens, as in Canna. The so-called nectary of Orchidaceous plants is merely a petal, which, being of a different shape from the others, is termed the labellum. 515. The duration of the floral envelopes varies greatly in different plants. Sometimes they fall off as the flower opens, or even before expansion, as the calyx of the Poppy and the corolla of the Grape-vine (Fig. 334); when they are said to be caducous. More commonly they are deciduous, or fall after anthesis but before the fruit forms. When they remain until the fruit is formed or matured, they are persistent, which is often the case with the calyx, especially when it has a green color and foliaceous texture. It is occasionally accrescent, or takes a further growth during fructification, as in Physalis. When the envelopes persist in a dry or withering state, as the corolla of Heaths, of Campanula, &c., they are said to be marcescent. 516. Besides serving as organs of protection, the sepals, when green, assimilate sap, and act upon the air like ordinary foliage (344, 346). The petals, like other uncolored (that is greenless) parts, do not evolve oxygen, but abstract it from the air, and give off carbonic acid; in other words, they decompose assimilated matter, - a process which appears to be needful in flowering, and to subserve some important end at the time (367- 373). The tissue of a petal is much the same as that of a leaf, except that it is much more delicate, and the fibro-vascular system is reduced to slender bundles of a few spiral vessels, &c., which form its veins. SECT. VI. THE STAMENS. 517. The Stamens, collectively forming the ANDRzECIUM (418), have been already considered in respect to their component parts, 25 290 THE FLOWER. their nature and symmetry, and their principal modifications as to relative number and disposition. Their absolute number in the flower, it may be remarked, is designated by Greek numerals pre. fixed to the word used for stamens, as employed by Linnmus in the names of his artificial classes. Thus, a flower with one stamen is said to be monandrous; with two, diandrous; with three, trian. drous; with four, tetrandrous; with five, pentandrous; with six, hexandrous; with seven, heptandrous; with eight, octandrous; with nine, enneandrous; with ten, decandrous~; with twelve, dodecandrous; and with a greater or indefinite number, polyandrous. (See the account of the classes of the Linnzean Artificial System, Part II. Chap. II.) 518. The terms employed to designate their various modifications, most of which have already been incidentally noticed, are likewise derived from the names of Linnnean artificial classes, with the exception of those which relate to their insertion; such as hypogynous, when inserted on the receptacle (466), or, in other words, free from all adhesion to neighboring organs; perigynous, when adherent to the tube of the calyx (as in Fig. 315); and epigynous, when adherent also to the ovary, and, as it were, raised to its summit (as in Fig. 316). To these may be added the Linnaean term gynandrous, expressive of their further cohesion with the style, as in the Orchis Family. 519. As to mutual cohesion, they are monadelphous when united by their filaments into one body (as in Fig. 307); diade7phous, when thus combined in two sets (as in Fig. 308); triadelphous, when in three sets, as in Hypericum and Elodea (Fig. 300, 301); pentadelphous, when in five sets, as in our Linden; and polyadelphous, when in several sets, irrespective of the particular number. They are syngenesious, when united by their anthers (Fig. 309, 310). As respects inequality of size, they are didynamous, when four stamens constitute two pairs of unequal length (481); and tetradynamous, when six stamens only are present, two of which are shorter than the others, as in Cruciferous flowers (455); a case which is sometimes, but less distinctly, seen in the allied Caper Family (Fig. 352). Their complete suppression in some flowers gives rise to such terms as moncecious, dicecious, and polygamous, which have already been defined (473). 520. The. proportion of the stamens to the corolla or other floral envelopes is sometimes to be noticed. When they are longer and THE STAMENS. 291 protruding, they are said to be exserted; when shorter or concealed within, they are included; - terms which apply to other organs as well. So of terms which indicate their direction; as declined, when curved towards one side of the blossom, as in the Horsechestnut. 521. The stamens are mostly too narrow to furnish any characters of oestivation, except as to the manner in which each one is separately disposed. In this respect they exhibit several varieties, to which the same terms are applied as to the vernation of individual leaves (257). 522. When the stamen is destitute of the filament, or stalk (Fig. 369, a), the anther (b) is said to be sessile: the filament being no more essential to the stamen than the claw is to the petal, or the petiole to b the leaf. When the anther is imperfect, abortive, or wanting, the stamen is said to be sterile, a-......... abortive, or rudimentary; its real nature being known by its situation. 523. The Filament, although usually slender and cylindrical, or slightly flattened, assumes a great variety of forms: it is sometimes dilated so as to be undistinguishable from the petals, except by its bearing an anther; as in the transition states between the true petals and stamens of Nymphaea (White Water-Lily, Fig. 266, 267). The filament is anatomically composed of a central bundle of spiral vessels or ducts, which represent the fibro-vascular system of the leaf, in the same state as in the petiole, enveloped by parenchyma; the outer stratum of which forms a delicate epidermis. 524. The Anther (Fig. 369, b), which is the essential part of the stamen, is usually borne on the apex of the filament; and commonly consists of two lobes, or cells (thecce), placed side by side, and connected by a prolongation of the filament, called the connectivum, or connective. As the filament answers to the petiole, so the connectivum answers to the midrib of the leaf, and the lobes, or cells, to the blade of the leaf; the portion each side of the midrib forming an anther-lobe. The pollen, or powdery substance contained in the anther, originates from a peculiar transformation of the cellular tissue, or parenchyma of the leaf. 525. The attachment of the anther to the filament presents three principal modes. 1st. When the base of the connective exactly corresponds with the apex of the filament and with the axis of the 292 THE FLOWER. anther, the latter is termed innate, and rests firmly upon the summit of the filament, as in Fig. 370. 2d. When the lobes of the anther adhere for their whole length to a prolonga. tion of the filament, or to a broad connective (whichever it be called), so as to appear lateral, it is said to be adnate; as in the Magnolia (Fig. 488). Here the anther must be either extrorse or introrse. It is introrse, or turned inwards, when it 370 371 372 occupies the inner side of the connective, and faces the pistils, as in Magnolia and the Water-Lily (Fig. 266); but when the anther looks away from the pistils and towards the petals or sepals, it is said to be extrorse, or turned outwards, as in the Iris, in Liriodendron (Fig. 371), and in Asarum (Fig. 373). 3d. When the anther is fixed by a point to the apex of the filament, on which it lightly swings, it is said to be versatile; as in all Grasses, in the Lily, and in the Evening Primrose (Fig. 372), &c. In this case, as in the preceding, the anther is said to be introrse, or incumbent, when it is turned towards the pistil, which is the most common form; and extrorse, when it faces outwards. 526. The connective is frequently inconspicuous or almost wanting, so that the lobes of the anther are directly in contact on the apex of the filament; as in Euphorbia (Fig. 346). It is often produced beyond them into an appendage, as in the Magnolia and Liriodendron (Fig. 371), the Papaw (Fig. 492, where it forms a rounded top), and Asarum (Fig. 373). Appendages or processes from the back of the connective are seen in the stamens of the Violet, and of many Ericaceous plants (Fig. 802 - 804). 527. Each of the two cells or lobes of the anther is marked with a lateral line or furrow, running from top to bottom; this is the suture or line of delhiscence, by which the anther opens at maturity, and allows the pollen to fall out (Fig. 369). This line, FIG. 370. Stamen of Isopyrum biternatum, with an innate anther. 371. Stamen of Liriodenalron, or Tulip-tree, with an adnate extrorse anther. 372. Stamen of CEnothera glauca, with the anther fixed by its middle and versatile. FIG. 373. Stamen of Asarum Canadense, with an adnate anther. THE ANTHER. 293 which answers to the margin of the leaf, is exactly lateral in innate anthers, as in Fig. 370; but it looks more or less evidently, and often directly, inward in introrse, and outward in extrorse anthers (Fig. 371, 373). 528. Various deviations from this normal structure of the anther frequently occur; some of which may be cursorily noticed. The opening of the anther, sometimes called its dehiscence, does not always take place by a longitudinal fissure for the whole length of the cell. Occasionally the suture opens only at the top, in the form of a chink or pore; as in Pyrola (Fig. 807), Rhododendron, and other Ericaceous plants, and in the Potato, &c. Sometimes the summit of the lobes is prolonged into a tube, which opens by a pore or chink at the apex; as in the Heath and Huckleberry (Fig. 802- 804). In the Barberry and other plants of the family (Fig. 507), the Benzoin, &c., nearly the whole face of each anther-cell separates by a continuous line, forming a kind of door, which is attached at the top, and turns back, as if on a hinge: in this case the anthers are said to open by valves. In the Sassafras (Fig. 999), and many other plants of the Laurel Family, each lobe of the anther opens by two such valves, like trap-doors. 529. Sometimes the anthers are one-celled by the suppression of one lobe, being dimidiate, or reduced as it were to half-stamens, as in Gomphrena, and some other Amaranthaceous plants; but they more frequently become one-celled by the confluence of the two lobes, and the disappearance of the partition between them. The kidney-shaped one-celled anthers of the Mallow Family may be conceived to arise from the divergence of the base of the two lobes, and their perfect confluence at the apex; and the opening consequently takes place by a continuous sutural line passing round the margin (Fig. 618). A somewhat similar case occurs in Monarda and some other plants of the Mint Family, where only one of the two lobes remains parallel with the filament or connective; while the other, describing a semicircle, is brought into the same vertical line, where it stands bottom upwards; and the two, cohering by their contiguous extremities, become confluent into a single cell, which opens by a continuous straight line from one end to the other. The anther of Teucrium differs from the last chiefly in the enlarged connective, on which the divaricate lobes rest; and the cells, at first distinct, are confluent into one after the anther opens. In the Thyme, the anther-lobes are also 25* 294 THE FLOWER. greatly divergent, but are separated by the thickened connective, which in this family is often larger than the cells. In the Sage, the singular elongated connective sits astride the apex of the filament, and bears an anther-cell at each extremity; one of which is perfect and contains pollen, while the other is imperfect or abortive. Illustrations of these diversities will be found under the Ord. Labiatoe. We have no room to pass in review even the more common of the almost endless variations which the anther exhibits. 530. As to its structure, each lobe of the full-grown anther consists of an epidermal membrane, lined with a delicate fibrous tissue, and surrounding a cavity filled with pollen. This fibrous lining, a part of which is shown in Fig. 32, from the anther of Cobea, is composed of simple or branching attenuated threads or bands, which formed the thickening deposit on the walls of large parenchymatous cells; all the membrane between the bands becoming obliterated as the anther approaches maturity, the latter alone remain, as a set of delicate fibres. This fibrous layer gradually diminishes in thickness as it approaches the line of dehiscence of the cell, and there it is completely interrupted. These very elastic and hygrometric threads lengthen or contract in different ways, according as the anther is dry or moist; which movements, after the pollen has appropriated all the juices of the tissue; aid in the disruption of the anther along the suture, and then favor the egress of the pollen. The walls of many anthers are curved outwards, or completely turned inside out, as in Grasses, by the unlike hygrometric state of the external and the internal layers. 531. Of all the floral organs, the anther shows least likeness to a leaf. Nevertheless, the early development is nearly the same. Like the leaf, the apex is earliest formed, appearing first as a solid protuberance, and the anther is completed before the filament, which answers to the leaf-stalk, makes its appearance. At first, the anther is of a greenish hue, although at maturity the cells assume a different color, more commonly yellow. A transverse section of the forming anther shows four places in which the transformation of the parenchyma into pollen commences, which answer to the centre of the four divisions of the parenchyma of a leaf, viz. the two sides of the blade, each distinguished into its upper and its lower stratum. So that the anther is primarily and typically four-celled; each lobe being divided by a portion of untransformed tissue stretching from the connective to the opposite THE POLLEN. 295 side, which corresponds to the margin of the leaf and the line of dehiscence.'This appearance is presented by a large number of full-grown anthers: but the partition usually disappears before the anther opens, when each lobe becomes single-celled. The normal anther is consequently considered as two-celled. In Menispermum and Cocculus (Fig. 496), however, the anther is strongly fourlobed externally, and each lobe forms a distinct cell, at maturity. Although the stamens originate a little later than the petals, when these are present, yet they outgrow them at first, and their formation is earlier completed (489). 532. The Pollen, contained in the anther, which appears to the naked eye like a mere powder, consists of grains of definite size and shape, which are uniform in the same plant, but often very different in different species or natural families. Although commonly spherical or oval, they are cylindrical in the Spiderwort (Tradescantia), nearly square in Colutea, many-sided in the Teasel, and triangular, with the angles dilated and rounded, in the Evening Primrose (Fig. 419). The most remarkable shape is that of Zostera (a marine aquatic plant), in which the grains consist of long and slender threads, which, as they lie side by side in the anther, resemble a skein of silk. Their surface, although more frequently smooth and even, is banded or crested in many cases; it is reticulated in the Passion-flower, and studded with strong points in Convolvulus purpureus (Fig. 417), or short bristles in the Mallow Family and the Gourd. The color is usually yellow. 533. The grains of pollen are single cells, formed usually in fours, by the division of the living contents of mother cells first into two, and these again into two parts, which, acquiring a layer of cellulose, become four specialized cells, nearly in the manner already described (31, 95). As the pollen completes its growth, the walls of the mother cells are usually absorbed or obliterated, when the grains lie loose in the cell. But sometimes the inclosing cells persist, and collect the pollen-grains into coherent masses of various consistence, as in the Milkweed Family (Fig. 422) and in the Orchis Family (Fig. 1098, 1101). Such pollen-masses are sometimes called pollinia. The threads, like cobweb, that are loosely mixed with the pollen of the Evening Primrose (Fig. 700), are vestiges of obliterated mother cells. 534. Not unfrequently the four grains developed in the same cell cohere, more or less firmly, as in most Ericaceous plants; or 296 THE FLOWER. grow as one compound grain, without undergoing complete di. vision. The grains of the pollen of the Evening Primrose Fam. ily (Fig. 419) thus consist of the rudiments of four, which remain in strict combination; one of them enlarging to form the main body of the grain, while the three others appear as bosses on its angles. Rarely the four cohering grains are placed in the same plane. They usually stand in the same relation to each other as the four angles of a cube. In the Mimosa Family, the division goes farther, and gives rise to eight or sixteen lightly coherent grains in each mass. 535. The pollen-grains have two coats; the exterior of which, called the extine, is quite firm and often wax-like, granular, or fleshy; to it the bands, points, or other markings belong. It is a secretion from the inner layer, which is the proper membrane of the cell. This inner coat, named the intine, is a thin, uniform, transparent and colorless, highly extensible membrane. It absorbs water rapidly, and when exposed to its action the grain swells and soon bursts, discharging its contents. These contents are a viscid fluid, rich in protoplasm, which often appears slightly turbid under the higher powers of ordinary microscopes, and, when submitted to a magnifying power of three hundred diameters, is found to contain a multitude of minute particles (fovillae) of spherical or oblong form, the larger of which are from the four-thousandth to the five-thousandth of an inch in length, and the smaller only one fourth or one sixth of this size. The smaller exhibit the constant molecular motion of all such minute particles when suspended in a liquid and viewed under,a sufficient magnifying power. The larger are some of them of the nature of starch-giains; some consist of oily matter, &c. The pollen of certain aquatic plants - that of Zostera very distinctly- has only a single (the internal or proper) membrane. 536. When wetted, the grains of pollen promptly absorb water by endosmosis (37), and are distended, changing their shape somewhat, and obliterating the longitudinal folds, one or more in number, which many grains exhibit in the dry state. Soon the more extensible and elastic inner coat inclines to force its way through the weaker parts of -the exterior, especially at one or more thin points or pores; sometimes projecting so as to form a tube of considerable length, when the absorption is slow and the exterior coating tough. The absorption continuing, the distention soon over THE PISTILS. 297 comes the resistance of the inner coat, which bursts, with the eruption of the contents in a jet. When fresh, living pollen falls upon the stigma, however, which is barely moist, but not wet, it does not burst, but the inner membrane is slowly projected, often through particular points, clefts, or valvular openings of the outer coat, in the form of an attenuated transparent tube (Fig. 416e418), filled with its fluid contents, which penetrates the naked and loose cellular tissue of the stigma, and buries itself in the style (Fig. 419). This, however, is not a mechanical protrusion, but a true growth, depending on nutrition imbibed from the stigma and style. Its further course and the office it subserves will be considered after the structure of the pistil is made known. SECT. VII. THE PISTILS. 537. The Pistils (419) occupy the centre of the flower, and ter rinate the axis of growth. Their number is designated by Greek numerals prefixed to the name applied to the pistil from the same language. Thus, a flower with a single pistil-is said to be monogynous; with two, digynous; with three, trigynous; with four, tetragynous; with five, pentagynous; with six, hexagynous; with seven, heptagynous; with eight, octogynous; with nine, enneagynous; with ten, decagynous; and so on: and when more numerous or indefinite, they are termed polygynous. (See the Linnzean Orders, 684.) 538. It is comparatively seldom that the pistils are actually equal to the petals or sepals (480) in number; they are sometimes more numerous, and arranged in several rows upon the enlarged or prolonged receptacle, as in the Magnolia, the Strawberry, &c., and perhaps more frequently they are reduced to less than the typical number, or to a single one. Yet often what appears to be a single pistil is not so in reality, but a compound organ, formed by the union of two, three, or a greater number of simple pistils; as is shown in Fig. 381 - 390. 539. A pistil, as already described (420), is composed of three parts; the OVARY, or seed-bearing portion; the STYLE, or tapering portion, into which the apex of the ovary is prolonged; and the STIGMA, usually situated at the summit of the style, consisting of a part, or sometimes a mere point, of the latter, divested of epidermis, with its moist cellular tissue exposed to the air. The 298 THE FLOWER. ovary, which contains the young seeds, or ovules, is of course a necessary part of the pistil: the stigma, which receives from the anthers the pollen (536) by which the ovules are fertilized, is no less necessary: but the intervening style is no more essential to the pistil than the filament is to the stamen, and is therefore not uncommonly wanting. In the latter case, the stigma is sessile upon the apex of the ovary. In Tasmannia it actually occupies the side of the ovary for nearly its whole length, and is separated from the line to which the ovules are attached only by the thickness of the walls; and it is nearly the same in our Schizandra (Fig. 375), another plant of the Magnolia Family. The style sometimes proceeds from the side, or even from the apparent base of the ovary; as in the Strawberry. 540. When the pistil is reduced to a single one, or when several coalesce into one, it will necessarily terminate the axis, and appear to be a direct continuation of it. When there are two pistils in the flower, they always stand opposite each other (so that if they coalesce it is by their inner faces); and are either lateral as respects the flower, that is, one on the right side and the other on the left, in a plane at right angles to the bract and axis (444), as in the Mustard Family, the Gentian Family, and a few others; or, more commonly, anterior and posterior, one before the axis and the other before the bract of the axillary flower. When they accord in number with the sepals or petals, they are either opposed to or alternate with them; and the two positions in this respect are sometimes found in nearly related genera, so as to baffle our attempts at explaining the cause of the difference. In Pavonia, for example, the five pistils are opposite the petals; in Malvaviscus and Hibiscus, alternate with them. In Sida, when five, they stand opposite the petals; in Abutilon, opposite the sepals. 541. To attain a correct morphological view of the simple pistil, we must contemplate it as resulting from the transformation of a leaf which is folded inwards, and the margins united; in a manner that will be perfectly evident on comparing Fig. 263 with Fig. 270. The line formed by the union of the margins of the leaf is called the INNER or VENTRAL SUTURE, and always looks towards the axis of the flower. This is a true suture, or seam, as the word denotes. The opposite line, which answers to the midrib, is sometimes apparent as a thickened line, and is termed the OUTER or DORSAL SUTURE. The surface of the pistil necessarily corresponds THE PISTILS. 299 to the lower, and its lining to the upper, surface of a leaf. The stalk of the pistil (487), when it is present, represents the petiole; and a prolongation of the apex of the specialized leaf forms the style. The stigma occupies some portion of what in the style answers to the confluent margins of the transformed leaf (and certainly is not a portion of the midrib, as has been thought); this is evident in Tasmannia, above mentioned, where these margins are actually stigmatic for almost their whole length, and in Schizandra, where the stigmatic surface (known by its papillose cells or other surface exposed directly to the air, without any epidermis) begins externally on the ventral edge of the pistil, just above the point where the ovules are attached within (Fig. 375). In the Pseony, in Isopyrum (Fig. 374), and a great number of instances, the stigma consists of two crested ridges or parallel lines running down the inner face of the style; and in a still larger number of cases (as in nearly all Caryophyllacese and a part of Malvaceme), a continuous stigmatic surface extends down this face of the style (Fig. 384). Such unilateral stigmas we accordingly take to be the normal form; and say 374 that, while the united margins of the typical leaf composing the ventral suture are turned inwards into the cell of the ovary to bear the ovules, in the simple style they are exposed externally to form the stigma. Where the stigma is terminal, or occupies only the apex of the style, we suppose that these margins are infolded in the style also, and form in its interior the loose conducting tissue through which a communication is established between the terminal stigma and the interior of the ovary. The double nature of the stigma (one 375 3 7s,7 lamella of which corresponds to each margin of a leaf) is still evident in the two lobes which the terminal stigma exhibits in many simple pistils, as in Hydrastis (Fig. 376), and Actsea (Fig. 377). 542. The ovary contains only OVULES, or bodies destined to beFIG. 374. A ventral view of a pistil of Isopyrum biternatum, showing the double stigma; the ovary cut across, showing the two rows of ovules. FIG. 375. Vertical section of a pistil of Schizandra coccinea; a side view. 376. Pistil of Hydrastis. 377. Pistil of Actra rubra, cut across, so as to show the interior of the ovary (the vntral suture turned towards the observer). 300 THE FLOWER,. come seeds after fertilization (420). These, in all ordinary cases, are borne on the part which represents the margins of the transformed leaf. They are in some sort analogous to buds, which are occasionally developed on the margins of leaves (as in the wellknown case of Bryophyllum, Fig. 271). Since both margins of the infolded leaf may bear ovules, the latter are normally arranged in two rows (one for each margin) on the inner or ventral suture; as is seen in Fig. 263, 374, 377. The ovule-bearing portion of the ventral suture, which often forms a -ridge or crest projecting more or less into the cavity of the ovary, is named 543. The Placeneta0 As it corresponds with the ventral suture, and is in fact a part of it, or a cellular growth from it, it is always placed next the axis of the flower; as is evidently the case when two, three, or more pistils are present (Fig. 379-383). Each placenta necessarily consists of two parts, one belonging to each of the confluent margins of the transformed leaf. It therefore is frequently two-lobed, or of two diverging lamelle (Fig. 263). The ovules vary greatly in number; being sometimes very numerous and in several rows on a broad placenta, as in the MayApple (Podophyllum); sometimes in two normal rows occupying the whole length of the ventral suture, as in the Larkspur, Columbine, Actea (Fig. 377), &c.; sometimes reduced to one row in appearance, as in the Pea, where on inspection they will be found, however, to be alternately attached to each lamnella of the placenta, that is, to each margin of the leaf: again, they occupy only its middle, base, or summit, where they are often reduced to a definite number, to a single pair (Fig. 375), or to a single one (Fig. 316). 544. When the pistils are distinct or uncombined, they are said to be apocarpous; when they are united, and form a compound pistil, they are syncarpous. We have carefully to distinguish between the simple pistil, which represents a single member of the gynmcium (419), and the compound pistil, which answers to the whole circle coalescent into one body. To subserve this purpose, botanists have coined the name of 545. The Carpel or Carpidium. This name designates an individual member of the gynmecial circle, whether it occur as a separate or simple pistil, or as one of the elements of a compound pistil. It is in the latter case that the name is principally needful. All degrees of union of the carpels may be observed, from the mere cohesion of their contiguous inner angles, to the perfect consolidation of the THE COMPOUND PISTIL. 301 ovaries while the styles remain distinct, as in Spergularia (Fig. 387), or of the latter also. Rarely the stigmas or styles are united while the ovaries remain distinct, as in Asclepias and Apocynum (Fig. 953). Numerous illustrations of all the varied 378 380 382 forms are given in the systematic part of this volume. The annexed diagrams represent, Fig. 378, 379, three distinct but approxi. mated pistils; Fig. 380, 381, three similar pistils with only their ovaries coalescent; and Fig. 382, c 383, three pistils with their styles as well as their ova- 379 381 383 ries united into one. 546. The Compound Pistil, From these illustrations the regular structure of the compound pistil is readily seen, at least as to the more common and normal case, namely, where the cross-section displays two or more cells, or separate cavities. For it is evident that, if the contiguous parts of a whorl of three or more carpels cohere, the resulting compound ovary will have as many cavities, or cells, as there are carpels in its composition, and the placentae will all be brought together in the axis; as is shown in Fig. 381, 383, in Fig. 291, and in the gynaecium of Fig. 306, as compared with Fig. 284, &c. 547. The partitions, or DISSEPIMENTS, which' divide the compound ovary into cells, are evidently composed of the united contiguous portions of the walls of the carpels. These necessarily consist of two layers, one belonging to each carpel; they are always vertical, and are equal in number to the carpels of which the compound pistil is constructed. 548. A single carpel, therefore, has no proper dissepiment. It is, however, sometimes divided by spurious partitions, separating the cavity into separate cells or joints, placed one above another, FIG. 378- A whorl of three pistils, the line which passes down the inner side representing the ventral suture. 379. A cross-section of their ovaries, showing the two rows of ovules, oc. cupying the inner angle, or ventral suture. 380. A whorl of three pistils, their ovaries united. 381. A cross-section of the same. 382. Three pistils, with their styles also united quite to the summit. 383. A cross-section of the united ovaries. 26 302 THE FLOWER. as in some species of Cassia, in Desmodium, &c. (Fig. 440, 441); or even by a vertical false dissepiment produced by the introflexion of the inner or placental suture, as is partially the case in some species of Phaca and Oxytropis (Fig. 445); or by a projection from the dorsal suture, as in the Flax (Fig. 630, 631), the Service. Berry, and many species of Vaccinium; or by its introflexion, as in Astragalus (Fig. 444). 549. A compound ovary of two cells, or loculi, is bilocular; of three, trilocular; of four, quadrilocular; of five, quinquelocular; and so on. If of several without reference to the number, it is said to be plurilocular, or multilocular; the former name being used when the cells are comparatively few, the latter when more numerous. We may, however, have a 550. Unilocular Compound Pistil, where the ovary, although composed of two or more carpels, is yet one-celled, that is, has a single cavity. The cases of the sort are of two principal kinds, namely, first, 551. With a free Placenta in the Axis, as in the Primrose Family (Fig. 825), and in a large part of the Chickweed and Pink Family, as shown in Fig. 384. This is usually explained on the supposition that the dissepiments are obliterated or torn away by the expansion during the growth of the ovary, these alone being wanting to complete the structure of the normal compound ovary already de. scribed, as will be seen by comparing the diagram, Fig. 387, with Fig. 383. This is demonstrably the true explanation in the Chickweed and Pink Family; for the dissepiments, or vestiges of them, 884 may be detected at an early stage, and sometimes at the base of the full-grown ovary; while certain plants of the same family, of otherwise identical structure, retain the partitions even in the ripe pod. Other cases, however, especially where there are a few ovules, or even a single one, as in Thrift (Fig. 840), arising from the base of the cell, are more properly referred to the other kind of unilocular compound pistil, namely, that 552. With Parietal Placentation, If we suppose a circle of three carpellary leaves, with their margins turned inwards, yet not so as to reach the axis, to cohere merely by their contiguous inflexed FIG. 3s4. Vertical section through the compound tricarpellary ovary of a plant of the Chickweed Family (Spergularia rubra), showing the free central placenta. PARIETAL PLACENTATION. 303 portions, a one-celled tricarpellary ovary would result, with three imperfect dissepiments projecting into the cavity, but not dividing it into distinct cells (as in the diagram, Fig. 385). The placentre are here borne upon the extremity of the imperfect dissepiments, which, if somewhat prolonged, would meet and unite in the centre, so as to present the regular three-celled struc385 386 387 ture (as in Fig. 383). This will be evident on comparing the pod of the Common St. John's-wort (Fig. 555), which is completely three-celled with the placentae united in the axis, with the ovary of another species (Fig. 388), where the three placentae touch in the centre without cohering, and with the full-grown E_.~ pod of the last (Fig. 389), where they are drawn asunder by the expansion of the growing pod, and remain attached only to its walls, borne on three slight introflexions, which stand in the place of dissepiments. Parnassia affords a similar instance, only there are usually four such placentae instead of three (Fig. 304, the centre of which represents a cross-section of the 4-carpellary ovary). These instances bring us to the frequent case in which we may say that the leaves of the gyntecial verticil, placed merely in apposition, as in valvate aestivation (499), directly cohere into one circle by their respective contiguous margins; which, being barely induplicate, form placentae which are borne directly on the walls. This is shown in the diagram, Fig. 386, representing a cross-section of three carpels thus combined into a compound one-celled ovary, without any appearance of dissepiments. Thus borne upon the walls, instead of in the axis of the compound ovary, the placentae are said to be parietal. Examples of the kind with a tricarpellary ovary are furnished by many FIG. 385-387. Diagrams illustrating parietal and free central placentation. 385. Crosssection of an ovary composed of three united carpels, where the introflexed portions do not reach the centre. 3S6. Section of a similar ovary, except that the placental margins unite' without any introfiexion (placentas strictly parietal). 387. Section of a tricarpellary ovary, with a free central placenta, produced by the obliteration of the dissepiments. FIG. 388. Magnified cross-section of the ovary of Hypericum graveolens. 389. Enlarged cross-section of the mature pod of the same, where the placenta become strictly parietal. 304 THE FLOWER. Hypericums, by the Violet Family, the Cistus Family (Fig. 548), Drosera (Fig. 390), &c. Also, in an ovary of two carpels, by the Caper Family (Fig. 537), the Fumitory Family (Fig. 298), the Gooseberry (Fig. 711), &c. 553. An ovary with parietal placentae is necessarily one-celled; except it be divided by an anomalous partition,such as that of Cruciferous plants, &c. 554. A compound pistil of this kind may have the sutures ovuliferous, or develope placentie, only at some particular part, as at the summit or the base of the cell; and there few or only solitary ovules may be developed, as in the Thrift (Fig. 840), in 390 Composite, &c., which reduces the case to the greatest simplicity. The confluence of two or more basilar parietal placentae will account for the free central placentation in cases where no dissepiments are discernible at an early period, as in the Primrose Family. 555. It will be seen that parietal placentae are necessarily double, like the placenta of a simple ovary, or of each carpel of a compound plurilocular ovary; but with this difference, that in these cases the two portions belong to the two margins of the same carpel; while in parietal placentae they are formed from the coalescent margins of two adjacent carpels. This will readily appear on comparing the diagrams, Fig. 379, 381, with Fig. 385, 386. 556. The number of carpels of which a compound ovary consists is indicated by the number of true dissepiments when these exist (547); or by the number of placentae, when these are parietal (552); or by the number of styles or stigmas, when these are not wholly united into one body. Thus a simple pistil has a single cell, a single placenta, and a single style. A pistil of two carpels may be two-celled, with two placentae, two styles, &c. 557. There are, however, some exceptions which qualify these statements: - 1. Each placenta being a double organ (555), it occasionally happens that the two portions are separated more or less, as in Orobanchaceous plants, where a dicarpellary ovary appears on this account to have four parietal placentae; either approximate in pairs (as in our Cancer-root, Conopholis), or equidistant (as in Aphyllon). 2. Analogous to this is the case where FIG. 390. Pistil of Drosera filiformibus, with three 2-parted styles; the ovary cut across, showing three parietal placentas. PLACENTATION. 305 the two constituent elements of the stigma (the only essential part of the style) separate into two half-stigmas; a tendency to which is seen in Fig. 376, 377, and which is carried out in most species of Drosera (Fig. 390). The stigma, no less than the placenta, belongs to the margins of the infolded leaf (541), these margins being ovuliferous in the ovary and stigmatiferous in the style; as Mr. Brown, the most profound botanist of this or any age, has clearly shown. These two constituent portions of the style or stigma are usually combined; but are not unfrequently separate, either entirely or in part, as in Euphorbiaceous plants, in Grasses, and especially in Drosera, where there are consequently twice as many nearly distinct styles as there are parietal placentae in the compound ovary. If the two component parts of the style of each carpel were reunited into one, in the usual manner, their number would equal the placentae, and their position would be alternate with the latter. But since, in parietal placentation, each half-lplacenta. is confluent, not with its fellow of the same carpel, but with the contiguous ha7f-placenta of the adjacent carpel (555), it were surely no greater anomaly for the elements of such half-stigmas as those of Drosera (Fig. 390) to follow the same course. This is precisely what takes place in Parnassia, and in other cases where the stigmas are opposite the parietal placentae; — cases which were thought to be very anomalous, merely on account of the adoption of a false principle (that of the necessary alternation of the stigmas and placentae), but which are really no more so than the parietal placentation itself. The division of the style in such cases furnishes further examples of collateral chorisis. Sometimes the simple style is repeatedly forked in this way, or cut into a fringe at the summit, as in Turnera, and the short lobes of the compound style in Dionea. 3. Furthermore, the production of ovules is not always restricted to what answers to the margins of the carpellary leaves. In the Poppy, the whole surface of the long, imperfect partitions is covered with ovules; in Butomus, they are borne over the whole internal face of each carpel, and in the Waier-Lilies over the whole surface (Fig. 268), except the inner angle of each cell, where alone they normally belong. Reduced to two in the allied Water-Shield (Brasenia, Fig. 515), the ovules grow from the dorsal suture, or the midrib of the carpellary leaf alone! And in Cabomba itself we usually find its three ovules, one in the dorsal and one on the ventral suture, and the third on 26* 306 THE FLOWER some variable part of the face of the cell in the vicinity of either suture. In Obolaria, a compound unilocular ovary is ovuliferous over the whole wall of the cell.* 558. When the styles are separate towards the summit, but united below, they are usually described as a single organ; which is said to be parted, cleft, lobed, &c., according to the extent of cohesion. This language was adopted, as in the case of leaves (281) and floral envelopes (461), long before the real structure was understood: but, as it involves an erroneous idea, the expressions, Styles distinct; united at the base; united to the middle, or summit, &c., as the case may be, should be employed in preference. 559. A few casual exceptions occur to the general rule that ovules and seeds are both produced and matured within an ovary, namely, in a closed carpellary leaf or set of combined carpellary leaves. In the Blue Cohosh, Leontice (Caulophyllum) thalictroides, the ovules rupture the ovary soon after flowering, and the seeds become naked; and in the Mignonette they are imperfectly protected, the ovary being open at the summit from an early period. In all such cases, however, the pistil is formed and the ovules are fertilized in the ordinary way. 560. Gynleium of Glmnospermous Plants. A far more important and remarkable exception is presented by two natural families, the Coniferoe (Pines, Firs, &c., Fig. 8 391-402), and the Cycadaceue (Cycas, Zamia, Fig. 403). Here the pistil, as likewise the wbhole flower, is reduced to the last degree of sim391 392 393 plicity; each fertile flower consisting merely of an open carpellary leaf, in place of a pistil, in the form I These various points are elucidated by Mr. Brown, in Plantke Javanicce Rariores, pp. 107 -112, in two notes which apparently are not sufficiently studied by many English botanists. — All placentation is very differently explained by those who adopt the hypothesis of Schleiden and others. According to this new view, as buds regularly arise from the axils of leaves and from the extremity of the stem or axis, and only in some exceptional and abnormal cases from the margins or surface of leaves, so ovules are considered to arise fiom the axils of the flower, like terminal -buds, or from the axils of the carpellary leaves, like axillary buds. Thus, placenta are supposed to belong to FIG. 391. A carpellary scale from the ament of a Larch, the upper side turned to the eye, showing the pair of ovules at its base 392. The same in fruit, reduced in size; one of the winged seeds still attached; the other, 393, separated. IN GYMNOSPERMOUS PLANTS. 307 of a scale, as in Fig. 391, or sometimes of a different shape (Fig, 402 400 401 394 396 395 399 398 407), which bears two or more ovules upon some part of its marthe axis, and not to the carpellary leaves; and a one-celled ovary, with one or more ovules arising from the base of the cell, would nearly represent the typical state of the gynaeciumr. This theory, which the intelligent student may easily apply in detail, offers the readiest explanation of free central placentation, especially in such cases as Primula, &c., where not the slightest trace of dissepiments is ever discoverable. It must be admitted that the monstrosities which occur in Primula, and some other plants with free central placentation, favor this new view. It is also perfectly applicable to ordinary central placentation; where we have only to suppose the cohesion of the inflexed margins of the carpellary leaves with a central prolongation of the axis or receptacle which bears the placenta. But in case of parietal placentation, FIG. 394. Carpellary scale of Cupressus sempervirens (the true Cypress), seen from within, and showing the numerous orthotropous ovules that stand on its base. 395. Branch of Abies Canadensis (Hemlock Spruce), with lateral staminate flowers, and a fertile strobile. 396. Staminate ament, magnified. 397. Carpellary scale of a fertile ament, with its bract. 398. Similar fertile scale, more magnified and seen from within; showing the two ovules adherent to its base: one of them (the left) laid open. 399. The scale in front, nearly of the natural size, its inner surface occupied by the two seeds. 400. Polycotyledonous embryos of Abies and Cypress. 401. Vertical section of one. 402. Strobile of Taxodium distichunm (Suborder Cupressinese). 308 THE FLOWER. gin or upper surface. The ovules, therefore, instead of being in407 409 408 405 I A,/ 406 403 404 closed in an ovary, and acted upon by the pollen through the inthe advocates of this theory are obliged to suppose that the axis divides within the compound ovary into twice as many branches as there are carpels in its composition, and that these branches regularly adhere, in pairs, one to each margin of all the carpellary leaves. Its application is attended with still greater difficulties in the case of simple and uncombined pistils, where the ovules occupy the whole inner suture, which are doubtless justly assumed as the regular and typical state of the gynmcium; but to which the new hypothesis can be adapted only by supposing that an ovuliferous branch of the axis enters each carpel, and separates into two parts, one cohering with each margin of the metamorphosed leaf. This view, however, not only appears very improbable, but may be disproved by direct observation, as it has been most completely by those monstrosities in which an anther is changed into a pistil, or even one part of the anther is thus transformed and bears ovules, while the other, as well as the filament, remains unchanged; - a case where the formaFIG. 403. Zamia integrifolia (the Coontie of Florida). 404. Section of the sterile ament. 405. One of its scales detached, bearing scattered anthers. 406. Fertile ament, from which a quarter-section is removed. 407. A pistillate fower, consisting of two ovules pendent from the thickened summit of the carpellary scale. 403. A drupaceous seed, from which a part of the pulpy outer portion is removed. 409. Vertical section through the seed (of the natural size), showing the pulpy outer coat, the hard inner integument, the albumen, and the embryo. THE OVULE. 