Introduction

m MEMOI Richard M. Richard *V, Holman A COMPENDIUM OF GENERAL BOTANY. BY DR. MAX WESTERMAIER, Professor in the Royal Lyceum, Freising, Germany. TRANSLATED BY DR ALBERT SCHNEIDER, Fellow in Botany, Columbia College, New York. 171 UUustratfons. FIRST EDITION. FIRST THOUSAND. NEW YORK : JOHN WILEY & SONS. LONDON: CHAPMAN & HALL, LIMITED. ST. LOUIS (17 S. Broadway): B, HERDER, 1896. BIOLOGY LIBRARf G Copyright, 1898, BY ALBERT SCHNEIDER ROBERT DRUMMOND, ELECTROTYPER AND PRINTER, NEW YORK. PREFACE. IN a compendium of botany intended for high schools it is permissible to introduce subject-matter which would be objec- tionable in a text-book of elementary instruction. Free use has been made of such privileges. It is assumed that the pupil has a general knowledge of chemistry, of physics, of the proper use of scientific terminology, and has the ability to estimate the value of hypotheses and undecided problems. From the con- sideration of the latter the disciple of our science will soon recognize the peculiar difference between layman and scientist. The layman looks upon many phenomena in plant-life as being quite clear and easy of explanation. The scientist, however, can demonstrate that we know but very little concerning these same phenomena. It must also be borne in mind that scientific progress depends upon the recognition of the present limits of our knowledge. Nearly every branch of science is more or less merged into general cosmology. It is therefore expected that every scientist We should attempt to explain this relation. find that the vari- ous authors have a tendency to call the reader's attention to the important (in the author's opinion) phases of cosmological rela- tionship. Even of this privilege I have made use. Incidentally I will make the following observation : The greater portion of physiology is intimately associated with anatomy. In accordance with this we find that the newer devel- opment of botanic rJ science considers the question, What for ? of prime importance when investigating plant-structures (ana- tomical-physiological tendency of Schwendener's school). In the special as well as in the general treatment of the subject-matter I have frequently made use of the works of NAGELI, SACHS, PFEFFEK, DE BARY, FRANK, GOBEL, and WARMING ; more especially those of SCHWENDENER and his pupils (Haberlandt among others). To this I have added the knowledge iii 921916 IV PREFACE. obtained through a long scientific association with my honored instructor, Professor Schwendener. The illustrations are added with the kind permission of various authors. For all this I express my sincerest gratitude. MAX WESTEBMAIEK. FREIPING, October 1893. TRANSLATOR'S PREFACE. IN presenting this translation it is perhaps well to offer a few explanatory statements. The book is just what the title implies, a compendium of gen- eral botany. Its great value as a text-book lies in the thoroughly logical and scientific treatment of the subject-matter. The necessarily condensed retrospect of the science of botany is well supplemented by the copious, well-chosen references to standard authorities. I have endeavored throughout to adhere as closely as possible to the author's form, style, and concept of the science of botany. The arrangement and treatment of the subject-matter are the same as in the original. In fact I have endeavored to make it a translation in the true sense of the word. I have, however, A added some foot-notes. few are explanatory ; others serve to indicate differences of opinion. Although it is difficult to make a good translation of the finer shades of meaning peculiar to a language, yet I sincerely hope I have met with fair success in such an attempt. Finally, I desire to express my grateful obligations to Dr. N. L. Britton, who made the final corrections of the proof for the first half of the translation. I am also greatly indebted to my wife, who has kindly aided me in correcting the manuscript and in reading the proof. ALBERT SCHNEIDER. COLUMBIA COLLEGE, July 1895. TABLE OF CONTENTS. PREFACE . TRANSLATOR'S PREFACE Divisions of Scientific Botany and General Considerations . PAGE . iii v . 1 PART I. The Cell. I. Introduction 4 II. Primordial Utricle and Cell wall in Their Mutual Relation- .... ship. Turgor. Plasmolysis .. . .. ... III. Cell-contents . . . . . . . . ... A. Living Inclusions of the Cytoplasm . . . 7 10 10 ... (a) Nucleus (b) Chlorophyll-grains, Chromoplastids, Leucoplastids 10 13 B. Dead Inclusions of Cytoplasm . . . . ... 16 (a) Starch . . . . ... ' . . ... . 17 (b) Aleuron-grains . (c) The Remaining Solid Dead Inclusions of the Cell . . C. The Cell-sap and the Remaining Fluid Contents of the Cell IV. The Cell-wall 21 .22 .25 . 24 A. Internal Structure and Method of Growth of the Cell- wall . 26 B. Chemical Composition and Subsequent Changes in