309 tervention of a stigma, are naked and exposed, - except as they are more or less covered in Pines, Firs, &c., by the irnbrication of the carpellary scales into a sort of ament or cone (as in Fig. 176, &c.), - and are fertilized by the direct application of the pollen. Their seeds, accordingly, are destitute of a pod, or any similar inclosure. On this account they have received the name of GYMNOSPERMOUS PLANTS (111); literally, plants with naked seeds. SECT. VIII. THE OVULE. 561. Oulles, the rudiments of future seeds (420), at first appear like minute pulpy excrescences of the placenta; but long before the flower expands they have acquired a regular, and generally round or oval form. They are attached to the placenta by one extremity, either directly, or by a short stalk called the Funiculus, or Podosperm (Fig. 413, 414). As to number, they vary from one in each ovary, or in each cell of the compound ovary, to several or many upon each placenta. In the former case, they are said to be solitary; in the latter, they are definite when their number is uniform and not remarkably great, and indefinite, when they are too numerous to be readily counted. 562. As to situation and direction with respect to the cavity that contains them, ovules are said to be erect when they arise from the very bottom of the ovary; ascending, when fixed to the placenta above the base hand directed obliquely upwards; horizontal, when they project from the side of the cell, without turning either upwards or downwards (Fig. 263); pendulous, when their direction is downwards; and suspended, when they arise from the sumtion of the placenta from a process of the axis is out of the question. This hypothesis is, therefore, entirely untenable as a general theory; and whether -it affords a correct explanation of any form of central or basilar placentation must be left for further observation to determine. We will only remark, that even the appearance of a placenta or ovuliferous body in the apparent axil of a carpellary leaf no more proves that the body in question belongs to the axis, than that the appendage before the petals of Parnassia and the American Linden, or the stamen of a Rhamnus or Vitis, represents the axis of a branch instead of a leaf. As to the terminal naked ovule of the Yew, where the structures on any view, is reduced to the greatest possible simplicity, it is surely as probable that it answers to -the earliest formed, or foliar, portion of the last phyton, here alone developed, as to the cauline part, which so seldom appears in the flower. 310 THE FLOWER. mit of the ovary and hang perpendicularly in the cavity (Fig. 316). In the Thrift (Fig. 840), and in the Sumach, the ovule is singularly pendent from an ascending funiculus. These terms are applicable to the seed as well as to the ovule. 563. As to its structure and formation, the ovule appears as a mere excrescence, or papilla, of soft and homogeneous parenchyma, which soon acquires a definite form. This NucLEU,s, as it is called,. is the essential part of the'organ; in the Mistletoe it actually constitutes the whole, its ovule having no integuments of its own. A hollow place is formed in its interior about the time of flowering, in which the embryo at length appears. Most ovules, however, in the course of their growth acquire an envelope, or more commonly two envelopes. Only one envelope is seen in the ovule of the Walnut, where, after the nucleus is formed and has assumed its ovate shape, a circular ring appears around its base, which gradually enlarges into a sheath, but at length covers it like a sac, which, however, remains open at the apex. This orifice, which leads to the nucleus, and through which, indeed, the nucleus often protrudes, is called the FORAMEN or the MICROPYLE. In far the greater number of cases, a second envelope is formed outside of the first, beginning in the same way, though always later than the inner one, which, however, it eventually overtakes and incloses. The outer envelope, when both are present, becomes the exterior 410 413 integument or testa of the seed; and the inner, its tegmen or inner coat. Mirbel named the exterior coat of the ovule the PRIMINE, and the interior the SECUNDINE, names --— I —-- \ i K @) which are attended with the second coat is actually older d...... - 5iil,, t than the primine or first coat 411 412 44 inthe order of position. Both sacs are open at the apex, and the summit of the nucleus points FIG. 410. An orthotropous ovule. 411. Longitudinal section of the same, more magnified: a, the primine; b, the secundine; c, the nucleus; d, the chalaza. 412. An amphitropous ovule. 413. Three anatropous'ovules, with their funiculi, attached to a portion of the placenta. 414 One of the same, more highly magnified, exhibiting its cellular structure. 415. A campylotroprouLs ovule. THE OVULE. 311 directly towards the apertures. The orifice or foramen of the exterior integument is called the ExosToBIE (or outer mouth), that of the interior, the ENDOSTOME (or inner mouth). The coats of the ovule and the nucleus are distinct and unconnected, except at the base, or point of attachment to the funiculus, where they are all perfectly confluent: this point of union receives the name of the CHALAZA (Fig. 41 1, d). 564. Through the funiculus and chalaza the ovule derives its nourishment from the placenta; through the opening at the summit, the nucleus receives the influence of the pollen, which results in the production of the embryo. 565. Our description applies to the complete ovule in its simplest form, where no change in the position of parts takes place during its growth, the chalaza remaining next the placenta, with which the funiculus directly connects it, while the apex, represented by the foramen, or orifice of the coats, is at the opposite extremity (as in Fig. 410). Such an ovule, not being curved or turned from its normal direction, is called atropous (literally, not turned), or usually orthotropous (straight). This simple orthotropous form occurs in the Cistus Family (Fig. 550), and the Polygonum Family (Fig. 986), and in many others. 566. In the greater number of cases, however, a change of relative position takes place during the development of the ovule; consisting either in its complete inversion upon the funiculus that bears it, so that the orifice or apex is brought down by the side of the stalk and points towards the placenta, while the chalaza looks in the opposite direction (as in Fig. 413, 414, and also in Fig. 263, where such ovules are seen in their natural position in the ovary); or else the ovule curves upon itself, and thus brings down the apex near the funiculus (as in Fig. 416). In the former case, the ovule is anatropous, or inverted; in the latter, it is campylotropous, or curved. Campylotropous ovules are found in the Mignonette, in all Cruciferous and Caryophyllaceous plants, and in many others; but the anatropous form is by far the most common of all. 567. In anatropous ovules, the funiculus coheres firmly with that part of the surface which is applied to it; and in the ripe seed breaks away at the point where it is free from the integument, to which the adherent portion remains attached. The latter receives the name of RHAPHE; and appears in the form of a ridge, cord, or line, passing from the HILUM (as the scar left by the breaking 312 THE FLOWER. away of the funiculus from the seed is termed) to the chalaza, maintaining the communication between the interior of the ovule or seed and the placenta. The rhaphe is only found in the anatropous ovule, and serves to distinguish it; since in all others the hilum or scar exactly corresponds to the chalaza, while in this the two occupy opposite extremities of the seed; the chalaza, which is the real base, being by this inversion situated at the apparent apex, while the micropyle, or organic apex, is found next the hilum, or the apparent base. This is perfectly simple on the supposition that an anatropous ovule is produced by the mere adhesion of the funiculus to the whole length of one side of what would otherwise be an orthotropous ovule.* 568. What are called ampihitropous or heterotropous ovules, which are straight, with the chalaza at one end, the micropyle or apex at the other, and the hilum half way between the two (as in Fig. 412), arise from the adhesion of the funiculus for a short distance only, forming a rhaphe of only half the length of the ovule. As the free funiculus in such cases generally diverges at right angles from the axis of the ovule, so that its proper base and apex become lateral, these ovules or seeds are sometimes termed peltate, or transverse. 569. Campylotropous ovules (Fig. 415) differ from the orthotropous in being curved during their development, so that the -orifice or apex is brought into juxtaposition with the base; which in this case is both hilum and chalaza. 570. It is important to notice the situation of the orifice, or foramen, of the ovule, as it indicates the future position of the radicle of the embryo (631), which is invariably directed towards the foramen. Its situation with respect to the hilum varies in the different kinds of seeds: in those which arise from orthotropous ovules, it points in the direction exactly opposite the hilum (Fig. 453); in the anatropous form, it is brought close to the hilum, so that it is ordinarily said to point to it (Fig. 454-456); in campylotropous seeds, it is also brought round to the hilum; while in the amphitro. pous, it points in a direction nearly at a right angle with the hilum. * Thus, in most Cistacee, the ovules are orthotropous, but in one small genus (Fumana) the funiculus usually adheres to the side of the ovule, and renders it anatropous. On the contrary, sometimes anatropous'ovules become orthotropous in the seed, by the separation of the rhaphe from its face. ACTION OF THE POLLEN. 313 SECT. IX. FERTILIZATION AND FORMATION OF THE EMBRYO. 571. THE action of the pollen, by means of which the ovule is fertilized, is now satisfactorily known. The points still contro. verted mostly relate to the first step in the formation of the embryo. 572. The arrangement and adjustment of parts, mechanical and otherwise, which secure the application of the pollen to the stig. ma, are so extremely diversified in different plants, that we cannot undertake to give even a general account of them here. The adaptation is sometimes in the relative length of the floral organs in connection with the position of the flower, whether erect, inclined, or nodding; sometimes juxtaposition is effected through transient and often sudden movements, whether mechanical (by elasticity) or spontaneous, which will be mentioned in another place. Frequently the anthers open and the pollen is applied to the stigma while the parts are still approximated in the bud. In moncecious plants the staminate blossoms are commonly situated adjacent to the pistillate, or else raised above them, as in Indian Corn. In dicecious plants, as indeed in a vast number of others, much is left to the action of the winds, or of insects, which convey the pollen from one blossom to another; and the immense abundance of pollen, especially in moncecious and dicecious plants, greatly diminishes the chance of failure. The loose papillse, or short projecting hairs of the stigma, and especially the viscous fluid which at this time al. ways moistens its surface, serve to retain the grains of pollen on the stigma when they have once reached it. The following brief statement comprises the essential substance of what is known respecting the immediate 573. Action of the Pollen. The grain of pollen becomes turgid as it absorbs by endosmosis (37) the viscous moisture of the stigma: its inner membrane consequently extends, breaks through the scarcely extensible outer coat at some one point (or occasionally at two or three points, Fig. 419), and lengthens into a delicate tube, filled with the liquid and molecular matter (foville, 535) that the grain contains. This tube (Fig. 416-419), remaining closed at the extremity, penetrates the loose tissue of the stigma, and is prolonged downwards into the style, gliding along the interspaces between the very loosely disposed cells of the now moist conducting tissue (541), which extends from the stigma to the 27 314 FERTILIZATION. cavity of the ovary, and at length reaching the placenta or some other part of the interior of the ovary. 416 417 418 This prolongation into a tube, often many'/l'A hundred times the diameter of the pollengrain, is a true growth, after the manner of elongating cells (35, 97), nourished by the organizable moisture of the style which it imbibes in its course. Now the orifice of the ovules, or a projection of the nucleus beyond the orifice, is at this time brought into contact with, or proxy419 imity to, that portion of the walls of the ovary from which the pollen-tubes emerge; and a pollen-tube thus reaches the nucleus, in which the nascent embryo subsequently appears. In the Gymnospermous plants (Coniferm and Cycadaceae, 560), the pollen-tubes grow on and immediately penetrate the nucleus of the ovule, just as they do the stigma in ordinary plants. 574. The pollen-tubes may be readily inspected under the microscope in many plants; in none more readily than in the Asclepias, or Milkweed, one of the plants in which this subject was so admirably investigated-by Mr. Brown. In that family, the pollengrains of each cell of the anther (Fig. 420) cohere in a mass; and these pollen-masses, dislodged from their cells (Fig. 421, 422), usually by the agency of insects, and brought into proximity with the base of the stigma, protrude their tubes in great abundance, and of a size which renders them visible with a very moderate magnifying power. They may readily be seen to penetrate the base of the stigma, as in Fig. 423, and separate grains with their tubes may be detached from the mass (Fig. 425, 426); but to trace their course down the style (as in Fig. 424), and to their final destination, requires much tact in manipulation and the best means of research. The formation of the pollen-tube commences in some cases almost immediately upon the-application of the pollen to the stigma; in many plants it is not perceptible until after the lapse of ten to twenty, or even thirty-six hours. The rate of the growth FIG. 416. A pollen-grain of Datura Stramonium, emitting its tube. 417. Pollen-grain of a C)nvolvulus, with its tube. 418. Other pollen-grains, with their tubes, less strongly mnagnified. 419. A pollen-grain of the Evening Primrose, resting on a portion of the stigma, into which the tube emitted from one of the angles penetrates; the opposite angle also emitting a pollentube. FORMATION OF THE EMBRYO. 315 of the pollen-tube down the style is also very various in different plants. In some 420 421 422 426 species, a week or more elapses before they have passed through a style even of a few lines in length. In others, a few hours suffice for their' passage through!.i even the longest styles, such as those of Colchi423 424 425 cum and Cactus grandiflorus. After the pollen-tubes have penetrated the stigma, the latter dries up, and its tissue begins to wither or die away, as likewise does the body of the pollen-grain, its contents being transferred to the pollen-tube, the lower part of which is still in a growing condition. 575. Formation of the Embryo, Before the pollen-tube reaches the ovule, the nucleus of the latter exhibits a cavity in its interior, towards the apex. In the Mistletoe, this cavity is said to be a mere hollowing out, produced by absorption, and having no evident lining membrane. Usually, however, it results from the special growth of a particular cell, which expands into a bladder or closed sac of considerable size lining the cavity,: sometimes remaining inclosed in the tissue of the nucleus towards its summit or orifice, sometimes displacing the upper part of the nucleus entirely, or even projecting through the micropyle. This is the sac of the amnios of Mr. Brown, the embryo-sac (sac embryonaire) of the French botanists.* In this sac the embryo is formed. * "The ovule is produced by the development of one cell of the placenta, FIG. 420. A back view of a stamen of the common Milkweed (Asclepias), the appendage cut away. 421. A stamen more magnified, with the two pollen-masses cohering by their caudicles, each to a gland from the summit of the stigmatic body, to which a pollen-mass from an adjacent anther is already adherent. 422. A pair of detached pollen-masses (each from a different anther) suspended by their caudicles from the gland. 423. Some of the pollen-masses, with their tubes penetrating the stigma (after Brown). 424. A section through the large stigmatic body and a part of the summit of one of the styles, showing the course of the pollen-tubes. 425, 426. Pollen-grains with their tubes, highly magnified. (The structure of these singular flowers will be mnore fully explained under the order Asclepiadacece.) 316 FERTILIZATION. 576. From Linnmeus downwards, until recently, it was universally supposed that the embryo originated in the ovule, which was in some way or other fertilized by the pollen. Since the discovery of the pollen-tube in 1824 by Amici, and its actual penetration to the nucleus of the ovule by Mr. Brown, however, the late Professor Horkel and his nephew, Schleiden, -who traced it quite to the embryo-sac, - have propounded a very different view. Schleiden and his followers strongly maintain, as the result of direct observation, that the apex of the pollen-tube itself becomes the embryo; that on reaching the embryo-sac it indents the latter, pushing it forwards so as to reverse a portion on itself, in which cavity the apex'of the pollen-tube swells into an oval or globular form, and its contents are transformed into new cells, which, as they grow and multiply, shape themselves into the embryo. Or, according to other observations, it is maintained that the apex of the pollen-tube pierces the embryo-sac and developes into the embryo in its interior, in the manner last stated. It is now unnecessary to adduce the details of the researches, or the theoretical considerations, by which this hypothesis was supported. For, besides the researches of Mir. bel, in 1839, the investigations made, between the year 1846 and the present time, by Amici, Mohl, K. Miiller, Unger (who had maintained the hypothesis in question), Hoffmeister, Henfrey, and Tulasne, have completely overthrown the foundations on which it rested; by proving, - 1st. That'the embryonal vesicle, from which the embryo is developed, exists in the embryo-sac, in some cases at least, before the pollen-tube has reached the ovule; so that it cannot owe its origin to the pollen-tube, directly or indirectly, and still less can it be a prolongation of it. 2d. That the end of the pollen-tube is, in many cases, applied to the exterior of the embryo-sac at a point distinguishably, and often considerably, distant from that where the embryo is developed within.* into a cellular body, which essentially consists of a central row of cells, inclosed by a variable number of layers of cells. One of the cells of the central row enlarges and displaces a varying quantity of the rest of the tissue of the ovule. This is the emlbryo-sac." Hoffmeister, as rendered by Henfrey, Bot. Gazette, 1, p. 127. * The latest memoir on this subject, that of Tulasne (in Ann. Sci. Nat. for July and August, 1849), is remarkable not only for its thoroughness and its admirable illustrations, but because the author here points out and corrects the error into which he had formerly fallen, which led him to conclude that FORMATION OF THE EMBRYO. 317 577. The general result& which all these recent investigations conspire to establish are these: —The pollen-tube, entering the orifice of the ovule, comes directly in contact with the apex of the embryo-sac, penetrating the layer of cells, if there be any, which covers it. Sometimes its extremity slightly indents it; often it glides downwards along the surface of the sac for a little distance; in either case it barely adheres to the membrane, makes no further growth, and after a time begins to wither away. Just before the pollen-tube reaches the embryo-sac, a portion of the protoplasm which the latter contains is attracted into its upper end, next the micropyle. In this protoplasm nuclei appear, usually to the number of three, but sometimes only one, and develope into as many cells. These are the germinal vesicles, or embryonal vesicles, one of which gives rise to the embryo. The further development of the germinal vesicle begins shortly after the meeting of the pollen-tube with the embryo-sac. The material effect of the former upon the germinal vesicle is supposed to take place by the transudation or endosmotic transference of part of its fluid contents through the membranes of each, and of the embryo-sac between them, into the germinal vesicle, which is thus fertilized; the vitally active contents of two cells of different origin being thus commingled, as in the simpler process of conjugation in the lower Cryptogamous plants (102). Thus endued with new force, the embryonal vesicle, which now adheres to the apex of the embryosac, commences an active development; it elongates downwards, or from its free extremity; minute granular matter appears in the interior, which was before perfectly clear and transparent; soon a few transverse partitions are seen, and it is thus converted into a chain of cells, each of which contains a distinct nucleus. This body, which may attain considerable elongation, by the conthe end of the pollen-tube actually penetrates the embryo-sac, and gives rise to the embryonal vesicle. — Hoffmeister asserts (as rendered by Henfrey), that although the pollen-tube generally rests upon the outside of the embryosac, yet in a very few isolated cases it perforates it; but "even when the pollen-tube thus penetrates into the interior of the embryo-sac, its end remains perfectly closed, and the membrane of the germinal vesicle quite uninjured: in no case can a direct passage of the contents of one into the other take place. The impregnation is the result solely of an endosmotic exchange of the fluid contents." Henfrey, Bot. Gazette, 1. c. 27 * 318 FERTILIZATION. tinued elongating growth and division of the terminal cell (32- 34), becomes the Suspensor. The lowest of its cells enlarges, and, through cell-formation by division, is converted into a cellular body: this is the nascent Embryo (Fig. 430). As it grows it soon 427 428 430 431 432 433 434 429 begins to assume its proper form. In a Dicotyledonous plant, as is rudely shown in the accompanying figures, the end farthest from the suspensor begins to be two-lobed (Fig. 432); the lobes increase by ordinary cellular growth, and form the Cotyledons (Fig. 433, 434); the opposite extremity is of course the Radicle. The suspensor usually disappears before the embryo has attained its full development. A monocotyledonous embryo has this end undivided. In the polycotyledonous embryo of Pines, &c., the budding apex divides successively as it grows into four, six, or more lobes, each of which becomes a cotyledon.* * The principal points of discordance in the later investigations are connected with the embryonal vesicle. According to Mohl, Henfrey, &c., in Orchis Morio as many as three germinal vesicles exist within the apex of the embryo-sac, anterior to fertilization, as minute free cells, formed from so many nuclei; one (or sometimes more than one) of them enlarges soon after the polFIG. 427.' Plan of a vertical section of the pistil of a Polygonum, and of the erect orthotropous ovule it contains, at the period of fertilization: the grains of pollen resting on the stigma have sent their tubes down the style to the mouth of the ovule: and the nascent embryo-sac is seen at the apex of the nucleus. 428. A pollen-grain detached, with its tube. 429. Plan of the vertical section of the ovule more magnified, and at a later period: the nascent embryo with its suspensor seen in the embryo-sac. 430. The nascent embryo with its suspensor, more magnified. 431- 433. Views of the successive developmnent of the embryo. 434. The embryo as it exists in the seed. FORMATION OF THE EMBRYO. 319 578. Through the fertilization of as many germinal vesicles, two or more embryos are frequently found in the same seed, in the Orange, the Onion, and many other cases. There are generally two embryos in the seed of the Mistletoe; and there is constantly a plurality of embryos in Pines and other'Gymnospermous plants (560), though all but one are more commonly abortive or rudimentary." 579. Contemporaneous with the production of the embryo, a cell-formation takes place in the protoplasm contained in the embryo-sac, soon filling the space with an exceedingly soft and delicate parenchyma, proceeding from the wall of the sac inwards. Sometimes the enlarging embryo, as it grows, obliterates this delicate, half-fluid tissue, is nourished by its contents, and at maturity len-tube has reached the embryo-sac, and developes in the manner above described. According to Hoffmeister, also, in CEnothera two or three germinal vesicles appear a long time before fertilization, from free cell-nuclei, forming so many delicate, free cells, one of which being fertilized developes into the embryo in the manner already described, while the others perish. The results of the more recent researches of Tulasne (upon the embryogeny of Scrophulariacee, Campanulacee, and Cruciferae) principally differ in this; - that he was unable to detect any embryonal vesicle before the pollen-tube had penetrated to the embryo-sac; and afterwards he finds only one, mostly of an elongated form, and always from the first attached by one end to the inside of the wall of the embryo-sac, at a point near that to which the pollen-tube is applied externally. He is led to conclude that the embryonal vesicle originates at this point, either from a sort of "' d6doublement' of the membrane of the embryo-sac, or from a nucleus adherent there; and he inclines to think that its formation does not precede the conjunction of the pollen-tube with the embryo-sac, but that it is the first visible result of this union. And, calling to mind that Unger met with free cells in the unimpregnated embryo-sac of Hippuris vulgaris, formed from free and floating nuclei, but which were always resolved before the appearance of the real- embryonal vesicle, he suggests that the free cells seen by Hoffmeister may be of the same kind. M. Tulasne plausibly considers that the embryo-sac is the cell which receives the fluid of the pollen, and that in its cavity, therefore, the contents of two cells are commingled; the result of which union gives rise to the embryonal vesicle, or potential embryo, endowed from the first with the new specific force which it manifests in its ulterior development. We can only refer the inquirer to this original memoir; an abstract can hardly be made intelligible to the uninstructed reader, without the plates. * In Coniferne (at least in the Pines) the embryo is not developed from the embryonal vesicle until long after the cavity of the embryo-sac is filled with the cellular tissue that forms the albumen of the seed; and its formation is in other respects peculiar. 320 THE FRUIT. fills the integuments of the seed completely. In other cases, the growth of the embryo in the seed is arrested before it fills the embryo-sac: then this new tissue that surrounds it, solidified by internal deposition, or with its cells filled with starch, &c., becomes permanent, and forms the albumen of the seed (627); or sometimes this cellular growth and deposit of nutritive matter take place in the persistent body of the nucleus of the ovule, external to the embryo-sac, as in Nymphuea. 580. With the development of the embryo, the ovule becomes the seed. Its further history should follow that of the fruit. CHAPTER X. OF THE FRUIT. SECT. I. ITS STRUCTURE, TRANSFORMIATIONS, AND DEHISCENCE. 581. THE fertilized ovary soon begins to increase in size, and commonly to undergo some change in texture; either becoming dry and membranaceous, crustaceous, or even woody, or else by an opposite change becoming fleshy, pulpy, or juicy: it is now called 582. The Pericarp, or Seed-vessel. The pericarp and the seeds it incloses together constitute the FRUIT; a term which has a more extensive signification in botanical than in ordinary language; being applied to all mature pistils, of whatever form, size, or texture. The fruit likewise comprises whatever organs may be adnate to the pistils (465). Such incorporated parts, like the fleshy calyx of the Apple and Quince (Fig. 685, 688), sometimes make up the principal bulk of the fruit. 583. It may be remarked that a similar accumulation of fleshy or pulpy matter may take place in adjacent organs wholly unconnected with the pistil; as in the free calyx of the Strawberry Blite (Fig. 993, 995), which becomes greatly thickened, red, and juicy; and in the Wintergreen (Fig. 795 -797), where the calyx, at first small and membranaceous, and entirely free from the ovary, gradually enlarges after flowering, and is transformed into a red, pulpy ITS STRUCTURE AND TRANSFORMIATIONS. 321 berry, surrounding the true fruit, which is a small and dry pod. The pulp of the strawberry, moreover, is no part of the proper fruit; but consists of the enlarged and juicy receptacle, or apex of the flower-stalk, bearing the numerous small and dry grains, or true fruits, upon its surface. The bread-fruit and the pine-apple are still more complex, being composed of a whole head or spike of flowers, with their bracts and common receptacle all consolidated into a single fleshy mass. The mulberry is a multiple fruit of the same kind (Fig. 244), in which the component parts may readily be identified. The structure of the fig, which may be likened to a mulberry or a bread-fruit turned inside out, has already been explained (395, Fig. 241- 243). 584. Under the general name of fruit, therefore, even as the word is used by the botanists, things of very different structure or of different degrees of complexity are confounded. These need to be properly distinguished. For the present, we will consider the fruit in the stricter sense, as consisting of.the matured pistil alone, whether simple or compound, either free or in combination with any floral organs, such especially as the tube of the calyx, which, being adnate to the ovary in the flower, is necessarily incorporated with the pericarp in fructification. 585. The pericarp, being merely the matured pistil, should accord in structure with the latter, and contain no organs or parts that do not exist in'the fertilized ovary. Some alterations, however, often take place during the growth of the fruit, in consequence of the abortion or obliteration of parts. Thus, the ovary of the Oak (Fig. 1044) consists of three cells, with a pair of ovules in each; but the acorn, or ripened fruit, presents a single cell, filled with a solitary seed. In this case, only one ovule is matured, and two cells and five ovules are suppressed. The ovary of the Horsechestnut and Buckeye is similar in structure (Fig. 659 - 661), and seldom ripens more than one or two seeds: but the abortive seeds and cells may be detected in the ripe fruit. The ovary of the Birch (Fig. 1053) is two-celled, with a single ovule in each cell: the fruit is one-celled, with a solitary seed; one of the ovules or young seeds being uniformly abortive, while the other in enlarging pushes the dissepiment to one side, so as gradually to close the empty cell (as in Fig. 1056). The Elm presents a similar case (Fig. 1013, 1014); and such instances of suppression in the fruit of parts actually extant in the ovary are not uncommon. 322 THE FRUIT. 586. On the other hand, the fruit sometimes exhibits more cells than the pistil; as in the two-celled ovary of Datura Stramonium, which soon becomes spuriously four-celled by the projection of the placentre on one side, so as to reach and cohere with a projection of the dorsal suture on each side. So, also, many legumes are divided transversely into several cells, although the ovary was onecelled with a continuous cavity in the flower. 587. Ripening. The growing fruit attracts its food from surrounding parts in the same manner as leaves. When the pericarp preserves its green color and leaf-like texture (as in the Pea, &c.), it is furnished with stomates, and acts upon the air like ordinary leaves. Those which become fleshy or juicy acquire that condition by the accumulation of elaborated sap in their tissue,; where it undergoes various transformations, analogous to those which take place in other parts of the plant. 588. Most pulpy fruits are tasteless or slightly bitter during their early growth; at which period their structure and chemical composition are similar to that of leaves, consisting of cellular with some woody tissue; and their action upon the atmosphere is likewise the same (346). In their second stage, they become sour, from the production of acids (353); such as tartaric acid in the grape; the citric in the lemon, orange, and the cranberry; the malic in the apple, gooseberry, &c. At this period they exhale very little oxygen, or even absorb that substance from the surrounding air. The acid increases until the fruit begins to ripen, when it gradually diminishes, and sugar is formed. In the third stage, or that of ripening, the acids, as well as the fibrous and cellular tissues, gradually diminish as the quantity of sugar increases; the latter being produced partly at the expense of the former, by transformations which are very intelligible to the chemist, and which he can partially imitate. A chemical change, similar to that of ripening, takes place when the green fruits are cooked; the acid and the mucilaginous or other products, by the aid of heat reacting upon each other, are both converted into sugar. Mingled with the saccharine matter, a large quantity of vegetable jelly (83) is also produced in most acidulated pulpy fruits, existing in the form of pectine and pectic acid. These arise from the reaction of the vegetable acids during ripening upon the dextrine and other assimilated neutral products accumulated in the fruit. 589. Frequently different parts of the thickness of the pericarp ITS DEHISCENCE. 323 undergo dissimilar changes during fructification and ripening; the inner portion hardening while the exterior becomes fleshy, or vice versa. When the walls of a pericarp are thus distinguished into two separable portions, the exterior receives the name of EPICARP, or EXOCARP, and the interior that of ENDOCARP. When the exterior part is fleshy or pulpy, as in the peach (Fig. 447) and plum, it is termed the SARCOCARP; and the hard shell or endocarp which contains the seed is called the PUTAMEN. 590. Often the walls of the pericarp preserve a nearly uniform texture throughout,,becoming either entirely membranaceous, as in many capsules or pods; or fleshy, as in the berry; or indurated throughout, as in the acorn. 591. A part, and in membranaceous or other dry fruits the whole, of the nutritive matter collected in the pericarp is absorbed by the placenta (543) and conveyed to the seed; where the portion which is not consumed in its growth is stored up, either in the embryo or around it, as a provision for its future development in germination. 592. Certain fruits remain closed and entire at maturity, as the acorn, apple, grape, &c.; when they are said to be indehiscent. Others separate (wholly or partially) into several pieces, and dis. charge the seeds; sometimes bursting irregularly, but commonly opening in a uniform and regular manner for each species; these are said to be dehiscent. 593. Dehiscence, when regular and normal, takes place in a vertical direction, by the opening of one or both sutures (541), or by the disjunction of confluent parts (546). The pieces into which a dehiscent pericarp separates are called its valves. 594. A simple carpel dehisces eitherby the opening of the ventral suture, as in the Columbine, the Peony, &c.; or by the dorsal suture also, as in the Pea and Bean. 595. The dehiscence of a pod which results from the union of two or more carpels may take place by the separation of the constituent carpels fiom each other, and by the opening of the ventral sutures, as in the Colchicum (Fig. 1115), Rhododendron (Fig. 793), and in the diagram (Fig. 435). In this case, the pericarp splits through the dissepiments; whence the dehiscence is said to be septicidal. Sometimes the carpels, although separating from each other in this manner, remain closed or indehiscent, as in the Mad. der (Fig. 478), the Vervain (Fig. 869), &c.: the separable car 324 THE FRUiT. pels are often termed cocci; and the fruit is said to be dicoccous, tricoccous, &c., according to their number. a b c 435 436 437 596. Otherwise, the dehiscence may take place by the dorsal suture of each component carpel opening directly into the back of the cells, when the perica-rp is more than one-celled; whence this dehiscence is said to be loculicidal (as in Fig. 621, 908, 919, and the diagram, Fig. 436). In such cases the dissepiments remain attached to the middle of each valve. In the Helianthemum (Fig. 549), and many other plants, we have an example of loculicidal dehiscence in a one-celled pericarp with parietal placentae; which in this case are borne directly on the middle of each valve. On the other hand, septicidal dehiscence in a similar pericarp is at once recognizable by the placentae occupying the margins of the valves. 597. Sometimes the placentae, being firmly coherent with each other, break away from the dissepiments and remain united in the axis, forming a column, or columella, as in Rhododendron (Fig. 793), Polemonium, and Collomia (Fig. 908), &c. 598. Occasionally the dissepiments remain coherent with the axis, while the valves separate from them, as in the Morning-Glory (Fig. 924), and in the diagram, Fig. 437. This modification is termed septifragal dehiscence. In like manner, parietal placentae occasionally separate from the valves, forming what has been termed a replum; as in Cruciferous plants, and in the Poppy Family. The same,name is applied to the persistent. border of the simple pod of Mimosa (Fig. 441). 599. Instead of splitting into separate pieces, the sutures of the pericarp sometimes open for a short distance at their apex only, as in some Chickweeds, and in Tobacco (Fig. 936), and the Primrose (Fig. 826); or by mere points or pores, as in the Poppy. FIG. 435 - 437. Diagrams of the dehiscence of capsules (horizontal sections); 435, the septicidal; 436, the loculicidal; 437, the septifragal. ITS KINDS. 325 600. In a few cases the opening takes place by a transverse line passing round the pericarp across the sutures, so that the upper part falls off like a lid; as in Anagallis (Fig. 830), the Plantain (Fig. 833), the Henbane (Fig. 941), and the Purslane (Fig. 568). In Jeffersonia, the opening extends only half round the pericarp, and the lid remains attached by the other side, as by a hinge. This anomalous dehiscence is termed circumcissile or transverse. SECT. II. THE KINDS OF FRUIT. 601. THE various kinds of fruits have been minutely classified and named; but the terms in ordinary use are not very numerous. A rigorously exact and particular classification, discriminating be. tween the fruits derived from simple and from compound pistils, or between those with and without an adnate calyx, becomes too recondite and technical for ordinary use in descriptive botany. Taking first the SIMPLE FRUITS, namely, those that result from single and separate flowers, the principal sorts may be briefly indicated as follows. 602. A Follicle is a fruit formed of a single carpel, dehiscing by the ventral suture (541); as in the Larkspur and Columbine (Fig. 483), and the Milkweed (Fig. 460). 439 442 446 438 a 440 441 443 444 445 603. A Legume, or Simple Pod, is a fruit formed of a single carFIG. 433. Open legume of the Pea: a, section of the ovary. 439. Embryo, with cotyledons laid open. 440. Loment of Desmodium. 441. Loment of Mimosa: b, one of its dehiscent joints which has fallen away from the persisting border or frame (replum), seen in 442. 443. The jointed indehiscent legume of Sophora. 444. A legume of Astragalus, cut across near the summit, to show how it becomes partly or entirely two-celled by the introflexion of the dorsal suture. 445. Similar view of a legume of Phaca, where the ventral suture is somewhat introflexed. 446. A legume of Medicago lupulina, spirally coiled into a globular figure. 28 326 THE FRUIT. pel, and dehiscent by both the ventral and dorsal sutures, so as to separate into two valves; as in the Bean and Pea. The name is extended to the fruit of all Leguminous plants (768), whatever be their form, and whether dehiscent or not. A legume, divided into two or more one-seeded joints, and falling to pieces at maturity, is called a LOMENT, or lomentaceous legume. Some of the various kinds of legume are shown in the foregoing figures. 604. A Drupe, or Stone-Fruit, is a one-celled, one or two seeded simple fruit which is not dehiscent, with the inner part of the peri. carp (endocarp, or stone) hard or bony, while the outer (exocarp, or sarcocarp) is fleshy or pulpy. It is the latter which in our fruits so readily takes an increased development in cultivation. The name is strictly applicable only to fruits of this kind produced by the ripening of a single carpel; as the plum, apricot, ~~\;ql, f:it:\i Gd peach (Fig. 447), &c.; but is extended in a general way to all one-celled and one or two seeded fruits of similar ~",'~?.";:3i X' / texture resulting from a coinpound ovary, and even to 448 447 those of several bony cells inclosed in pulp, as in the Dogwood (Fig. 240, b). The latter, however, are more strictly said to be drupaceous, or drupe-like fruits. 605. An Achenium is a small and dry indehiscent one-seeded pericarp, formed of a single carpel; as in the Buttercup, and the allied genera Anemone and Clematis, where they are often terminated by the persistent and often plumose style, in the form of a long tail. In the Rose (Fig. 684), the achenia are borne on the hollow expansion of the receptacle which lines the fleshy tube of the calyx: itn Calycanthus the achenia (Fig. 693) are similarly inclosed in a sort of false pod (Fig. 691, 695) of the same nature as the rose-hip, while in the Strawberry (Fig. 678, 679) they are scattered on the surface of the enlarged and pulpy receptacle; where, as in many other cases, they are commonly mistaken for seeds. But they are all furnished with styles, which show their nature; and on cutting them across, we observe the real seed loose FIG. 447. Vertical section of a peach. 448. An almond; where the exocarp, the portion of the pericarp that represents the pulp of the peach, remains thin and juiceless, and at length separates by dehiscence from the endocarp, or shell. ITS KINDS. 327 in the cell. These seed-like fruits were incorrectly called naked seeds by the earlier botanists. The strawberry, raspberry, &c., therefore, taken as a whole, are not simple, but aggregate fruits. In the Raspberry and Blackberry (Fig. 680), the achenia are changed into little drupes (604). The name of achenia is also applied to similar one-seeded fruits resulting from a one-celled ovary, even when formed of more than one carpel, and invested by the calyx-tube; as that of the Sunflower and all Composite or Syngenesious plants, where the limb of the calyx, assuming a variety of unusual forms, is termed the Pappus (Fig. 776). 606. A Cremocarp consists of a pair of achenia placed face to face, and invested by the calyx-tube; which, when ripe, separate from each other, or from a slender central axis, called'the Carpophore; as in all Umbelliferous plants (Fig. 735-737), to which, indeed, the name is restricted. Each separate carpel, or half-fruit, is termed a HEIIICARP, or MERICARP, and its inner face the Commissure. 607. A Caryopsis is a thin and membranaceous pericarp, like an achenium, but adherent to the surface of the seed, so as to be inseparable from its proper covering. The grains of Wheat, Maize, and most Grasses, are examples (Fig. 463-465). 608. A Utricle is a caryopsis which does not adhere to the seed; or it is an achenium or other one-celled and one-seeded fruit, with a thin and membranous loose pericarp, as in Chenopodium and Amarantus. 609. A Nut is a hard one-celled and one-seeded indehiscent fruit, like an achenium, but usually produced from an ovary of two or more cells with one or more ovules in each, all but a single ovule and cell having disappeared during its growth (585); as in the Hazel, Beech, Oak (Fig. 1044), Chestnut, Cocoa-nut, &c. The nut is often inclosed or surrounded by a kind of involucre (393), termed a Cupule; as the cup at the base of the acorn, or the burr of the chestnut. 610. A Samara is a name applied to a nut, or achenium, having a winged apex or margin; as in the Birch and Elm (Fig. 1014). The fruit of the Maple consists of two united samarme (Fig. 653). 611. A Berry is an indehiscent fruit which is fleshy or pulpy throughout; as the grape, gooseberry (Fig. 707), and persimmon (Fig. 818). The orange, sometimes termed a HESPERIDIUM, is merely a berry with a leathery rind. 328 THE FRUIT. 612. A Pome, such as the apple, pear, and quince (Fig. 685688), is a fruit composed of two or more papery, cartilaginous, or bony carpels, usually more or less involved in a pulpy expansion of the receptacle or disc, and the whole invested by the thickened and succulent tube of the calyx. It may be readily understood by comparing a rose-hip with a haw, a quince, or an apple. 613. A Pepo is an indehiscent fleshy or internally pulpy fruit, composed usually of three carpels, invested by the calyx, and with a firm rind; as the cucumber, melon, and gourd. Its proper structure, which has been variously misconceived, may readily be gathered from a cross-section of a very young melon or gourd (Fig. 449). The three large placentae project from the axis to the parietes of the cell, where their two constituent parts, more or less separated and recurved, bear the ovules. As the ovary enlarges, the F. ends of the placentae usually cohere with the contiguous walls, and the thin dissepiments are at the same time obliterated; so that the fruit presents the deceptive appearance of a three-celled (or, by obliteration of the axis, a one-celled) pericarp, 449: /:/ with abnormal parietal placenta. Sometimes the placentae are parie449 450 tal; in that case they are revolute without meeting or cohering in the axis. 614. A Capsule is a general term for all dry and dehiscent pods resulting from a compound ovary, whether opening by valves (593, Fig. 621, &c.), or bursting irregularly, as in Lobelia, or shedding the seeds through chinks or pores, as in the Poppy. 615. A Silique is a two-valved capsule, rendered two-celled by a false partition stretched between the parietal placentae (552), from which the valves separate; as in all Cruciferous plants (Fig. 527), to which family it is confined. A short and broad silique is called a SILICLE; as in the Shepherd's Purse or Capsella (Fig. 532). 616. A Pyxidium, or Pyxis, is a capsule that opens transversely by a lid or cover, as already explained (600). 617. Anthocarpous Fruits are those which, in addition to the periFIG. 449. Section of the ovary of the Gourd; and 450, a diagram of one of its constituent carpels. ITS KINDS. 329 carp, have an accessory covering derived from some exterior organ, which, however, does not cohere with the ovary in the fruit; as the nut-like fruit of Mirabilis, the hard outer envelope of which is the indurated and persistent base of the tube of the calyx, which was perfectly free in the blossom. And the berry-like fruit of Shepherdia consists of a fleshy calyx-tube, inclosing a free nut-like pericarp. Instances of this kind are common among what are called 618. Multiple or Collective Fruits; or those which result from the aggregation of several flowers into one body or mass. They are, in fact, dense forms of inflorescence, with the fruits or floral envelopes matted together or coherent with each other; as in the pineapple, the mulberry (Fig. 244), &c. The grains of the latter are not the ovaries of a single flower, like those of the blackberry (Fig. 680), but belong to as many separate flowers; and the pulp of these belongs to the floral envelopes instead of the pericarp (583). The fig results from a multitude of flowers concealed in a hollow flower-stalk, if it may be so called, which becomes pulpy and edible (Fig. 241-243). Thus the fruit seems to grow directly from the branch without being preceded by a flower. In the Partridgeberry (Mitchella repens), and in several species of Lonicera (Fig. 741), the ovaries of two flowers are uniformly united, so as to form a double berry; just as twin apples or cherries are sometimes accidentally produced. 619. A Cone, or Strobile, is a collective fruit of the Pine and Cycas Families (Fig. 395, 403); each scale representing an open carpel (375), bearing one or more naked seeds. 620. The cone of a Magnolia (Fig. 489) is, however, entirely different, consisting of the numerous aggregated carpels of a single flower, crowded and persistent on an elongated receptacle. 29 " 330 THE SEED. CHAPTER XI. OF THE SEED. SECT. I. ITS STRUCTURE AND PARTS. 621. The Seed, like the ovule (561), of which it is the fertilized and matured state, consists of a NUCLEUS, usually inclosed within two INTEGUMENTS. 622. Its Integuments. The outer, or proper seed-coat, corresponding to the exterior coat (563) of the ovule, is variously termed the EPISPERM, SPERMODERM, or more commonly the TESTA (Fig. 451, b). It varies greatly in texture, from membranaceous or papery to crustaceous or bony (as in the Papaw, Nutmeg, &c.), and also in form; being sometimes closely applied (conformed) to the nucleus, and in other cases loose and cellular (as in Pyrola, Fig. 810, and Sullivantia, Fig. 725), or expanded into wings (as in the Catalpa and Bignonia), which render the seeds buoyant, and facilitate their dispersion by the wind; whence winged seeds are only met with in dehiscent fruits. For the same purpose, the testa is sometimes provided with a tuft of hairs at one end, termed a Coma; as in Epilobium, Asclepias, or Milkweed (Fig. 963), and Apocynum (Fig. 954). In the Cotton-plant, the whole testa is covered with long wool. It should likewise be noticed, that the integument of numerous small seeds (and also seed-like achenia) is furnished with a coating of small hairs containing spiral threads (one form of which is represented in Fig. 31), and usually appressed and confined to the surface by a film of mucilage. When the seed is moistened, the mucilage softens, and these hairs shoot forth in every direction. They are often ruptured, and the extremely attenuated elastic threads they contain uncoil, and are protruded in the greatest abundance to a very considerable length. This minute mechanism subserves an obvious purpose in fixing these small seeds to the moist soil upon which they lodge, when dispersed by the wind. Under the microscope, these threads may be observed on the seeds of most Polernoniaceous plants, and the achenia of Labiate and Composite plants, as, for example, in many species of Senecio, or Groundsel. 623. The inner integument of the seed, called the TEGMEN or ITS STRUCTURE AND PARTS. 331 ENDOPLEURA, although frequently very obvious (as in Fig. 451), is often indistinguishable from its being co5 — t -l herent with the testa, or else altogether adJ;${S~ wanting. Nor when present does it always ea:, l: originate from the secundine or inner coat of the ovule (563). In the Hypericum 451 452 Family (Fig. 454), in the Pea Family, and probably in a great many other cases, especially where it is tumid or fleshy, or where it adheres firmly to the albumen, it doubtless consists of the remains of the nucleus of the ovule, or of the embryo-sac. 624. The stalk of the seed, as in the ovule from which it originated, is called the FUNICULUS (Fig. 452). The scar left on the face of the seed by its separation from the funiculus at maturity is termed the HILMrrr. The relation of the hilum to the chalaza, micropyle (563), and other parts of the seed, has been sufficiently indicated when considering the structure of the ovule. The chalaza and rhaphe (567), when present, are commonly obvious in the mature seed, as well as in the ovule (Fig. 455, b). The terms orthiotropous, anatropous, campylotropous, &c., originally applied to the ovules, are extended to the seeds which result from them; so that we may say, Seeds anatropous, as well as Ovules anatropous, &c. 625. Aril (Arillus). Some seeds are furnished with a covering, usually incomplete and of a fleshy texture, wholly exterior to their proper integuments, arising from an expansion of the apex of the seed-stalk, or funiculus, or of the placenta itself when there is no manifest seed-stalk. This is called the ARIL, It, forms the pulpy envelope of the seed of Podophyllum, Euonymus, and Celastrus, or a mere lateral scale in Turnera, or a tough, lacerated body, known by the name of mace, in the Nutmeg. In the White Water-Lily it is a thin, cellular < / bag, open at the end (Fig. 453). It does not appear in the 453 ovule, but is developed subsequent to fertilization, during the growth of the seed. Of the same nature is the CARUNCLE which grows from the hilum in Polygala, forming a loose lateral appendFIG. 451. Vertical magnified section of the (anatropous) seed of the American Linden: a, the hilum; b, the testa; c, the tegmen; d, the albumen; e, the embryo. 452. Vertical section of the (orthotropous) seed of Helianthemum Canadense: a, the funiculus. FIG. 453. Seed of Nymphsea (White Water-Lily), in its membranaceous sac-like aril. 332 THE SEED. age. Strictly speaking, it is to be distinguished from the STROPHIOLE, the latter being a cellular growth from the micropyle; but the two are not well discriminated. A similar cellular growth takes place on the rhaphe of the Bloodroot; of the Prickly Poppy, and of Dicentra, forming a conspicuous crest on the whole side of the seed. 626. The Nucleus, or kernel of the seed, consists of the ALBUMEN, when this substance is present, and the EMBRYO. 627. The Albumen (Fig.'451, d, 456,f) -also variously named the PERISPERM or the ENDOSPERM - which forms the floury part of the e seed in our various kinds of grain, consists of whatever portion of the tis45 a,55 a 456 sue of the ovule persists, and becomes loaded with nutritive matter accumulated in its cells, —sometimes in the form of starch-grains principally, as in wheat and the other cereal grains, sometimes as a continuous, often dense, incrusting deposit, as in the cocoa-nut, the date, the coffee-grain, &c. When it consists chiefly of starchgrains, and may readily be broken down into a powder, it is said to be farinaceous, or mealy, as in the cereal grains generally, in buckwheat, &c. When a fixed oil is largely mixed with this, it becomes oily, as in the seed of the Poppy, &c.; when more compact, but still capable of being readily cut with a knife, it is fleshy, as in the Barberry, &c.; when it chiefly consists of mucilage or vegetable jelly, as in the Morning-Glory and the Mallow, it is said to be mucilaginous; when dense and tough, so as to offer considerable resistance to the knife, as in the Coffee, the Blue Cohosh (Leontice), &ec., it is corneous, that is, of the texture of horn. Between these all gradations occur. Commonly the albumen is a uniform deposit. But in the nutmeg, as also in the seeds of the Papaw (Fig. 494) and of all plants of the Custard Apple Family, it presents a wrinkled or variegated appearance, owing to numerous transverse divisions, probably caused by inflections of the innermost integument of the seed: in these cases the albumen is said to be ruminated. FIG. 454. Vertical section of a seed of Elodea Virginica, showing the two integuments of the seed, and the embryo. FIG. 455. Seed of Delphinium tricorne (anatropous), enlarged: a, the hilum; b, the rhaphe; c, the chalaza. 456. Vertical section of the same: c, the chalaza; d, the testa; e, the tegmen; f, the albumen; g, the minute embryo near the hilum, a. THE ALBUMEN. 333 628. As already intimated, the albumen may originate from new tissue formed either within the embryo-sac (579), which is probably the more common case; or in the nucleus of the ovule exterior to the embryo-sac, which is certainly the case in the Water-Lily and its allies (the Water-shield, &c., Fig. 518), and in Saururus, for here the thickened embryo-sac persists within or at one extremity of the copious albumen; or both kinds may coexist. In the first-named case, if any of the proper tissue of the nucleus' remains, it is condensed and forms the inner integument of the seed, or becomes confluent with it (623). 629. The office to which the albumen in subservient is the nourishment of the embryo when it begins to develop into a plant. It is a store of nutritive matter, in a very compact or condensed form, accumulated around or next the embryo, which feeds upon it in germination, until it is so far developed that it can obtain and assimilate food for itself (118). The name, therefore, which was applied to it by Gmertner, from its analogy to the albumen or white of the egg of birds, is not inappropriate, although the comparison will not bear to be carried out in detail. As would be expected firom its functions, the albumen is the more copious in the seed in proportion as the embryo is smaller and feebler, or less developed. (Fig. 456, compared with Fig. 461, &c.) 630. When the embryo, instead of being arrested in its growth in the seed while yet minute and rudimentary, developes so far as to exhibit its component organs, and form its cotyledons into evident, but usually more or less thickened leaves (as in the Almond, Fig. 457, 458, the Bean, the Maple, Fig. 105, &c.), it absorbs the nutritive matter of the nucleus immediately in the course of its growth; either completely, as in the examples just adduced, or partially, so as to leave a thin albumen (as in Polygala, the Bladdernut, &c.). In such exalbumininous seeds (viz. those entirely destitute of albumen), the requisite store of nourishment, whether of farinaceous, mucilaginous, or oily matter, or frequently of all these kinds combined (as in flax-seed, the walnut, the almond, &c.), is lodged in the embryo, chiefly in the cotyledons, instead of being accumulated around it. Here the embryo occupies the whole cavity, or forms the whole kernel of the seed, and is directly invested by the integuments (Fig. 454, 1047); while in albuminous seeds the albumen is interposed between them, at least on one side (Fig. 463, 559), and more commonly on all sides (Fig. 451, 452). 334 THE SEED. 631. The Embryo, being an initial plantlet or new individual, is of course the most important part of the seed; and to its production, protection, and support all the other parts of the fruit and flower are subservient. It becomes a plant by the mere development of its parts: it therefore possesses, in a rudimentary or undeveloped state, all the essential organs of vegetation, namely, a root, stem, and leaves, as has already been explained (113, 118, Fig. 105107). In numerous cases,.as in the Maple, the Linden (Fig. 626), and the Convolvulus (Fig. 927), &c., these several parts are perfectly distinguishable in the seed; and the seed-leaves are already foliaceous: sometimes they are large, but thickened by the nourishing matter they contain, as in the Ala mond (Fig. 457), and the Oak (Fig. 1047). Frequently, however, we only observe an 457 458 oblong body, cleft or barely two-lobed at one end, as in Fig. 454; but in germination the undivided extremity elongates into a root, the two lobes at the opposite end disclose their real nature by expanding into leaves, and the stem rises between them. 632. The two lobes, or rudiments of the first pair of leaves, are termed COTYLEDONS; the bud, which, if not actually visible in the seed, as in the Almond (Fig. 458, a), appears between them when germination commences, is called the PLUMULE; and the portion below, which gives rise to the root, is named the RADICLE. 633. In these illustrations, we have assumed the embryo with a pair of cotyledons to be the typical, as it is the most common form, occurring as it does in all the families of Exogenous plants (186). Hence the latter are also called DicOTYLEDONOUS PLANTS (188). 634. But in all Endogenous plants only one cotyledon appears, or at least only one on the primary node; if two rudimentary leaves are present, one of them is alternate with the other, and belongs to a second node. Hence Endogens are also termed MONoCOTYLEDONOUS PLANTS. The monocotyledonous embryo does not usually present the same manifest distinction into radicle, cotyledons, and plumule, as the dicotyledonous; but often appears like a homogeneous and undivided cylindrical or club-shaped body, as in Triglochin (Fig. 460). In this, as in many other FIG. 457. Embryo (the whole kernel) of the Almond. 458. The same, with one of the cotyledons removed, showing the plumule, a. THE EM3BRYO. 335 monocotyledonous embryos, however, a vertical slit, or chink, is observed near the radicular extremity, through which the plumule is protruded in germination. If the embryo be divided parallel with this slit, the plumule is brought into view; as in Fig. 461. If a horizontal section be made at this point (as in Fig. 462), the cotyledon is found to be wrapped around the inclosed plumule, sheathing it, much as the bud and the younger parts of the stem are sheathed by the bases of the leaves in most mono. cotyledonous plants. The plumule is more manifest in Grasses, especially in the cereal grains, and more complex, exhibiting the rudiments of several concentric leaves, or of a strong bud, previous to germination (Fig. 463-465). In many cases, however, no distinction of parts is apparent until germination commences; as in the Onion, the Lily, &c.''.C~il:. i........ 463 464 465 635. The more common of the extremely varied forms under which the embryo occurs may readily be gathered from the numerous illustrations scattered through this volume; which need not be specially enumerated. Its position as respects the albumen, when that is present, is also various. Although more commonly in the axis, it is often excentric, or even external to the albumen, as in all Grasses (Fig. 463-465), in Polygonum (Fig. 787), &c. When external or nearly so, and curved circularly around the FIG. 459. Seed of Triglochin palustre; the rhaphe, leading to the strong chalaza at the summit, turned towards the eye. 460. The embryo detached from the seed-coats, showing the longitudinal chink at the base of the cotyledon; the short part below is the radicle. 461. Same, with the chink turned laterally, and half the cotyledon cut away, bringing to view the plumule concealed within. 462. A cross-section through the plumule, more magnified.,FIG. 463. Vertical section of a grain of Indian Corn, passing through the embryo: c, the cotyledon; p, the plumule; r, the radicle. (A highly magnified portion of the albumen, which makes up the principal bulk of the grain, is shown in Fig. 52, p. 57.) 464. Similar section of a grain of Rice. 465. Vertical section of an Oat-grain: a, the albumen; c, the cotyledon; p, the plurnule; and r, the radicle of the embryo. 336 THE SEED. albumen, as in Fig. 559, 565, 995, and generally in the families from which these illustrations are taken, it is called periplieric. When the embryo is bent so that the radicle is placed against the edges of the cotyledons, the latter are said to be accumbent (Fig. 529); or when the radicle rests against the back of one of them (Fig. 538), they are called incumbent. 636. The situation of the embryo with respect to the base and apex of the seed is so far uniform, that the radicle always points to the micropyle, as already mentioned. As the nature of the seed may usually, after some practice, be readily determined by external inspection, so the situation of the embryo within, consequently, may often be inferred without actual dissection. 637. The direction of the embryo with respect to the pericarp is also particularly noticed by systematic writers; who employ the terms ascending, or radicle superior, when the latter points to the apex of the fruit; descending, or radicle inferior, when it points to its base; centripetal, when the radicle is turned towards the axis of the fruit; centrifugal, when turned towards the sides; and vague, when it bears no evident or uniform relation of the kind to the pericarp. 638. Sometimes the two cotyledons of a dicotyledonous embryo are consolidated or more or less coherent by their contiguous faces into one mass, when they are said to be conferruminate, as in the Horsechestnut (Fig. 661). 639. In the Cuscuta, or Dodder, which never produces foliage, the embryo also is entirely destitute of cotyledons (Fig. 122 - 124). Here these organs are suppressed in an embryo of considerable size; but in most such parasites, the embryo is very minute, as well as reduced to the greatest degree of simplicity, and seems to remain until germination in a very rudimentary state. 640. On the other hand, the embryo assumes the highest complexity in Pines and many other Coniferous plants (400); where the cotyledons as they form are increased in number, from two to four, six, or even fifteen, by collateral chorisis (455); here the embryo is polycotyledonous. SECT. II. GERMINATION. 641. OUR narrow limits prevent us from illustrating the various arrangements for the natural dissemination of seeds, which would GERMINATION. 337 form the subject of an interesting chapter; and from considering the circumstances under which the embryo retains its vitality, in many species ordinarily for a few months only, in some perhaps for many centuries.* We must very briefly notice the conditions under which this latent vitality is called into activity, and the embryo is developed into a plant. 642. The conditions requisite to germination are exposure to moisture and to a certain amount of heat, varying from 50~ to 800 (Fahrenheit) for the plants of temperate climates, to which must be added a free communication with the air. Direct light, so essential to subsequent vegetation, is unnecessary, if not unfavorable to germination. The degree of heat required to excite the latent vitality of the embryo is nearly uniform in the same species, but widely different in different plants; since the common Chickweed will germinate at a temperature not far above the freezing-point of water, while the seeds of many tropical plants require a heat of 90~ to 110~ (Fahrenheit) to call them into action, and are often exposed to a considerably higher temperature. Seeds are in the most favorable condition for germination in spring or summer, when loosely covered with soil, which excludes the light while it freely admits the air, moistened by showers, and warmed by the rays of the sun. The water which is slowly absorbed softens all the parts of the seed; the embryo swells, and bursts its envelopes; the radicle is protruded, and, taking a downward direction, fixes itself in the soil; while the other extremity elongates in the opposite direction, bringing the cotyledons (except when these remain under grou'nd, as in the Pea, the Horsechestnut, Wheat, &c.) and * It is well known that seeds which have been kept for sixty years have germinated; and it seems that grains of wheat, taken from ancient mummies under circumstances which leave little doubt of their high antiquity, have been made to germinate; but in these cases there are several sources of possible deception. Dr. Lindley records the remarkable case of some Raspberries, "raised in the garden of the Horticultural Society from seeds taken from the stomach of a man, whose skeleton was found thirty feet below the surface of the earth, at the bottom of a barrow which was opened near Dorchester. He had been buried with some coins of the Emperor Hadrian; and it is therefore probable that the seeds were sixteen or seventeen hzturdred years old." Most seeds, when buried deep in the soil, where they are subject to a uniform and moderate temperature, and removed from the influence of the air and light, are in a favorable state for the preservation of vitality, and will germinate when brought to the surface after a long interval. 29 338 THE SEED. the plumule, or growing apex of the young stem, to the surface, when the primordial leaves expand in the air. As soon as the root and leaves are developed, each in their appropriate medium, the process of germination is finished; and the plant, deriving through them its nourishment, continues to grow in the manner already described (113). 643. The nourishment which the embryo requires during germination is furnished by the starch, &c. of the albumen (627), when this substance is present in the seed; or by starchy or other matter accumulated in its own tissue (630). But as starch is insoluble in cold water, certain chemical changes are necessary to bring it into a fluid state, so that it may nourish the embryo. These changes are incited by the proteine compounds, or neutral azotized products (354), which are largely accumulated in the seed, whether in the albumen or in the embryo itself (356), and which here, as elsewhere, take the initiative in all the transformations of vegetable matter (27). Here, just as in growth from a bulb or tuber, the changes essentially, consist in the transformation of the starch, first into dextrine, or gum, and thence into sugar (350), a part of which is destroyed by resolution, first into acetic acid, and finally into carbonic acid and water, with the abstraction of oxygen from the air, and the evolution of heat (372), while the remainder is,rendered directly subservient to the growth of the plantlet. The reason why light, so essential to subsequent growth, impedes or prevents incipient germination, becomes evident when we remember that it incites the decomposition of carbonic acid, and the fixation of carbon by the plant (344-350); while germination is necessarily attended by an opposite transformation, namely, the destruction of a portion of organized matter, with the ) evolution of carbonic acid. 644. In most Dicotyledonous plants, the cotyledons rise out of the ground, and perform more or less perfectly the'office of leaves, until those of the plub. }d mule expand (Fig. 100- 107): but when the cotyleJr>% ~dons are very thick and fleshy, as in the Hiorsechest. nut, the Pea, the Oak, &c., they serve merely as reservoirs of nourishment, and remain under ground, 466 that is, are hiypogaous in germination, the first leaves FIG. 466. The germinating seed of Scirpus, a Monocotyledonous plant: a, the cotyledon, remaining within the albumen, b, inclosed in the pericarp, c; from which the plumule (d) elongates. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 339 which appear being those of the plumule. This is also the case in all Monocotyledonous plants; in which the cotyledon remains within the integuments of the seed, while the radicle and plumule together pass out at or near the micropyle, as shown in the germinating seed of Scirpus (Fig. 466). 645. Seeds may casually germinate while attached to the parent plant, especially such as are surrounded with pulp, like those of the Cucumber and Melon. The process is liable to commence in wheat and other grain, when protracted warm and rainy weather occurs at the period of ripening; and the albumen becomes glutinous and sweet, from the partial transformation of the starch into gum and sugar. In the Mangrove, which forms dense thickets along tropical coasts, germination commonly takes place in the pericarp while the fruit remains on the tree; and the radicle, piercing the integuments which inclose it, elongates in the air; such a plant being, as it were, viviparous. This very naturally takes place, also, in the seeds of hypogceous fruits, namely, when the fruit is produced on radical branches, beneath the surface of the soil, as in the Peanut, in Amphicarpaea, Polygala polygama, and many other plants. CHAPTE R XII. OF REPRODUCTION IN CRYPTOGAMOUS OR FLOWERLESS PLANTS. 646. THE general morphology of these simpler forms of vegetation has been very briefly adverted to (Chapter II.) in sketching the progressive development of plants, from those of a single cell or a simple congeries of cells up to those which exhibit the completed type of vegetation. Taken collectively, we distinguish this lower series of the vegetable kingdom by negative characters only; saying that they do not bear true flowers (consisting essentially of stamens and pistils), and accordingly do not produce seeds, or bodies consisting of a distinguishable embryo plantlet, developed in an ovule, through fertilization by means of pollen. Their spores (101), or the bodies produced in their fructification by which they are propagated, and which therefore answer to seeds, are single cells, 340 REPRODUCTION IN in most cases. These, as they germinate in the soil, or whatever medium they grow in, undergo a development at the time of their germination which has been compared with that of the embryonal vesicle (577) during its development into the embryo in the ovule of a Phsenogamous plant. But the organs of fructification, and the modes in which the spores are produced, are so exceedingly diverse in the different families of Cryptogamous plants, that botanists are as yet unable to reduce them to a common formula or type, as they have done in Phaenogamous vegetation. Each great farnily of the Cryptogamia seems to be formed on a plan peculiar to itself; each presents a special morphology, and has to be independently treated, -with considerable fulness too, and much particularity of illustration, if the subject is to be made intelligible to the unpractised student. Moreover, the functions of the different organs are in some cases as unsettled as their morphology. The leading characters of the several orders of Cryptogamic plants, and the principal terms applied to their different organs, will be succinctly illustrated in the systematic part of this work (927). Here we have only to notice, very briefly, what is known in respect to their fertilization; concerning which some interesting discoveries have recently been made. 6461. The truth of the statement that Cryptogamous plants are lowerless depends upon what a flower is defined to be. For it is now demonstrated that at least all the higher orders of Cryptogamous plants are provided with two kinds of reproductive organs, which are so far analogous to stamens and pistils, respectively, that the fertilization of one by the other is essential to reproduction. The structure of these organs, however, the process of fertilization, and the resulting product, are widely different from those of Phsenogamous plants. In the latter, one of the grains of pollen, which are the essential part of the stamen, by a peculiar growth (573) comes into proximity with and fertilizes an embryonal vesicle (577) contained in an ovule, which is the essential part of a pistil; and the result is the formation of an embryo, or plantlet ready formed in the seed. In Cryptogamous plants the fertilizing cells, or seminal filaments; do not resemble pollen in structure and appearance: the large cells that contain them, being analogous to anthers in function merely, are called ANTHERIDIA, or anther-like bodies: the cells or organs upon which they act are analogous in function only either to pistils or ovules, and are therefore named CRYPTOGAMOUS OR FLOWERLESS PLANTS. 341 PISTILLIDIA, or pistil-like bodies: and the resulting SPORES (109) are formed, usually four together, free in a mother cell in precisely the same manner that pollen-grains are formed in the anther. The spore, moreover, does not grow at once into a plant like the parent, nor is one part of it predetermined to form one organ of the plant and one another, as in the simplest embryo; but in germination it developes, in all the higher Cryptogamous plants, by a somewhat indefinite multiplication and extension of cells, into a cellular structure, or thallus, called by Hofmeister the PRO-EnIBRYO; which is of vari6us form in different orders of plants, but always unlike the parent, and from certain cells of which buds or growing points originate and grow into adult plants. The whole process of fertilization and development presents remarkable differences in different orders of the Cryptogamia. 6462. Reproduction in Mlosses. It is in Mosses that the antheridia and pistillidia were first recognized, and are the readiest observed. The antheridia occur either in the axils of the leaves, or collected into a head at the summit of the stem. They are found either in the same heads as the pistillidia, or in distinct heads on the same individuals (moncecious), or on separate individuals (dicecious). The antheridium (Fig. 1162) is merely a cylindrical or clubshaped sac, composed of a single layer of cells, united to form a delicate membrane; within which are developed vast numbers of minute, very delicate cells, completely filling the sac. The sac bursting at its apex when mature, the delicate vesicles are discharged. These at their first formation contain only an amorphous substance, which turns yellow on the application of iodine: but when mature, a slender filament, thickened at one end and tapering off to a fine point at the other, may be seen through the transparent walls, spirally coiled up in the interior of each vesicle. When these vesicles are extruded in water under the rhicroscope, the contained filaments may be seen to execute lively movements, wheeling round and round,in the vesicle, or, when disengaged from the latter, and assuming a corkscrew form, at the same time advancing forward, the thin end of the filament almost always preceding. Minute observation, which is very difficult, both from the rapidity of the motion (which, however, is arrested by poisons), and from the great delicacy of. the whole structure, shows that the movements arise from two long and extremely delicate cilia, attached to the tapering end of the filament. The filament itself 29 *' 342 REPRODUCTION IN exhibits no independent motion. The resemblance of these moving filaments to the so-called spermatozoa in animals is manifest. The pistillidia of Mosses (Fig. 1161), which appear at the same time as the antheridia, and often mixed with them, are flaskshaped bodies (like ovaries in shape), with long necks (resembling a style), composed of a single cellular membrane. The neck is perforated by an open canal, leading to the enlarged cavity below, at the base of which a single cell, projecting free into the open space, is the germ of the future capsule or sporangium (105), in which a great number of spores are formed. The dntheridia are supposed to fertilize the pistillidia by means of the spiral filaments, which are assumed to penetrate the canal of the neck of the pistillidium, and to reach the cell which is afterwards developed into the sporangium or fruit. No such process of fertilization has actually been observed in Mosses: but it is well known that no fruit is produced by plants that bear antheridia alone, and none by the plants that bear only pistillidia unless those with antheridia occur in the vicinity. The spores of Mosses are single cells, with a double coat, like a pollen-grain. In germination,'the inner or proper membrane of the spore swells and protrudes, from any part of its surface favorably situated, a tubular process, which forms partitions as it elongates and branches, giving rise to a proembryo or rudimentary plantlet, which resembles a branched Conferva. Certain cells of its various branches, taking a special development, produce buds, which are soon covered with a tuft of rudimentary leaves, and grow up into the leafy stems of the perfected plant. Here a single spore, or rather the pro-embryo developed from it, gives rise at once to a number of individuals. 6463. Reproduction in Ilepatiaer appears to be affected in a manner physiologically similar to that of the Mosses, especially in those which resemble Mosses in their vegetation. Their antheridia are filled with vesicles containing the same active spiral filaments. In some of the frondose kinds the pistillidia are more like those of the Ferns; but they do not exhibit the remarkable peculiarity of the latter family, which may now be described. 6464. Reproduction in Ferns. In Mosses, as in all Phenogamous plants, the organs of fructification occur as the last stage of the vegetable development, the perfecting of the seed even involving the death of the individual in numerous cases: and the fertilizing and the fertilized organs are produced at the same time, and the CRYPTOGAMOUS OR FLOWERLESS PLANTS. 343 action of one upon the other is immediately succeeded by the full development of the fruit, with its seeds, or spores, as the case may be. But the Ferns, according to recent and most unexpected discoveries, present a very different state of things. Their sporangia (Fig. 1149, 1153), which are not essentially unlike those of Mosses, are, as in the latter, produced and matured on the fullgrown plant (usually on the leaves, however, instead of in their axils). But all search for antheridia, whether accompanying the sporangia or upon any other part of the Fern, has been in vain; and consequently the doctrine of sexuality of Cryptogamia, so well established in respect to Mosses, entirely failed in one of the highest Cryptogamic orders. The germination of the spores of Ferns had long since been observed. The process begins in the same manner as in Mosses: but the extremity of the tubular pro. longation of the spore, converted by partitions into a row of cells, is developed into an expanded, leaf-like body (the pro-embryo, as it is now called), which on a small scale resembles a frondose Liverwort. Upon this body, Nageli, in 1844, met with moving spiral filaments, like those of the antheridia of Chara, &c. "The announcement of this discovery seemed," as Henfrey remarks, " to destroy all grounds for the assumption of distinct sexes, not only in the Ferns, but in the other Cryptogamia; since it was argued that the existence of these cellular organs producing moving spiral filaments, the so-called spermatozoa, upon the germinating fronds, proved that they were not to be regarded as in any way connected with the reproductive processes. But an essay published by the Count Suminski in 1848 totally changed the face of the question." On the under side of the delicate, Marchantia-like, germinating frond, Suminski found a number of cellular organs of two distinct kinds, namely, antheridia and what he calls " ovules." The former, which are the more numerous, are pedicellated cells on the surface of the germinating frond, in the cavity of which is formed a second cell, filled with minute vesicles containing each a spiral filament coiled up in its interior. The organ bursts at its summit, and discharges the vesicles in a mucilaginous mass; the spiral filaments moving within the vesicles at length make their way out of them and swim about in the water. They resemble those of Mosses, but are flat and ribbon-like, as in Chara, and possess ac. cording to Suminski about six, according to Thuret numerous cilia, by whose vibrations they are moved. The so-called " ovules" 344 REPRODUCTION IN are round cavities in the cellular tissue of the same body, opening on the under side, in the bottom of which is a single globular cell called by Suminski the embryo-sac. Count Suminski asserts that he has even witnessed the process of fertilization in a single in. stance, observing the entrance of one of the moving filaments into the " ovule." Adopting the Schleidenian doctrine as to the origin of the embryo, he maintains that the vesicular head of a spiral filament penetrates the cell which represents the embryo-sac, and becomes the embryo, producing the first frond and the terminal bud from which the stem of the Fern is developed. These observations and statements have been criticized and extended by Thuret (as to the antheridia), Iofmeister, Schacht, Mettenius, and Merklin (who also testifies to the entrance of spiral filaments into the "ovule "), and in the essential particulars confirmed, except as to the mode of formation of the so-called " embryo " or bud. In Ferns, therefore, it is not the sporangium that is fertilized, nor the spores, but the germinating plantlet formed by the growth of a spore. Without this fertilization, it appears that the pro-embryo of a Fern is incapable of producing leaf-buds and perfecting the development of the plant, as does the Moss: with it, not only buds and the whole vegetation of the individual plant are formed and perfected, but even the fruit and the spores are matured, without further impregnation. While thus in the Ferns the spore forms only the pro-embryo without impregnation, in Mosses it goes on to form the whole leafy stem without impregnation; this operation then taking place, at the same period as in Phuenogamous plants, causes the development of the spore-producing part of the plant only. These facts, which may be expressed in various theoretical forms, open some interesting questions and speculations in general physiology.* 6465. Reproduction in Equisetace~t is physiologically the same as in Ferns; the antheridia, first detected by Thuret, and so-called "ovules," being produced on an irregular, many-lobed proembryo, which results from the germination of the spore. * The English reader is referred to Henfrey's Translation of Mohl's Anatonmy and Physiology of the Vegetable Cell; and Henfrey's Report on the Reproduction and supposed Existence of Sexual Organs in the higher Cryptogamous Plants, in the Report of the British Association for the Advancement of Science, for 1851, reprinted in Silliman's Journal, Vol. 14 and 15; from which the above account has been condensed. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 345 6466. Reproduction in Hiydropterides and Lycopodiaceae presents still other modifications, not readily explained without many details, and as yet incompletely investigated. Most of these plants produce two kinds of reproductive bodies; namely, rather large spores, mostly definite in number; and minute, pollen-like grains, in great abundance. The latter have also been taken for real spores: but it appears that in germination they produce minute vesicles or antheridial cells containing spiral filaments. These doubtless fertilize the minute and transitory pro-embryo formed by the germina. tion of the larger or true spores, on which one or more of the socalled " ovules," and later, "embryos " or growing points, have been detected; the latter giving immediate origin to the leafy plant. The great difficulty which remains is, that in true Lycopodium only these smaller, pollen-like bodies are produced. 6467. Reproduction of Characem. The two kinds of reproductive organs in Chara have long been recognized, and their relative functions suspected; the red or orange-colored globule, situated at the base of the conspicuous nucule or sporocarp (Fig. 1186), having by the earlier botanists been taken for an anther. This is composed of eight shield-shaped valves, containing the coloring matter, and surrounding a cavity into which projects a flask-shaped cell; and to the apex of this are attached a mass of fine confervoid filaments, divided into a close row of cells, in each of which a spiral filament is developed. These filaments move by means of two very long cilia, attached near one extremity: they escape from the cells after the valves of the globule open, execute very lively movements, and doubtless fertilize the spore-bearing organ, but in what particular manner is not yet well made out. The Charm are so simple in their organs of vegetation that they have been ranked with the Algme, and even referred to one of the lowest tribes of that family. But their organs of reproduction ally them rather with the higher Cryptogamia. The remaining, lower forms of Cryptogamous plants have generally been supposed to be strictly asex ual, even by those who have maintained the sexuality of Mosses, &c. But very recent researches have now rendered it much more probable that 6468. Reproduction in Thallophytes generally, both in Lichenes and in the higher grades, at least, of Algma and Fungi, is effected through the agency of fertilizing cells, or corpuscles of some form, upon the cells in which the spores are produced. The corpuscles 346 SPONTANEOUS MOVEMENTS IN PLANTS. of the antheridia do not, indeed, occur in the form of spiral filaments, but are oblong or globular: they are, moreover, motionless, as far as has yet been ascertained, except in the Fucaceae or olive-colored series of Alge; in which they execute free and lively movements; and even the cilia by which the motion is effected have been detected by Thuret. As similar, although motionless, corpuscles have been discovered in the Florideme or Rose-red Algae, in many Fungi, and in almost all the genera of Lichenes, occurring as a regular part of the structure, and at a certain epoch, there can be little doubt that they subserve similar functions in all these cases; and it is in the highest degree probable that these functions are analogous to those of the spiral filaments of Chara, the Mosses, and the other Cryptogamia of the higher grades. We can here barely refer to those recent memoirs in which these important discoveries are recorded or illustrated, viz.: — Ngeli in Bot. Zeitung, 1849. Itsigsohn in Bot. Zeitung, 1850. Thuret in Ann. Sci. Nat., 3d ser. 14 & 16, 1850-1. Harvey, Nereis Bor.-Amer. in Smithsonian Coniributions, 1852. Berkeley and Broome in Report of British Association for 1851. Tulasne in Comptes Rendus, 1851, and Ann. Sci. Nat. 17, 1852. CHAPTER X II. OF THE SPONTANEOUS MOVEMENTS WVHICH PLANTS EXHIBIT. 647. THE facts brought to view in the preceding chapter respecting the production by Cryptogarnous plants of minute bodies'temporarily endowed with the power of locomotion, leads to the consideration of the various movements which are executed by the ordinary organs of vegetables. Plants, like other living beings, execute certain movements, or changes in the position of their parts, through some inherent powers, which, though far less striking and less varied than in animals, and of a nature different from muscular motion, must not be overlooked. 648. The Special Directions which the organs of the plant assume belong to this class of manifestations, although the movements are mostly much too slow to be directly observed. Among these the THEIR SPECIAL DIRECTIONS. 347 most universal are the invariable descent of the root in germination, the ascent of the stem into the light and air, and the turning of branches and the upper surface of leaves towards the light (113, 139, 294). Although these movements are incited by common physical agents, and cannot be the result of any thing like volition, yet all of them are inexplicable upon mechanical principles. Some of them, at least, are spontaneous motions of the plant or organ itself, due to an inherent power, which is merely put in action by light, attraction, or other external influences. 649. The external agencies concerned in the descent of the root and the rise of the stem seem chiefly to be, - 1st, the attraction of the earth acting upon the root; and 2d, the influence of light upon the stem. The influence of gravitation, or of a similar force, was proved by the celebrated experiment of Mr. Knight; who caused the seeds of the Bean to germinate in a quantity of Moss fastened to the circumference of a wheel, which was made to revolve vertically at a rapid rate; where the effect of gravity was replaced by that of centrifugal force. On examination, after some days, the young root and stem were found to have taken the direction of the axis of rotation; the former being turned towards the circumfer. ence, and the latter towards the centre of the wheel. The same result took place when the wheel was made to revolve horizontally with considerable rapidity; but when the velocity was moderate, the roots were directed obliquely downwards and outwards, and the stems obliquely upwards and inwards, in obedience both to the centrifugal force and the power of gravitation, acting at right angles to each other. The different behavior of the root and stem is here supposed to depend upon their different mode of growth. The former growing at its extremity only, the soft substance of the growing point was supposed to obey the attraction of gravitation, and curve'downwards; while the latter growing by the elongation of a series of internodes already formed, the solid tissues would be unaffected by gravity, which could affect only its nutri. tive juices, causing their accumulation on the lower side of a stem out of the perpendicular line, which side, thus more actively nourished, would grow more vigorously than the upper, and so cause the stem to turn upwards. There are several objections to this explanation; among them is the fact that the root is capable of penetrating a fluid of greater density than its own substance, such as mercury. That light is the chief cause of the upward direction 348 SPONTANEOUS MOVEMENTS IN PLANTS. of the stem, while it is avoided by the roots, appears from experiments by Schultz and Mohl; who reversed the natural condition, by causing seeds to germinate in Moss, so arranged that the only light they could receive was reflected from a mirror, which threw the solar rays upon them directly from below; in which case it was found that their roots were sent upward into the Moss, contrary to the ordinary direction, and their stems downward towards the light. 650. The Mistletoe obeys the attraction of the trunk or branch upon which it is parasitic (134), just as ordinary plants obey the attraction of the earth; its roots penetrating towards the centre, while the stems grow perpendicular to the surface of the branch, and are therefore placed in various positions as respects the earth. When the germinating seeds of the Mistletoe were fixed on the surface of a cannon-ball, all the radicles were found to be directed towards its centre. A well-devised experiment made by Dutrochet goes to show, that the pointing of the radicle to the adjacent body (and consequently of the germinating root generally towards the earth's centre) is not the result of the immediate attraction of the adjacent body, or of the earth, but is a spontaneous movement due to some internal, vital cause, put in action by the exterior influence. He mounted the seed of a Mistletoe upon one extremity of a very delicately balanced needle, which would turn with the slightest force, and placed it at the distance of half a line from the surface of a large cannon-ball. In germination the radicle directed its point to the ball, and soon came into contact with the surface; but the end of the needle had not moved in the slightest degree towards the ball, as it would have done from a mere exterior attraction. By such experiments Dutrochet has proved that the curvature of the root to grow downward or from the light, and of the stem in the opposite direction, is independent of their growth; and that the cause must be looked for in the cells of the organs themselves. He has attempted the explanation by the aid of endosmosis under different conditions of light, &c.; but without full success, except in showing that curvature is not produced by a contraction of the side which becomes concave, but by the enlargement of that which becomes convex. 651. When the stem has emerged from the earth, it tends to expose itself as much as possible to the light, the growing parts always turning towards the side most strongly illuminated; as is observed when a plant is placed in an apartment lighted from a THEIR SPECIAL DIRECTIONS. 349 single aperture. This is mechanically accounted for by De Candolle, on the supposition, that, as the side upon which the light strikes will fix most carbon by the decomposition of carbonic acid, so its tissue will become more solid than the shady side, and therefore elongate less rapidly; and the stem or branch will consequently bend towards the light. But when the light is equally diffused around a plant, the decomposition of carbonic acid will take place uniformly on all sides, and the perpendicular direction naturally be maintained. The insufficiency of this explanation is shown by the fact, that, when a stem so curved is split through, the concave side curves more than before, while the convex side springs back into the upright position. Moreover, the decomposition of carbonic acid is effected chiefly under the influence of the yellow rays, and the curvature of green stems by the blue (6521). The same relation of upward-growing organs to light regulates the disposition of branches and branchlets, which are invariably so arranged as to have the greatest possible exposure to the light; the uppermost branches of a tree growing nearly erect, those beneath extending more horizontally until they reach beyond their shade, when they curve upwards (unless too slender to support their own weight, as in the Weeping WAillow), and the lower being still more divergent, or even turned downwards, when the foliage is dense. Certain drooping branches, however, are exceptions to this rule, such as those of the Weeping Ash, which have a constitutional tendency to turn downwards. And the widely different positions assumed by the branches of different species under the very same external influences, show that the directions are owing to differences in their own specific organization. The direct action of light is confined to the green parts of plants. Where the surface has lost its green color, branches are no longer affected by the light; and those which creep under ground beyond its influence (173), and have the white color and much the external appearance of roots, show little upward tendency so long as they remain in this situation; but whenever their extremities are exposed to the light, they first acquire a green hue by the formation of chlorophyll, and then tend to assume a vertical direction. 652. The principal exception to the rule that green parts turn to the light is that of certain tendrils, such as those of the Vine and the Virginia Creeper, which avoid it, although of a green color. This has been said to be the case in tendrils generally; but, ac30 350 SPONTANEOUS MOVEMENTS IN PLANTS. cording to Mohl, many turn towards the light, while others appear indifferent to its influence. 652'. It has been shown both by Payer and Macaire, that curvature towards the light is produced in unequal degrees by the different rays of the spectrum, and this independently of their illuminating power; the blue and violet rays being most efficient, the yellow producing little effect, -and the red none at all. There is no real connection, therefore, between this phenomenon and the evolution of oxygen or fixation of carbon, which does not take place under blue light. 653. In leaves it is the denser and deeper green upper surface (262) that is presented to the light, while the paler lower surface, of looser tissue, avoids it, like a rootlet. The recovery of the natural position when the leaf is artificially reversed, is the more promptly effected in proportion to the difference in structure and hue between the two strata. This movement in leaves is so prompt, that those of many plants follow the daily course of the sun. The leaf is more capable of executing such movements, on account of its extended surface, and its pliancy, and also on account of its usual attachment by an articulation. Herethe slender vascular bundles oppose little resistance to lateral motion, while the soft and usually cellular enlargement favors it. Indeed, the efficient cause of the movement appears to be exerted here, and to be connected with the unequal tension or turgescence of the cells on the two sides. But how the light acts in producing the movement, we are wholly ignorant. One of the most striking and general of these changes of position was termed by Linnaeus 654. The Sleep of Plants, namely, the peculiar position which the leaves of many 3 661 662 658 761. Subord. Hippocastanaceme. Trees or shrubs; with opposite FIG. 655. Flowering branch of AEsculus Pavia, a species of Buckeye. 656. A flower. 657. Flower with the calyx and two of the petals removed. 658. A ground-plan of the flower, showing that its parts are unsymmetrical. 659. Vertical section of an ovary, showing two of the cells with a pair of ovules in each, one ascending, one descending. 660. Cross-section of an ovary. 661. Cross-section of the immature fruit; only one fertile seed; the others abortive. 662. The dehiscent fruit. 35 * 414 EXOGENOUS OR DICOTYLEDONOUS PLANTS. digitate leaves, without stipules. Fruit roundish, coriaceous, dehiscent, with one to three very large seeds, resembling chestnuts. Embryo very large and fleshy, showing a two-leaved plumule: the cotyledons united. —Ex. JEsculus, the Horsechestnut, and Buckeye: fine ornamental trees. The large, starchy seeds are nutritious, but they contain a bitter principle which is more or less noxious. Those of 2E. Pavia are used to stupefy fish. The root, according to Elliott, is employed as a substitute for soap. 762. Ord. Celastracee~ (the Spindle-tree Family). Shrubs or trees, with alternate or opposite simple leaves. Calyx of four or five sepals, imbricated in zestiVation. Petals as many as the sepals, inserted under the flat expanded disc which closely surrounds the ovary, imbricated in westivation. Stamens as many as the petals, and alternate with them, inserted on the margin or upper surface of the disc. Ovary free from the calyx. Fruit a capsule or berry, with one or few seeds in each cell. Seeds usually arilled, albuminous, with a large and straight embryo. - Ex. Celastrus (False Bittersweet), Euonymus (Burning Bush, Spindle-tree): they are all somewhat bitter and acrid; but of little economical importance. The crimson capsules and bright scarlet arils of Euonymus atropurpureus and E. Americanus (sometimes called Strawberrytree), present a striking appearance when the fruit is ripe. 763. Ord. Rhamnacem (the Buckthorn Family). Shrubs or trees, often with spinose branches; the leaves mostly alternate, simple. Flowers small. Calyx of four or five sepals, united at the base, valvate in vastivation. Petals four or five, cucullate or convolute, inserted on the throat of the calyx, sometimes wanting. Stamens as many as the petals, inserted with and opposite them! Ovary sometimes coherent with the tube of the calyx, and more or less immersed in a fleshy disc, with a single erect ovule in each cell. Fruit a capsule, berry, or drupe. Seeds not arilled. Embryo straight, large, in sparing albumen. - Ex. Rhamnus (Buckthorn) is the type of the order. Ceanothus is peculiar to North America; just as some genera are to the Cape, and others to New Holland. The berries of most species of Rhamnus are somewhat nauseous; but those of Zizyphus are edible. The genuine Jujube paste is prepared from those of Z. Jujuba and Z. vulgaris of Asia. Syrup of Buckthorn and the pigment called Sap-green are prepared from the fruit of Rhamnus catharticus. The herbage and bark in this order are more or less astringent and bitter. An infusion of the THE POLYPETALOUS ORDERS. 415 leaves of Ceanothus Americanus (thence called New Jersey Tea) has been used as a substitute for tea.'764. Ord, Staphyleacee (the Bladder-nut Family), consisting chiefly of Staphylea, is intermediate between the order Sapin. dacere, from which it differs in its more symmetrical flowers and straight embryo in fleshy albumen, and Celastracem, from which the compound leaves, partly separate pistils, and bony seeds distinguish it. 765. Ord, Vitacese (the Vine Family). Shrubby plants climbing by tendrils, with simple or compound leaves, the upper alternate. Flowers small, often polygamous or dioecious. Calyx very small, 664 665 (CQ\) 669 66 67 668 666~ 663 667 668 666 entire or four- or five-toothed, lined with a disc. Petals four or FIG. 663. A branch of the Grape; showing the nature of the tendrils. 664. A flower; the petals separating from the base, and falling off together without expanding. 665. A flower from which the petals have fallen; the lobes of the disc seen alternate with the stamens. 666. Vertical section through the ovary and the base of the flower: a, calyx, the limb of which is a mere rim: b, petal; having the stamen, c, directly before it; and the lobes of the disc are shown between this and the ovary. 667. A seed. 668. Section of the seed; showing the thick crustaceous testa, and the albumen, at the base of which is the minute embryo. 669. A horizontal plan of the flower. 416 EXOGENOUS OR DICOTYLEDONOUS PLANTS. five, inserted upon the outside of the disc, valvate in aestivation, sometimes cohering by their tips, and caducous. Stamens as many as the petals, and opposite them! Ovary two-celled, with two erect ovules in each cell. Fruit a berry. Seeds with a bony testa, and a small embryo in hard albumen. -Ex. Vitis (the Vine), Ampelopsis (the Virginia Creeper). The fruit of the Vine is the only important product of the order. The acid of the grape, which also pervades the young shoots and leaves, is chiefly the tartaric. Grape-sugar is very distinct from cane-sugar, and the only kind that can long exist in connection with acids. - The symmetry of the flower is explained on p. 269. 766. Ord. Polygalacewa (the Milkwort Family). Herbs or shrubby plants, with simple entire leaves, destitute of stipules; the roots sometimes with a milky juice. Pedicles with three bracts. Flow. ers perfect, unsymmetrical, and irregular, falsely papilionaceous. Calyx of five irregular sepals; the odd one superior, the two inner (wings) larger, and usually petaloid. Petals usually three, inserted 672 671 676 675 674 670 673 on the receptacle, more or less united; the anterior (keel) larger FIG. 670. Polygala paucifolia. 671. A flower, enlarged. 672. The calyx displayed. 673. The corolla and stamineal tube laid open. 674. The pistil and the free portion of the stamens. 675. Vertical section of the ovary. 676. Vertical section of the seed, showing the large embryo and scanty albumen. THE POLYPETALOUS ORDERS. 417 than the rest. Stamens six to eight, combined in a tube, which is split on the upper side, and united below with the claws of the petals: anthers innate, mostly one-celled, opening by a pore at the apex. Ovary compound, two-celled, with a single suspended ovule in each cell: style curved and often hooded. Capsule flat. tened. Seeds usually with a caruncle. Embryo straight, large, in fleshy, thin albumen. - Ex. Polygala, the type of the order, is dispersed nearly throughout the world. A bitter principle pervades the order; and many species also yield an acrid extractive matter. The Polygala Senega (Seneca Snakeroot) is the most important medicinal plant of the family. Other species are employed medicinally in Brazil, Peru, Nepaul, &c.; where, like our own, they are reputed antidotes to the bites of venomous reptiles. 767. Ord. Krameriaceca (the Rhatany Family) consists of the genus Krameria only, which has ordinarily been annexed to the Polyga. laceae; but it is much nearer the Leguminosme, having the odd sepal inferior, a simple unilocular pistil, and an exalbuminous seed. In fact it is distinguishable from the latter only by the hypogynous stamens and the want of stipules. The roots contain a red coloring matter, and are astringent without bitterness. Rhatany-root, used to adulterate port-wine, and as an ingredient in tooth-powders, &c., is the produce of K. triandra of Peru. That of our own Southern K. lanceolata possesses the same properties. 768. Ord, Leguminoste (the Pulse Family). Herbs, shrubs, or trees, with alternate and usually compound leaves, furnished with stipules. Calyx mostly of five sepals, more or less united; the odd sepal inferior (Fig. 382). Corolla of five petals, either papil. ionaceous or regular. Stamens perigynous, or sometimes hypogynous. Ovary single and simple. Fruit a legume, various forms of which are shown in Fig. 438-446. Seeds destitute of albumen.-This immense family is divided into three principal suborders; viz.: -- 769. Subord. Papilionacea (the Proper Pulse Family); which has the papilionaceous flower, already illustrated (468, Fig. 317 - 321), ten stamens (or rarely fewer), which are diadelphous (Fig. 308), sometimes monadelphous (Fig. 307, 324), or rarely distinct (Fig. 322), inserted into the base of the calyx. Radicle bent on the large cotyledons. Leaves only once compound, the leaflets entire. 418 EXOGENOUS OR DICOTYLEDONOUS PLANTS. (Ex., the Pea, Bean, Locust, Clover, &c.) The vexillum is the largest petal, and external in oestivation, in all true papilionaceous corollas, as in the diagram, Fig. 382. But in the 770. Subord. Caesalpinew (to which Cassia, Cercis, and the HoneyLocust belong), the corolla gradually loses its papilionaceous character, and always has the vexillum, or superior petal, covered by the lateral ones in aestivation; the stamens are distinct, and the embryo straight. The leaves are often bipinnate. 771. Subord. Mimosa (a large group to which the Acacia and the Sensitive Plant belong) has a perfectly regular calyx and corolla, the latter mostly valvate in mstivation and hypogynous, as well as the stamens, which are sometimes definite, but often very numerous; and the embryo is straight. The leaves are frequently tripinnate. 772. Papilionaceve are found in every part of the world, from the tropics to the frigid zones: Cmesalpineme and Mimoseme are confined to the tropical and warmer temperate regions. - A full account of the useful plants and products of this large order would require a separate volume. Many, such as Clover, Lucerne (Medicago sativa), &c., are extensively cultivated for fodder; Peas and Beans, for pulse. The roots of the Licorice (Glycirrhiza glabra of Southern Europe) abound in a sweet mucilaginous juice, from which the pectoral extract of this name is prepared. The sweet pulp of the pods of Ceratonia Siliqua (Carob-tree of the South of Europe, &c.), of the Honey-Locust (Gleditschia), &c., is likewise eaten. The laxative pulp of Cathartocarpus Fistula, and of the Tamarind, is well known; the latter is acidulated with malic, and a little tartaric and citric acid. - A peculiar volatile principle, (called Coumarin) gives its vanilla-like fragrance to the well-known Tonka-bean, and to the Melilotus, or Sweet Clover. The flowers and seeds of the latter and of Trigonella caerulea give the peculiar odor to Scheipzeiger cheese. -Astringents and tonics are also yielded by this order: such as the African Pterocarpus erinaceus, the hardened red juice of which is Gum Kino; that of P. Draco, of Carthagena, &c., is Dragon's Blood. The bark of most Acacias and Mimosas contains a very large quantity of tannin, and is likely to prove of great importance in tanning. The valuable astringent called Catechu is obtained by boiling and evaporating the heart-wood of the Indian Acacia Catechu. — Leguminosme yield the most important coloring matters; such as the Brazil-wood, the THE POLYPETALOUS ORDERS. 419 Logwood of Campeachy (the peculiar coloring principle of which is called HIematin), and the Red Sandal-wood of Ceylon. Most important of all is Indigo, which is prepared from the fermented juice of the Indigofera tinctoria (a native of India), and also from I. caerulea, and other species of the genus. This substance is highly azotized, and is a violent poison. - To -the same order we are indebted for valuable resins and balsams; such as the Mexican Copal, Balsam of Copaiva of the West Indies, Para, and Brazil, the bitter and fragrant Balsam of Peru, and the sweet, fragrant, and stimulant Balsam of Tolu. - It also firnishes the most useful gums;' of which we need only mention Gum Tragacanth, derived from Astragalus verus of Persia, &c.; and Gum Arabic, the produce of numerous African species of Acacia. The best is said to be obtained from Acacia vera, which extends from Senegal to Egypt; while Gum Senegal is yielded by A. Verek, and some other species of the River Gambia. The Senna of commerce consists of the leaves of several species of Cassia, of Egypt and Arabia. C. Marilandica of this country is a succedaneum for the officinal article. - More acrid, or even poisonous properties, are often met with in the order. The roots of Baptisia tinctoria (called Wild In. digo, because it is said to yield a little of that substance), of the Broom, and of the Dyers' Weed (Genista tinctoria, used for dying yellow), possess such qualities; while the seeds of Laburnum, &c. are even narcotico-acrid poisons. The branches and leaves of Tephrosia, and the bark of the root of Piscidia Erythrina (Jamaica Dogwood, which is also found in Southern Florida), are commonly used in the West Indies for stupefying fish. Cowitch is the stinging hairs of the pods of Mucuna pruriens of the West, and M. pru. rita of the East, Indies.- Among the numerous valuable timbertrees, our own Locust (Robinia Pseudacacia) must be mentioned; and also the Rosewood of commerce, the produce of a Brazilian species of Mimosa. Few orders furnish so many plants cultivated for ornament. 773. Ord, Rosacere (the Rose Family). Trees, shrubs, or herbs, with alternate leaves, usually furnished with stipules. Flowers regular. — Calyx of five (rarely three or four) more or less united sepals, and often with as many bracts. Petals as many as the sepals (rarely none), mostly imbricated in estivation, inserted on the edge of a thin disc that lines the tube of the calyx. Stamens peri. gynous, indefinite, or sometimes few, distinct. Ovaries with soli 420 EXOGENOUS OR DICOTYLEDONOUS PLANTS. tary or few ovules: styles often. lateral. Albumen none. Embryo straight, with broad and flat or plano-convex cotyledons (Fig. 457). —This important order is divided into four suborders; viz.,: -'774. Subord. Chrysobalaneae (the Cocoa-plum Family). Ovary solitary, free from the calyx, or else cohering with it at the base on one side only, containing two erect ovules: style arising from the apparent base. Fruit a drupe. Trees or shrubs.- Ex. Chry. sobalanus. 775. Subord. Amygdalea (the Almond or Plum Family). Ovary solitary, free from the deciduous calyx, with two suspended ovules, and a terminal style. Fruit a drupe (Fig. 447, 448). Trees or shrubs. -Ex. Amygdalus (the Almond, Peach, &c.), Prunus (the Plum), Cerasus (the Cherry). 776. Subord. Rosacece proper, Ovaries several, numerous, or rare679 677 678 681 680 FIG. 677. The Strawberry (Fragaria). 678. Half of a flower, divided vertically, from which the petals are removed; showing the perigynous insertion of the stamens, and the enlarged receptacle, which, increasing in size, forms the pulpy, edible fruit, bearing the achenia, or real fruits, on its surface. 679. One of the carpels magnified, showing the lateral style. 680. Fruit of the Blackberry (Rubus villosus), with a longitudinal section:'here the elongated receptacle does not enlarge, but the ovaries becomd drupes. 681. Section of the endocarp; the cavity of which is filled by the seed, and that by the embryo, with its large cotyledons. 682. A flower of Sanguisorba Canadensis, enlarged. 683. Vertical section of the same in fruit; the solitary ovary inclosed by, but not coherent with, the persistent calyx-tube; the single seed with its large embryo filling the achenium. THE POLYPETALOUS ORDERS. 421 ly solitary, free from the calyx (which is often bracteolate, as i double), but sometimes inclosed in its persistent tube, in fruit becoming either follicles or achenia. Styles terminal or lateral. Herbs or shrubs.- The three tribes of this suborder are Tribe 1. SPIREJE, where the fruit is a follicle. Ex. Spirma and Gillenia. Tribe 2. DRYADE., where the fruits are achenia, or sometimes little drupes, and when numerous crowded on a conical or hemispherical torus. Ex. Dryas, Agrimonia, Potentilla, Fragaria (Strawberry), Rubus (Raspberry aud Blackberry). Tribe 3. RoSEJE, where numerous achenia cover the hollow torus which lines the urn-shaped calyx-tube; and the latter, being contracted at the mouth, and becoming fleshy or berry-like, forms a kind of false pericarp; as in the Rose. 777. Subord. Pomer (the Pear Family). Ovaries two to five, or rarely solitary, cohering with each other and with the thickened and fleshy or pulpy calyx-tube; each with one or few ascending seeds. Trees or shrubs. - Ex. Cratagus (the Thorn), Cydonia (the Quince), Pyrus (the Apple, Pear, &c.). 778. This important order is diffused through almost every part 688 684 686 685 687 689 of the world; but chiefly abounds in temperate climates, where it FIG. 684. Vertical section of an unexpanded Rose, showing the attachment of the carpels to the lining of the calyx-tube, and of the stamens and petals to its summit or edge. 6S5. Vertical section of the fruit of the Quince, exhibiting the carpels invested by the thickened calyx which forms the edible part of the fruit; one of the ovaries laid open to show the seeds. 686. A magnified seed; the rhaphe and chalaza conspicuous. 687. The embryo. 685. Cross-section of an apple. 689. Flower, &c. of the American Crab-apple (Pyrus coronaria). 36 422 EXOGENOUS OR DICOTYLEDONOUS PLANTS. furnishes the most important fruits. It is destitute of unwholesome qualities, with one or two exceptions; viz.:- 1st. The bark, leaves, and kernel of Amygdalem contain prussic acid, as is indicated by their peculiar odor, - a trace of which is perceived insome species of Spirma, and in the Mountain Ash, &c., among Pomeae; and 2d. The root of Gillenia (Bowman's Root, Indian Physic) is emetic in large doses, but in small doses it acts as a tonic. The bark and root in all are astringent. The bark of Amygdaleae also exudes gum. That of the Wild Black Cherry is febrifugal; and the timber is useful in cabinet-work. The leaves of Cerasus Caroliniana contain so much prussic acid as to destroy cattle that feed upon them. It takes the place in this country of the Cerasus Lauro-cerasus (Cherry-Laurel) of the Old World, from which the poisonous Laurel-water and the virulent Oil of Laurel are obtained. Sweet and bitter almonds are the seeds of varieties of Amygdalas communis (indigenous to the East), differing in the quantity of the prussic acid they contain: the oil of the former resembles olive-oil; that of the latter is a deadly poison. Of the Peach, Apricot, Nectarine, Plum, and Cherry, it is unnecessary to speak. The kernels, as well as the flowers, of the former, especially, abound in prussic acid. -The strawberry, raspberry, and blackberry are the principal fruits of the proper Rosaceru. The leaves of Rosa centifolia are more commonly distilled for Rose-water: and Attar of Roses is obtained from R. Damascena, &c. - Pomaceous fr.uits, such as the apple, pear, quince, services, medlar, &c., yield to none in importance: their acid is usually the malic. 779. Ord. Calycanthacete, Shrubs, with quadrangular stems (which when old exhibit four axes of growth exterior to the old wood), opposite entire leaves without stipules, and solitary, axillary and terminal, lurid flowers. Calyx of numerous somewhat thickened colored sepals, in several rows, confounded with the petals, all united below into a fleshy tube or cup, bearing numerous stamens upon its rim. Outer stamens with adnate extrorse anthers: the inner sterile. Ovaries indefinite, two-ovuled, becoming hard achenia in fruit, inserted on the whole inner surface of the disc which lines the calyx-tube, in which they are inclosed, as in the Rose. Albumen none. Cotyledons convolute. - Consists of two genera; namely, Calycanthus (Carolina Allspice, Sweet-scented Shrub, &c.), and Chimonanthus, of Japan. They are cultivated for their fragrant flowers. The bark and foliage of Caly THE POLYPETALOUS ORDERS. 423 canthus exhale a camphoric odor; and the flowers a fragrance not unlike that of strawberries. 691 692 694 693 690 697 695 780. Ord. Myrtacewt (the Myrtle Family). Trees or shrubs, with opposite and simple entire leaves, which are punctate with pellucid dots, and usually furnished with a vein running parallel with and close to the margin; without stipules. Calyx-tube adherent to the compound ovary; the limb four- or five-cleft, valvate in mstivation. Petals four or five, or sometimes wanting. Stamens indefinite, usually with long filaments and small round (introrse) anthers. Style one. Seeds usually numerous, destitute of albumen. — Ex. Myrtus, the Myrtle, is the most familiar representative of this beautiful tropical and subtropical order; which is well distinguished from its allies by its opposite dotted leaves and aromatic properties. The species abound in a pungent and aromatic volatile oil, and an astringent principle. Cloves are the dried flower-buds of Caryophyllus aromaticus. Pimento (Allspice) is the dried fruit of Eugenia Pimenta. Cajeput oil, a powerful sudorific, is distilled FIG. 690. Flowers of Calycanthus floridus. 691. Vertical section of a flower, showing the hollow receptacle, &c.; the floral envelopes cut away. 692. A stamen, seen from without. 693. A pistil. 694. Section of the ovary, showing the two ascending ovules. 695. The closed pod-shaped receptacle in fruit. 696. A vertical section of an achenium, showing the embryo of the seed. 697. Cross-section of an embryo, showing the finely convolute cotyledons. 424 EXOGENOUS OR DICOTYLEDONOUS PLANTS. from the leaves and fruit of a Melaleuca of the Moluccas. Numerous Australian species of Eucalyptus, which compose a great part of the forests of that country, yield a large quantity of tannin. The aromatic fruits of many species, filled with sugar and mucilage, and acidulated with a free acid, are highly prized; such, for instance, as the Pomegranate, the Guava, Rose-Apple, &c. 781. Ord. Melastomaceee. Trees, shrubs, or herbs, with opposite ribbed leaves, and showy flowers, with as many or twice as many stamens as petals; the anthers mostly appendaged' and opening by pores, inflexed in oestivation: further distinguished from Myrtacem by the leaves not being dotted; and from Lythraceme by the adnation of the calyx-tube (at its nerves at least) with the ovary. — Ex. The, beautiful species of Rhexia represent this remarkable order in the United States: all the rest are tropical. The berries of Melastoma are eatable, and tinge the lips black, like whortleberries; whence the generic name. 782. Ord, Lythraceve (the Loosestrife Family) is distinguished among these perigynous orders, with exalbuminous seeds, by its tubular calyx inclosing the 2 - 4-celled ovary, but entirely free'from it. The styles are perfectly united into one: the fruit, is a thin capsule. The stamens are inserted on the tube of the calyx below the petals. - Ex. Lythrum. Chiefly tropical, of little consequence. 783. Ord. Rhizophoracewe (the Mangrove Family) consists of a few tropical trees (extending into Florida and Louisiana), growing in maritime swamps; with the ovary often partly free from the calyx, two-celled, with two pendulous ovules in each cell; they are remarkable for their opposite leaves, with interpetiolar stipules, and for the germination of the embryo while within the pericarp (645). — Ex. Rhizophora, the Mangrove (Fig. 118). The astringent bark has been used as a febrifuge, and for tanning. 784. Ord, Combretaceta consists of tropical trees or shrubs (which have one or two representatives in Southern Florida), often apeta. lous, but with slender colored stamens; distinguishable from any of the preceding orders of this group by their one-celled ovary, with several suspended ovules, but only a solitary seed, and convolute cotyledons. - Ex. Combretum. Some species cultivated for ornament; some are used by tanners. The seeds of Terminalia Catappa (which extends into Florida) are eaten like almonds. 785. Ord. OnagraceEa (the Evening-Primrose Family). Herbs, or rarely shrubby plants, with alternate or opposite leaves, not dotted THE POLYPETALOUS ORDERS. 425 nor furnished With stipules. Flowers usually showy, tetramerous. Calyx adherent to the ovary, and usually produced beyond it into a tube. Petals usually four (rarely three or six, occasionally ab. sent), and the stamens as many, or twice as many, inserted into the throat of the calyx. Ovary commonly four-celled: styles united; the stigmas four, or united into one. Fruit mostly capsular. — Ex. Chiefly an American order; many are ornamental in cultivation. Fuchsia, remarkable for its colored calyx and berried fruit; (Enothera (Evening Primrose); Epilobium, where the seeds bear a coma; Gaura, where the petals are often irregular; Ludwigia, which is sometimes apetalous; and Circtea, where the lobes of the calyx, petals, stamens, cells of the ovary, and the seeds, are reduced to two; showing a connection with the appended I 698 3 701 639 702 704 786. Subord. lHalorageae, which are a sort of reduced aquatic Onagraceae, often apetalous: the solitary seeds furnished with a little albumen, as in Myriophyllum (Water-Milfoil) and Hippuris (Horse-tail), where the limb of the calyx is almost wanting; the petals none; the stamens reduced to a single one, and the ovary to a single cell, with a solitary seed. FIG. 698. Flower of CEnothera fruticosa. 699. The same, about the natural size, with the petals removed. 700. Magnified grains of pollen, with some of the intermixed cellular threads. 701. Cross-section of the four-lobed and four-celled capsule. FIG. 702. Hippuris vulgaris (suborder Haloragem). 703. Magnified flower, with the subtending leaf. 704. Vertical section of the ovary. 705. Vertical section of the fruit and seed. 36 * 426 EXOGENOUS OR DICOTYLEDONOUS PLANTS. 787. Ord. Cactacewe (the Cactus Family). Succulent shrubby plants, peculiar in habit, with spinous buds, usually leafless; the stems either subglobose and many-angled, columnar with several angles, or flattened and jointed. Flowers usually large and showy. Calyx of numerous sepals, imbricated, coherent with and crowning the one-celled ovary, or covering its whole surface; the inner usually confounded with the indefinite petals. Stamens indefinite, with long filaments, cohering with the base of the petals. Styles united: stigmas and parietal placentae several. Fruit a berry. Seeds numerous, with little or no albumen. -All American, the greater part Mexican or on the borders of Mexico. The common Opuntia (Prickly Pear) extends north to New England. The mucilaginous fruit is eatable. 788. Ord. Grossulacete (the Gooseberry Family). Small shrubs, either spiny or prickly, or unarmed; with alternate, palmatelylobed and veined leaves, usually in fascicles, often sprinkled with 714 712 706 710 711 709 7C8 707 resinous dots. Flowers in racemes or small clusters. Calyx-tube FIG. 706. The Gooseberry (Ribes Uva-crispa); a branch in flower. 707. Branch in fruit. 708. The calyx, bearing the petals and stamens, cut away from the summit of the ovary (709), and laid open. 710, 711. Sections of the unripe fruit. 712. Magnified seed (anatropous). 713. The same from the ripe fruit, where the rhaphe separates from the side of the seed, and forms a part of the funiculus. 714. Longitudinal section of the same, showing the minute embryo at the extremity of the albumen. THE POLYPETALOUS ORDERS. 427 adherent to the one-celled ovary, and more or less produced beyond it, five-lobed, sometimes colored. Petals (small) and stamens five, inserted on the calyx. Ovary with two parietal placentae: styles more or less united. Fruit a many-seeded berry, crowned with the shrivelled remains of the flower. Embryo minute, in hard albumen. - Ex. Ribes (Gooseberry and Currant). Natives of temperate and colder regions, chiefly of the northern hemisphere. Never unwholesome: the fruit usually esculent, containing mucilaginous and saccharine pulp, with more or less malic or citric acid: Several Oregon and Californian species are showy in cultivation. 789. Ord. Loasacae,. Herbs usually clothed with rigid or stinging hairs; the leaves opposite or alternate, without stipules; the flowers showy. Calyx-tube adherent to the one-celled ovary; the limb mostly five-parted. Petals as many, or twice as many, as the lobes of the calyx. Stamens perigynous, indefinite, and in several parcels, or sometimes definite. Style single. Ovary with three to five parietal placentae. Seeds few or numerous, albuminous. - Ex. Loasa, Mentzelia, Cevallia; the latter with solitary seeds and no albumen. All American, and in the United States nearly confined to the regions beyond the Mississippi. The bristles of Loasa sting like nettles. 790. Ord. Turneracete. Herbs, with the habit of Cistus or Helil anthemum; the alternate leaves without stipules. Flowers solitary, showy. Calyx five-lobed; the five petals and five stamens inserted on its throat. Ovary free from the calyx, one-celled, with three parietal placentae. Styles distinct, commonly branched or many-cleft at the summit. Fruit a three-valved capsule. Seeds numerous (anatropous), with a crustaceous and reticulated testa, and a membranaceous aril on one side. Embryo in fleshy albumen. - Ex. Turnera, of which there is one species in Georgia. 791. Ord. Passifloraceat (the Passion-flower Family). Herbs, or somewhat shrubby plants, climbing by tendrils; with alternate, entire, or palmately lobed leaves, mostly furnished with stipules. Flowers often showy, sometimes involucrate. Calyx mostly of five sepals, united below, free from the one-celled ovary; the throat bearing five petals and a filamentous crown. Stamens as many as the sepals, monadelphous, and adhering to the stalk of the ovary, which has usually three club-shaped styles or stigmas, and as many parietal placentm. Fruit mostly fleshy or berry-like. 428 EXOGENOUS OR DICOTYLEDONOUS PLANTS. Seeds numerous, with a brittle sculptured testa, inclosed in pulp. Embryo inclosed in thin, fleshy albumen. - Ex. Passiflora (the Passion-flower, Granadilla): nearly all natives of tropical America. Two species are found as far north as Virginia and Ohio. Many are cultivated for their singular and showy flowers. The acidulous refrigerant pulp of Passiflora quadrangularis (the Granadilla), P. edulis, and others, is eaten in the West Indies, &c. But the roots are emetic, narcotic, and poisonous. They contain a principle resembling morphine, which, in some species, extends even to the flowers and fruit. 792. Ord. Papayacer comprises merely a small genus of tropical dioecious trees, of peculiar character: the principal one is the Papaw-tree (Carica Papaya) of tropical America, which has been introduced into East Florida. The fruit, when cooked, is eatable; but the juice of the unripe fruit, as-well as of other parts of the plant, is a powerful vermifuge. The juice contains so much fibrine that it has an extraordinary resemblance to animal matter: meat washed in water impregnated with this juice is rendered tender; even the exhalations from the tree produce the same effect upon meat suspended among the leaves. 793. Ord. Cucurbitaceu (the Gourd FamilD). Juicy herbs, climbing by tendrils; with alternate, palmately veined or lobed, rough leaves, and moncecious or dicecious flowers. Calyx of four or five (rarely six) sepals, united into a tube, and in the fertile flowers adherent to the ovary. Petals as many as the sepals, commonly more or less united into a monopetalous corolla, which coheres with the calyx. Stamens five or three, inserted into the base of the corolla or calyx, either distinct or variously united by their filaments, and long, sinuous or contorted anthers. Ovary two- to fivecelled (rarely one-celled by obliteration, and even one-ovuled); the thick and fleshy placenta often filling the cells, or diverging before or after reaching the axis and carried back so as to reach the walls of the pericarp, sometimes manifestly parietal; the dissepiments often disappearing during its growth: stigmas thick, dilated or fringed. Fruit (pepo, 613) usually fleshy, with a hard rind, sometimes membranous. Seeds mostly flat, with no albumen. Embryo straight. Cotyledons foliaceous. - Ex. The Pumpkin and Squash (Cucurbita), Gourd, Cucumber, and Melon. When the acrid principle which prevails throughout the order is greatly diffused, the fruits are eatable and sometimes delicious: when con THE POLYPETALOUS ORDERS. 429 centrated, as in the Bottle Gourd, Bryony, &c., they are dangerous or actively poisonous. The officinal Colocynth, a resinoid, bitter extract from the pulp of Cucumis Colocynthis (of the Levant, India, &c.), is very acrid and poisonous; and Elaterium, obtained from the juice of the Squirting Cucumber (Momordica Elaterium of the South of Europe), is still more violent in its effects. Momordica Balsamina (the cultivated Balsam-Apple) contains the same principle in smaller quantity. The seeds of all are harmless. 716 720 715 718 719 794. Ord. Crassulacece (the Orpine Family). Herbs, or slightly shrubby plants, mostly fleshy or succulent; with scattered leaves, and flowers usually in cymes or racemes. Calyx of three to twenty sepals, more or less united at the base, free from the ovaries, persistent. Petals as many as the sepals, rarely combined into a monopetalous corolla. Stamens as many or twice as many as the sepals, inserted with the petals on the base of the calyx. Pistils always as many as the sepals, distinct, or rarely (in Penthorum and Diamorpha) partly united: ovaries becoming follicles in fruit, several-seeded. Embryo straight, in thin albumen. —Ex. Sedum (Stone-crop, Orpine, Live-for-ever), Crassula, Sempervivum, or Houseleek, &c. Distinguished by their completely symmetrical flowers, on which account they have already been illustrated (449, 450). They mostly grow in arid places: of no economical importance. FIG. 715. Staminate flower of the Gourd; the calyx and corolla cut away. 716. Cross-section of the united anthers. 718. Separate stamen of the Melon. 719. Section of the ovary of the Gourd. 720. Plan of one of the three constituent carpets. 430 EXOGENOUS OR DICOTYLEDONOUS PLANTS. 795. Ord. Saxifragaceem (the Saxifrage Family). Herbs or shrubs, with alternate or opposite leaves. Calyx of four or five more or less united sepals, either free from or more or less adherent to the ovary, persistent. Petals as many as the sepals, rarely wanting. Stamens as many, commonly twice as many, or rarely three or four times as many, as the sepals, perigynous. Ovaries mostly two (sometimes three or four), usually united below and distinct at the summit. Seeds numerous, with a straight embryo in fleshy albumen. There are three principal divisions, or suborders; viz. - 721 726 725 724 723 722 796. Subord. Saxifragcm (the true Saxifrage Family). Herbs. Petals imbricate in mestivation. Capsule (when the carpels are united) either two-celled with the placentae in the axis, or onecelled with parietal placentae. - Ex. Saxifraga, Sullivantia (Fig. 721), Heuchera. Of little consequence, except as ornamental plants. The roots are generally astringent; powerfully so in Heuchera, especially in the common H. Americana (sometimes called Alum-root). FIG. 721. Sullivantia Ohionis. 722. Flower with the calyx laid open, somewhat enlarged. 723. Fruit surrounded by the persistent calyx and withered petals, enlarged. 724. Section of the lower part of the capsule, magnified; showing the central placenta covered with the ascending seeds. 725. A magnified seed, with its cellular, wing-like testa. 726. Section of the nucleus, showing the embryo in the midst of albumen. THE POLYPETALOUS ORDERS. 431 797. Subord. lHydrangeae (the Hydrangea Family). Shrubs. Petals valvate in aestivation. Capsule two- (rarely five- to ten-) celled: the styles or stigmas distinct or united. Stamens sometimes numerous. - Ex. Hydrangea, Decumaria. 798. Subord. Philadelphew (the Mock Orange Family). Shrubs. Petals convolute in Testivation. Capsule three- or four-celled: styles more or less united. Stamens mostly numerous. - Ex. Philadelphus, the Mock Orange. 799. Ord. HJamamelacee (the Witch-Hazel Family). Shrubs or small trees, with alternate simple leaves, without stipules. Flowers often polygamous. Petals valvate in mestivation. Stamens twice as many as the petals, half of them sterile; or numerous, and the petals none. Summit of the ovary free from the calyx, a single ovule suspended from the summit of each cell: styles two, distinct. Capsules cartilaginous or bony. Seeds bony, with a small embryo in hard albumen. - Ex. Hamamelis (Witch-Hazel), Fothergilla. A small order, of little importance. Hamamelis is remarkable for flowering late in autumn, just as its leaves are falling, and perfecting its fruit the following spring. 800. Ord. Umbellifekr (the Parsley Family). Herbs, with hollow stems, and alternate, dissected leaves, with the petioles sheathing or dilated at the base. Flowers in simple or mostly compound umbels, which are occasionally contracted into a kind of head. Calyx entirely coherent with the surface of the dicarpellary ovary; its limb reduced to a mere border, or to five small teeth. Petals five, valvate in aestivation, inserted, with the five stamens, on a disc which crowns the ovary; their points inflexed. Styles two; their bases often united and thickened, forming a stylopodium. Fruit dry, separating from each other, and often from a slender axis (carpophore), into two indehiscent carpels (called mericarps): the face by which these cohere receives the technical name of com. missure: they are marked with a definite number of ribs (juga), which are sometimes produced into wings: the intervening spaces (intervals), as well as the commissure, sometimes contain canals or receptacles of volatile oil, called vittce: these are the principal terms peculiarly employed in describing the plants of this difficult family. Embryo minute. Albumen hard or corneous. - Ex. The Carrot, Parsnip, Celery, Caraway, Anise, Coriander, Poison Hem. lock, &c. are common representatives of this well-known family. Nearly all Umbelliferous plants are furnished with a volatile oil or 432 EXOGENOUS OR DICOTYLEDONOUS PLANTS. balsam, chiefly accumulated in the roots and in the reservoirs of the fruit, upon which their aromatic and carminative properties depend: sometimes it is small in quantity, so as merely to flavor the saccharine roots which are used for food; as in the Carrot and Parsnip. But in many an alkaloid principle exists, pervading the foliage, stems, and roots, especially the latter, which renders them 730 729 728 732 731 727 acrid-narcotic poisons. And finally, many species of warm regions yield odorous gum-resins (such as Galbanum, Assafcetida, &c.), which have active stimulant properties. The stems of Celery (Apium graveolens), which are acrid and poisonous when the plant grows wild in marshes, &c., are rendered innocent by cultivation in dry ground, and by blanching. Among the virulent acrid-narcotic species, the most famous are the Hemlock (Conium maculatum, naturalized in this country), and Cicuta maculata (Cowbane, Water-Hemlock) indigenous to this country, the root of which (like that of the C. virosa of Europe) is a deadly poiFIG. 727. Conium maculatum (Poison Hemlock), a portion of the spotted stem, with a leaf; and an umbel with young fruit. 728. A flower umbellet. 729. A fower, enlarged. 730. The fruit. 731. Cross-section of the same, showing the involute (caelospermous) albumen of the two seeds. 732. Longitudinal section of one mericarp, exhibiting the minute embryo near the apex of the albumen. THE POLYPETALOUS ORDERS. 433 son. A drachm of the fresh root has killed a boy in less than two hours. 735 737 734 733 801. Ord. Araliacete (the Spikenard Family). A small family, scarcely differing from Umbelliferoe in botanical character, except that the ovary is mostly composed of more than two carpels, which do not separate when ripe, but become drupes or berries; and the albumen is not hard like horn, but only fleshy. - Ex. Aralia (the Spikenard, the Wild Sarsaparilla, and the Angelica-tree), Panax (Ginseng), and Hedera (the Ivy). Their properties are aromatic, stimulant, somewhat tonic, and alterative. 738 739 740 802. Ord. Cornacce (the Cornel Family). Chiefly trees or shrubs; with the leaves almost always opposite, destitute of stipules. Flowers in cymes, sometimes in heads surrounded by colored involucres. Calyx coherent with the two-celled ovary; the very small FIG. 733. Flower of Osmorrhiza longistylis. 734. Umbel of the same in fruit: a, the involucels. 735. The ripe mericarps separating from the axis or carpophore. 736. Cross-section of the fruit of Angelica, where the lateral ribs are produced into wings: the black dots represent the vitte, as they appear in a cross-section. 737. One of the mericarps of the same, showing the inner face, or commissure, as well as the transverse section, with two of the vittme, a. FIG. 738. Flower of Aralia nudicaulis (Wild Sarsaparilla); a vertical section, displaying two of the cells of the ovary. 739. Cross-section of the ovary. 740. Longitudinal section of a seed, magnified, showing the small embryo at the upper end. 37 434 EXOGENOUS OR DICOTYLEDONOUS PLANTS. limb four-toothed. Petals four, valvate in oestivation. Stamens four, alternate with the petals. Styles united into one. Fruit a two-celled drupe. - Ex. Cornus, the Dogwood. Chiefly remarkable for their bitter and astringent bark, which in this country has been substituted for Cinchona. The peculiar principle they contain is named Cornine. Cornus Canadensis (Fig. 240) is a low and herbaceous species. Division II. - MONOPETALOUS OR GAMOPETALOUS EXOGENOUS PLANTS.* Floral envelopes consisting of both calyx and corolla: the petals more or less united (corolla gamopetalous). CONSPECTUS OF THE ORDERS. Group 1. Ovary coherent with the calyx, two- to several-celled, with one or many ovules in each cell. Seeds albuminous, with a small embryo. Stamens inserted on the corolla. Leaves opposite. Stipules wanting. CAPRIFOLIACEE, p. 436. Stipules interpetiolar (or leaves whorled). RUBIACEA, p. 437. Group 2. Ovary coherent with the calyx, one-celled and one-ovuled; rarely three-celled with two of the cells empty. Seeds with little or no albumen. Stamens inserted on the corolla. Calyx a mere ring, crown, or pappus, or obsolete. Fruit like an achenium. Stamens distinct. Seeds suspended. Stamens 3 or fewer. VALERIANACEAz, p. 439. Stamens 4. Heads involucrate. DIPSACEXE,p. 440. Stamens syngenesious. Seed erect. CbMPOSIT2E, p. 441. Group 3. Ovary coherent with the calyx, with two or more cells and numerous ovules. Seeds albuminous. Satmens inserted with the corolla (epigyncous): anthers not opening by pores. Corolla irregular. Stamens united in a tube. LOBELIACE2E, p. 443. Corolla regular. Stamens distinct. CAMPAEULACEIE, p. 444. Group 4. Ovary free from the calyx, or sometimes coherent with it, with two or more cells and numerous ovules. Seeds albuminous. Stamens inserted with the corolla, or rarely coherent with its base, as many, or twice as many, as its lobes: anthers mostly opening by pores or chinks. * Cucurbitacexe, placed in the Polypetalous series, are commonly somewhat gamopetalous: so are some exotic Crassulaceve, &c. THE MONOPETALOUS ORDERS. 435 Anthers two-celled. ERICACEX, p. 444. Anthers one-celled. EPACRIDACEE, p. 447. Groutp 5. Ovary free, or rarely coherent with the calyx, several-celled, with a single ovule (or at least a single seed) in each cell. Seeds mostly albuminous. Stamens definite, as many as the lobes of the (sometimes almost polypetalous) corolla and alternate with them, or two to four times as many: anthers not opening by pores. - Trees or shrubs. Stamens as many as the lobes of the corolla and alternate with them. AQUIFOLIACEAE, p. 447. Stamens more numerous and all fertile. Flowers polygamous: calyx free. EBENACEBE, p. 447. Flowers perfect: calyx more or less adnate. STYRACACEX, p. 448. Stamens as many fertile as there are lobes of the corolla and opposite them; and with a sterile series alternate between them. SAPOTACEFE, p. 448. Group 6. Ovary free, or with the base merely coherent with the tube of the calyx, one-celled, with a free central placenta. Stamens inserted into the regular corolla opposite its lobes! which they equal in number. Seeds albuminous. Shrubs or trees: fruit drupaceous. MYRSINACEA{, p. 448. Herbs: fruit capsular. PRIMULACEJ, p. 448. Group 7. Ovary free, one-celled, with a single ovule; or two-celled with several ovules attached to a thick central placenta. Stamens as many as the lobes of the regular corolla or the nearly distinct petals. Seeds albuminous. Ovary two-celled: style single: stamens 4. PLANTAGINACE2E, p. 449. Ovary one-celled: styles and stamens 5. PLUMBAGINACEE, p. 450. Group 8. Ovary free, one- or two- (or spuriously four-) celled, with numerous ovules. Corolla bilabiate or irregular; the stamens inserted upon its tube, and mostly fewer than its lobes. Ovary one-celled with a central placenta. Stam. 2. LENTIBULACEJE, p. 451. Ovary one-celled with parietal placenta. OROBANCHACE-E, p. 451. Ovary spuriously 4- 5-celled: seeds exalbuminous. Subord. SEsAxMEr, p. 452. Ovary two-celled: placenta in the axis. Seeds indefinite, winged: albumen none. BIGNONIACEM, p. 452. Seeds, few, wingless: albumen none. Corolla convolute in aestivation. ACANTHACEE, p. 452. Seeds mostly iindefinite: albumen copious. Corolla imbricative in estivation. SCROPHULARIACEX, p. 453. Group 9. Ovary free, two- to four-lobed, and separating or splitting into as many one-seeded nuts or achenia, or drupaceous. Corolla regular or irregular; the stamens inserted on its tube, equal in number or fewer than its lobes. Albumen little or none. Stamens 4, didynamous, or 2. Corolla more or less irregular. Ovary not 4-lobed. VERBENACEE, p. 454. 436 EXOGENOUS OR DICOTYLEDONOUS PLANTS. Ovary 4-lobed, forming 4 achenia. LABIAT2E, p. 455. Stamens 5. Flower regular. Leaves alternate. BORAGINACEIE, p. 456. Group 10. Ovary free, compound, or the carpels two or more and distinct: the ovules usually several or numerous. Corolla regular; the stamens inserted upon its tube, as many as the lobes and alternate with them. Seeds albuminous. * Ovary compound (of two or more united carpels). Placentae 2, parietal (sometimes expanded). Embryo minute. Corolla not valvate in sestivation. Leaves lobed, mostly alternate. Seeds few. HYDROPHYLLACEX, p. 457. Leaves entire, opposite. Seeds indefinite. GENTIANACEIE, p. 462. Corolla valvate-induplicate in mestivation. Subord. MENYANTHIDEr, p. 462. Placentae in the axis: ovary 2 - 3-celled. Embryo large, bent or coiled, with little albumen. Seeds one or two in each cell. CONVOLVULACE, p. 459. Embryo straight or arcuate, in copious albumen. Styles 2, distinct. Seeds indefinite. HYDROLEACEXE, p. 458. Styles united nearly or quite to the summit. Ovary 3-celled. Cor. convolute in astivation. POLEMONIACEAE, p. 458. Ovary 3-celled. Cor. imbricated in a3stivation. DIAPENSIACEm, p. 458. Ovary 2-celled. Corolla plaited or valvate in aestivation. SOLANACEE, p. 461. ~ * Ovaries mostly two and distinct, at least in fruit. Anthers introrse: pollen granular. APOCYNACERE, p. 463. Anthers extrorse: pollen in waxy masses. ASCLEPIADACE2E, p. 463. Group 11. Ovary free, two-celled, few-ovuled; the cells of the fruit oneseeded. Corolla regular (sometimes nearly polypetalous or wanting); the stamens (two) fewer than its lobes. - Shrubs or trees. Seeds erect. Cor. imbricated or contorted in westivation. JASMINACE3E, p. 464. Seeds suspended. Corolla valvate in aestivation. OLEACEAE, p. 465. 803. Ord. Caprifoliaceme (the Honeysuckle Family). Mostly shrubs, often twining, with opposite leaves, and no stipules. Calyx-tube adnate to the 2- 5-celled ovary; the limb 4- 5-cleft. Corolla regular or irregular. Stamens inserted on the corolla, as many as the petals of which it is composed, and alternate with them, or rarely one fewer. Fruit mostly a berry or drupe. Seeds pen. dulous, albuminous. - Ex. The Honeysuckles (Lonicera), which have usually a peculiar bilabiate corolla (470, Fig. 743), the Snowberry (Symphoricarpus), Diervilla, which has a capsular fruit, &c., compose the tribe LONICEREE, characterized by their tubular flowers and filiform style: while the Elder (Sambucus) and Viburnum, which have a rotate or urn-shaped corolla, form the tribe SAMBUCEM. These plants chiefly belong to temperate THE MONOPETALOUS'ORDERS. 437 regions. Several are widely cultivated for ornament. They are generally bitter, and rather active or nauseous in their properties: but the fruit of some few is edible. r'\ 741 743 742 744 804. Ord. Rubiaaen (the Madder Family). Shrubs or trees, or often herbs, with the entire leaves either in whorls, or opposite and furnished with stipules. Calyx-tube completely, or rarely in. completely, adnate to the 2 - 5-celled ovary; the limb four- or fivecleft or toothed, or occasionally obsolete. Stamens as many as the lobes of the regular 6orolla, and alternate with them, inserted on the tube. Fruit various. Seeds albuminous. - This extensive family divides into two suborders, to which a third may be appended, which differs in the free ovary, and is by most botanists deemed a distinct order. 805. Subord. Stellatere (the true Madder Family). Herbs, with the leaves in whorls; but all except a single pair are generally supposed to take the place of stipules. - Ex. Galium, Rubia (the Madder), &c., nearly all belonging to the colder parts of the world. 806. Subord Cinchonere (the Peruvian-Bark Family). Shrubs, trees, or herbs; the leaves opposite and furnished with stipules, FIG. 741. Branch of Lonicera (Xylosteon) oblongifolia: the two ovaries united! 742. Lonicera (Caprifolium) parviflora. 743. A flower about the natural size. 744. Longitudinal section of the ovary. 745. Longitudinal section of a magnified seed, showing the albumen and minute embryo. 37 * 43S EXOGENOUS OR DICOTYLEDONOUS PLANTS. which are very various in form and appearance. - Ex. Cephalanthus (Button-bush), Hedyotis, and an immense number of tropical genera. Their stipules distinguish them from Caprifoliacee. 807. Subord. Loganiem, or Spigeliew, have opposite stipulate leaves, and the ovary nearly or entirely free from the persistent calyx.Ex. Mitreola, Spigelia (the Pink-root), and other genera intermediate between Rubiaceoe and Apocynaceae. 808. Very active, and generally febrifugal properties prevail in this large order. The roots of Madder yield a most important dye: and many Galiums have a similar red coloring matter. — 749 750 753 752 748 746 751 The division Cinchonee furnishes two of the most valuable known remedial agents, namely, Peruvian bark, or Cinchona, and Ipecacuanha. The febrifugal properties of the former depend on the presence of two alkalis, Cinchonia and Quinia, both combined with Kinic acid. The Quinquina barks, which are derived from some species of Exostemma and other West Indian, Mexican, and Brazilian genera, contain neither cinchonia nor quinia. The bark of Pinckneya pubens, of the Southern United States, has been substituted for Cinchona.- The true Ipecacuanha is furnished by the FIG. 746. Piece of Rubia tinctoria (the Madder) in flower. 747. The fruit. 748. The two constituent portions of the fruit separating. 749. Vertical section of one carpel, showing the curved embryo. 750. Section of a flower of Galium. FIG. 751. Cephalanthus occidentalis, the Button-Bush. 752. A flower, taken from the head. 753. The corolla laid open. THE MONOPETALOUS ORDERS. 439 roots of Cepha]lis Ipecacuanha of Brazil and the mountains of New Granada. Its emetic principle (called Emetine) also exists in Psychotria emetica of New Granada, which furnishes the striated, black, or Peruvian Ipecacuanha. Coffee is the horny seed (albumen) of Coffiea Arabica. According to Blume, the leaves of the Coffee-plant are used as a substitute for tea in Java.- The roots and leaves of Spigelia Marilandica (Carolina Pink-root) form a well-known vermifuge. 762 756 760 758 7 761 759 754 755 809. Ord, Valerianacec (the Valerian Family). Herbs with opposite leaves, and no stipules. Flowers often in cymes, panicles, or heads. Limb of the adnate calyx two- to four-toothed, obsolete, or else forming a kind of pappus. Corolla tubular or funnel-form, sometimes with a spur at the base, four- or five-lobed. Stamens distinct, inserted on the corolla, usually fewer than its lobes. Ovary one-ovuled, with one perfect cell and two abortive ones. Fruit a kind of achenium. Seed suspended, exalbuminous. Embryo straight. Radicle superior. - Ex. Valeriana, the Valerian; Fedia, the Lamb-lettuce: the latter is eaten as a salad. The roots, &c. of the perennial species exhale a heavy and peculiar FIG. 754. Hedyotis (Houstonia) cerrulea. 755, 756. The two sorts of flowers that different individuals bear, with the corolla laid open; one with the stamens at the base, the other at the summit of the tube: the lower figure shows also a section of the ovary. 757. Cross-section of an anther, magnified. 758. Anther less enlarged, opening longitudinally. 759. Capsule with the calyx. 760, 761. Views of the capsule in dehiscence. 762. Diagram of a cross-section of the unexpanded flower. 440 EXOGENOUS OR DICOTYLEDONOUS PLANTS. odor, have a somewhat bitter, acrid taste, and are antispasmodic and vermifugal. The Valerian- of the shops is chiefly derived from Valeriana officinalis of the South of Europe. It produces a peculiar intoxication in cats. The roots of V. edulis are used for food by the aborigines of Oregon. The Spikenard of the ancients, esteemed as a stimulant medicine as well as a perfume, is the root of Nardostachys Jatamansi of the mountains of the North of India. 764 767 765 766 763 768 810. Ord. Dipsacet (the Teasel Family). Herbs, with opposite or whorled sessile leaves, destitute of stipules. Flowers in dense heads, which are surrounded by an involucre. Limb of the adnate calyx cup-shaped and entire or toothed, or forming a bristly or plumose pappus. Corolla tubular; the limb four- or five-lobed, somewhat irregular. Stamens four, distinct, or rarely united in pairs, often unequal, inserted on the coralla. Ovary one-celled, one-ovuled. Seed suspended, albuminous. —Ex. Dipsacus, the Teasel, and Scabiosa, or Scabious. All natives of the Old World. Some are cultivated for ornament. Teasels are the dried heads of Dipsacus Fullonum, covered with stiff and spiny bracts, with recurved points. FIG. 763. Branch of Fedia Fagopyrum. 764. A magnified flower. 765. A fruit. 766. An enlarged cross-section of the same, and the cotyledons of the seed in the single fertile cell: the two empty cells are confluent into one. FIG. 767. Flower of a Valerian, with one of the pappus-like bristles of the calyx unrolled. 768. Section through the ovary and embryo; the bristles of the calyx broken away. THE MONOPETALOUS ORDERS. 441 811. Ord, Composite (the Composite or Sunflower Family). Herbs or shrubs; with the flowers in heads (compound flowers of the older botanists), crowded on a receptacle, and surrounded by a set of bracts (scales) forming an involucre; the separate flowers often furnished with bractlets (chaff, paleae). Limb of the adnate calyx obsolete, or a pappus (305), consisting of hairs, bristles, scales, &c. Corolla regular or irregular. Stamens five, as many as the lobes or teeth 769 770 of the regular corolla, inserted on its tube: anthers united into a tube (syngenesious, Fig. 769). Style twocleft. Fruit an achenium, with a single erect exalbuminous seed, either naked or crowned with a pappus. Embryo straight. - This vast but very natural family is divided into three sets or suborders; viz.: 812. Subord. Tubuliflorm, Corolla tubular and regularly four- or five-lobed, either in all the flowers (when the head is discoid), or in the central ones (those of the disc) only, the marginal'or ray-flowers presenting a ligulate or strap-shaped corolla. - Ex. Liatris, Eupatoriurn, &c.; where the heads are homogamous, that is, the flowers all tubular, similar, and perfect: Helianthus (Sunflower), Helenium, Aster, &c.; where the heads are heterogamous; the disc flowers being tubular and perfect, while those of the ray are Zigulate, and either pistillate only, or neutral (473, note), that is, destitute of both stamens and pistils. 813. Subord. Labiatiflore. Corolla of the disc-flowers bilabiate. - Ex. Chaptalia, of the United States, Mutisia, Choetanthera, &c., of South America. 814. Subord. Liguliflorae. Corolla of all the flowers (both disc and ray) ligulate; all perfect. - Ex. The Dandelion, Lettuce, Cichory, &c. 815. This vast family comprises about a tenth part of all Phenogamous plants. A bitter and astringent principle pervades the whole order; which in some is tonic (as in the Camomile, Anthemis nobilis, the Boneset, or Thoroughwort, Eupatorium perfoliatum, &c.); in others, combined with mucilage, so that they are dernulcent as well as tonic (as in Elecampane and Coltsfoot); in many, aromatic and extremely bitter (such as Wormwood and'all the speFIG. 769. Syngenesious stamens of a Composita. 770. The anthers laid open. 442 EXOGENOUS OR DICOTYLEDONOUS PLANTS. cies of Artemisia); sometimes accompanied by acrid qualities, as in the Tansy (Tanacetum vulgare), and the Mayweed (Maruta Cotula), the bruised fresh herbage of which blisters the skin. The species of Liatris, which abound in terebinthine juice, are among the reputed remedies for the bites of serpents. The juice of Silphium and of some Sunflowers is resinous. The leaves of Solidago odora, which owe their pleasant anisate fragrance to a peculiar volatile oil, are infused as a substitute for tea. From the seeds of Sunflower, and several other plants of the order, a bland 774 775 776 777 778 782 7779 W'4 < 771 772 773 780 781 oil is expressed. The tubers of Helianthus tuberosus are eaten FIG. 771. Head of Liatris squarrosa (discoid; the flowers all tubular and perfect). 772. The same, with the scales of one side of the imbricated involucre removed; and also all the flowers but one, showing the naked flat receptacle. 773. Portion of one of the plumose bristles of the capillary pappus. 774. Head of Helenium autumnale (heterogamous); the rays neutral, consisting merely of a ligulate corolla. 775. The same, with the flowers all removed from the roundish receptacle, except a single disc-flower and one or two rays: the reflexed scales of the involucre in a single series. 776. Magnified disc-flower of the same: the corolla exhibiting the peculiar venation of the family; namely, the veins corresponding to the sinuses, and sending a branch along the margins of the lobes. 777. The same with the corolla removed; the achenium crowned with the limb of the calyx in the form of a chaffy pappus, of about five scales. 778. A chaff of the pappus more magnified. 779. A tubular, corolla of this family laid open, showing the venation; and also the five syngenesious anthers united in a tube, through which the twocleft style passes. 780. Head of Dracopis amplexicaulis, with the flowers removed from the elongated spike-like receptacle, except a few at the base: a, achenium of one of the disc-flowers, magnified, partly inclosed by its bracelet (chaff or palea); the pappus obsolete. 781. Part of the involucre and alveolate (honeycomb-like) receptacle of Onopordton or Cotton-Thistle. 782. A perfect and ligulate flower of the Dandelion, with its hair-like or capillary pappus. THE MONOPETALOUS ORDERS. 443 under the name of Jerusalem artichokes. True artichokes are the fleshy receptacle of Cynara Scolymus. The flowers of Carthamus tinctorius, often called Saffron, yield a yellow dye. - The Ligulifioroe, or Cichoraceue, all have a milky juice, which is narcotic, and has been employed as a substitute for opium. The bland young leaves of the Garden Lettuce are a common salad. The roasted roots of the Wild Succory (Cichorium Intybus) are extensively used to adulterate coffee: and the roots of some species of Tragopogon (Salsify, Oyster-plant) and Scorzonera are well-known esculents. 816. Ord. Lobeliacece (the Lobelia Family). Herbs or somewhat shrubby plants, often yielding a milky juice, with alternate leaves and usually showy flowers. Limb of the adnate calyx five-cleft. Corolla irregularly five-lobed, usually appearing bilabiate, cleft on one side nearly or quite to the base. Stamens 5, epigynous, co783 78 788 8 783 784 788 herent into a tube. Stigma fringed. Fruit capsular, two- or threeFIG. 783. Campanula rotundifolia, much reduced in size. 784. Lobelia inflata, rqduced in size. 785. A flower, enlarged. 786. The united filaments and anthers inclosing the style; the corolla and limb of the calyx cut away. 787. The stigma surrounded by a fringe. 788. Tranaverse section of a capsule. 789. Section of a magnified seed, showing the embryo. 444 EXOGENOUS OR DICOTYLEDONOUS PLANTS. (rarely one-) celled, many-seeded. Seeds albuminous. - Ex. Lobelia. All narcotico-acrid poisons. The well-known Lobelia inflata (Indian Tobacco) is one of the most powerful articles of the materia medica, and the most dangerous in the hands of the reckless quacks who use it. Less than a teaspoonful of the seeds or powdered leaves will destroy life in a few hours. 817. Ord. Campanulaceae (the Campanula Family). Herbs, with a milky (slightly acrid) juice, alternate leaves, and usually showy flowers. Tube of the calyx adnate, the limb commonly five-cleft, persistent. Corolla regular, campanulate, usually five-lobed, withering. Stamens five, distinct. Style furnished with collecting hairs. Capsule two- to several-celled, many-seeded. Seeds albuminous. - Ex. Campanula (Bell-flower, Harebell). Of little importance, except for ornament. 818. Ord. Ericaceae (the Heath Family). Shrubs or sometimes herbs. Flowers regular or nearly so, 4-5-merous, the petals sometimes distinct. Stamens mostly distinct, free from the corolla, as many or twice as many as its lobes, and inserted with it (either hypogynous or epigynous), anthers two-celled, often appendaged, commonly opening by terminal pores. Styles and stigmas united into one. Ovary with two or more cells and usually numerous ovules, free, or in Vaccineme coherent with the calyxtube. Seeds usually indefinite, albuminous. - Some botanists give the rank of orders to the following suborders. 790 792 793 791 819. Subhord. Vacciniee (the Whortleberry Family). Ovary adnate FIG. 790. Branch of Rhododendron Lapponicum. 791. Enlarged flower, with its pedicel and bracts. 792. Flower with the corolla removed, more enlarged. 793. Capsule of R. maximum, opening by septicidal dehiscence; the valves breaking away froni the persistent axis, or columella. THE MONOPETALOUS ORDERS. 445 to the tube of the calyx, becoming a berry or a drupe-like fruit. Shrubs, with scattered leaves, often evergreen. — Ex. Vaccinium (Whortleberry), Oxycoccus (the Cranberry). 820. Subord. Ericinete (the proper Heath Family). Ovary free from the calyx. Fruit capsular, sometimes baccate or drupaceous. Testa conformed to the nucleus of the seed. Mostly shrubs. Leaves various, often evergreen. Petals rarely almost or entirely distinct. - Ex. Erica (Heath), Kalmia, Rhododendron, Gaultheria, Andromeda, &c. 801 802 803 804 799 80578797 790798 799 800 794 797 796 821. Subord, Pyrolea (the Pyrola Family). Ovary free from the calyx. Petals distinct or nearly so. Fruit a capsule. Seeds with FIG. 791. Gaultheria procumbens (Wintergreen, &c.). 795. The enlarging calyx in the immature fruit. 796. Vertical section of the pulpy or berry-like calyx and the included capsule (the seeds removed from the placenta in one cell). 797. Horizontal section of the same, showing the five-celled capsule, with a placenta proceeding from the inner angle of each cell. 798. Section of a seed, magnified. 799. Flower of a Vaccinium (Whortleberry). 800. Vertical section of the ovary and adherent calyx. 801. Anther of Vaccinium Vitis-Idtea; each cell prolonged into a tube, and opening by a terminal pore. 802. Anther of Vaccinium Myrtillus; the connectivum furnished with two appendages. 803. Stamen of an Andromeda (Cassiope), showing the appendages of the connectivum. 804. Stamen of Arctostaphylos Uva-Ursi, showing the separate anther-cells, opening by a terminal pore, the appendages of the connectivumrn and the filament, which is swollen at the base. 38 446 EXOGENOUS OR DICOTYLEDONOUS, PLANTS. a loose cellular testa, not conformed to the nucleus. Mostly herbs. Leaves flat and broad. - Ex. Pyrola, Chimaphila. 822. Subord, Monotropeac (the Indian-Pipe Family). Ovary free from the calyx. Petals distinct or united. Anthers opening longitudinally or by transverse chinks. Fruit a capsule. Seeds with a loose or winged testa. Parasitic herbs, destitute of green color, and with scales instead of leaves. - Ex. Monotropa, the Indian Pipe. - In this widely diffused order the bark and foliage are generally astringent, often stimulant or aromatic from a volatile oil or a resinous matter, and not seldom narcotic. Thus, the leaves of Rhododendron, Kalmia, and all the related plants, are deleterious (being stimulant narcotics), or suspicious. The honey made from their flowers is sometimes poisonous. The Uva-Ursi and the Chi807 813 809 81 2 814 8015 809 815 812 814 maphila (Pipsissewa) are the chief medicinal plants of the order. FIG. 805. Pyrola chlorantha, reduced in size. 806. Enlarged flower. 807. Magnified stamen. 803. Pistil. 809. Cross-section of the capsule. 810. A highly magnified seed. 811. The nucleus removed from the loose cellular testa, and divided, showing the very minute embryo. FIG. 812. Monotropa uniflora. 813. A petal. 814. Capsule, with the stamens. 815. Transverse section of the same; the thick and lobed placenta covered with very minute seeds. THE MONOPETALOUS ORDERS. 447 The berries are generally edible (Whortleberries, Wintergreen, &c.). Many are very ornamental plants. 823. Ord, Epacridaceea, which takes the place of Heaths in Australia, essentially differs from them only in the one-celled anthers. 824. Ord. Aquifoliacem (the Holly Family). Trees or shrubs, commonly with coriaceous leaves, and small axillary flowers. Calyx of four to six sepals. Corolla four- to six-parted or cleft: the stamens as many as its segments and alternate with them, inserted on the base of the corolla. Anthers opening longitudinally. Ovary two- to six-celled; the cells with a single suspended ovule. Fruit drupaceous, with two to six stones or nucules. Embryo minute, in hard albumen. - Ex. Ilex (the Holly) and Prinos.'The bark and leaves contain a tonic, bitter, extractive matter. The leaves of a species of Ilex are used for tea in Paraguay: and the famous black drink of the Creek Indians is prepared from the leaves of Ilex vomitoria (Cassena); which are still used as a substitute for tea in some parts of the Southern States. 825. Ord. Ebenacere (the Ebony Family). Trees or shrubs, destitute of milky juice, with alternate, mostly entire leaves, and polygamous flowers. Calyx three- to six-cleft, free from the ovary. Corolla three- to six-cleft, often pubescent. Stamens twice to four times as many as the lobes of the corolla, inserted on them. Ovary three- to several-celled; the style with as many divisions. Friuit a kind of berry, with large and bony seeds. 817 818 821 oe-~~ / 7 816 819 820 Embryo shorter than the hard albumen.-Ex. Diospyros, the FIG. 816. Perfect flower of Diospyros Virginiana, the Persimmon. 817. The corolla, laid open, and stamens. 818. The fruit. 819. Section through the fruit and bony seeds. 820. Vertical section of a seed. 821. The detached embryo. 448 EXOGENOUS OR DICOTYLEDONOUS PLANTS. Persimmon. The fruit, which is extremely austere and astringent when green, is sweet and eatable when fully ripe. The bark is powerfully astringent. Ebony is the wood of D. Ebenus and other African and Asiatic species. 826. Ord. Styracacete (the Storax Family). Shrubs or trees with perfect flowers. Calyx-tube coherent either with the base of the ovary, or with its whole surface. Styles and stigmas perfectly united into one. Stamens more or less united. Cells of the ovary opposite the calyx-lobes. Otherwise much as in the last family. - Ex. Styrax, Halesia, Symplocos. Some yield a fragrant, balsamic resinous substance; such as Storax and Benzoin, containing Benzoic acid. The sweet leaves of our Symplocos tinctoria afford a yellow dye. 827. Ord. Sapotaceet (the Sapodilla Family). Trees or shrubs, usually with a milky juice; the leaves alternate, entire, coriaceous, the upper surface commonly shining. Flowers perfect, regular, axillary, usually in clusters. Calyx four- to eight-parted. Corolla fourto eight- (or many-) cleft. Stamens distinct, inserted on the tube of the corolla, commonly twice as many as its lobes, half of them fertile and opposite the lobes, the others petaloid scales or filaments and alternate with them: anthers extrorse. Ovary 4-12-celled, with a single ovule in each cell. Styles united into one. Fruit a berry. Seeds with a bony testa, with or without albumen. - Ex. Bumelia of the Southern United States. The fruit of many species is sweet and eatable; such as the Sapodilla Plum, the Marmalade, the Star-Apple, and other West Indian species. The large seeds, particularly of some kinds of Bassia, yield a bland fixed oil, which is sometimes thick and like butter, as in the Chee of India (B. butyracea), and the African Butter-tree, or Shea, described by Mungo Park. 828. Ord. Myrsinaceie. Trees or shrubs, mostly with alternate coriaceous leaves, which are often dotted with glands, and with all the characters of Primulacese, except the drupaceous fruit and arborescent habit.- Nearly all tropical (Ardisia, Myrsine). 829. Ord. Primulacet. Herbs, with opposite, whorled, or alternate leaves, often with naked scapes and the ]eaves crowded at the base. Calyx four- or five-cleft or toothed, usually persistent Corolla rotate, hypocrateriform, or campanulate. Stamens insert. ed on the tube of the corolla, as many as its lobes and opposite them! Ovary free, one-celled with a free central placenta! THE MONOPETALOUS ORDERS. 449 Ovules mostly indefinite and amphitropous. Style and stigma sin. gle. Fruit capsular: the fleshy central placenta attached to the base of the cell. Seeds albuminous. Embryo transverse. - Ex. Primula (Primrose), Cyclamen, Anagallis, In Samolus, the calyx coheres with the base of the ovary, and there is a row of sterile filaments occupying the normal position of the first set of stamens, namely, alternate with the lobes of the corolla. Of little consequence, except for their beauty.'28@30~~~~~823 826 822 825 830. Ord, Plantaginacem (the Plantain Family). Chiefly low herbs, with small spiked flowers on scapes, and ribbed radical leaves.-Calyx four-cleft, persistent..Corolla tubular or urnshaped, scarious and persistent; the limb four-cleft. Stamens four, inserted on the tube of the corolla alternate with its segFIG. 822. Primula pusilla. 823. The corolla removed; its tube laid open, 824. The calyx divided vertically, showing the pistil. 825. Vertical section of the ovary and of the free central placenta, covered with ovules, which nearly fills the cell. 826. Capsule of Primula veris, de. hiscent at the summit by numerous teeth. 827. A magnified seed. 828. Section of the same, exhibiting the transverse embryo. FIG. 829. Branch of Anagallis arvensis (Pimpernel), with a capsule showing the line of circumscissile dehiscence. 830. The capsule (pyxis, 616), with the lid falling away. 38 " 450 EXOGENOUS OR DICOTYLEDONOUS PLANTS. ments; the persistent filaments long and flaccid. Ovary two. 834 833 celled: style single. Capsule (pyxis) membranaceous, opening by circumscissile dehiscence; the cells one- to sev eral-seeded. Embryo large, straight, in fleshy albumen. - Ex. Plantago, the Plantain, or Ribgrass, is the principal genus of the order. It is destitute of 835 / any important economical qualities. 831. Ord, Plumbaginacee (the Leadwort Family). Perennial herbs, or somewhat X shrubby plants; with the flowers often on simple or branching scapes; and the leaves crowded at the base, entire, mostly sheathing or clasping. - Calyx tubular, plaited, five-toothed, persistent. Corolla hypocrateriform, with a five832 831 parted limb, the five stamens inserted on the receptacle opposite itsjlobes (Plumbago); or else of five almost distinct unguiculate (scarious or coria- 836 838 ceous) petals, with the stamens inserted on their claws! (Statice, &c.) In the former case the five styles are united nearly to the top; but in the latter they are separate! Ovary one-celled, with a single ovule pendulous from a strap-shaped funiculus which rises from the base of the cell. Fruit a utricle, or opening by five valves. Embryo large, in thin albu- 837 839 men.- Ex. Statice (Marsh Rosemary, Sea Lavender), and Armeria (Thrift); sea-side or saline plants. The Statices have astringent roots: none more so than those of our own Marsh Rosemary or Sea Lavender (S. Caroliniana), one 840 of the best and most intense astringents of the materia medica. FIG. 831. A flower enlarged. 832. Pistil. 833. Capsule (pyxis, 616) with the marcescent corolla. 834. Cross-section of the capsule and seeds. 835. Vertical section of a seed. FIG. 836. Corolla, and 837, calyx of Thrift (Armeria vulgaris). 838. Pistil with distinct styles. 839. Cross-section of the pod and seed. 840. Vertical section of the ovary, magnified, to show the ovule. THE MONOPETALOUS ORDERS. 451 832. Ord, Lentibulacem (the Bladderwort Family). Herbs, grow. ing in water, or wet places, with the flowers on scapes; the leaves either submersed and dissected into filiform segments resembling rootlets, and commonly furnished with air-bladders to render them buoyant; or, when produced in the air, entire and somewhat fleshy, clustered at the base of the scape. Flowers showy, very irregular. Calyx of two sepals, or unequally five-parted. Corolla bilabiate, personate; the very short tube spurred. Stamens two, inserted on the upper lip of the corolla: anthers one-celled. Ovary free, one-celled, with a free central placenta! bearing numerous ovules. Fruit a capsule. Seeds destitute of albumen. Embryo straight. - Ex. Utricularia (Bladderwort), Pinguicula.. Unimpor. tant plants. 833. Ord, Orobanchacec (the Broom-Rape Family). Herbs, des. 4 855 \\551850 843 842 841 848 titute of green foliage, and with scales in place of leaves, parasitic FIG. 841. Branch of Epiphegus Virginiana (Beech-drops), nearly of the natural size: the lower flowers, with short imperfect corollas, alone producing ripe seeds. 842. A flower enlarged. 843. Longitudinal section of the same. 844. Longitudinal section of the ovary, more magnified, showing one of the parietal placentae covered with minute ovules. 845. Cross-section of the same, showing the two parietal placentae. 846. A highly magnified seed. 847. Section of the same, exhibiting the minute embryo next the hilum. FIG. 848. Orobanche uniflora, reduced in size. 849. A flower about the size of nature. 850. The same laid open, showing the didynamous stamens and the pistil. 851. A magnified anther. 852. A magnified seed. 853. Section of the same. 452 EXOGENOUS OR DICOTYLEDONOUS PLANTS. on the roots of other plants; the flowers solitary or spicate. Calyx persistent, four- or five-toothed or bilabiate. Corolla withering or persistent, with a bilabiate or more or less irregular limb. Sta. mens four, didynamous, inserted on the corolla. Ovary free, onecelled, with two parietal placentae! which are often two-lobed, or divided. Capsule inclosed in the persistent corolla.' Seeds very numerous, minute. Embryo minute at the extremity of the albumen. -Ex. Orobanche, Epiphegus (Beech-drops), &c. Astringent, bitter, and escharotic. The pulverized root of Epiphegus (thence called Cancer-root) is applied to open Cancers.* 834. Ord. Bignoniacet (the Bignonia Family). Mostly trees, or climbing or, twining shrubby plants, with large and showy flowers, and opposite, simple, or mostly pinnately-compound leaves. Calyx five-parted, two-parted, or bilabiate, often spathaceous. Corolla with an ample throat, and a more or less irregular five-lobed or bilabiate limb. Stamens five, inserted on the corolla, of which one, and often three, are reduced to sterile filaments or rudiments: when four are fertile, they are didynamous. Ovary two-celled, with the placentae in the axis; the base surrounded by a fleshy ring or disc. Capsule woody or coriaceous, pod-shaped, twovalved, many-seeded. Seeds winged, destitute of albumen. Cotyledons foliaceous, flat, heart-shaped, also notched at the apex. — Ex. Bignonia (Trumpet-Creeper), Catalpa, and other tropical genera. Of little importance, except as ornamental plants. 835. Subord. Sesames (the Sesamum Family) has few and wingless seeds; the fruit indurated or drupaceous, often two- to four-horned, sometimes perforated in the centre from the dissepiments not reaching the axis before they diverge and become placentiferous, and spuriously four- to eight-celled by the various cohesion of parts of the placentae with the walls of the pericarp. - Ex. Sesamum, Martynia (Unicorn-plant), and some other tropical plants. 836. Ord. Acanthacewe (the Acanthus Family). Herbs or shrubby plants, with bracteate, often showy flowers, and opposite, simple leaves, without stipules. Calyx of five sepals united at the base, or combined into a tube, persistent. Coralla bilabiate, or some* ORD. GESNERIACEIE, consisting of tropical herbs, with green foliage and showy flowers, the calyx often partly adherent to the ovary, agrees with Orobanchacea in the parietal placentation, by which both are distinguished from all other orders of this group. THE MONOPETALOUS ORDERS. 453 times nearly equally five-lobed': estivation convolute! Stamens four and didynamous, or only two, the anterior pair being abortive or obsolete, inserted on the corolla. Ovary two-celled, with the placentae in the axis, often few-ovuled. Seeds (sometimes only one or two in each cell) usually supported by hooked processes of the placenta, destitute of albumen. — Ex. Acanthus, Dianthera. A large family in the tropics. Many are ornamental. 837. Ord. Scrophulariacee (the Figwort Family). Herbs, or sometimes shrubby plants; with opposite, verticillate, or alternate leaves. Calyx of four or five more o r less united sepals, persistent. Corolla bilabiate, personate, or more or less irregular; the lobes imbricated in aestivation. Stamens four and didynamous, the fifth stamen sometimes appearing in the form of a sterile filament, 856 855 858 859 854 - 857 862 860 861 or very rarely antheriferous; or often only two, one pair being FIG. 854. Branch of Gerardia purpurea. 855. Corolla, of the natural size, laid open. 856. Calyx and style of the same. 857. Magnified transverse section of the capsule, with one of the valves removed. 858. Magnified section of a seed. FIG. 860. Gratiola aurea, natural size. 861. Corolla laid open, showing the two perfect stamens and two rudimentary filaments (481) as well as the pistil. 859. The perfect stamens and sterile filament of Chelone. 862. Flower of a Linaria (Toadfax, or Snapdragon), with a personate corolla (511). 454 EXOGENOUS OR DICOTYLEDONOUS PLANTS. either suppressed or reduced to sterile filaments, inserted on the corolla. Ovary free, two-celled, with the placentae united in the axis. Capsule two-valved. Seeds indefinite, albuminous. Embryo small. - Ex. Scrophularia, Verbascum (Mullein, which is remarkable for the nearly regular corolla, with five perfect stamens), Linaria, Antirrhinum (Snapdragon), &c.-The plants of this large and important order are generally to be suspected of deleterious (bitter, acrid, or drastic) properties. The most important medicinal plant is the Foxglove (Digitalis purpurea), so remarkable for its power of lowering the pulse. Numerous species are cultivated for ornament. 838. Ord. Verbenacere (the Vervain Family). Herbs, shrubs, or even trees in the tropics, mostly with opposite leaves. Calyx tubular, four- or five-toothed, persistent. Corolla bilabiate, or the four- or five-lobed limb more or less irregular. Stamens mostly four and didynamous, occasionally only two, inserted on the corolla. Ovary free, entire, two- to four-celled. Fruit drupaceous, baccate, or dry, and splitting into two to four indehiscent oneseeded portions. Seeds with little or no albumen. Embryo straight, inferior. - Ex. Verbena (Vervain, Fig. 863 - 871) is the 870 871 864 867 868 865 863 866 869 principal representative in cooler regions. There are many others FIG. 863 and 864. Flower of a Verbena enlarged. 865. The corolla laid open. 866. Pistil. 867. The fruit. 868. Cross-section of the young fruit and the contained seeds. 869. Fruit separating into its four nucules. 870. Cross-section of one nucule or pericarp, and a vertical section of the lower part, showing the surface of the contained seed. 871. Vertical section through the nucule, seed, and embryo. THE BIONOPETALOUS ORDERS. 455 in the tropics, mostly trees; one of which is the gigantic Indian Teak (Tectona grandis), remarkable for its very heavy and durable wood, which abounds in silex. The leaves of the Aloysia citriodora of the gardens yield an agreeable perfume. Others are bitter and aromatic. 839. Subord,? Phrymhceae (Phryma) is separated on account of its simple pistil, uniovulate ovary, spirally convolute cotyledons, and superior radicle. 840. Ord. Labiatce (the Labiate or Mint Family). Herbs, or somewhat shrubby plants, with quadrangular stems, and opposite or sometimes whorled leaves, replete with receptacles of volatile oil. Flowers in axillary or terminal cymules (412), rarely solitary. Calyx tubular, persistent, five-toothed or cleft, or bilabiate. Corolla bilabiate. Stamens inserted on the corolla, four, didynamous, or only two, one of the pairs being abortive or wanting. Ovary free, deeply four-lobed; the central style proceeding from the base of the lobes. Fruit consisting of four (or fewer) little nuts or achenia, included in the persistent calyx. Seeds with little or no albumen. —Ex. The Sage, Rosemary, 875 873 a 886 885 876 872 874 877 878 879 881 882 883 884 Lavender, Thyme, Mint, &c., are familiar representatives of this FIG. 872. Flower of Glechoma hederacea, or Ground Ivy. 873. Approximate anthers of one pair of stamens, magnified 874. Flower of a Lamium. 875. Corolla of L. amplexicaule (Dead Nettle), laid open, showing the didynamous stamens, &c. 876. Calyx and corolla of Scutellaria galericulata (Skull-cap). 877. Section of the enlarged calyx of the same, bringing to view the deeply four-lobed ovary, raised on a short gynobase. 878. Cross-section of a magnified achenium. 879. Vertical section of the same, showing the embryo. 881. Flower of Teucrium Canadense. 882. Magnified anther of the same. 883. Stamen of the Thyme. 884. Flower of Monarda. 885. Magnified anther of the same. 886. Flower of a Salvia; the calyx as well as the corolla bilabiate. 880. Magnified stamen of the same, with widely separated anther-cells, one of which (a) is polliniferous, the other (b) imperfect. 456 EXOGENOUS OR DICOTYLEDONOUS PLANTS. universally recognized order. Their well-known cordial, aromatic, and stomachic qualities depend upon a volatile oil, contained in glandular receptacles which abound in the leaves and other herbaceous parts, with which a bitter principle is variously mixed. None are deleterious. 841. Ord, Boraginaceae (the Borage Family). Herbs, or sometimes shrubby plants; with round stems, and alternate, rough leaves; the flowers often in one-sided clusters (406), which are spiral before expansion. Calyx of five leafy and persistent sepals, more or less united at the base, regular. Corolla regular; the limb five-lobed, often with a row of scales in the throat. Stamens inserted on the corolla, as many as its lobes and alternate with them. Ovary deeply four-lobed, the style proceeding from the base of the lobes, which in fruit become little nuts or hard achenia. Seeds with little or no albumen. - Ex. Borago (Borage), Lithospermum, Myosotis, Cynoglossum (Hound's-tongue), Heliotropium, &c. In Echium, the limb of the corolla is somewhat irregular, and the stamens unequal. Innocent mucilaginous plants, with a 8893 890 889 887 892 slight astringency: hence demulcent and pectoral; as the roots of FIG. 887. Myosotis, or Forget-me-not. 888. The rotate corolla laid open, showing the scales of the throat, and the short stamens. 889. The pistil, with its four-lobed ovary. 890. The calyx in fruit; two of the little nuts having fallen away from the receptacle. 891. Section of a nut, or rather achenium, showing the embryo. 892. Raceme of Symphytum officinale (Comfrey). 893. A corolla laid open; exhibiting the lanceolate and pointed scales of the throat, alternate with the stamens. THE MONOPETALOUS ORDERS. 457 the Comfrey. The roots of Anchusa tinctoria (Alkanet) and Bat-. schia canescens (used by the aborigines under the name of Puccoon) yield a red, dre. 842. Ord. Ilydrophyllaceae (the Water-leaf Family). Herbs, usually with alternate and lobed or pinnatifid leaves; the flowers mostly in cymose clusters or unilateral racemes. Calyx five-cleft, with the sinuses often appendaged, persistent. Corolla regular, imbricated or convolute in oestivation, usually furnished with scales or honey-bearing grooves inside; the five stamens inserted into its base, alternate with the lobes. Ovary free,,with two parietal placentae, which sometimes dilate in the cell and appear like a kind of inner pericarp in the capsular fruit. Styles partly united. Seeds few, crustaceous. Embryo small, in hard albumen. - Ex. Hydrophyllum, Nemophila, and Phacelia; nearly all North American plants, some of them handsome in cultivation. 894 897 898 FIG. 894. Hydrophyllum Virginicum. 895. A flower, nearly of the natural size. 896. Corolla laid open. 897. Capsule, with the persistent calyx and style. 898. Cross-sectikn of the same, the cavity filled by two seeds. 899. Magnified seed. 900. Section of the same. 901. Highly magnified embryo. 39 458 EXOGENOUS OR DICOTYLEDONOUS PLANTS. 843. Ord. ITydroleaceae differs (not sufficiently) from the last by the simple and entire leaves, the two-celled ovary, the two distinct styles, and the numerous seeds. - Ex. Hydrolea, Nama: chiefly natives of warm regions. 844. Ord. Polemoniaeee (the Polemonium Family). Herbs, with alternate or opposite leaves, and panicled, corymbose, or clustered flowers. Calyx five-cleft. Corolla regular, with a five-lobed limb, convolute in oestivation. Stamens five, inserted on the corolla alternate with its lobes, often unequal. Ovary free, three-celled, with a thick axis, bearing few or numerous ovules: styles united into one: stigmas three. Capsule three-valved, loculicidal; the valves also usually breaking away from a thick central column which bears the seeds. Embryo straight, in fleshy or horny albumen. - Ex. Polemonium (Greek Valerian), Phlox, Gilia. Chiefly North American; many are very common ornamental plants in cultivation. 902 903 905 904 ~906 907 908 99 91 906 907 9D8 999 910 845. Ord. Diapensiacem. Low, prostrate, and tufted suffruticose plants; with crowded and evergreen heath-like leaves, and solitary terminal flowers. Differing from the last family chiefly in the transversely two-valved anthers, and amphitropous seeds; and doubtless to be united to it. Consists of two plants only, viz. the Alpine FIG. 902. Flowers of Polemonium. 903. Flowers of Phlox. 904. Corolla of the same, laid open, showing the stamens unequally inserted on its tube. 905. Pistil of the same. 906. Crosssection of the capsule of Polemonium. 907. Cross-section of a magnified seed. 911. Perpendicular section of the same. 912. Magnified embryo. 908. Cross-section of the dehiscent capsule of Collomia. 909, 910. Capsule of Leptodactylon. THE MONOPETALOUS ORDERS. 459 Diapensia, and Pyxidanthera, of the Pine-barrens of New Jersey, &c. 916 917 915 914 918 919'913 846. Ord. Convolvulaeae (the Convolvulus Family). Twining or trailing herbs or shrubs, often with milky juice; the leaves alternate, and the flowers regular. Calyx of five sepals, imbricated, or usually more or less united, persistent. Corolla supervolute in westivation (Fig. 363); the limb often entire. Stamens five, inserted on the tube of the corolla near the base. Ovary free, two- to four-celled, with one or two erect ovules in each cell: styles united, or more or less distinct. Capsule two- to four- (or by obliteration one-) celled; the valves falling away from the persistent dissepiments (septifragal). Seeds large, with a little mucilaginous albumen: embryo curved, and the foliaceous cotyledons usually crumpled. - Ex. Convolvulus (Morning-Glory, Bindweed). They all contain a peculiar strongly purgative resinous matter, which is chiefly found in the acrid, milky juice of their thickened or tuberous roots. Convolvulus Jalapa, and other Mexican species, furnish the Jalap of the shops. The more drastic Scammony is derived from the roots of C. Scammonia of the Levant. There is much less of this in those of Convolvulus panduratus (Mechameck, Man-of-the-Earth, Wild Potato-vine): while those of C. macrorhizus of the Southern States, which sometimes weigh 40 or 50 pounds, are farinaceous, with so slight an admixture of the peculiar resin FIG. 913. Pyxidanthera barbulata, natural size. 914. Pistil, in fruit, and the persistent calyx, enlarged. 915. Corolla and stamens. 916. Same, laid open. 917. A separate stamen, magnified. 918. Section of the dehiscent capsule. 919. A seed. 460 EXOGENOUS OR DICOTYLEDONOUS PLANTS. as to be quite inert; as is also the case with the Babatas, or Sweet Potato, an important article of food. - To this family are appended 924 921 927 926 925 922 923 847. Subord. Diehondree. Ovaries two to four, either entirely distinct or with their basilar styles united in pairs. Creeping 929 928 933 934 931 930 928 933 934 931 932 FIG. 921. Convolvulus purpureus. 922. The pistil. 923. Section of the capsule, and of the two seeds in each cell. 924. Capsule (reduced in size), when the valves have fallen away from the dissepiments; and one of the seeds. 925. Magnified cross-section of a seed. 926. Embryo, with the leaf-like two-lobed cotyledons spread out. 927. Same, with the two cotyledons separated and laid open. FIG. 928. A piece of Cuscuta Gronovii, the common Dodder of the Northern United States, of the natural size. 929. A flower, enlarged. 930. The same, laid open. 931. Section of the ovary. 932. Section of the capsule and seeds. 933. The spiral embryo detached. 934. The same in germination. THE MONOPETALOUS ORDERS. 461 plants, with axillary and scape-like one-flowered peduncles. - Ex. Dichondra. 848. Subord. Cuscutineae. Ovary two-celled; the capsule opening by circumscissile dehiscence, or bursting irregularly. Embryo filiform, and spirally coiled in fleshy albumen, destitute of cotyledons! Parasitic, leafless, twining herbs, destitute of green color (135). Stamens usually furnished with fringed scales within. - Ex. Cuscuta (Dodder). 849. Ord, Solauacem (the Nightshade Family) differs from Scrophulariaceue chiefly in the regular (rarely somewhat irregular) flowers, with as many fertile stamens as there are lobes to the corolla (four or five), and the plaited or valvate aestivation of the corolla. Fruit either capsular or baccate. Embryo small, mostly curved, in fleshy albumen.- Ex. Solanum (Potato), Nicotiana. The fruit of Datura is spuriously four-celled. - Stimulant narcotic properties pervade the order, the herbage and fruits of which are mostly deleterious, often violently poisonous, and furnishing some of the most active medicines; such as the Tobacco, the Henbane (Hyoscyamus niger), the Belladonna (Atropa 9 93 937 93 941 936 937 938 941 Belladonna), the Thorn-apple or Jamestown Weed (Datura Stramonium), and the Bittersweet (Solanum Dulcamara); the last FIG. 935. Flower of Tobacco (Nicotiana Tabacum). 936. The capsule, dehiscent at the apex, with the persistent calyx. 937. Cross-section of the same. 938. Magnified section of the seed of Solanum. 939.-Flowers and berries of Solanum iulcamara. 940. Flower of Hyoscyamus niger. 941. Fruit (pyxis, 616) of the same. 39 * 462 EXOGENOUS OR DICOTYLEDONOUS PLANTS. only slightly narcotic. Yet the berries of some Solanums are eatable when cooked (as Tomatoes, the Egg-Plant, &c.), and the starchy tubers of the Potato are a most important article of food. But the fruit and seeds of Capsicum (Cayenne pepper) are stimulant. 850. Ord. Gentianacete (the Gentian Family). Herbs, with a watery juice; the leaves opposite and entire. Flowers regular, often showy. Calyx of usually four or five persistent, more or less united sepals. Corolla mostly convolute in aestivation; the stamens inserted on its tube. Ovary one-celled, with two parietal, but often introflexed, placentae; styles united or none. Capsule many-seeded. Seeds with fleshy albumen and a minute embryo. - Ex. Gentiana, Frasera (the American Columbo). A pure bit. ter and tonic principle (Gentianine) pervades the whole order. Gentiana lutea of Middle Europe furnishes the officinal Gentian,.for which almost any of our species mdy be substituted. 851. Subord. Ienyanthidece (the Buckbean Family) has alternate, sometimes trifoliolate or toothed leaves, and a valvate-induplicate mestivation of the corolla. -Ex. Menyanthes, Limnanthemum (this bears the peduncles on the petiole, Fig. 949). 943 949 947 946 942 948 945 944 852. Subord. Obolariet has an imbricative testivation of the coFIG. 942. Flower of Gentiana angustifolia. 943. Corolla, and 944, the calyx, laid open. 945. The pistil. 946. Cross-section of the pistil, showing the parietal attachment of the ovules. 947. Ripe capsule of G. Saponaria, raised on a stype: the persistent withering corolla, &c. torn away. 948. A magnified seed, with its large and loose testa. 949. Leaf of Limriantheinum (Villarsia), bearing the flowers on its petiole. THE MONOPETALOUS ORDERS. 463 rolla, opposite leaves, and the whole internal surface of the ovary ovuliferous! - Ex. Obolaria. 853. Ord. Apoeynacere (the Dogbane Family). Trees, shrubs, or herbs, with milky juice, and opposite entire leaves, without stipules. Flowers regular. Calyx five-cleft, persistent. Corolla five-lobed, twisted in aestivation. Filaments distinct; the anthers sometimes slightly connected: pollen granular. Ovaries two, distinct, or rarely united, but their styles or stigmas combined into one: in fruit usually forming two follicles. Seeds often with a coma. Embryo large and straight, in sparing albumen. - Ex. Apocynum (Dog's-bane, Fig. 950), Vinca (Periwinkle); and a great number of tropical shrubs and trees. In all, the juice is drastic or poison. ous, and often yields caoutchouc; which in Sumatra is obtained from Urceola elastica. The well-known Nux vomica is the seed of Strychnos Nux-vomica of India. S. toxifera yields the famous Woorari poison of Guiana.' One kind of Upas is obtained from the bark of the root of S. Tieute in Java. The poisonous principle in these plants is an alkaloid, called Strychnia. 1?' 953 952 950 854. Ord. Aselepiadace (the Milkweed Family). Herbs or shrubs, with milky juice, and opposite entire leaves; mainly differing from the preceding order (as they do from all other Exogenous plants) by the peculiar connection of the stamens with the stigma, and the cohesion of the pollen into wax-like masses, which are attached in FIG. 950. Apocynum androsenlifolium. 951. Flower, of the natural size. 952. Stamens with the anthers connivent around the pistils. 953. The pistils with their large colllmmon stigma. 954. Seed with its coma, or tuft of silky hairs. 464 EXOGENOUS OR DICOTYLEDQONOUS PLANTS. pairs to five glands-of the stigma, and removed from the anther. cells usually by the agency of insects. Fruit consisting of two follicles. Seeds usually with a silky coma. - Ex. Asclepias (Milkweed, Wild Cotton). The juice of A. tuberosa (Pleurisy-root, Butterfly-weed) is not milky. In all, it is bitter and acrid, and contains caoutchouc. 956 957 958 955 963 965 959 960 964 962 855. Ord, Jasminacege (the Jessamine Family) consists of a few FIG. 955. Flower-bud of the Common Milkweed (Asclepias Cornuti). 956. Expanded flower; the calyx and corolla reflexed; showing the stamineal crown. 957. One of the hooded appendages of the latter removed and seen sidewise, with its included process or horn., 958. A vertical section of a flower (the hooded appendages removed) through the tube of stamens, the thick stigma, ovaries, &c. 959. Flower with the calyx, and the fertilized enlarging ovaries, crowned with the large stigma common to the two, from the angles of the peltate summit of which the pairs of pollen-masses, detached from the anther cells, hang by their stalks or caudicle from a gland. [See page 315: Fig. 420. An anther, from which the hooded appendage is cut away. 421. One more magnified: its two pollen-masses still in the open cells, but attached by their stalks each to one of the glands, to which a pollen-mass of an adjacent stamen on each side is already similarly attached. 422. One of these pairs of pollen-masses separate. 423. Pollenmasses of Asclepias incarnata, connected by their emitted pollen-tubes (much magnified) with the stigma. 424. Section through the stigma and into one of the styles, showing the course of the pollen-tubes.] 960 Fruit (follicle) of the Common Milkweed. 961. Cross-section of the last, in an early state. 962. Detached placenta in fruit, covered with seeds. 963. Seed (cut across), with its coma. 964. Section of the seed, as it lies in 963, parallel with the cotyledons. 965. Vertical section of the seed perpendicular to the face of the cotyledons. THE APETALOUS ORDERS. 465 chiefly Asiatic shrubs, with compound leaves and fragrant flowers; differing from Oleacema by the imbricated or twisted vestivation of the hypocrateriform corolla, erect seeds, &c. -Ex. Jasminum, the Jessamine. Cultivated for ornament, and for their very fragrant blossoms. 856. Subord. Bolivarieu consists of a few American (three or four of them Texan) plants, and one from the Cape of Good Hope, sometimes with simple leaves, and scarcely differing from the true Jasminaceue; though most of them have four ovules in each cell. 857. Ord. Oleaccea (the Olive Family). Trees or shrubs, with opposite leaves, either simple or pinnate. Calyx persistent. Corolla four-cleft, or of four separate petals, valvate in oestivation, sometimes none. Stamens mostly two, adnate to the base of the corolla. Ovary free, two-celled, with two pendulous ovules in each cell. Fruit by suppression, usually one-celled and one- or two-seeded. Seed albuminous. Embryo straight. —Ex. Olea (the Olive), and Chionanthus (Fringe-tree), where the fruit is a drupe. Syringa, the Lilac, which has a capsular fruit. Fraxinus, the Ash; where the fruit is a samara, the flowers are polygamous, and often destitute of petals. Olive oil is expressed from the esculent drupes of Olea Europma. The bark, like that of the Ash, is bitter, astringent, and febrifugal. Manna exudes -from the trunk of Fraxinus Ornus of Southern Europe, &c. - Forestiera, of doubtful affinity, is perhaps to follow this order, although entirely apetalous. Division III. - APETALOUS EXOGENOUS PLANTS.* Corolla none; the floral envelopes consisting of a single series (calyx), or sometimes entirely wanting. CONSPECTUS OF THE ORDERS. Group 1. Flowers perfect, with a conspicuous or colored mostly adnate calyx. Ovary several-celled and many-ovuled. Capsule or berry many-seeded. - Herbs or climbing shrubs. ARISTOLOCHIACE2, p. 467. * Numerous plants of the Polypetalous orders are apetalous. such as Clematis, Anemone, and other Ranunculace.e, some Rhamnacere, Caryophyllacee, Onagraceve, Portulacaceme, CrassulaceTe, Rosaceme, Aceracese, &c. Also some Oleacese and Primulaceme of the Gamopetalous series are apetalous. 466 EXOGENOUS OR DICOTYLEDONOUS PLANTS. Group 2. Flowers perfect, or rarely polygamous, with a regular and often petaloid calyx. Ovary free. Ovules solitary in each ovary or cell. Embryo curved or coiled around mealy albumen, rarely in the axis or exalbuminous. - Chiefly herbs. Ovary several-celled, consisting of a whorl of several one-ovuled carpels. PHYTOLACCACEAE, p. 468. Ovary one-celled, with a single ovule. Stipules none. Ovule campylotropous or amphitropous. Calyx herbaceous. CHENOPODIACEM, p. 469. Calyx and bracts scarious. AMARANTACEA., p. 470. Calyx corolline, the persistent base indurated. NYCTAGINACEmE, p. 470. Stipules sheathing (ochree).; Calyx corolline. Ovule orthotropous. POLYGONACE.M, p. 470. Group 3. Flowers perfect, polygamous or dioecious, not disposed in aments, with a regular, and often petaloid calyx. Ovary one-celled, or rarely two-celled, with one or few ovules in each cell: but the fruit one-celled and one-seeded. Embryo not coiled around albumen. -Trees or shrubs. * Style or stigma one. Calyx free from the ovary, and not enveloping the fruit. Flowers polygamo-dicecious. Anth. opening by valves. LAURACEmE, p. 471. Flowers perfect. Anthers opening longitudinally. THYMELACEE, p. 472. Calyx free, but baccate in fruit and inclosing the achenium. ELEAGNACEAE, p. 472. Calyx adnate to the ovary. Ovules several, pendulous from a stipe-like placenta. SANTALACEAE, p. 473. Ovule solitary, suspended. Parasitic shrubs. Ovule without integuments. LORANTHACE-A, p. 474. Trees. Fruit a drupe. NYSSACE, p. 473. * * Styles or stigmas two, divergent. ULMACEA, p. 474. Group 4. Flowers perfect, entirely destitute of calyx as well as corolla. Embryo minute, inclosed in the persistent embryo-sac at the apex of the albumen. - Herbs or suffrutescent plants. SAURRAcRCEiA, p. 475. Group 5. Flowers perfect or diclinous, frequently destitute of both calyx and corolla. - Submersed or floating aquatic herbs. Flowers moncecious. Fruit one-celled and one-seeded. CERATOPHYLLACEAE, p. 476. Flowers mostly perfect. Fruit four-celled and four-seeded. CALLITRICHIIACE, p. 476. Flowers mostly perfect. Capsule several-celled, several-seeded. PODOSTEMACE&, p. 477. Group 6. Flowers moncecious or dioecious, not amentaceous. Fruit capsular or drupaceous, with two or more cells, and one (or rarely two) seeds in each. - Herbs, shrubs, or trees. Fruit mostly dry. Juice milky. Pollen simple. EUPHORBIACE2E, p. 477. Fruit drupaceous. Pollen-grains quaternary. EMPETRACEM, p. 478. THE APETALOUS ORDERS. 467 Group 7, Flowers moncecious or dioecious; the sterile, and frequently the fertile also, in aments, or in heads or spikes. Ovary often two- to severalcelled, but the fruit always one-celled.- Trees, shrubs, or (only in Urticaceme) herbs. ~ Fruit drupaceous. Calyx adherent. JUGLANDACErE, p. 479. ~ * Fruit a nut, involucrate. Calyx adherent. CUPULIFERXE, p. 479. * * * Fruit one-seeded, indehiscent. Fertile and sterile flowers both in aments, and entirely destitute of calyx. Ovary one-celled; ovule solitary, erect. MynRICACEXE, p. 480. Ovary two-celled, two-ovuled: ovule pendulous. BETULACEXE, p. 480. * * ~ * iFruit dehiscent, many-seeded. Seeds with a coma. Fertile and sterile flowers both in aments, and destitute of calyx. SALICACEXc, p. 481. * * * * * Fruit a nut or a two-celled and few-seeded capsule, Fertile and sterile flowers both in aments or heads, and destitute of calyx. Capsule two-beaked, many-seeded. BALSAMIFLUJ, p. 482. Nut club-shaped, one-seeded, bristly-downy. PLATANACE.E, p. 482~* * * * s* Fruit an achenium, often inclosed in a baccate calyx. Flowers variously disposed, sometimes collected in fleshy heads. - Juice milky, when trees or shrubs. URTICACEIE, P. 482. 858. Ord. Aristolochiace (the Birthwort Family). Herbaceous 969 968 966 970 967 FIG. 966. Asarum Canadense. 967. Calyx displayed, and a vertical section through the rest of the flower. 968. Cross-section of the ovary; the upper portion (from which the limb of the calyx is cut away) showing the stamens, the united styles, &c. 969. A separate stamen, enlarged. 970. Vertical section of a seed. 468 EXOGENOUS OR DICOTYLEDONOUS PLANTS. or climbing shrubby plants, with alternate leaves. Flowers brown or greenish, usually solitary. Calyx-tube more or less united with the ovary; the limb valvate. Stamens six to twelve, epigynous, or adherent to the base of the short and thick style: anthers ad. nate, extrorse. Stigmas radiate. Ovary 3- 6-celled. Capsule or berry three- to six-celled, many-seeded. Embryo minute, in fleshy albumen. -Ex. Asarum (Wild Ginger, Canada Snakeroot), Aristolochia (Virginia Snake-root). Pungent, aromatic, or stimulant tonics; generally termed Snake-roots, being reputed antidotes for the bites of venomous snakes.* 859. Ord, Phytolaccacewv (the Poke-weed Family). Chiefly repreI 992 994 993 988 991 sented by the common Poke (Phytolacca decandra), which has a * The ORD. RAFFLESIACE]E, and perhaps other RHIZANTHE2E, consisting of most remarkable fungus-like parasites (136, and Fig. 125) are to be placed somewhere in this vicinity. FIG. 988, 989. Phytolacca decandra (Poke). 990. A flower. 991. Unripe fruit. 992. Cross-section of the same, a little enlarged. 993. Magnified seed. 994. Section of the same across the embryo. 995. Vertical section, showing the embryo coiled around the albumen into a ring. 996. Magnified detached embryo. THE APETALOUS ORDERS. 469 compound ovary of ten confluent (one-seeded) carpels, the short styles or stigmas distinct; the fruit a flattened berry. The root is acrid and emetic: yet the young shoots in the spring are used as a substitute for Asparagus. The berries yield a copious deep. crimson juice. Other genera connect the order with the next; but are distinguished, when the stamens are of the same number as the sepals, by their position alternate with them, as in Portulacacece. 860. Ord. Chenopodiacee (the Goosefoot Family). Chiefly weedy herbs, with alternate and more or less succulent leaves, and small herbaceous flowers. Calyx sometimes tubular at the base, persistent; the stamens as many as its lobes, or fewer, and inserted at their base. Ovary free, one-celled, with a single ovule arising from its base. Fruit a utricle or achenium. Embryo curved or coiled around the outside of mealy albumen, or spiral, without any albumen (in Salsola, &c.). - Ex. Chenopodium, Atriplex, Beta (the Beet), &c. Sea-side plants, or common weeds: some are pot-herbs, such as Spinach: a few are cultivated for their esculent roots; as the Beet, which contains sugar. Soda is largely extract. ed from the maritime species, especially from those of Salsola and Salicornia (Samphire, Glass-wort). Chenopodium anthelminticum yields the Worm-seed oil. 972 977 980 983 A n d 973 @ @ (AS 976 978 982 971 974 975 979 981 FIG. 971. Part of the spike of Salicornia herbacea: the flowers placed three together in excavations of the stem, protected by a fleshy scale. 972. Separate flower. 973. A flower of Blitum, with its fleshy calyx and single stamen. 974. Same, more enlarged, with the thick. ened juicy calyx (975) removed. 976. The ripe fruit. 977. Same, divided vertically, showing the embryo coiled around the central albumen. 978. Flower of Chenopodium album (common Goosefoot). 979. Section of the same, more enlarged. 980. Section of the utricle and seed, showing the embryo. 981. Calyx of Salsola kali (Saltwort), in fruit, with its wing-like border. 982. Section of the same, bringing the ovary into view. 983. The spirally coiled embryo of Chenopodina maritima. 40 470 EXOGENOUS OR DICOTYLEDONOUS PLANTS. 861. Ord. Amarantaceee (the Amaranth Family). Herbs, with opposite or alternate leaves; the flowers in heads, spikes, or dense clusters, imbricated with dry and scarious bracts which are usually colored. Calyx of three to five sepals, which are dry and scarious, like the bracts. Stamens five or more, hypogynous, distinct or monadelphous: anthers frequently one-celled. Embryo annular, always vertical. Otherwise nearly as in Chenopodiacee.Ex. Amarantus, Gomphrena, &c. Weeds. A few Amaranths are cultivated for their dry and enduring richly-colored flowers. 862. Ord. Nyetaginacete. Herbs or shrubs, with opposite leaves; distinguished by their tubular and infundibuliform calyx, the -upper part of which resembles a corolla, and at length separates from the base, which hardens and incloses the one-cellej achenium-like fruit, appearing like a part of it. Stamens hypogynous, 1 - 20. Embryo coiled around the outside of mealy albumen. Flowers involucrate, often showy. Mirabilis' (Four-o'clock) has a oneflowered involucre exactly like a calyx, while the latter resembles the corolla of a Morning-Glory. Plants of warm latitudes; many on our Southwestern frontiers. 863. Ord. Polygonaceae (the Buckwheat Family). Herbs with al. 987 986 984 985 FIG. 984. Polygonum Pennsylvanicum. 985. Flower, laid open. 986. Section of the ovary, showing the erect ovule. 987. Section of the seed, showing the embryo, at one side of albumen. THE' APETALOUS ORDERS. 471 ternate leaves; remarkable for their stipules (ochreve, 304), which usually form sheaths around the stems above the leaves, and for their orthotropous ovules. Stamens definite, inserted on the petaloid calyx. Fruit achenium-like, compressed or triangular. Embryo curved, or nearly straight, applied to the outside (rarely in the centre) of starchy albumen. - Ex. Polygonum, Rumex (Dock, Sorrel), Rheum (Rhubarb). The stems and leaves of Rhhubarb and Sorrel are pleasantly acid: while several Polygonums (Knotweed, Smart-weed, Water Pepper, &c.) are acrid or rubefacient. The farinaceous seeds of P. Fagopyrum (the Buckwheat) are used for food. The roots of most species of Rhubarb are purgative: but it is not yet known what particular species of Tartary yields the genuine officinal article. The ERIoGONEYm (of southern and western North America) form a tribe remarkable for their exstipulate leaves and involucrate flowers. 864. Ord. Lauraceca (the Laurel Family). Trees or shrubs, with pellucid-punctate alternate leaves, their margins entire. Flowers sometimes polygamo-dicecious. Calyx of four to six somewhat united petaloild sepals, which are imbricated in two series, free from the ovary. Stamens definite, but usually more numerous than the sepals, inserted on the base of the calyx: anthers two- to four-celled, opening by recurved valves! Fruit a berry or drupe, the p'edicel often thickened. Seed with a large almond-like em999 1001 1002 997 998 1000 bryo, destitute of albumen. -Ex. Laurus, Sassafras, Benzoin. All aromatic plants, almost every part abounding in warm and FIG. 997. A staminate, and 998, a pistillate flower of Sassafras. 999. A stamen with its glands at the base: the anthers opening by two sets of valves. 1000. Pistil; the ovary divided. 1001. Branch in fruit. 1002. Section of the drupe and seed. 472 EXOGENOUS OR DICOTYLEDONOUS PLANTS. stimulant volatile oil, to which their qualities are due. Camphor is obtained from Camphora officinarum of Japan, China, &c. Cinnamon is the bark of Cinnamomum Zeylanicum; Cassia bark, of Cinnamomum aromaticum of China. The aromatic bark and wood and the very mucilaginous leaves of our own Sassafras are well known. Our Benzoin odoriferum is the Spice-wood, or Feverbush. Laurus nobilis is the true Laurel, or Sweet Bay. Persea gratissima, of the West Indies, bears the edible Avocado pear. 865. Ord. Thymelacere (the Mezereum Family). Shrubby plants, with perfect flowers, and a very tough bark; the tube of the petaloid calyx being free from the (one-ovuled) ovary; its lobes imbricated in Vestivation; the pendulous seed destitute of albumen. Stamens often twice as many as the lobes of the calyx, inserted upon its tube or throat.- Ex. Daphne, &c., of Europe and Middle Asia; and Dirca (Leather-wood, Moose-wood, Wickopy), which is the only North American genus. The tough bark is acrid, or even blistering, and is also usefull for cordage. The reticulated fibres may be separated into a kind of lace in the Lagetta or Lace-bark of Jamaica. The fruit of all the species is deleterious. 1009 1010 1011 1008 866. Ord. Eleagnacee (the Oleaster Family). Shrubs or small trees, with the flowers more commonly dicecious, the leaves either opposite or alternate; readily distinguished from the preceding by FIG. 1008. Flowering branch of Dirca palustris. 1009. A flower. 1010. The sanlle, laid open and enlarged. 1011. Branch in fruit. THE APETALOUS ORDERS. 473 having the foliage and shoots covered with scurf, by the ascending albuminous seed, and the persistent tube of the calyx, which, although free from the ovary, becomes succulent, like a berry in fruit, and constricted at the throat, inclosing the crustaceous achenium! - Ex. Eleagnus, Shepherdia; cultivated for their silvery foliage. The fruit is sometimes eaten. 867. Ord. Santalaceme (the Sandal-wood Family). Trees, shrubs, or sometimes herbs; with alternate entire leaves, and small (very rarely dimecious) flowers. Calyx-tube adherent to the ovary; the limb four- or five-cleft, valvate in mestivation; its base lined with a fleshy disc, the edge of which is often lobed. Stamens as many as the lobes of the calyx, and opposite them, inserted on the edge of the disc. Ovules several, destitute of proper integuments, pendulous from the apex of a stipe-like basilar placenta. Style one. Fruit indehiscent, crowned with the limb of the calyx. Seed albuminous. Embryo small. -Ex. Comandra, Pyrularia, &c. The fragrant Sandal-wood is obtained from several Indian and Polynesian species of Santalum. The large seeds of Pyrularia oleifera (Buffalo-tree, Oil-nut) would yield a copious fixed oil. 1006 1004 1003 1007 1005 868. Ord. Nyssacew (the Tupelo Family). Trees, with diaeciopolygamous flowers, differing from the last in the solitary ovule suspended from the summit of the cell, and furnished with integuments in the ordinary manner. Style one, stigmatose down one FIG. 1003. Branch of Comandra umbellata. 1004. Enlarged flower, laid open. 1005. Vertical section of a flower. 1006. One of the segments of the calyx, enlarged, showing the tuft of hairs which connects its surface with the anther! 1007. The fruit, reduced in size. 40 * 474 EXOGENOUS OR DICOTYLEDONOUS PLANTS. side. Drupe baccate. Embryo large, in sparing albumen. - Consists only of the genus Nyssa. The Black Gum-tree, &c. is remarkable for the toughness of the interlaced fibres, so that it is very difficult to split the timber. The acid berries give the name of Sour Gum to Nyssa capitata. 869. Ord. Loranthacee (the Mistletoe Family) consists of shrubby plants, with articulated branches, and opposite coriaceous and dull greenish entire leaves, parasitic on trees. The floral envelopes are various. In Mistletoe (which is dicecious) the anthers are sessile and adnate to the face of the sepals, one to each. The ovary is one-celled, with a single suspended ovule, consisting of a nucleus without integuments. Fruit a one-seeded berry. Embryo small, in fleshy albumen. - Ex. Loranthus; Viscum, the Mistletoe, from the glutinous berries of which birdlime is made. The bark is astringent. 870. Ord. Ulmacete (the Elm Family). Trees or shrubs, with a watery juice, and alternate rough leaves, furnished with deciduous 1012 1017 1019 1013 1016 1015 1014 1020 1018 stipules. Flowers in axillary clusters or fascicles, rarely solitary, FIG. 1012. Flower of the Slippery Elm. 1013. Calyx laid open and the ovary divided vertically. 1014. Fruit, the cell laid open to show the single seed. 1015. The latter magnified. 1016. Its embryo. FIG. 1017. Branch of Celtis Americana, in flower. 1018. Enlarged flower, divided vertically. 1019. Drupe, the flesh divided to show the stone. 1020. The coiled embryo. THE APETALOUS ORDERS. 475 perfect or polygamous. Calyx campanulate, four- or five-cleft, free from the ovary; the lobes imbricated in mestivation. Stamens inserted on the base of the calyx, as many as its lobes and opposite them, or more numerous. Ovary one- or two-celled, with a single suspended ovule in each: styles or stigmas two. Fruit onecelled and one-seeded, either a samara with a straight embryo and no albumen, as in the Elm (Ulmus); or a drupe with a curved embryo and scanty albumen, as in Celtis (Hackberry), the type of the suborder or tribe CELTIDEm. Timber-trees. The inner bark of the Slippery Elm is charged with mucilage. Hackberries are edible. 1021 1022 1027 1026 1020 1023 1024 871. Ord. Saururaceo -(the Lizard's-tail Family). Herbs (growing in swampy places), with the stems jointed at the nodes; the FIG. 1020. Saururus cernuus. 1021. A separate flower, with its bract and a part of the axis magnified. 1022. A more magnified anther, discharging its pollen from one cell. 1023. Cross-section of the ovary. 1024. Vertical section of one of the carpels in fruit, and of the contained seed, with the sac at the extremity of the albumen, containing the minute embryo. 1025. A seed. 1026. Same, with the outer integument (testa) removed, showing the sac of the amnios. 1027. The latter, highly magnified. 1023. Section of the same, showing the inclosed heart-shaped embryo. 476 EXOGENOUS OR DICOTYLEDONOUS PLANTS. leaves alternate, entire, with somewhat sheathing petioles; the flowers perfect, in racemes or spikes, destitute of all floral envelopes. Stamens definite. Ovary composed of three to five, more or less united, few-ovuled carpels, with distinct styles or stigmas. Capsule or berry with usually a single seed in each cell. Embryo heart-shaped, minute, inclosed in the persistent embryo-sac, at the apex of the albumen! - Ex. Saururus (Lizard's-tail). Slightly pungent plants. They are scarcely distinct from the Pepper Family.* 872. -Ord, Ceratophyllacete (the Hornwort Family) consists of the single genus Ceratophyllum (growing in ponds and streams in many parts of the world); distinguished by the whorled and dissected leaves with filiform segments; the flowers moncecious, and sessile in the axil of the leaves; the stamens indefinite, with sessile anthers; and the simple one-celled ovary, which forms a beaked achenium in fruit, containing an orthotropous suspended seed, with four cotyledons! and a manifest plumule. 873. Orid Callitrichaceae (the Water-Starwort Family), formed of 1031 1030 1032 1029 1033 1034 * ORD. PIPERACEZE (the Pepper Family), a chiefly tropical order with the embryo inclosed in the persistent embryo-sac, differing from Saururacem principally in the one-celled simple ovary, with a solitary ovule (fruit a berry), and the extrorse anthers; the leaves often opposite or whorled; the jointed FIG. 1029. Callitriche verna, about the natural size. 1030. Perfect flowers, magnified. 1031. A staminate and pistillate flower, magnified. 1032. The fruit. 1033. Cross-section of the fruit. 1034. Vertical section through the pericarp, seeds, and embryo. THE APETALOUS ORDERS. 477 the genus Callitriche; aquatic annuals, with opposite entire leaves; the axillary flowers (either perfect or moncecious) with a twoleaved involucre, but entirely destitute of calyx and corolla; stamen one (or rarely two), hypogynous, with a slender filament, and a reniform one-celled anther; the ovary four-lobed, four-celled, indehiscent in fruit; the seeds albuminous. 874. Ord. Podostemacere (the River-weed Family) comprises a few (American and Asiatic) aquatics, with the aspect of Mosses or Hepaticme; their small flowers arising from a kind of spathe; the calyx often entirely wanting; the stamens frequently reduced to one, or two and monadelphous; the ovary two- or three-celled, with distinct styles; in fruit forming a ribbed capsule, containing numerous exalbuminous seeds attached to a central column. - Ex. Podostemum. 875. Ord. Euphorbiaceme (the Spurge Family). Herbs, shrubs, or even trees, often with a milky juice: in northern temperate climes chiefly represented by the genus Euphorbia (Fig. 344- 349); which is remarkable for having numerous staminate flowers, reduced to a single stamen (484), inclosed in an involucre along with one pistillate flower, reduced to a compound pistil, and also achlamydeous, or with an obsolete calyx. But other genera have a regular calyx both to the staminate and pistillate flowers; and a few are likewise provided with petals. Ovary of two to nine more or less united carpels, coherent to a central prolongation of the axis: styles distinct, often two-cleft. Fruit mostly capsular, separating into its elementary carpels, or cocci (usually leaving a per. sistent axis), which commonly open elastically by one or both sutures. Seed with a large embryo in fleshy albumen, suspended. - Ex. Euphorbia (Spurge), Croton, Buxus (the Box). Acrid and deleterious qualities pervade this large order, chiefly resident in the (usually) milky juice. But the starchy accumulations in the rhizoma, or underground portion of the stem, as in the Mandioc or Cassava (Janipha Manihot) of tropical America, are perfectly innocuous, when freed from the poisonous juice by washing stems sometimes woody, but scarcely exhibiting annual layers. They all possess stimulant, aromatic, and pungent qualities, the common Pepper (the dried berries of the Indian Piper nigrum) representing the ordinary properties of the order. The intoxicating Betel of the Malays consists of the leaves of Piper Betle. The Ava of the Society and Sandwich Islands, from which an inebriating drink is made, is Piper methysticum. 478 EXOGENOUS OR DICOTYLEDONOUS PLANTS. and exposure to heat. The starch thus obtained is the Cassava, which, when granulated, forms the Tapioca of commerce. The farinaceous albumen of the seed is also innocent, and the fixed oil which it frequently contains is perfectly bland. But the oil procured by expression abounds in the juices of the embryo and integuments of the seed, and possesses more or less active properties. The seeds of Ricinus communis yield the Castor oil: and those of Croton Tiglium, and some other Indian species, yield the violently drastic Croton oil or Oil of Tiglium. Some plants of the family are most virulent poisons; as, for example, the Malchineal-tree of the West Indies (Hippormane Manicella), which is said even to destroy persons who sleep under its shade; and a drop of the juice falling upon the hand produces an instantaneous blister. The hairs of some species (such as Jatropha stimulosa) sting like Nettles. The hard and close-grained wood of the box is invaluable to the wood-engraver. The purple dye called Turnsole is derived from Crozophora tinctoria. Another most important product of this order is caoutchouc, which is yielded by various plants of different families; but the principal supply of the article (that of Para, I)emarara, and Surinam) is furnished by the tree named Hevea Guianensis by Aublet, the Siphonia elastica of Persoon. 1040 1041 1036 1037 1012 1035 1038 1039 876. Ord. Empetracee (the Crowberry Family). Low, shrubby FIG. 1035. Branch of Ceratiola ericoides in fruit. 1036. Magnified staminate flower, with its bracts. 1037. The two stamens, with an inner bract or sepal. 1038. Magnified pistillate flower, with its imbricated bracts. 1039. The pistil separate; one of the cells laid open by a vertical section, showing the erect ovule. 1040. Drupe, with the persistent scales at the base. 1041. Transverse section of its endocaip, or two nucules, with the inclosed seed and embryo. 1042. Vertical section of the seed. THE APETALOUS ORDERS. 479 evergreens, with the aspect of Heaths; the leaves crowded and acerose, with small (dioecious or polygamous) flowers produced in the axils of the uppermost. Calyx consisting of regular imbricated sepals, or represented by imbricated bracts. Stamens few: pollen of four grains coherent in one, as in Heaths. Ovary three- to nine-celled, with a single erect ovule in each cell: style short or none: stigmas lobed and often laciniated. Fruit a drupe, with from three to nine bony nucules. Seeds albuminous; the radicle inferior. - Ex. Empetrum, Ceratiola, Corema; unimportant plants. 877. Ord. Juglandace (the Walnut Family). Trees, with alternate pinnated leaves, and no stipules. Flowers monoecious. Ster. ile flowers in aments, with a membranous irregular calyx, and indefinite stamens. Fertile flowers few, clustered, with the calyx adherent to the incompletely two- to four-celled but one-ovuled ovary, the limb small, three- to five-parted; sometimes with as many small petals. Ovule orthotropous. Fruit drupaceous; the epicarp fibrous-fleshy and coherent, or else coriaceous and dehiscent: endocarp bony. Seed four-lobed, without albumen. Embryo oily: cotyledons corrugate, 2-cleft. - Ex. Juglans (Walnut, Butternut), Carya (Hickory, Pecan, &c.). - The greater part of the order is North American. The timber is valuable; es. pecially that of Black Walnut, for its rich dark-brown color when polished; that of Hickory, for its great elasticity and strength. The young fruit is acrid: the often ediblei seeds abound in a dry. ing oil. 878. Ord. Cupuliferae (the Oak Family). Trees or shrubs, with alternate and simple straight-veined leaves, and deciduous stipules. Flowers usually moncecious. Sterile flowers in aments, with a scale-like or regular calyx, and the stamens one to three times the number of its lobes. Fertile flowers solitary, two to three together, or in clusters, furnished with an involucre which incloses the fruit or forms a cupule at its base. Ovary adnate to the calyx, and crowned by its minute or obsolete limb, two- to six-celled with one or'two pendulous ovules in each cell-: but the fruit is a one-celled and one-seeded nut (585). Seed without albumen. Embryo with thick and fleshy cotyledons, which are sometimes coalescent. — Ex. Quercus (the Oak), Fagus (the Beech), Corylus (the Hazel. nut), Castanea (the Chestnut), &c. Some of the principal foresttrees in northern temprerate regions. Their valuable timber and 480 EXOGENOUS OR DICOTYLEDONOUS PLANTS. edible seeds are too well known to need enumeration. The as. tringent bark and leaves of the Oak abound in tannin, gallic acid, and a bitter extractive called Quercine; they are used in tanning and dyeing. Quercitron is obtained from the Quercus tinctoria. Galls are swellings on the'leafstalks, &c., when wounded by certain insects; those of commerce are derived from Q. infectoria of Asia Minor. Cork is the exterior bark of the Spanish Quercus Suber. 1043 _ 1045 1044 1042 1046 1047 879. Ord. Myricacem (the Sweet-Gale Family). Shrubs, with alternate and simple aromatic leaves, dotted with resinous glands; moncecious or diecious. Differs from the next principally by the one-celled ovary, with a single erect orthotropous ovule, and a drupe-like nut. - Ex. Myrica, Comptonia, the Sweet Fern. The drupes of M. cerifera (our Candleberry) yield a natural wax. 880. Ord. Betulaceca (the Birch Family). Trees or shrubs, with alternate and simple straight-veined leaves, and deciduous stipules. Flowers moncecious; those of both kinds in aments and commonly achlamydeous, placed three together in the axil of each three-lobed FIG. 1042. Quercus Chinquapin in fruit: a, cluster of sterile aments. 1043. A magnified staminate flower. 1044. Transverse section of an ovary, showing the three cells with two ovules in each. 1045. The immature seed, with the accompanying abortive ovule. 1046. The nut (acorn), in its scaly involucre, or cupule. 1047. Vertical section of the same, and of the included seed and embryo, showing the thick cotyledons. THE APETALOUS ORDERS. 481 bract. Stamens definite. Ovary two-celled, each cell with one suspended ovule: styles or stigmas distinct. Fruit membranaceous or samara-like, one-celled and one-seeded, forming with the three-lobed bracts a kind of strobile. Albumen none. -Ex. Be. tula (the Birch), Alnus (Alder). The bark is sometimes astringent, and that of the Birch is aromatic. The peculiar odor of Russia leather is said to be owing to a pyroligneous oil obtained from Betula alba. 1051 1053 54 1055 105 881. Ord. galieaeem (the Willow Family). Trees or shrubs, with alternate simple leaves, furnished with stipules. Flowers dimecious; both kinds in aments, and destitute of floral envelopes (achlamydeous), one under each bract. Stamens two to several, sometimes monadelphous. Ovary one-celled, many-ovuled! Styles or stigmas two, often two-cleft. Fruit a kind of follicle opening by two valves. Seeds numerous, ascending, furnished with a silky FI(G. 1048. Ament of staminate flowers of Betula fruticosa. 1049. One of the three-lobed scales f the same enlarged, sh lowers (stamens) on the inner side. 050. Arubsent of aistllate flowers. 151. Branch in fruit. 1052. One of the stcales with its three flowers (pistils) seen from within. 103. Magnifie d section stitute of fthe two-clled pistils, displaying the olamydle suspended from the summit of each cell. 1054. The pistils (with their subtending bract) in a more advanced'state. 1055. Magnified cross-section of one of the ovaries. sub1056. The mbract) ture fruit, with the cell divided vertically; the single seed occupying the cavity; a mere trace of the other cell being visible. 1057. The seed removed. 1058. The embryo. 41 482 EXOGENOUS OR DICOTYLEDONOUS PLANTS. coma! Albumen none. - Ex. Salix (Willow, already illustrated, 473, Fig. 326 - 329), and Populus (the Poplar). Trees with light and soft wood: the slender flexible shoots of several Willows are employed for wicker-work. The bark is bitter and tonic; containing a peculiar substance (Salicine), which possesses febrifugal qualities. The buds of several Poplars exude a fragrant balsamic resin. 882. Ord. Balsamiflluw (the Sweet- Gum Family) consists of a single genus of three or four species (natives of Eastern India, the Levant, and North America): which are trees, with alternate palmately-lobed leaves, and deciduous stipules; the moncecious flowers in rounded aments or heads, destitute of floral envelopes; the indurated capsules and scales forming a kind of strobile; the former two-celled, two-beaked, opening between the beaks, severalseeded: the seeds with a little albumen. It has recently been referred to the order Hamamelacewe (799). -Ex. Liquidambar, or Sweet-Gum: so called from the fragrant balsam or Storax it exudes. 883. Ord. Platanaeew (the Plane-tree Family) consists of the single genus Platanus (Plane-tree, Button-ball), with one Asiatic and one or more North American species: which are fine trees, with a watery juice, and alternate palmately-lobed leaves, with sheathing stipules. Flowers in globose amentaceous heads; both kinds destitute of floral envelopes. Fruit a one-seeded club-shaped little nut, the base furnished with bristly hairs. Seed albuminous. 884.0#rd. Urtieaceta (the Nettle Family). Trees or shrubs with milky juice, or herbs with a watery juice. Leaves often stipulate. Flowers moncecious, dicecious, or polygamous, sometimes collected in aments or fleshy heads, furnished with a regular calyx. Stamens definite. Ovary free from the calyx, simple, with a solitary ovule. Fruit an achenium or utricle, often inclosed in a fleshy or baccate calyx. The order comprises the following principal divisions, viz.: — 885. Subord. Artocarpew, (the Bread-fruit Family); which are trees or shrubs with a milky or yellow juice; the flowers mostly aggregated into fleshy heads, and forming a compound baccate fruit, or else inclosed in a dry or succulent involucre. Albumen none. - Ex. Artocarpus (the Bread-fruit), Antiaris (Upas): all tropical. 886. Subord. Ioreve (the Mulberry Family); which are shrubs or THE APETALOUS ORDERS. 483 trees, very rarely herbs, with a milky juice; the staminate and pistillate flowers either in separate aments or spikes, or often intermixed and included in the same hollow and closed fleshy receptacle (as in the Fig): the calyx, &c. becoming succulent, and forming a compound fruit. Seeds albuminous. - Ex. Morus (the Mulberry, Fig. 244-246), Maclura (the Osage Orange), Ficus (the Fig, Fig. 241 -243): nearly all tropical. 887. Subord. Urticet (the proper Nettle Family); which are herbs in colder countries, but often shrubs or trees in the tropics, with a watery juice, often with stinging hairs; the flowers mostly loose, spicate, or panicled; the achenium usually surrounded by a dry and membranous calyx. Embryo straight, in fleshy albumen. - Ex. Urtica (the Nettle), Parietaria. 888. Subord. Cannabinewe (the Hemp Family); which are annual erect herbs, or perennial twining plants, with a watery juice; the staminate flowers racemose or panicled; the pistillate glomer. ate, or imbricated with bracts, and forming a kind of strobile-like ament. Embryo curved: albumen none. —Ex. Cannabis (the Hemp), Humulus (the Hop): natives of northern temperate regions. 889. The fiuit in this large and polymorphous family is mostly innocent and edible, at least when cooked; while the milky juice is more or less acrid or deleterious. It also abounds in caoutchouc; much of which'is obtained from some South American trees of this order, and from Ficus elastica in Java. In one in-stance, however, the milky juice is perfectly innocent; that of the famous Cow-tree of South America, which yields copiously a rich and wholesome milk. One of the most virulent of poisons, the Bohon Upas, is the concrete juice of Antiaris toxicaria of the Indian Archipelago. The Bread-firuit is the fleshy receptacle and multiple fruit of Artocarpus. Fustic is the wood of the South Americall Morus tinctoria. The resin called Gu2m Lacc exudes and forms small grains on the branches of the celebrated Banyan-tree (Ficus Indica, Fig. 119). Nettles are remarkable for their stinging venomous hairs, and tough fibres of the bark, which, as in those of Hemp, are used for cordage. The leades of the Hemp are stimulant and narcotic, and are used extensively in the East for intoxication. Hops are the catkins of Humulus Lupulus; the bitter and sedative principle chiefly resides in the yellow grains that cohere to the scales and cover the fruit. 484 EXOGENOUS OR DICOTYLEDONOUS PLANTS. Subclass 2. GYM-NOSPERaOUS EXOGENOUS PLANTS. 890. Ovules, and consequently the seeds, naked, that is, not inclosed in an ovary (560); the carpel being represented either by an open scale, as in Pines; or by a more evident leaf, as in Cycas; or else wanting altogether, as in the Yew. 891. Ord. Conifersv (the Pine Family). Trees or shrubs, with branching trunks, abounding in resinous juice (the wood chiefly consisting of a tissue somewhat intermediate between ordinary woody fibre and vessels, which is marked with circular discs); the leaves mostly evergreen, scattered or fascicled, usually rigid and needle-shaped or linear, entire. Flowers monoecious or dioecious, commonly amentaceous. Staminate flowers consisting of one or more (often monadelphous) stamens, destitute of calyx or corolla, arranged on a common rhachis so as to form a kind of loose ament. - The particular structure of the flowers and fruit varies in the subordinate groups chiefly as follows: — 892. Subord. Abietinete (the Fir, or proper Pine Family). Fer. tile aments formed of imbricated scales; which are the flat and open carpels, and bear a pair of ovules adherent to their base, with the foramen turned downwards. Scales subtended by bracts. Fruit a strobile or cone (619). Integument of the seed coriaceous or woody, more or less firmly adherent to the scale. Embryo in the axis of fleshy albumen, with two to fifteen cotyledons. (Illus. trated in Fig. 391-401, pp. 306, 307.) 893. Subord, Cupressinew (the Cypress Family). Fertile aments of few scales crowded on a short axis, or more numerous and peltate (Fig. 402), not bracteate. Ovules one, two, or several, borne on the base of the scale, erect (the foramen looking towards its apex, Fig. 394). Fruit an indurated strobile, or fleshy and with the scales concreted, forming a kind of drupe. Integument of the seed membranous or bony. Cotyledons two or more. Anthers of several parallel cells, placed under a shield-like connectivum. - Ex. Cupressus (Cypress), Taxodium (American Cypress), Juniperus (Juniper, Red Cedar). 894. Subord. Taxinere (the Yew Family). Fertile flowers solitary, terminal, consisting merely of an ovule, forming a drupaceous seed at maturity. There are, therefore, no strobiles and no carpellary scales. Embryo with two cotyledons. -Ex. Taxus (the Yew), Torreya. ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 485 895. It is unnecessary to specify the important uses of this large and characteristic family, which comprises the most important timher-trees of cold countries, and also furnishes resinous products of great importance, such as turpentine, resin,pitch, tar, Canada balsam (obtained from the Balsam Fir), &c. The terebinthine Juni. per-berries are the fruit of Juniperus communis. The Larch yields Venetian turpentine. The powerful and rubefacient Oil of Savin is derived from J. Sabina of Europe: for which our J. Virginiana (Red Cedar) may be substituted. The leaves of the Yew are narcotic and deleterious. The bark of Hemlock and Larch is used for tanning. 896. Ord, Cycadacee (the Cycas Family). Tropical plants, with an unbranched cylindrical trunk, increasing, like Palms, by a single terminal bud; the leaves pinnate and their segments rolled up from the apex (circinate) in vernation, in the manner of true Ferns. Flowers dicecious; the staminate in a strobile or cone; the pistillate also in strobiles, or else (in Cycas) occupying contracted and partly metamorphosed leaves; the naked ovules borne on its margins. - Ex. Cycas, Zamia, the dwarf Florida species of which is illustrated in Fig. 403-409, p. 308. — A kind of Arrowroot is obtained from these thickened stems; and a sort of Sago from the trunk of Cycas. Class II. ENDOGENoUS OR MONOCOTYLEDONOUS PLANTS. 897. Stem not distinguishable into bark, pith, and wood; but the latter consisting of bundles of fibres and vessels irregularly imbedded in cellular tissue; the rind firmly adherent; no medullary rays, and no appearance of concentric layers: increase in diameter effected by the deposition of new fibrous bundles, which, at their commencement at least, occupy the central part of the stem. Leaves seldom falling off by an articulation, commonly sheathing at the base, usually alternate, entire, and with simple parallel veins (nerved). Floral envelopes when present mostly in threes; the calyx and corolla frequently undistinguishable in texture and appearance. Embryo with a single cotyledon; or if the second is present, it is much smaller than the other and alternate with it (634). 41 456 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. CONSPECTUS OF THE ORDERS. Group 1. Flowers on a spadix, furnished with a double perianth (calyx and corolla). Ovary one- to three-celled, with a single ovule in each cell. Embryo in hard albumen.- Trees with unbranched columnar trunks. PALM2E, p. 487. Group 2. Flowers on a spadix; with the perianth simple, scale-like, or commonly altogether wanting. - Chiefly herbs. Terrestrial, mostly with a spathe. Fruit baccate. ARACE2E, p. 488. Terrestrial. Fruit nut-like, one-seeded. TYPHACEX, p. 489. Aquatic (floating or immersed). Flowers from the edge of the floating frond. LEMNACE2E, p. 489. Flowers axillary or on a spadix. NAIADACEXA, p. 490. Group 3. -Flowers not spadiceous, furnished with a double perianth (calyx and corolla). Ovaries several, distinct, or sometimes united, free. — Aquatic herbs. ALISMIACEE, p. 490. Group 4. Flowers with a simple or double perianth, adherent to the ovary (ovary inferior), either completely or partially. - Herbs. * Perianth regular. Ovary one-celled, with parietal placentat, or rarely threeto six-celled, with the placentae in the axis. Dicecious or polygamous; aquatic. HYDrOCHARIDACEs, p. 491. Flowers perfect; terrestrial. URVMANNIACE.E, p. 491. * * Perianth irregular. Ovary one-celled, with parietal placenta. Stamens one or two, adherent to the style (gynandrous). O}RCHIDACEM, p. 491. * * * Perianth irregular. Ovary three-celled. Perfect stamens usually one. Fertile stamen 1, inferior. ZINGIBERACEAE, p. 492. Fertile stamen 1, superior. CANNACEE, p. 493. Fertile stamens mostly 5, the sixth abortive. MUSACEE, p. 493., * ~ * Perianth regular, or sometimes a little irregular. Ovary three-celled, many-ovuled (in Tillandsia free, in Lophiola nearly so). Stamens either three or six. Anthers introrse. Stamens mostly 6. Bulbous. AMARtYLLTDACEX, p. 494. Not bulbous: root fibrous: leaves indurated or scurfy. BROMELIACEri, p. 493, and HEI-cIODORACE.M, p. 493. Anthers extrorse. Stamens 3. IRIDACEE, p. 494. * * * * Perianth regular. Ovary three-celled, with one or two ovules in each. Flowers dicecious. Stamens six. DIOSCOREACEAE, p 495. Group 5. Flowers with a regular perianth, which is more or less petaloid (the two series when present are similar), or rarely glumaceous, and free from the ovary. Embryo inclosed in albumen. Perianth not glumaceous. Anthers introrse. Styles or stigmas separate. SaI1LACxE;, p. 495. -ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 487 Anthers introrse. Styles united into one. Terrestrial, not spathaceous. Flower regular. LILIACE, p. 495. Aquatic, spathaceous. Flower oftener irregular. PONTEDERIACEXr, p. 496. Anthers extrorse (except Tofieldia). MELANTHACE.M, p. 496. Perianth glumaceous. JUNCACEE, p. 497. Group 6. Flowers with a double or imbricated perianth: the exterior herbaceous or glumaceous; the inner petaloid, free from the one- to three-celled ovary. Seeds orthotropous; the embryo at the extremity of the albumen farthest from the hilum. Flowers perfect. Sepals herbaceous. COMMELYNACE, p. 498. Flowers perfect, capitate. Sepals and bracts glumaceous. XYRIDACEIE, p. 498. Flowers moncecious or dioecious, capit'ate. ERIOCAULONACE., p. 498. Grouip 7. Flowers imbricated with bracts (glumes) and disposed in spikelets; the proper perianth none or rudimentary. Ovary one-celled, one-ovuled. Embryo at the extremity of the albumen next the hilum. Sheaths closed. Glume or bract single. CYPERACEXA, p. 498. Sheaths open. Glumes in pairs. GRAMINEIm, p. 499. 898. Ord. Palmte (Palms). Chiefly trees, with unbranched cylindrical trunks growing by a terminal bud. Leaves large, clustered, fan-shaped or pinnated, plaited in vernation. Flowers small, perfect or polygamous, mostly with a double (6-merous) perianth; the stamens usually as many as the petals and sepals together. Ovary 1 - 3-celled, with a single ovule in each cell. Fruit a drupe or berry. Seeds with a cartilaginous albumen, often hollow; the embryo placed in a small separate cavity. - Ex. Palms, the most majestic race of plants within the tropics, and of the highest value to mankind, are scarcely found beyond the limits of these favored regions. The Date-tree (Phcenix dactylifera, the leaves of which are the Palms of Scripture), a native of Northern Africa, endures the climate of the opposite shores of the Mediterranean: while in the New World, Chamrerops Palmetto (Fig. 166), the only arbo. rescent species of the United States, and one or two low Palms with a creeping caudex (.Dwarf Palmettos), extend from Florida to North Carolina. Palms afford food and raiment, wine, oil, wax, flour, sugar, salt, thread, weapons, utensils, and habitaotins. The Cocoa-nut (Cocos nucifera) is perhaps the most important, as well as the most widely diffused species. Besides its well-known fruit, and the beverage it contains, the hard trunks are employed in the construction of huts; the terminal bud (as in our Palmetto and other Cabbage Palms) is a delicious article of food; the leaves are used for thatching, for making hats, baskets, mats, fences, for 483 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. torches, and for writing upon; the stalk and midrib for oars- their ashes yield abundance of Potash; the juice of the flowers and sterns (replete with sugar, which is sometimes separated under the name of Jagery) is fermented into a kind of wine, or distilled into Arrack/; from its spathes (as from some other Palms), when wounded, flows a grateful laxative beverage, known in India by the name of Toddy; the rind of the fruit is used for culinary vessels; its tough, fibrous, outer portion is made into very strong cordage (Coir rope); and an excellent fixed oil is'copiously expressed from the kernel. Sago is procured from the trunks of many Palms, but chiefly from species of Sagus of Eastern India. Canes and Rattans are the slender, often prostrate, stems of species of Calamus. The Phytelephas of South America yields the larger sort of nuts, the hard and white albumen of which is the vegetable ivory, now so largely used by the turner. 1063 1064 1065 1060 Eli ~ l 1059 1061 1062 1065 899. Ord, Aracee' (the Arum Family). Herbes, with a fleshy corm or rhizoma, occasionally shrubby or climbing plants in the tropics; the leaves sometimes compound or divided, frequently with more or less reticulated veins. Flowers mostly on a spadix (often naked at the extremity) usually- surrounded by a spathe. Flowers commonly monmcious, and destitute of envelopes, or with a single perianth. Ovary one- to several-celled, with one or more FIG. 1059. Branch of the inflorescence of Chame.rops Hystrix (Blue Palmetto). 1060. A sterile flower. 1061. Perfect flower, with the calyx and corolla removed. 1062. Same, with three of the stamens removed, so as more distinctly to show the three somewhat united carpels. 1063. One of the carpels enlarged, seen laterally. 1064 Same, with a section of its inner face, showing the ovule or young seed. 1065. Vertical section of a young cocoa-nut, showing the hollow albumen; and also the small embryo in a separate little cavity. 1066. Section of a Palm-stem. ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 489 ovules. Fruit a berry. Seeds with or without albumen. — Ex. Arum, Calla, Symplocarpus (Skunk-Cabbage), Orontium, Acorus (Sweet Flag): the three latter bear flowers furnished with a peri. anth. - All are endowed with an acrid volatile principle, which is merely pungent and aromatic in Sweet Flag (Acorus Calamus). 1073 1074 1072 107i) ~ s~ ~K'10 1068 1067 900. Ord. Typhaceme (the Cat-tail Family) consists of two genera; namely, Typha (the Cat-tail), and Sparganium (Burr-reed), of no important use; they are somewhat intermediate between'Araceme and Cyperacere. 901. Ord. Lemnacewe (the Duck-weed Family), consisting chiefly of Lemna (Duckweed, or Water Flax-seed); floating plants, with their roots arising' from the bottom of a flat frond, and hanging loose in the water; their flowers produced from the margin of the frond, bursting through a membranous spathe; the sterile,,of one FIG. 1067. Young leaf, and 1068,. pathes and flowers, of Symplocarpus fcetida. 1069. A separate flower. 1070. A sepal and stamen seen from within. 1071. An-anther seen from the front. 1072. The spadix or collective head in fruit; a quarter-section removed, showing sections of the immersed seeds. 1073. A seed detached, of the natural size. 1074. Section of the seed, with its large globular embryo and plumule: in this plant there is no albumen. 490 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. or two stamens; the fertile, of a one-celled ovary; in fruit a utricle: they are a kind of minute and greatly reduced Aracea. 1077 1075 1076 1082 D, 1078 1079 1080 1081 902. Ord, Naiadaceae (the Pond-weed Family). Water-plants, with cellular leaves, and sheathing stipules or bases: the flowers inconspicuous, sometimes perfect. Perianth simple or none. Stamens definite. Ovaries solitary, or two to four and distinct, oneseeded. Albumen none. Embryo straight or curved. - Ex. Potamogeton (Pond-weed), Najas, Ruppia, Zostera; the two latter in salt or brackish water. 903. Ord. Alismaceet (the Water-Plantain Family). Marsh herbs, with the leaves and scapes usually arising from a creeping rhizoma; the former either linear, or bearing a flat limb, which is ribbed or nerved, but the veinlets commonly reticulated. Flowers regular, perfect or polygamous, mostly in racemes or panicles, not on a spadix. Perianth double. Sepals three. Petals three. Seeds solitary in each carpel or cell,. straight or curved, destitute of albumen. - Ex. Alisma (Water-Plantain), Sagittaria (Arrowhead); belonging to the proper Alisma Family, which has the seed (and consequently the embryo) curved or doubled upon itself. Triglochin and Scheuchzeria chiefly constitute the suborder JUNCAGINE:E; FIG. 1075. Whole plant of Lemna minor, magnified, bearing a staminate monandrous flower. 1076. An individual with a diandrous perfect flower; which at 1077 is seen separate, with its spathe, highly magnified. 1078. Flower of Lemna gibba, much magnified. 1079. Vertical highly magnified section of the pistil and the contained ovule of Lemna minor. 1080. The fruit, and 1031, its section, showing the seed. 1082. Section through the highly'magnified seed and large embryo. ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 491 where the seed and embryo are straight, and the petals (if present) greenish like the calyx. 1084 1085 1086 1095 1093 1092 \1,.... 1087 1088 1089 1090 1083 1094 1091 904. Ord, Iydrocharidacewe (the Frog's-bit Family) consists of a few aquatic herbs, with dicecious or polygamous regular flowers on scape-like peduncles from a spathe, and simple or double floral envelopes, which in the fertile flowers are united in a tube, and adnate to the 1- 6-celled ovary, more commonly one-celled with three parietal placentm. Seeds numerous, without albumen. - Ex. Limnobium, Vallisneria, Udora.* 905. Ord, Burmanlniaceme consists of small, mostly tropical, annual herbs, differing from Orchidacese by their regular and perfect flow. ers with three stamens. - Ex. Burmannia, Apteria, of the Southern States. 906. 0rd, Orehidacew (the Orchis Family). Herbs, of varied aspect and form; distinguished from the other orders with an adnate * ORD. BUTOMACEAI consists of Butomus, Hydrocleis, &c.: plants resembling the Alisma tribe, but with a milky juice, and the numerous seeds attached to the whole inner surface of the carpels! iIG. 1083. Raceme or spike of Triglochin palustre. 1084. Enlarged flower. 1085. A petal and stamen. 1086. The club-shaped capsule. 1087. A magnified seed, exhibiting the rhaphe and chalaza. 1088. Embryo of the same, showing the lateral slit just ab6ve the radicular end (634, where this structure is explained). 1089. Vertical section of the same passing through the slit, bringing the plumule to view. 1090. Cross-section (more magnified), showing the cotyledon wrapped around the plumule. FIG. 1091. Leaf, and 1092. flower, of Alisma Plantago. 1093. More enlarged flower, with the petals removed. 1094. Carpel, with the ovary divided, showing the double ovule. 1095. Vertical section of the germinating seed of Alisma Damasonium: a, the cotyledon; b, the plumule; c, the protruding radicle. 492 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. ovary, and from all other plants, by their irregular flowers, with a perianth of six parts; their single fertile stamen (or in Cypripedium their two stamens) coherent with the style (composing the column); their pollen usually combined into two or more compact or regular masses (pollinia), or of the consistence and appearance of wax: the ovary one-celled, with three parietal placentae, covered with numerous small seeds. —Ex. Orchis, Cypripedium (Ladies'-Slipper), Arethusa, &c. - In the tropics many are Epiphytes (132, Fig. 120). Many are cultivated for their beauty and singularity. The tuberiferous roots are often filled with a very dense mucilaginous or glutinous substance (as those of our Aplectrum, thence called Putty-root). Of this nature is the Salep of commerce, the produce of some unascertained species of Middle Asia. The fragrant Vanilla is the fleshy fruit of the West Indian Vanilla claviculata. 1098 1096 1097 1099 1098 1096 1097 1099 907. Ord. Zingiberacea (the Ginger Family) consists of some tropical aromatic herbs, the nerves of their leaves diverging from FIG. 1096. Orchis spectabilis: a, a separate flower. 1097. Column (somewhat magnified), from which the other parts are cut away: the two anther-cells opening and showing the pollenmasses. 1098. Magnified pollen-mass, with its stalk. 1099. Arethusa bulbosa.'1100. The column, enlarged: the anther terminal and opening by a lid. 1101. Magnified anther, with the lid removed, showing the two pollen-masses in each cell. ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 493 a midrib; the adnate perianth irregular and triple (having a corolla of two series as well as a calyx); fertile stamen one, on the anterior side of the flower, free; the fruit a three-celled capsule or berry; the seeds several: with the embryo in a little sac at one extremity of the farinaceous albumen. -There are, in fact, six stamens in the andrceciumrn, the three exterior petaloid and forming the so-called inner corolla, and two of the inner verticil are sterile. - Ex. Zingiber (Ginger), Amomum (Cardamon). Stimulant and aromatic. Some afford a coloring matter (Turmeric). They are all showy plants. 908. Ord. Cannacewa (the Arrowroot Family), which are equally tropical plants, differ from the preceding chiefly in the want of aroma, and in having the single fertile stamen posterior, with a one-celled anther. Ex. Maranta arundinacea (the Arrowroot) of the West Indies; the tubers of which are filled with pure starch. 909. Ord. Musacere (the Banana Family). Tropical plants, of which the Banana and Plantain are the type; distinguished by their simple perianth and five or six perfect stamens. The fruit is most important in the tropics; the gigantic leaves are used in thatch. ing; and the fibres of Musa textilis yield Manilla hemp, as well as a finer fibre from which a delicate linen is made. 910. Ord, Bromeliacee (the Pine-Apple Family) consists of American and chiefly tropical plants; with rigid and dry channelled leaves, often with a scurfy surface, a mostly adnate perianth of three sepals and three petals, and six or more stamens; the seeds with mealy albumen. - Ex. Ananassa, the Pine-Apple; the fine fruit of which is formed by the consolidation of the imperfect flowers, bracts, and receptacle into a fleshy, succulent mass. Tillandsia, the Black Moss or Long Moss, which, like most Bromelias, grows on the trunks and branches of trees in the warmer and humid parts of America, has the ovary free from the perianth. 911. Ord. tllmodoracea (the Bloodwort Family) is composed of perennial herbs, with fibrous roots, equitant or ensiform leaves; which, with the stems and flowers, are commonly densely clothed with woolly hairs or scurf. Perianth with the tube either nearly free from, or commonly adherent to, the three-celled ovary;, the limb six-cleft, regular. Stamens six, or only three, with introrse anthers. Style single, the stigma standing over the dissepiments of the ovary. Embryo in cartilaginous albumen. - Ex. Lachnanthes (Red-Root), Lophiola. 42 494 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 912. Ord. Amaryllidacee (the Amaryllis Family). Bulbous plants (sometimes with fibrous roots), bearing showy flowers mostly on scapes. Perianth regular, or nearly so; the tube adherent to the ovary, and often produced above it, six-parted. Stamens six, distinct, with introrse anthers. Stigma undivided or three-lobed. Fruit a three-celled capsule or berry. Seeds with fleshy albumen. - Ex. Amaryllis, Narcissus, Crinum, &c. The bulbs acrid, emetic, &c.: those of Hoemanthus (with whose juice the Hottentots poison their arrows) are extremely venomous. The fermented juice of Agave is the intoxicating Pulque of the Mexicans. 913. Ord. Iridacee (the Iris Family). Perennial herbs; the flower-stems springing from bulbs, corms, or rhizomas, rarely with fibrous roots, mostly with equitant leaves. Flowers regular or irregular, showy, often springing from a spathe. Perianth with the tube adherent to the three-celled ovary, and usually elongated 1103 1105 1102 1104 above it; the limb six-parted, in two series. Stamens three, disFIG. 1102. Iris cristata. 1103. The summit of the style, petaloid stigmas, and stamens. 1104. Vertical section of the ovary (the equitant leaves cut away) and long tube of the perianth. 1105. Cross-section of the pod. 1107. Seed. 1106. Enlarged section of the same, showing the embryo, &c. ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 495 tinct or monadelphous; the anthers extrorse! Stigmas three, dilated or petaloid! Seeds with hard albumen. -Ex. Iris, Crocus. The rootstocks, corms, &c. contain starch, with some volatile acrid matter. Orris-root is the dried rhizoma of Iris florentina, of Southern Europe. Saffron is the dried orange stigmas of Crocus sativus. 914. Ord. Dioscoreacear (the Yam Family) consists of a few twining plants, with large tuberous roots or knotted rootstocks; distinguished by their ribbed and netted-veined leaves, with distinct petioles, and by their inconspicuous dioecious flowers. Perianth in the pistillate flowers adherent to the ovary; the limb six-cleft in two series. Stamens six. Ovary three-celled, with only one or two ovules in each cell: styles nearly distinct. Fruit often a threewinged capsule. Albumen cartilaginous. - Ex. Dioscorea. The tubers of one or more species, filled with starch and mucilage (but more or less acrid until cooked), are Yams, an important article of food in tropical countries. 915. Ord. Smilaceam (the Smilax Family). Herbs or shrubby plants, often climbing, with the veins or veinlets of the leaves reticulated. Flowers perfect or dicecious. Perianth six-parted or double, the three sepals green, and the three petals colored. Stamens six: anthers introrse. Cells of the ovary and distinct styles or stigmas three. Berry few- or many-seeded. Albumen hard. -Ex. Smilax (Greenbrier, Catbrier, &c.). The Sarsaparilla of the shops consists of the roots of numerous species of Smilax, chiefly of tropical America. Trillium is the type of the suborder TRILLIACER. 916. Ord. Liliaeet (the Lily Family). Herbs, with the flowerstems springing from bulbs, tubers, or with fibrous or fascicled roots. Leaves simple, sheathing or clasping at the base. Flowers regular, perfect. Perianth colored, mostly of six parts, or six-cleft. Stamens six: anthers introrse. Ovary free, three-celled; the styles united: stigma often three-lobed. Fruit capsular or fleshy, with several or numerous seeds in each cell. Albumen fleshy. - Ex. This large and widely diffused order comprises a great variety of forms: the Lily and Tulip represent one division; the Polianthes (Tuberose), a second; the Aloe and Yucca, a third; the Hyacinth, the Onion, &c. (Allium), the Asphodel, Asparagus, &c., a fourth. Acrid and often bitter principles prevail in the order, and are most concentrated in the bulbs, &c., which abound in 496 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. starchy or mucilaginous matter, and are often edible when cooked. Squills are the bulbs of Scilla maritima of the South of Europe. Aloes is yielded by the succulent leaves of species of Aloe. The original Dragon's-blood was derived from the juice of the famous Dragon-tree (Dracaena Draco) of the East. 1111~~~~~~~~~~~~ ~1110 1108 1109 917. Ord. Pontederiacea (the Pickerel-weed Family) comprises a few aquatic plants, with the flowers, either solitary or spicate, arising from a spathe or from g fissure of the petiole; the six-cleft perianth persistent and withering, often adherent to the base of the three-celled ovary; the stamens three, and inserted on the throat of the perianth, or six, and unequal in situation. Ovules numerous; but the fruit often one-celled and one-seeded. - Ex. Pontederia (Pickerel-weed), Heteranthera, &c. 918. Ord. IMelanthacem (the Colchicum Family). Herbs, with bulbs, corms, or fasciculated roots. Perianth regular, in a double series; the sepals and petals either distinct, or unite'd below into a tube. Stamens six; the anthers extrorse (except in Tofieldia). FIG. 1108. Erythronium Americanum (Dog-tooth Violet, Adder's-tongue). 1109. Perianth laid open, with the stamens. 1110. The pistil. 1111. Cross-section of the capsule. ENDOGENOUS OR MONOCOTYLEDONOUTS PLANTS. 497 Ovary free, three-celled, several-seeded: styles distinct. Albumen fleshy. The true Melanthaceae, or 919. Subord. lIelanthiea have a mostly septicidal capsule and a marcescent or persistent perianth. - Ex. Colchicum has a perianth with a long tube, arising from a subterranean ovary; it is also remarkable for flowering in the autumn, when it is leafless, ripening its fruit and producing its leaves the following spring. In most of the order, the leaves of the perianth are uncombined; as in Veratrum (White Hellebore), Helonias, &c. Acrid and drastic poisonous plants, with more or less narcotic qualities; chiefly due to a peculiar alkaloid principle, named Veratria, which is largely extracted from the seeds of Sabadilla, or Cebadilla; the produce of Schoenocaulon officinale, &c., of the Mexican Andes. 1115 1114 1116 1117 1113 1112 920. Sblbord, Uvularieaw (the Beliwort Family) has a few-seeded loculicidal capsule or berry, more or less united styles, and a deciduous perianth; the stems from rootstocks. - Ex. Uvularia. 921. Ord. Juneace (the Rush Family). Herbaceous, mostly grass-like plants, often leafless: the small glumaceous flowers in FIG. 1112. Colchicum autumnale; afloweringplant. 1113. Perianthlaidopen. 1114. Pistil, with the long distinct styles. 1115. Leafy stem and fruit (capsule opening by septicidal dehiscence). 1116. Capsule divided transversely. 1117. Section of a seed, and a separate embryo. 42 498 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. clusters, cymes, or heads. Perianth mostly dry, greenish or brownish, of six leaves (sepals and petals) in two series. Stamens six, or three. Ovary free, three-celled, or one-celled from the placentae not reaching the axis; their styles united into one: stigmas three. Capsule three-valved, few- or many-seeded. Albumen fleshy. - Ex. Juncus (Rush). 922. Ord. Commelynacea (the Spiderwort Family), with usually sheathing leaves; distinguished from other Endogens (except Alismaceme and Trillium) by the manifest distinction between the calyx and corolla; the former of three herbaceous sepals; the latter of as many delicate colored petals. Stamens six, or fewer: anthers with two separated cells: filaments often clothed with jointed hairs, hypogynous. Ovary two- or three-celled; the styles united into one. Capsule few-seeded, loculicidal. Seeds orthotropous. Embryo small, pulley-shaped, partly sunk in the apex of the albumen. - Ex. Commelyna, Tradescantia (Spiderwort). Mucilaginous plants. 923. Ord. Xyridacete, Swampy, rush-like plants; with ensiform, grassy or filiform radical leaves, sheathing the base of a simple scape, which bears a head of flowers at the apex, imbricated with bracts. Calyx of three glumaceous sepals, caducous. Petals three, with claws, more or less united into a monopetalous tube. Stamens six, inserted on the corolla; three of them bearing extrorse anthers, the others mere sterile filaments. Ovary one-celled, with three parietal placenta, or three-celled: styles partly united: stigmas lobed. Capsule many-seeded. Seeds orthotropous, albuminous. - Ex. Xyris (Yellow-eyed Grass). 924. Ord, Eriocaulonaceae (the Pipezbort Family). Swampy or aquatic herbs, with much the aspect and structure of the preceding; their leaves cellular or fleshy; their minute flowers (moncecious or dioecious) crowded, along with scales or hairs, into a very compact head: the corolla less petaloid than in Xyridaceae; the six stamens often all perfect; the ovules and seeds solitary in each cell. - Ex. Eriocaulon. 925. Ord. Cyperacere (the Sedge Family). Stems (culms) usually solid, caespitose. Sheaths of the leaves closed. Flowers one in the axil of each glumaceous bract. Perianth none, or of a few bristles. Stamens mostly three, hypogynous. Styles two or three, more or less united. Fruit an achenium. Embryo small, at the extremity of the seed next the hilum. —Ex. Cyperus, Scirpus, ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 499 Carex. Sedge-Grasses. -rThe papyrus of the Egyptians was made from the stems of Cyperus Papyrus. 1122 fy/, 1119 1120 1123 1124 1121 a 1118 926. Ord, Glraminet (the Grass Family). Stems (cuims) cylindrical, mostly hollow, and closed at the nodes. Sheaths of the leaves split or open. Flowers in little spikelets, consisting of two-ranked imbricated bracts; of which the exterior are called glumes, and the two that immediately inclose each flower, palece. Perianth none, or in the form of very small and membranous' hypogynous scales, from one to three in number, distinct or united (termed squamulce, squamellce, or lodicule). Stamens commonly three: anthers versatile. Styles or stigmas two; the latter feathery. FIG. 1118. Scirpus triqueter, with its cluster of spikelets. 1119. A separate flower, enlarged, showing its rudimentary perianth of a few denticulate bristles, its three stamens, and pistil with a three-cleft style: a, section of the seed, showing the minute embryo. 1120. Carex Careyana, reduced in size (flowers moncecious, the two kinds in different spikes). 1121. Stem, with the staminate and upper pistillate spike, of the size of nature. 1122. A scale of the staminate spike, with the flower (consisting merely of three stamens) in its axil. 1123. Magnified pistillate flower, with its scale or bract: the ovary inclosed in a kind'of sac (perigynium), formed by the union of two bractlets. 1124. Cross-section of the perigynium; with the pistil, p, removed. 1125. Vertical section of the achenium, showing the seed. 500 ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. Fruit a,caryopsis (607). Embryo situated on the outside of the farinaceous albumen, next the hilum. - Ex. Agrostis, Phleum, Poa, Festuca, which are the principal meadow and pasture grasses: Oryza (Rice), Zea (Maize), Milium (Millet), Avena (the Oat), Triticum (Wheat), Secale (Rye), Hordeum (Barley), are the chief cereal plants, cultivated for their farinaceous seeds. This universally diffused order, one of the largest of the vegetable kingdom, is doubtless the most important; the floury albumen of the seeds, and the nutritious herbage, constituting the chief support of man and the herbivorous animals. No unwholesome properties are known in the family, except in the seeds of Lolium temulentum, which are deleterious. The Ergot, or Spurred Rye, forms no real exception to this rule, as it is caused by parasitic fungus. - The 1134 1135 1136 1137 1138 1140 1133 1X26 > c 0 t1139 1126 1128 1130 1132 stems of grasses frequently contain sugar in considerable quantity; FIG. 1126. One-flowered spikelet or locusta of Alopecurus, with the glumes separated. 1127. Same, with the glumes removed: an awn on the back of the outer palea. 1128. Oneflowered spikelet of an Agrostis. 1129. Pistil of a Grass, showing the two feathery stigmas, and the two hypogynous scales or squamulhe (representing the perianth). 1130. Two-flowered spikelet of an Avena; with the glumes spreading. 1131. One of the flowers with its palete; the exterior pointed, with two bristles or cusps at the apex, and with a bent awn on the back. 1132. Many flowered spikelet of Glyceria fluitans. 1133. An enlarged separate flower of the same, seen from within, showing the inner palea, &c. 1134. The fruit (caryopsis) of the Wheat, with an oblique section through the integuments of the embryo, which is exterior to the albumen. 1135. Detached magnified embryo: a, the imperfect lower cotyledon; b, the large cotyledon; c, the plumule; d, the radicle. 1136. The caryopsis of Hordeum (Barley). 1137. A cross-section. 1138. A vertical section, showing the external embryo at the base. 1139. Magnified detached embryo, with its broad cotyledon and the plumule. 1140. More magnified vertical section of the same: a, the plumule; b, the radicle. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 501 especially in the few instances where it is solid, as in the Maize, and more largely in the Sugar-Cane (Saccharum officinarum), which affords the principal supply of this article. Series II. CRYPTOGAMOUS OR FLOWERLESS PLANTS. PLANTS destitute of proper flowers (stamens and pistils), and propagated by spores instead of seeds (101, 109). Class III. AcROGENOUS PLANTS. Vegetables with a distinct axis, growing from the apex, with no provision for subsequent increase in diameter (containing woody and vascular tissue), and usually with distinct foliage (108). 927. Ord. Equisetaceaw (the Horse-tail Family). Leafless plants; with striated, jointed, simple or 1142 1141 branched stems (containing ducts and some spiral vessels), which are hollow and closed at the 00 joints; each joint terminating in a toothed sheath, which surrounds the base of the one above it. Inflorescence consisting of peltate scales crowded in a terminal spike, or kind of strobile: each with several thecce attached to its lower surface, longitudinally dehiscent. Spores numerous, with four elastic club-shaped bodies 143 1144 (of unknown use, called elaters) wrapped around them. —Ex. Equisetum. The epidermis of Equisetum hyemale (Scouring Rush) contains so much silex that it is used for polishing. 1145 1146 928. Ord. Filiees (Ferns). Leafy plants; with the leaves (fronds) FIG. 1141. Summit of the stem of Equisetum sylvaticum. 1142. Part of the axis of the cone of fructification, with some of the fruit-bearing organs, shown magnified in Fig. 1143. 1144. A separate theca, more magnified. 1145, 1146. Spores with elaters, still more magnified. 502 CRYPTOGAMOUS OR FLOWERLESS PLANTS. spirally rolled up or circinate in vernation (except in one suborder), usually rising from prostrate or subterranean rootstocks, sometimes from an erect arborescent trunk (Fig. 94), and bearing, on the veins of their lower surface, or along the margins, the simple fructification, which consists of one-celled spore-cases (thecce or sporangia), opening in various ways, and discharging the numerous minute spores. The stalk or petiole of the frond is termed a stipe.- There are three principal suborders, viz. — 1152 1153 1148 1150 1151 1147 1154 929. Subord. Polypodinee. Sporangia collected in dots, lines, or variously shaped clusters (sori or fruit-dots) on the back or marFIG. 1147. Asplenium (Camptosoros) rhizophyllum (Walking Fern); the fronds rooting, as they frequently do, at the apex; the sori occupying the reticulated veins on the back. 1148. Division (pinnula) of a frond of Aspidium (Nephrodium) Goldianum; the roundish sori attached to the simple veins, and covered with an indusium, which is fastened in the centre, and opens all around the margin. 1149. Magnified sporangium of this division of Ferns, with its stalk, and elastic ring partly surrounding it; which, tending to straighten itself when dry, tears open the sporangium, shedding the minute spores (1150). 1151. Schizma pusilla of about the natural size, with simple and slender radical leaves; the contracted fertile frond pinnate. 1152. A division (pinna) of the fertile frond, magnified, showing the sessile sporangia occupying its lower surface. 1153. One of the sporangia more magnified; they have no proper ring, and open by a longitudinal cleft. 1154. Ophioglossum vulgatum (Adder-tongue); the sporangia forming a two-ranked spike on a transformed and contracted frond: a, portion of the spike enlarged, showing the coriaceous sporangia, destitute of a ring, and opening transversely. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 503 gins of the frond or its divisions, stalked, cellular-reticulated, the stalk running into a vertical incomplete ring, which by straightening at maturity ruptures the sporangium transversely on the inner side, discharging the spores. Fruit-dots often covered, at least when young, by a membrane called the involucre, or indusium. 930. Subord, Osmundinea, Sporangia variously collected, destitute of any proper ring, cellular-reticulated, opening lengthwise by a regular slit. 931. Subord, Ophioglosseue. Sporangia spiked, closely sessile, naked, coriaceous and opaque, not reticulated, destitute of a ring, opening by a transverse slit into.two valves, discharging the very copious spores which appear like floury dust. Fronds straight, never rolled up (circinate) in the bud! 932. Ord. Lycopodiacece (the Club-Moss Family). Plants with creeping or erect leafy stems, mostly branching; the crowded leaves lanceolate or subulate, one-nerved. Thece sessile in the axils of the leaves, sometimes all collected at the summit under leaves which are changed into bracts and crowded into a kind of ament, one-celled, or rarely two- to three-celled, dehiscent, containing either minute grains, appearing like fine powder, or a few rather large sporules; both kinds often found in the same plant. -Ex. Lycopodium (Club-Moss, Ground Pine, Fig. 89-93), Psilotum. -Appended to this family, rather than to the next, is the 933. Subord. Isoetineae (the Quillwort Family), consisting of a few acaulescent submersed aquatics, with sporangia in the axils and immersed in the inflated base of the grassy stalk-like leaves. -Ex. Isoetes. 934. Ord. iydropterides. Aquatic cryptogamous plants of diverse habit, with the fructification borne at the bases of the leaves, or on submerged branches, consisting of two sorts of organs, contained in indehiscent or irregularly bursting involucres (sporocarps):- comprising the 935. Subord. Marsilee (the Pepperwort Family); with creeping stems; the leaves long-stalked, circinate in vernation; — of four obcordate leaflets in Marsilea, or filiform and destitute of leaflets in Pilularia (the Pillwort). 936. Subord. Salvinie e; which are free floating plants, with al. ternate and sometimes imbricated sessile leaves; the fructification borne on the stem or branches underneath. - Ex. Salvinia, Azolla. 504 CRYPTOGAMOUS OR FLOWERLESS PLANTS. Class IV. ANOPHYTES. Vegetables composed of parenchyma alone, with acrogenous growth, usually with distinct foliage, sometimes the stem and foliage confluent into a frond (105, Fig. 87, 88). 937. Ord. Musci (Mosses). Low, tufted plants, always with a stem and distinct (sessile) leaves, producing spore-cases which mostly open by a terminal lid, and contain simple spores alone. Reproductive organs of two kinds: - 1. The sterile flower, consisting of numerous (4-20) minute cylindrical sacs (antheridia) which discharge from their apex a mucous fluid filled with oval particles, and then perish. 2. The fertile flower, composed of numerous (4-20) flask-like bodies (pistillidia), each having a membranous covering (calyptra), terminated by a long cylindri1157 1160 1168 1166 t/\>(L ~~ X^.1164 1158 159 1162 1155 1161 1165 1163 cal funnel-mouthed tube (style). The ripened pistillidium (selFIG. 1155. Mniumcuspidatum. 1156. The calyptradetached from the theca. 1157. Magnified theca, from which the lid or operculum, 1158, has been removed, showing the peristome. 1159. A portion of the annulus, magnified. 1160. A portion of the outer and inner peristome, highly magnified. 1161. The so-called flowers in a young state, consisting of the young theca, and the antheridia A, with some cellular jointed threads intermixed; the involucral leaves cut away. 1162. One of the antheridia more magnified (with the accompanying cellular threads), opening at the apex, and discharging the fovilla. 1163. Simple peristome of Splachnum; the teeth united in pairs. 1164. Double peristome of Hypnum; the exterior spreading. 1165. Physcomitrium (Gymnostomum) pyriforme. 1166. Its calyptra, detached from 1167, the tHleca. 1168. The lid removed from the orifice, which is destitute of a peristome. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 505 dom more than one in a flower maturing) becomes the capsule, which is rarely indehiscent or splitting by four longitudinal slits, but usually opens by a lid (operculum): beneath the lid and arising from the mouth of the capsule are commonly either one or two rows of rigid processes (collectively the peristome), which are always some multiple of four: those of the outer row are called teeth, of the inner, cilia. An elastic ring of cells (annulus) lies between the rim of the capsule and operculum. The powdery particles filling the capsule are spores. The thread-like stalk (pedicel) supporting the capsule is inserted into the elongated torus (vaginula) of the flower. The pedicel continued through the capsule forms the columella: enlarged under the capsule it sometimes forms an apophysis. The calyptra separating- early at its base is carried up on the apex of the capsule; if it splits on one side, it is hood-shaped or cuculliform, if not, it is mitre-shaped or mitriform. Intermixed with the reproductive organs are jointed filaments (parapvhyses). The leaves next the antheridia are called perigonial leaves, those around the pistillidia or pedicel the perichcetial leaves. 938. Ord. llepatica (Livervworts). Frondose or Moss-like plants, of a loose cellular texture, usually procumbent and emitting rootlets from beneath; the calyptra not separating from the base, but usually rupturing at the apex; the capsule not opening by a lid, containing spores usually mixed with elaters (which are thin, thread-like cells, containing one or two spiral fibres, uncoiling elastically at maturity). Vegetation sometimes frondose, i. e. the stem and leaves confluent into an expanded leaf-like mass; sometimes foliaceous, when the leaves are distinct from the stem, as in true Mosses, entire or cleft, two-ranked, and often with an imperfect or rudimentary row (amphigastria) on the under side of the stem. Reproductive organs of two kinds, viz. antheridia and pistillidia, much as in Mosses (937), variously situated. The matured pistillidium forms the capsule, which is either sessile or borne on a long cellular pedicel, and dehiscent by irregular openings, by teeth at its apex, or lengthwise by two or four valves. A columella is rarely present. The perianth is a tubular organ inclosing the calyptra, which directly includes the pistillidium. Sur. rounding the perianth are involucral leaves of particular forms. The antheridia in the foliaceous species are situated in the axils of perigonial leaves. 939. Subord, Ricciacewa are chiefly floating plants, rooting from 43 506 CRYPTOGAMOUS OR FLOWERLESS PLANTS. beneath, with the fructification immersed-in the frond, the sporangium bursting irregularly. No involucre nor elaters. - Ex. Riccia. 1169 1170 1171 1172 1173 940. Subord. Anthocerotere. Terrestrial frondose annuals, with the fruit protruded from the upper surface of the frond. Perianth none. Capsule pod-like, one- to two-valved, with a free central columella. Elaters none or imperfect. 941. Subord, MIarchantiaeete (true Liverworts). Frondose and terrestrial perennials, growing in wet places, with the fertile receptacle raised on a peduncle, capitate or radiate, bearing pendent calyptrate capsules from the under side, which open variously, not four-valved. Elaters with two spiral fibres. 942. Subord. Jungermanniacee. Frondose or mostly foliaceous plants; with the sporangium dehiscent into four valves, and the spores mixed with elaters (Fig. 84- 86). CLASS V. THALLOPHYTES. Vegetables composed of parenchyma alone, of congeries of cells, or even of separate cells, often vaguely combined in a thallus, never exhibiting a marked distinction into root, stem, and foliage, or into axis and leaves (94-104, 106). Fructification of the most simple kinds. (Spores often termed sporules or sporidia.) 943. Ord. Lichenes (Lichens) form the highest grade of this lower series. They consist of flat expansions, which are rather crustaFIG. 1169, 1170. Riccia natans, about the natural size. 1171. Magnified section through the thickness of the frond, showing the immersed sporangia; one of which has burst through and left an effete cavity. 1172. Magnified vertical section of one of the sporangia, with the contained spores. 1173. Sporangium torn away from the base, and a quaternary group of spores, united and separated. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 507 ceous than foliaceous. Their structure is, as it were, anticipated in Riccia, above mentioned (Fig. 1170). They are by no means aquatic, however, but grow on the ground, on the bark of trees, or on the surface of exposed rocks, to which they cling by their lower surface, often with the greatest tenacity, while by the upper they draw their nourishment directly from the air (Fig. 1174). The fructification is in cups, or shields (apothecia, Fig. 1176), resting on the surface of the thallus, or more or less immersed in its substance (Fig. 1178), or else in pulverulent spots scattered over the surface. A magnified section through an apothecium (Fig. 1176) brings to view a stratum of elongated sacs (asci), with filaments 1176 1177 1179 1175 s ___-1178 L 1/ 1174 intermixed, as seen detached and highly magnified at Fig. 1177. FIG. 1174. A stone upon which several Lichens are growing, such as (passing from left to right) Parmelia conspersa, Sticta miniata, Lecidea geographica (so called from its patches resembling the outline of islands, &c. on maps), &c., &c. 1175. Piece of the thallus of Parme. lia conspersa, with a section through an apothecium. 1176. Section of a smaller apothecium, more magnified. 1177. Two asci and their contained spores, with the accompanying filaments, highly magnified. 1178. Section of a piece of the thallus of Sticta miniata, showing the immersed apothecia. 1179. Cladonia coccinea, bearing its fructification in rounded red masses on the edges of a raised cup. 508 CRYPTOGAMOUS OR FLOWERLESS PLANTS. Each ascus, or sac, contains a few spores, which divide into two, but generally remain coherent. The vegetation of some Lichens rises into a kind of axis, as in the Cladonia coccinea, which abounds on old logs (Fig. 1179); or in Cladonia rangiferina, the Reindeer Moss; also in Usnea, where it forms long, gray tufts, hanging from the boughs of old trees in our Northern forests. 944. Ord, Fungi (Mushrooms, Moulds, dc.) are parasitic (137) Flowerless plants, either in a strict sense, as living upon and drawing their nourishment from living, though more commonly languishing, plants and animals, or else as appropriating the organized matter of dead and decaying animal and vegetable bodies. Hence they fulfil an office in the economy of creation analogous to that of the infusory animalcules. Those Fungi which produce Rust, Smut, Mildew, &c. are of the first kind; those which produce Dry-rot, &c. hold a somewhat intermediate place; and Mushrooms, Puff-balls, &c. are examples of the second. Fungi are consequently not only destitute of any thing like foliage, but also of the green matter, or chlorophyll, whichl appears to be essential to the formation of organic out of inorganic matter (87, 135, 344). A full account of the diversified modifications of structure that Fungi display, and of the remarkable points in their economy, would require a volume. We will notice three sorts only, which may represent the highest, and nearly the lowest, forms of this vast order or class of plants. They all begin (in germination or by offsets) with the production of copious filamentous threads, or series of attenuated cells, appearing like the roots of the fungus that arises from them (Fig. 1179, 1181), and to a certain extent performing-the functions of roots: this is called the mycelium, and is the true vegetation of Fungi. The subsequent developments properly belong to the fructification, or are analogous to tubers, rhizomas, &c. In one part of the order, the masses that arise, of various definite shapes, and often attaining a large size, contain in their interior a multitude of asci (Fig. 1180), inclosing simple or double sporules, just as in Lichens. The esculent Morel has this kind of fructification; as well as the less conspicuous Sphberia (Fig. 1179), which is in other respects of a lower grade. The Agarics, like the Edible Mushroom (Fig. 1181), present a different type. Rounded tubercles appear on the mycelium; some of these rapidly enlarge, burst an outer covering which is left at the base (the volva, or wrapper), and, protrude a thick stalk (stipes), CRYPTOGAMOUS OR FLOWERLESS PLANTS. 509 bearing at its summit a rounded body that soon expands into the pileus, or cap. The lameilce, or gills (hymenium), that occupy its 1182 1184 1183 Tic 1181 1179 1180 lower surface, consist of parallel plates (Fig. 1182), which bear naked sporules over their whole surface. A careful inspection with the microscope shows Ahatci these sporules are grouped in fours; and a view of a section of one of the gills shows their true origin (Fig. 1183). Certain of the cells (basidia), one of which is shown more magnified at Fig. 1184, produce four small cells at their free summit, apparently by gemmation and constriction: these are the sporules. It is maintained that the larger intermingled cells, (of which one is shown at Fig. 1183, a,) filled with an attenuated form of matter, are the analogues of stamens. The lowest Fungi produce from their mycelium only simple or branching series of cells (Fig. 74-76). The mycelium itself either ramifies through decaying organized matter, as the Moulds, FIG. 1179. Sphweria rosella. 1180. Asci from its interior, containing sporules, highly magnified. 1181. Agaricus campestris, the Edible Mushroom, in its various stages. 1182. Section through the pileus, to display the gills. 1183. A small piece of a slice through the thickness of one of the gills, magnified; showing the spores borne on the summit of salient cells of both surfaces. 1184. One of the sporule-bearing cells, with some subjacent tissue, more magnified. 43 510 CRYPTOGAMOUS OR FLOWERLESS PLANTS. &c.; or else, like the Blight and Rust in grain, and the Muscardine so destructive to silkworms, it attacks and spreads throughout living tissues, often producing great havoc before its fructification is revealed at the surface. Sometimes the last cells of the stalks swell into a vesicle, in which the minute sporules are formed; as in Fig. 74. Sometimes the branching stalks bear single sporules, like a bunch of grapes (Fig. 76), or long series of cells, or sporules, in rows, like the beads of a necklace (Fig. 75), which, falling in pieces, are the rudiments of new plants. 1187 945. Ord. Characee, The Chcara Family consists of a few aquatic plants, which have all the simplicity of the lower Algae in their i cellular structure, being composed of simple tubular cells placed end to end, and often with a set of smaller tubes applied to the surface of the main one (Fig. 1186). Hence they have been placed among Algme. But their fructification is of a higher order. It consists of two kinds of bodies (both shown in Fig. 1186), of which the smaller (and lower) is probably a mass of antheridia of curious structure, while the upper and larger is a sporocarp, formed of a budding cluster of leaves wrapped around a nucleus, which is a spore or sporangium. The order should have been introduced between the Equisetaceme (to which the verticillate branches show some analogy) and the Hydropterides, which they somewhat resemble in fructification. They are, of all plants, those in which the rotary movement of the contents of the cells (36, which has been called Cyclosis) may be most readily observed. 946. Ord. Algt (Seaweeds). This vast order, or rather class, consists of aquatic plants; for the most part strictly so, but some grow in humid terrestrial, situations. The highest forms are the proper Seaweeds (Wrack, Tang, Dulse, Tangle, &c.); " some of which have stems exceeding in length (although not in diameter) F1G. 1185. Branch of the common Chara, nearly the natural size. 1186. A portion magnified, showing the lateral tubes inclosing a large central one (a portion more magnified at 1187); also a spore, invested by a set of tubes twisted spirally around it; and with an antheridium borne at its base. CRYPTOGAMOUS OR FLOWERLESS PLANTS. 511 the trunks of the tallest forest-trees, while others have leaves (fronds) which rival in expansion those of the Palm." "Others again are so minute as to be wholly invisible, except in masses, to the naked eye, and require the highest powers of our microscopes to ascertain their form and structure." Some have the distinction of stems and fronds; others show simple or branching solid stems only; and others flat foliaceous expansions alone (Fig. 82), either green, olive, or rose-red in hue. From these we descend by successive gradations to simple or branching series of cells placed end to end, such as the green Confervas of our pools, and many marine forms (Fig. 81): we meet with congeries of such cells capable of spontaneous disarticulation, each joint of which becomes a new plant, so that the organs of vegetation and of fructification become at length perfectly identical, both reduced to mere cells; and finally, as the last and lowest term of possible vegetation, we have the plant reduced to a single cell, giving rise to new ones in its interior, each of which becomes an independent plant (94 - 99). 947. The fructification of Algue exhibits four principal varieties. In the great division of olive-brown or olive-green proper Seaweeds, the MELANOSPERMEI.E of Harvey, the fructification forms tubercles immersed in the tissue of the summit of the branches of the frond (Fig. 1188- 1191), which are filled with a mass of simple spores with filaments intermixed (1191), invested by a proper membranous coat, and finally escaping from the frond by a minute orifice. The beautiful red-colored Seaweeds, or RHODOSPERMEZ, exhibit two kinds of spores; one large, simple, superficial; and resembling those above described, except that they have no proper integument; the others, dispersed through the interior of the frond, are formed four together in a mother cell. The bright green series, or CHLOROSPERMEIE, have the whole green contents of certain cells, or of some part of the cell, (as in Vaucheria, Fig. 71, 72, 467, and in Conferva vesicata, Fig. 474, &c.,) condensed into a spore, in some of the ways already described (95-101), or else they result from the conjugation of two cells (102, Fig. 78 - 81). This conjugation occurs throughout in the 948. Subord. Desmidiea), which are microscopic and infusory green Algae of single cells (Fig. 77- 80) often of crystal-like forms, invested with mucus, and belonging to fresh water. They multiply largely by division, but propagate only by conjugation. Many of them have long been claimed for the animal kingdom, or esteemed 512 CRYPTOGA1MOUS OR FLOWERLESS PLANTS. of ambiguous nature, on account of the free movements they exhibit (661); but these are nearly as well marked in Oscillaria, &c. (Fig. 66). More ambiguous still, and on the lowest confines of the vegetable kingdom, are those minute vegetables, as they doubtless are, which constitute the 1188 1192. 1200 1202 ~1190D2 _ ~1ni9 1196 H.it 1204 M 1193 1199 1198 1206 1205 1207 949. Sulbord, Diatomacem. These essentially differ from the last in the brown instead of green color of their contents, in the siliceous and durable nature of their cell-wall, and in being natives of salt instead of fresh water. Their movements, as they break up from their connections, are still more vivid and varied. Some are fixed (Fig. 1207); others are free. Some are extremely minute; others consist of clusters of cells of considerable size. FIG. 1188. Summit of the frond of Fucus vesiculosus. 1189. Section of one of the receptacles. 1190. One of the contained globules. 1191. Spores and jointed filaments of which the globules are composed. 1192. Delesseria Le Prieurii. 1193. The sterile plant. 1194. Magnified portion of the fertile frond. 1195. Portion of the same, more magnified, showing its tissue from the midrib to the margin. A. Theca, opened, with the spores. 1196. Portion of the network of Hydrodyction utriculatum. 1197. A magnified joint, filled with the green matter which developes into a new plant. 1198. Single filament of Tyndaridea cruciata, showing the star-shaped bodies, enveloped in mucus. 1199. Two filaments of the same united side by side. 1200. Vaucheria geminata, in fruit. B. Vesicular receptacles, enlarged. -The remaining figures represent some of the ambiguous Diatomaceae. 1201. Gonium glaucum, of Ehrenberg, who thinks it a congeries of animalcules; while Me" en has described it as an Alga. C. Closterium Lunula; usually filled with floating green globules: a, the perfect vegetable; b, the same, separating into two by spontaneous division; c, an individual resulting from this. spontaneous division, developing a second; d, two individuals conjugately united; the green matter all collected in the uniting globule. 1202. Euastrum Pecten, and 1203, E. Crux-Melitensis. 1204. A Diatoma, breaking up into separate individuals. 1205. A Fragillaria. 1206. Meridion circulare, front and side views. 1207. Echinella flabellata; perhaps a group of animalcules. APPENDIX. OF THE SIGNS AND ABBREVIATIONS EMPLOYED IN BOTANICAL WRITINGS. LINNEUS adopted the following signs for designating the duration of a plant, viz.: - ( An annual plant. & A, biennial plant. I A perennial herb. I5 A shrub or tree. Among the signs recently introduced, the following have come into general use:o A monocarpic plant, whether annual or biennial. c_ An annual plant. ~ A biennial plant.., A perennial herb. 2 A plant with a woody stem.. A staminate flower, or plant. v A pistillate flower, or plant. { A perfect flower, or a plant bearing perfect flowers.! The exclamation point is employed as the counterpart of the note of interrogation. When it follows the name of an author appended to the name of a plant, it imports that an authentic specimen of the plant in question, under this name, has been examined by the writer: when it is appended to a locality, it signifies that the writer has seen or collected specimens of the plant from that locality, &c.? The note of interrogation is similarly employed in case of doubt or uncertainty; and is affixed either to a generic or specific name, or to that of an author or locality cited. * As used by De Candolle, indicates that a good description is found at the reference to which it is appended. It is not in common use. 514 APPENDIX. Those abbreviations of the names of organs which are commonly employed, such as Cal. for calyx, Cor. for corolla, Fl. for flower, Fr. for fruit, Gen. for genus, Hab. for habitat) Herb. for herbarium, Hort. for garden, Mus. for Museum, Orad. for order, Rad. (Radix) for root, Syn. for synonymy, Sp. or Spec. for species, Var. for variety, &c., scarcely require explanation. V. sp. denotes, in general terms, that the writer has seen the plant under consideration. V. s. c. (Vidi siccam cultam), that a dried specimen of a cultivated plant has been examined. V. s. s. (Vidi siccam spontaneam), that a dried specimen of the wild plant has been examined. V. v. c. ( Vidi vivam cultam), that the living cultivated plant has been under examination. V. v. s. ( Vidi vivam spontaneam), that the wild plant has been examined in a living state. The names of authors, when of more than one syllable, are commonly abridged by writing the first syllable, and the first letter or the first consonant of the second. Thus, Linn., or L., is the customary abbreviation for Linnoeus; Juss. for Jussieu; Willd. for Willdenow; Muhl. for Muhlenberg; Michx. for Michaux; Rich. for Richard; De Cand., or DC., for De Candolle; Hook. for Hooker; Endl. for Endlicher; Lindl. for Lindley, &c. OF COLLECTING AND PRESERVING PLANTS. 1. THE botanist's'collection of specimens of plants, preserved by drying under pressure between folds of paper, is termed a Hortus Siccus, or commonly an Herbarium. 2. A complete specimen consists of one or more shoots, bearing the leaves, flowers, and fruit; and, in case of herbaceous plants, a portion of the root is also desirable. 3. Fruits and seeds which are too large to accompany the dried specimens, or which would be injured by compression with sections of wood, &c., should be separately preserved in cabinets. 4. Specimens for the herbarium should be gathered, if possible, in a dry day; and carried either in a close tin box, as is the common practice, or in a strong portfolio, containing a quire or more of firm paper, with a few loose sheets of blotting-paper to receive delicate plants. They are to be dried, under strong pressure, (but without crushing the parts,) between dryers composed of six to ten thicknesses of bibulous paper; which should be changed daily, or even more frequently, until all the moisture is extracted from the plants; - a period which varies in different species, and with the season, from two or three days to a week. All delicate speci APPENDIX. 515 mens should be laid in folded sheets of thin and smooth bibulous paper (such as tea-paper), and such sheets, filled with the freshly gathered specimens, are to be placed between the dryers, and so transferred entire, day after day, into new dryers, without being disturbed, until perfectly dry. This preserves all delicate flowers better than the ordinary mode of shifting of the papers which are in immediate contact with the specimens, and also saves much time usually lost in transferring numerous small specimens, one by one, into dry paper, often to the great injury of the delicate corolla, &c. 5. The dried specimens, properly ticketed with the name, locality, &c., and arranged under their respective genera and orders, are preserved in the herbarium, either in separate double sheets, or with each species attached by glue or otherwise to a half-sheet of strong white paper, with the name written on one corner. These are collected in folios, or else lie flat (as is the best mode) in parcels of convenient size, received into compartments of a cabinet, with close doors, and kept in a perfectly dry place. 6. The seeds of plants intended for cultivation, which are to be transported to a distance before being committed to the earth, should first be dried in the sun, wrapped in coarse-paprcand preserved in a dry state. They should not be packafiFin close boxes, at least so long as there is danger of the retention of ~noisture. 7. Roots, shrubs, &c., designed for cultivation, should be taken from the ground at the close of their annual vegetation, or early in the spring before growth recommences, and packed in successive layers of slightly damp (-but not wet) Peat-moss (Sphagnum). Succulent plants, however, such as Cacti, may be packed in dry sand. 8. Plants in a growing state can only be safely transported to a considerable distance, especially by sea, in the closely glazed cases invented by Mr. Ward; * where they are provided with the requisite moisture, while they are fully exposed to the light. * On the Growth,of Plants in Closely Glazed Cases, by N. B. Ward, F. L. S., London, 1842. -Ed. 2. 1853. INDEX AND GENERAL GLOSSARY OF BOTANICAL TERMS. Abbreviations, 513. Alkaloids, 61. Abietineae, 474. Almond Family, 420. Abortion, 246, 263. Alsineax, 400. Abortive stamens, 291. Alternate, 140, 241. Abruptly pinnate, 168. Alternate leaves, 142. Acanthaceav, 452. Alveolate; honey-combed. Acanthus Family, 452. Amarantacee, 470. Acaulescent; apparently.stemless, 94. Amaranth Family, 470. Accessory buds, 100. Amaryllidacee, 494. Accrescent, 289. Amaryllis Family, 494. Accumbent, 335. Ament, 218. Aceracem, 412. Amentaceous trees, 219. Acerose; needle-shaped, as the leaves Amnios, 315. of Juniper. Amphigastria, 505. Achenium, 326. Amphitropous, 312. Achlamydeous, 264. Amplexicaul; clasping. Acrogenous plants, 74, 501. Amygdalese, 420. Acrogens, 74. Amyridacea, 411. Aculeate; armed with prickles. Anacardiaceae, 411. Aculeolate; armed with little prickles. Anastomosing, 161. Acuminate, 168. Anatropous, 311. Acute, 167. Ancipital; two-edged. Adder's-tongue Family, 503. Andrcecium, 228, 289. Adnate, 259, 292. Androgynous, 277. Adnation, 246, 258. Angiospermia, 360. Adventitious buds, 100. Angiospermous, 364. Adventitious roots, 87. Angiospermous plants, 371. Aerial roots, 87. Angular divergence, 143. iEstivation, 278. Anisomerous, 270. Air cells, 54. Annual layers, 113. Air passages, 54. Annual roots, 85. Air plants, 89. Annular ducts, 50. Ale, 261. Annulus, 505. Alate, 172. Anonaceve, 386. Albumen, 319, 332. Anophytes, 373, 504. Alburnum, 125. Anterior, 2434 298. Algae, 510. Anther, 228, 291. Alismaceae, 488. Antheridia, 340, 505. INDEX AND GLOSSARY, 517 Anthesis, 281. Bent, 151. Anthocarpous fruits, 328. Berberidacem, 388. Anthocerotea, 506. Berry, 327. Anthophore, 277. Betulacee, 481. Apetalse, 264, 375. Biennial roots, 85. ApetaloUs, 264. Bifid, 166. Apetalous plants, 465. Bifoliate; with two leaflets. Apocarpous, 300. Bifurcate; two-forked. Apocynacema, 463. Bignoniaceae, 452. Apophysis, 505. Bignonia Family, 452. Apothecia, 508. Bilabiate, 261, 288. Appressed; lying flat against. Bilocular,. 302. Aquifoliaceme, 447. Binate, 170. Araceae, 488. Bipinnate, 170. Arachnoid; with cobwebby hairs. Bipinnatifid, 167. Araliacese, 433. Birch Family, 480. Areolate; divided into angular spaces. Birthwort Family, 467. Aril, 331. Bisexual, 264. Arillus, 331. Biternate, 170. Aristate; with an awn. Bixaceae, 398. Aristolochiaceae, 468. Bladder-nut Family, 415. Arrangement of leaves, 140. Bladderwort Family, 451. Arrow-headed, 164. Blade, 157, 286. Arrowroot Family, 493. Bloodwort Family, 493. Articulated, 168. Bloom, 156. Articulation, 176. Bolivariwa, 463. Artificial system, 364. Borage Family, 456. Artocarpeae, 482. Boraginaceae, 456. Arum Family, 488. Bothrenchyma, 48. Ascending, 309. Brachiate; with opposite spreading Ascending axis, 93. branches. Ascending radicle, 335. Bracteoles, 221. Ascidia, 173. Bractlets, 221. Asclepiadacean, 463. Bracts, 151, 216. Ascus, 508. Branches, 98. Assimilation, 21, 194. Branchlets, 99. Assurgent; obliquely ascending. Bread-fruit Family, 482. Atropous, 311. Breathing-pores, 157. Augmentation, 245. Bristles, 55. Aurantiaceae, 405. Bromeliaceve, 493. Auriculate; eared, with two round Broom-Rape Family, 451. lobes at the base. Buckbean Family, 462. Automatic movements, 353. Buckthorn Family, 414. Awn; a bristle-like appendage. Buckwheat Family, 470. Axillary, 225. Budding, 32. Axillary buds, 98. Buds, 95. Axis of inflorescence, 216. Bulb, 110. Baccate; berry-like. Bulblets, 110. Balsam Family, 408. Burmanniacea3, 491. Balsamniflue, 482 Burseraceae, 411. Balsaminaceae, 408. Butomacere, 491. Balsams, 200. Byttneriacece, 403. Banana Family, 493. Cabombaceme, 389. Banded ducts, 49. Cactaceae, 426. Banner, 261. Cactus Family; 426. Barberry Family, 388. Caducous; falling off early. Bark, 118, 127. Cesalpinese, 418. Basidia, 510. Cespitose; forming a tuft. Bassorin, 59. Calcarate, 296. Bast tissue, 46. Callitrichacese, 476. Bearded; with a tuft of hairs. Calycanthacene, 422. Bellwort Family, 444. Calyculate; with an outer calyx. 44 518 INDEX AND GLOSSARY Calyptra, 505. Cilia, 505. Calyx, 227, 263, 285. Ciliate; the margin fringed with hairs. Cambium, 121. Cinchonete, 438. Cambium layer, 121. Cinenchyma, 52. Campanulacea, 444. Circinate, 225. Campanula Family, 444. Circinnate, 151. Campanulate, 287. Circulation in cells, 33. Campylotropous, 311. Circumscissile, 325. Canaliculate; channelled. Circumscription; the general outline. Canescent; whitened with close hairs. Cirrhose; furnished with tendrils. Cannabineae, 483. Cistacene, 397. Cannacete, 493. Classes, 362. Caoutchouc, 57. Classification, 15, 357. Cap, 509. Clavate; club-shaped. Caper Family, 394. Claw, 278, 286. Capillary; hair-like. Cleft, 166, 257. Capitulum, 219. Club-Moss Family, 503. Capparidaceae, 394. Clusiacen, 398. Caprifoliacea, 436. Coalescence, 246, 256. Capsule, 328, 505. Cocci, 323. Carina, 261. Cocoa-plum Family, 420. Carinate; keeled. Cohesion, 258. Carpel, 300. Coils in cells, 42. Carpet-weed Family, 401. Colchicum Family, 496. Carpidium, 300. Collateral chorisis, 250. Carpophore, 277, 327. Collective fruits, 328. Caruncle, 331. Colored, 263. Caryophyllacew, 399. Columella, 324, 497. Caryophyllaceous, 287. Column, 484. Caryopsis, 327. Coma, 330. Cashew Family, 411. Commelynacew, 498. Catkin, 218. Commissure, 327. Cat-tail Family, 489. Complete flower, 227, 339. Caudate; with an appendage or pro- Composite, 440. longation like a tail. Composite Family, 440. Caudex, 104. Compound corymb, 221. Cauline, 150. Compound flowers, 220. Cedrelacet, 406. Compound leaves, 168. Celastracene, 414. Compound organs, 64. Cells, 24, 228. Compound pistil, 301. Cellular, 152. Compound raceme, 221. Cellular envelope, 119. Compound spike, 221. Cellular plants, 73, 372. Compound umbel, 221. Cellular structure, 23. Compressed; flattened laterally. Cellular tissue, 24. Concentric layers, 113. Cellulose, 28, 196. Conduplicate, 284. Centrifugal, 223, 226, 335. Cone, 329. Centripetal, 218, 226, 835. Conferruminate, 336. Ceratophyllacee, L476. Coniferne, 484. Chaff, 220, 441. Conjugate; in pairs. Chalaza, 311. Conjugation, 69. Characee, 510. Connate, 259. Characters, 362. Connate-perfoliate, 174. Chara Family, 510. Connective, 291. Chenopodiaceu, 469. Connectivum, 291. Chickweed Family, 400. Connivent; converging. Chlorophyll, 60, 194. Constituents of plants, 183. Chlorospermete, 511. Contorted, 282. Chorosis, 246, 249. Convolute, 151, 281, 282. Chlorisis, 235. Convolvulaceae, 459. Chromule, 61. Convolvulus Family, 459. Chrysobalanen, 420. Cordate, 164. OF BOTANICAL TERMS. 519 Coriaceous; leathery in texture. D6doublement, 253. Corky envelope, 119. Deduplication, 246, 249. Corm, 109. Definite, 309. Cormophytes, 73, 373. Definite inflorescence, 222. Cormus, 109. Dehiscence, 293, 323. Cornacese. 433. Dehiscent, 323. Cornel Family, 433. Deliquescent stems, 101. Corneous, 332. Deltoid; with a triangular outline. Corolla, 228, 286. Demersed; under water. Corrugate, 279. Dentate, 166. Coryrb, 217. Depressed; flattened vertically. Corymbose; in corymbs. Descending axis, 80. Costate; ribbed. Descending radicle, 335. Cotyledons, 77, 151, 317. Descriptive Botany, 15. Cranesbill Family, 407. Desmidieme, 511. Crassulacece, 429. Determinate inflorescence, 222. Cremocarp, 326. Development of cells, 26. Crenate, 166. Development of the embryo, 77. Crowberry Family, 478. Development of leaves, 160. Crowfoot Family, 384. Dextrine, 59, 197. Crown, 289. Diadelphia, 358. Cruciate, 287. Diadelphous, 257, 290. Cruciferme, 393. Diandria, 357. Cruciform, 287. Diandrous, 290. Crude sap, 56, 194. Diapensiacece, 458. Crumpled, 279. Diatomaceme, 512. Cryptogamia, 366. Dichondrete, 460. Cryptogamous plants, 74, 339, 501. Dichotomous; successively forked. Crystals, 62. Diclinous, 264. Cucullate; hooded. Dicoccous, 323. Cuculliform, 505. Dicotyledonous, 334. Cucurbitacese, 428. Dicotyledonous plants, 114, 379. Culm, 104, 491. Dicotyledonous stem, 114. Cuneate; see Cuneiform. Didynamia, 365. Cuneiform, 163. Didynamous, 271, 290. Cup, 278. Diffuse; loosely spreading. Cupressinse, 484. Digynia, 368. Cupuliferm, 479. Digynous, 297. Curvinerved, 165. Dimerous, 240. Cuscutineae, 461. Dimidiate, 293. Cuspidate; tipped with a sharp and Dicecia, 358, 369. strong point. Dicecious, 266. Custard-Apple Family, 386. Dioscoreaceme, 495. Cuticle, 156. I)iphyllous, 285. Cycadaceae, 485. Diplostemons, 267. Cycas Family, 485.. Dipsaceae, 440. Cycle, 143. Dipterocarpeme, 404. Cyclosis, 511. Discoid, 441. Cyme, 223. Disepalous, 285. Cymules, 223. Disc, 259. Cyperacece, 498. Dissepiment, 301. Cypress Family, 484. Distichous, 142. Cytoblast, 28. Distinct, 258, 278. Decagynia, 368. Divaricate; very widely spreading. Decagynous, 297. Divided, 166. Decandria, 365. Dodecagynia, 368. Decandrous, 290. I)odecandria, 365. Deciduous, 175, 289. Dodecandrous, 290. Declined, 291. Dogbane Family, 463. Decompound, 170. Dorsal suture, 298, 305. Decumbent; lying on the ground. Dotted ducts, 39, 48. Decurrent, 172. Double flowers, 234. 520 INDEX AND GLOSSARY Droseraceme, 396. Exogenous structure, 114. Drupaceous, 326. Exogens, 114. Drupe, 325. Exosmosis, 34. Duck-weed Family, 489. Exserted, 291. Ducts, 48. Exstipulate, 175. Duramen, 124. Exterior, 227. Duration of leaves, 175. Extine, 296. Earthy constituents, 189. Extra-axillary, 225. Ebenaceae, 447. Extrorse, 292. Ebony Family, 447. Falcate; scythe-shaped, somewhat Echinate; clothed with prickles. bent to one side. Elaborated sap, 56. Falsely ribbed, 167. Elaters, 505. Families, 361. Elatinacete, 399. Farina, 57. Eleagnaceve, 472. Farinaceous, 332. Elliptical, 163. Fascicle, 224. Elm Family, 474. Fascicled, 150. Emarginate, 168. Fastigiate; level-topped. Embryo, 77, 317, 333. Favose; deeply pitted. Embryonal vesicle, 316. Feather-veined, 162. Embryo-sac, 315. Fecula, 57. Emersed; raised out of water. Ferns, 493. Empetraceae, 478. Fertile, 264 Endocarp, 322, 325. Fertilization, 313. Endogenous plants, 485. Fibrils, 82. Endogenous structure, 114. Fibrous roots, 85. Endogens, 114, 129. Fibro-vascular system, 54. Endophleum, 119. Fibro-vascular tissue, 54. Endopleura, 330. Figwort Family, 445. Endosmosis, 34. Filament, 228, 291. Endosperm, 331. Filices, 361, 501. Enneagynia, 368. Filiform; thread-like. Enneandria, 365. Filiformly dissected, 165. Enneandrous, 298. Fimbriate; fringed. Entire, 165, 256, 286. Fir Family, 484. Epacridaceae, 447. Five-ranked, 143. Epicarp, 322. Fixed oils, 60. Epidermal system, 55. Flabelliform; fan-shaped. Epidermis, 55, 155. Flax Family, 406. Epigynous, 259, 290. Floral envelopes, 227, 277. Epiphlaeum, 119. Floral leaves, 151, 216. Epiphytes, 89. Floret; a small or imperfect flower. Episperm, 329. Flower, 227. Equisetacea, 501. Flowering, 209. Equitant, 152, 171. Flowering plants, 75, 379. Erect, 309. Flowerless plants, 74, 339, 501. Ericaceae, 444. Folded. 151. Ericinee, 445. Foliaceous, 497. Erigonece, 471. Follicle, 325. Eriocaulonaceae, 498. Food of plants, 181, 183. Essential oils, 57. Foramen, 310. Essential organs, 228, 229. Forcing, 214. Euphorbiacead, 477. Formation of cells, 27. Evening-Primrose Family, 424. Forms of leaves, 160. Evolution of heat, 212. Foville, 296. Exalbuminous, 333. Free, 259. Excentric, 335. Frog's-bit Family, 491. Excurrent stems, 101. Frondose, 497. Exhalation, 179. Fronds, 493. Exocarp, 322, 325. Fruit, 320. Exogenous plants, 371. Fugacious, 175. Exogenous stem, 114. Fumariaceae, 393. OF BOTANICAL TERMS. 521 Fumitory Family, 393. HalorageEe, 425. Fundamental organs, 79. Hamamelace:e, 431. Fungi, 369, 508. Hastate, 164. Funiculus, 309, 330. Head, 218, 219. Fusiform; spindle-shaped, 85. Heart-shaped, 164. Galea, 288. Heart-wood, 124. Gamopetale, 375. Heath Family, 444. Gamopetalous, 256. Helicoid, 225. Gamopetalous plants, 434. Helmet, 288. Gamophyllous, 278. Hemicarp, 327. Gamosepalous, 256. Hemp Family, 483. Geminate; in pairs. Hepaticas, 505. Gemmation, 32. Heptagynia, 368. Genera, 360. Heptagynous, 297. Generic character, 363. Heptandria, 365. Gentianaceae, 462. Heptandrous, 290. Gentian Family, 462. Herbs, 103. Genus, 360. Hesperidium, 327. Geraniacene, 407. Heterogamous, 277, 433. Germ; the growing point of a bud, a Heterotropous, 312. rudiment. Hexagynia, 368. Germen; the old name for the ovary. Hexagynous, 297. Germinal vesicle, 317. Hexandria, 365. Germination, 336. Hexandrous, 290. Gesneriacem, 452. Hexaphyllous, 285. Gibbous; enlarged on one side. Hexasepalous, 285. Gills, 509. Hilum, 311, 330. Ginger Family, 492. Hippocastanacem, 413. Glabrous; smooth, without pubes- Hirsute; clothed with coarse spreadcence. ing hairs. Glands, 55, 267. Hispid; clothed with rigid hairs or Glandular; furnished with glands. bristles. Glandular hairs, 55. Holly Family, 447. Glaucous; covered with a grayish Homogamous, 277, 441. white powder, or bloom, that rubs Homologous, 230. off. Honeysuckle Family, 436. Glomerule, 224. Horizontal, 309. Glossology, 15. Hornwort Family, 476. Glumaceous; glume-like. Horse-tail Family, 501. Glumes, 409. Hybrids, 352. Gluten, 202. Hydrangeae, 431. Gonophore, 277. Hydrangea Family, 431. Gooseberry Family, 426, Hydrocharidacee, 491. Goosefoot Family, 469. Hydroleacene, 458. Gourd Family, 428. HIydrophyllacen,, 457. Gramineee, 499. Hydropterides, 503. Grass Family, 499. Hymenium, 509. Green layer, 119. Hypericacene, 398. Grossulacee, 427. Hypocrateriform, 288. Gutta percha, 57. Hypogeous, 338. Guttifera, 398. Hypogynous, 259, 290. Gymnospermia, 368. Icosandria, 365. Gymnospermous, 309, 372. Illecebrem, 400. Gymnospermous plants, 484. Imbibition, 34. Gynaecium, 228, 306. Imbricated, 152, 280. Gynandria, 366. Imbricative, 279. Gynandrous, 290. Impari-pinnate, 169. Gynophore, 277. Incised, 166. HMmodoraceae, 493. Incisions, 165. Hairs, 55. Included, 291. Halberd-shaped, 164. Incomplete, 263. Half-equitant, 152. Incumbent, 292, 335. 44 * 522 INDEX AND GLOSSARY Indefinite, 249, 309. Lamina, 152, 286. Indefinite inflorescence, 216. Lanate; woolly. Indehiscent, 322. Lanceolate, 163. Indeterminate inflorescence, 216. Lateral, 298. Indian-Cress Family, 408. Lateral buds, 98. Indian-Pipe Family, 446. Laticiferous tissue, 152. Individual plant, 64. Lauraceae, 471. Individuals, 20, 349. Laurel Family, 471. Induplicate, 152, 279. Leadwort Family, 450. Indusium, 503. Leaflets, 168. Inferior, 243, 260. Leafstalk, 152, 171. Ieferior radicle, 335. Legume, 325. Inflexed, 151. Legumine, 202. Inflorescence, 215. Leguminosee, 417. Infundibuliform, 287. Lemnaceue, 489. Innate, 292. Lentibulacewe, 451. Inner bark, 119. Lepidote, 55. Inner suture, 298. Liber, 46, 119. Inserted, 229. Lichens, 507. Insertion, 141, 259. Lid, 505. Integuments of the seed, 329. Life, 21. Intercellular passages, 54. Lignine, 37, 199. Intercellular spaces, 24. Ligulate, 441. Intercellular system, 54. Ligule, 172. Interlaced tissue, 52. Liguliflorm, 441. Internal glands, 54. Liliacem, 495. Internodes, 94. Liliaceous, 287. Interpetiolar, 175. Lily Family, 495. Interruptedly pinnate, 169. Limb, 152, 286. Intine, 296. Limnanthacem, 409. Intrafoliaceous, 175. Linacemu, 406. Introrse, 292. Linden Family, 403. Inuline, 198. Linear, 163. Involucel, 221. Line of dehiscence, 292. Involucellate; with an involucel. Linnuan system, 364. Involucrate; with an involucre. Liverworts, 505. Involucre, 219, 495. Lizard-tail Family, 475. Involute, 151, 284. Loasacee, 427. Iridacem, 494. Lobed, 166, 257. Iris Family, 494. Lobeliacee, 443. Irregular, 260, 270. Lobelia Family, 443. Irregularity, 246, 260. Lobes, 165, 286. Isoetinee, 503. Loculi, 302. Isomeric, 198. Loculicidal, 324. Jasminacem, 464. Loganieoe, 438. Jessamine Family, 464. Loment, 325. Juglandaceam, 479. Lomentaceous, 325. Juncaceam, 497. Longitudinal system, 53, 113. Juncaginee, 490. Longitudinal tissue, 48. Jungermanniaceee, 506. Loosestrife Family, 424. Keel, 261. LoranthaceT, 474. Kidney-shaped, 164. Lunate; crescent-shaped. Knawel Family, 401. Lunulate; diminutive of lunate. Knotwort Family, 400. Lycopodiacem, 503. Krameriacern, 417. Lyrate, 166. Labellum, 289. Lyrately pinnate, 169. Labiathe, 455. Lythraceae,-424. Labiate, 288. Madder Family, 437. Labiate Family, 455. Magnoliacete, 385. Labiatiflorme, 441. Magnolia Family, 385. Laciniate; cut into irregular incisions. Magnoliea-, 385. Lamellm, 509. Mahogany Family, 406. OF BOTANICAL TERMS. 523 Mallow Family, 402. Mosses, 504. Malpighiaceae, 412. Mould, 68, 502. Malvacewi, 402. Mucilaginous, 332. Mangrove Family, 424. Mucronate, 168. Maple Family, 412. Mulberry Family, 482. Marcescent, 289. Multifid, 166. Marchantiacem, 506. Multilocular, 302. Fig-Marigold Family, 402. Multiple fruits, 328. Marsileme, 503. Multiplication, 245. Masked, 288. Multiplication of cells, 29. Medullary rays, 115. Muricate; clothed with short and hard Medullary sheath, 116. points. Mielanospermeve, 511. Musaceue, 493. Melanthaceme, 496. Musci, 369, 504. Melanthiea, 497. Mushrooms, 508. Melastomaceve, 424. Mustard Family, 393. Meliacee, 405. Mycelium, 508. Membranaceous, of the texture of Myricaceae, 480. Membranous, membrane. Myristicacewe, 387. Menispermacem, 387. Myrsinaceve, 448. Menyanthidem, 452. Myrtaceue, 423. Merenchyma, 43. Myrtle Family, 423. Mericarp, 327. Naiadaceae, 490. Mesenibryanthemacea, 402. Napiform; turnip-shaped, 86. Mesophleum, 119. Nasturtium Family, 408. Metamorphosed leaves, 237. Natant; swimming. Metamorphosis, 233. Natural system, 369. Mezereum Family, 472. Navicular; boat-shaped. Micropyle, 310. Nectaries, 275, 289. Midrib, 162. Nelumbiaceee, 390. Mignonette Family, 395. Nelumbo Family, 390. Milkweed Family, 463. Nerved, 161. Milkwort Family, 416. Netted-veined, 161. Mimoste, 418. Nettle Family, 482. Mint Family, 455. Neutral, 433. Mistletoe Family, 474. Nightshade Family, 461. Mitriform, 505. Nodes, 94. Mock Orange Family, 431. Nomenclature, 375. Modified leaves, 237. Normal; agreeing with the pattern or iMollugineve, 401. type. Monadelphia, 365. Nucleus, 28, 310, 329. Monadelphous, 257, 290. Nucules; little nuts, or nuts like enMonandria, 365. docarps. Monandrous, 290. Nut, 327. Monochlamydeous, 264. Nutrition of plants, 181. Monocotyledonous, 334. Nyctaginacee, 469. Monocotyledonous plants, 114, 485. Nymphaeacee, 391. Moncecia, 356, 369. Nyssaceta, 473. Moncecious, 266. Oak Family, 479. Monogamia, 369. Obcordate, 168. Monogynia, 368. Obliqte, 170. Monogynous, 297. Oblong, 163. Monopetalm, 375. Obolariea), 462. Monopetalous, 256. Obovate, 163. Monopetalous plants, 434. Obtuse, 167. Monophyllous, 285. Obvolute, 152. Monosepalous, 256. Ochnacete, 410. Monotropee, 446. Octandria, 365. Monstrous, 233. Octandrous, 290. Moonseed Family, 387. Octogynia, 368. Moreze, 482. Octogynous, 297 Morphology, 14. Offset, 105. 524 INDEX AND GLOSSARY Oleaceae, 465. Pectine, 59. Oleaster Family, 472. Pedate, 167. Onagraceme, 424. Pedicels, 216. Operculum, 505. Peduncle, 215, 216. Opposed, 241. Peloria, 288 Opposite, 140. Peltate, 164, 312. Orange Family, 405. Pendulous, 309. Orchidaceee, 491. Pentadelphous, 290. Orchis Family, 491. Pentagynia, 368. Orders, 361. Pentagynous, 297. Ordinal character, 363. Pentamerous, 241. Ordinary leaves, 151. Pentandria, 365. Organic constituents, 184. Pentandrous, 290. Organization, 17. Pentaphyllous, 285. Organogeny, 277. Pentasepalous, 285. Organography, 14. Pentastichous, 143. Organs of plants, 64. Pepo, 327. Organs of reproduction, 79, 209. Pepper Family, 476. Organs of vegetation, 76, 79. Pepperwort Family, 503. Origin of the wood, 131. Perennial roots, 86. Orobanchaceae, 451. Perfoliate, 174. Orpine Family, 429. Perianth, 228. Orthotropous, 311. Perianthium, 228. Osmundineae, 503. Pericarp, 320. Outer suture, 298. Perichaetal, 505. Oval, 163. Perigonial, 505. Ovary, 229, 297. Perigonium, 228. Ovate, 163. Perigynous, 259, 290. Ovules, 75, 229, 299, 309. Perisperm, 331. Ovuliferous, 305. Peristome, 505. Oxalic acid, 61. Permeability, 34. Oxalidace'e, 408. Persistent, 176, 289. Palate, 288. Personate, 288. Palem, 220, 441, 499. Peruvian Bark Family, 438. Palmate, 167. Petaloid, 263. Palmately cleft, 167. Petals, 228. Palmately divided, 167. Petiole, 152, 171. Palmately parted, 167. Petiolula, 170. Palmately veined, 163. Petiolulate, 170. Palmee, 487. Pheanogamous, 379. Palms, 487. Phuenogamous plants, 75, 379. Panicle, 221. Philadelpheee, 531. Papaveraceee, 391. Phrymaceae, 455. Papayacew, 428. Phylla, 285. Papilionacee, 417. Phyllodia, 172. Papilionaceous, 260, 287. Phyllodium, 173. Pappus, 263, 326. Phyllotaxis, 140. Parallel-veined, 161. Phvsiological Botany, 14, 17. Paraphyses, 505. Phytolaccacee, 468. Parasites, 90. Phytons, 139. Parasitic plants, 90. Phytozoa, 42. Parenchyma, 43. Pickerel-weed Family, 494. Pariethl, 303. Pileus, 493. Parietal placentation, 302. Pine-Apple Family, 493. Parnassieee, 397. Pine Family, 493. Parsley Family, 431. Pink Family, 399. Parted, 166, 257. Pinne, 170. Partial petiole, 170. Pinnate, 168. Passifloraceoe, 427. Pinnately cleft, 166. Passion-flower Family, 427. Pinnately divided, 166. Pear Family, 421. Pinnately parted, 166. Pectinate, 166. Pinnately trifoliolate, 169. OF BOTANICAL TERMS. 525 Pinnately veined, 162. Prefloration, 278. Pinnatifid, 166. Prxefoliation, 151. Piperaceae, 474. Prickles, 55. Pipewort Family, 498. Prickly-Ash Family, 409. Pistillate, 264. Primary axis, 216. Pistillidia, 341, 504. Primary root, 80. Pistils, 228, 297. Primine, 310. Pitchers, 173. Primordial, 151. Pith, 116. Primulacee, 446. Pitted tissue, 48. Pro-embryo, 341. Placenta, 300. Propagation from buds, 103. Placentation, 302. Proper juices, 57. Plaited, 151. Prosenchyma, 44. Plane-tree Family, 482. Protecting organs, 229. Plantaginacew, 449. Proteine, 28, 200. Plantain Family, 449. Protoplasm, 201. Plantlets, 139. Pulse Family, 417. Platanaceae, 482. Purslane Family, 401. Pleurenchyma, 44. Putamen, 322. Plicate, 151. Pyrola Family, 445. Plumbaginacea, 450. Pyroleae, 445. Plum iFamily, 420. Pyxidium, 328. Plumule, 334. Pyxis, 328. Podosperm, 309. Quadrangular, 302. Podostemaceae, 477. Quillwort Family, 503. Pointed, 168. Quinary, 241. Pokeweed Family, 468. Quinate, 169. Polemoniacet. 458. Quincuncial, 143, 280. Polemonium Family, 458. Quinquelocular, 302. Pollen, 228, 291, 295. Quintuple-ribbed, 162. Pollinia, 295, 492. Quintupli-nerved, 162. Polyadelphia, 366. Raceme, 217. Polyadelphous, 257, 290. Races, 351. Polyandria, 357. Rachis; see Rhachis. Polyandrous, 249, 290. Radiate; diverging from a centre; or Polycotyledonous, 336. furnished with ray-flowers. Polygalaceae, 416. Radiated-veined, 163. Polygamia, 366. Radical, 150. Polygamia 2Equalis, 368. Radical peduncle, 226. Polygamia Frustrauea, 369. Radicle, 77, 317, 334. Polygamia Necessaria, 369. Rafflesiancre, 468. Polygamia Segregata, 369. Rameal, 150. Polygamia Superflua, 368. Ramification, 98. Polygamous, 266. Ranunculacem, 384. Polygonacewe, 470. Raphe; see Rhaphe. Polygynia, 368. Raphides, 62., Polygynous, 297. Ray-flowers, or rays, 265, 441. Polypetale, 375. Receptacle, 219, 229. Polypetalous, 257. Receptacles of secretions, 54. Polypetalous plants, 379. Reclinate, 151. Polyphyllous, 286. Reduplicate, 279, 284. Polypodinee, 502. Reniform, 164. Polysepalous, 257, 286. Repand, 166. Pome, 327. Replum, 324. Pomee, 421. Reproduction, 21, 69, 339. Pond-weed Family, 490. Resedacea, 395. TPontederiaceae, 496. Rest of plants, 213. Poppy Family, 391. Reticulated leaves, 161. Porous cells, 48. Reticulated ducts, 49. Porous vessels, 48. Retrograde metamorphosis, 234. Portulacaceae, 401. Retrorse; bent backwards. Posterior, 243, 298. Retuse, 168. 526 INDEX AND GLOSSARY Revolute, 151. Scleranthem, 401. Rhachis, 216. Sclerogen, 37. Rhamnaceae, 414. Scorpioid, 225. Rhaphe, 311. Scrophulariacee, 453. Rhatany Family, 417. Scurf, 55. Rhizantheae, 468. Seaweeds, 510. Rhizoma, 107. Secondary axes, 216. Rhizophoraceae, 424. Secondary roots, 85, 87. Rhodospermeme, 571. Secondary spirals, 145. Rhomboid; oval, and a little angular Secund; turned to one side, as the in the middle. flowers of some spikes, &c. Ribs, 152, 162. Secundine, 310. Ricciacem, 505. Sedge Family, 498. Ringent, 288. Seed, 329. Ripening, 321. Seed-leaves, 77, 333. Rise of sap, 179. Segments, 166, 286. River-weed Family, 477. Seminal, 151. Rock-Rose Family, 497. Sensitiveness of plants, 351. Rosaceae, 419. Sepals, 228. Rosaceous, 287. Separated, 264. Root, 80. Septicidal, 323. Rootlets; ramifications of the root. Septifragal, 324. Rootstock, 107. Serrate, 165. Rose Family, 419. Sesames, 452. Rostrate; beaked. Sesamum Family, 452. Rostellate; with a small beak. Sessile, 152, 215, 291. Rosulate; in a rosette. Setae, 55. Rotate, 288. Sheath, 172. Rubiaceae, 437. Shield-shaped, 164. Rudimentary, 291. Shrubs, 103. Rue Family, 409. Signs, 505. Rugose; wrinkled. Silenem, 400. Ruminated, 332. Silex, 63. Runcinate, 166. Silicle; 328. Runner, 105. Siliculosa, 368. Rush Family, 497. Silique, 328. Rutaceae, 409. Siliquosa, 368. Saccate, 288. Silky; clothed with a shining apSaZittate, 164. pressed pubescence. Salicaceae, 481. Silver-grain, 118. Salver-shaped, 288. Simarubaceae, 410. Salvinien, 503. Sinuate, 166. Samara, 327. Sinus, 163. Sandal-wood Family, 473. Sleep of plants, 350. Santalacee, 473. Smilacefn, 495. Sap, 56, 194. Smilax Family, 495. Sapindaceme, 413. Soapberry Family, 413. Sapodilla Family, 448. Solanaceae, 461. Sapotacem, 448. Sori, 502. Sap-wood, 124. Spadix, 218. Sarcocarp, 322. Spathe, 218. Sarraceniaceae, 391. Spatulate; oblong or obovate, wnith Saururacea, 475. the lower end much narrowed. Saxifragacet, 430. Specialized cell, 53. Saxifrage Fami4y, 430. Species, 21, 358. Scalariform ducts, 49. Specific character, 363. Scale-like hairs, 55. Spermoderm, 329. Scales, 433. Spiderwort Family, 498. Scaly buds, 96. Spigeliea, 439. Scape, 226. Spike, 218. Scarious; dry, thin, and colorless. Spikenard Family, 433. Schizandreve, 386. Spindle-tree Family, 414. OF BOTANICAL TERMS. 527 Spine, 105. Sucker, 105. Spinose; furnished with spines. Suffrutescent; scarcely shrubby, 103. Spiral ducts, 50. Suffruticose; somewhat shrubby, 103. Spirally, 280. Sugar, 60. Spiral markings, 41. Sulcate; grooved. Spiral vessels, 50. Sundew Family, 396. Spongioles or Spongelets, 82. Sunflower Family, 440. Sporangia, 72, 502. Superior, 243, 260, 335. Spores, 69, 339, 501. Supervolutive, 284. Spore-cases, 72. Suppression, 246, 263. Sporidia, 508. Suspended, 309. Sporocarp, 503. Suspensor, 317. Sporules, 69, 508. Suture, 292. Spur, 288. Sweet-Gale Family, 480. Spurge Family, 477. Sweet-Gum Family, 482. Squamelle, or Squamulm, 499. Symmetrical flower, 238. Squamellate; bearing small scales. Syncarpous, 258, 300. Squarrose; spreading at right angles Syngenesia, 366. in all directions from a common axis. Syngenesious, 257, 290. Stamens28,28, 289. Systematic Botany, 15,357. Staminate, 264. Tamariscinete, 399. Staminodium, 275. Tap-root, 84. Standard, 261. Taxineve, 484. Staphyleacece, 415. Tea Family, 405. Starch, 57, 198. Teasel Family, 440. Stellate; in star-shaped whorls. Tendril, 105. Stellatene, 437. Terminal, 225. Stem, 93. Terminal bud, 95. Sterile, 264, 290. Terminology, 15. Stigma, 229, 297, 299. Ternate, 169. Stigmatic, 299. Ternstrcemiacece, 405. Stigmatiferous, 305. Testa, 310, 329. Stings, 55. Tetradynamia, 365. Stipe, 277. Tetradynamous, 250, 290. Stipellate, 175. Tetragynia, 368. Stipelles, 175. Tetragynous, 297. Stipes, 508. Tetrandria, 365. Stipitate, 277. Tetrandrous, 290. Stipulate, 175. Tetraphyllous, 285. Stipules, 174. Tetrasepalous, 285. St. John's-wort Family, 398. Thallophytes, 73, 373, 506. Stolon, 104. Thallus, 71, 373. Stoloniferous, 104. Thecae, 291. Stomates or Stomata, 55, 157. Thecaphore, 277. Storax Family, 448. Thorn, 105. Striate; marked with longitudinal, Three-ranked, 142. lines or stripes. Thymelacene, 472. Strobile, 329. Thyrsus, 222. Strophiole, 331. Tiliaceae, 403. Structural Botany, 14, 17. Toothed, 166, 257. Structure of the flower, 230. Toothings, 165. Style, 229, 297. Torus, 229. Styracacen, 448. Trachea. 50. Sub; a prefix of qualification; thus, Trachenchyma, 49. subcordate means slightly cordate; Transverse, 312, 324. subovate, somewhat ovate, &c. Trees, 104. Subclasses, 362. Triadelphous, 257, 290. Suborders, 362. Triandria, 365. Subgenera, 362. Triandrous, 290. Subulate; awl-shaped; tapering to a Tribes, 354. sharp point from a broader base. Tricoccous, 323. Succulose; bearing suckers, 105. Trifid, 166. 528 INDEX AND GLOSSARY. Trigynia, 368. Vegetable mucilage, 60, 197. Trigynous, 297. Veinlets, 162. Trilliaceme, 495. Veins, 152. Trilocular, 302. Venation, 161. Trimerous, 241. Ventral suture, 298. Tricecia, 369. Verbenaceae, 454. Triphyllous, 285. Vernation, 151, 279. Tripinnate, 170. Versatile, 292. Tripinnatifid, 167. Vertical leaves, 170. Triple-ribbed, 162. Vertical system, 48, 53, 113. Tripli-nerved, 162. Verticil, 94, 141. Trisepalous, 285. Verticillaster, 226. Tristichous, 142. Verticillate, 141, 226. Triternate, 170. Vervain Family, 454. Tropmolacem, 408. Vessels, 48. Truncate, 168. Vexillary, 282. Tube, 278, 286. Vexillum, 261. Tuber, 108. Vibratile cilia, 355. Tubular, 288. Villous, or Villose; clothed with long Tubuliflore, 441. and shaggy hairs. Tufted, 150. Vine Family, 415. Tupelo Family, 473. Violacee, 395. Turbinate; top-shaped, inversely con- Violet Family, 395. Turneracete, 427. [ical. Vitaceme, 415. Two-ranked, 142. Voluble; twining. Type, 229, 350. Volva, 508. Typhacee, 489. Walnut Family, 479. Ulmacee, 474. Water-leaf Family, 457. Unmbel, 217. Water-Lily Family, 391. Umbellets, 221. Water-Pitcher Family, 391. Umbellifera, 431. Water-Plantain Family, 490. Umbilicate; depressed in the centre. Water-Shield Family, 389. Unarmed; not prickly. Water-Starwort Family, 476. Uncinate; hooked. Waterwort Family, 399. Undershrubs, 103. Wax, 60. Unguis, 286. Wheel-shaped, 288. Unijugate, 170. Whorl, 94, 141. Unilateral; one-sided. Whorled, 141, 226. Unisexual, 264. Whortleberry Family, 444. Unlining, 249, 253. Willow Family, 481. Urticacen, 482. Winged, 172. Urticem, 483. Wings, 261. Utricle, 327. Winteren, 486. Uvularieie, 497. Winter's-Bark Family, 386. Vacciniene, 444. Witch-Hazel Family, 431. Vaginula, 505. Wood, 117. Vague, 335. Wood-Sorrel Family, 408. Valerianacem, 439. Woody, 152. Valerian Family, 439. Woody fibre, 44. Valvate, 151, 284. Woody tissue, 44. Valves, 323. Woolly; clothed with long, matted Valvular, 284. hairs. Varieties, 359. Wrapper, 508. Vascular plants, 73, 372. Xyridacew, 498. Vascular tissue, 48. Yam Family, 495. Vasiform tissue, 48. Yew Family, 484. Vegetable acids, 61, 200. Zanthoxylacene, 409. Vegetable digestion, 194. Zingiberacem, 492. Vegetable jelly, 59. Zygophyllaceae, 408. THE END.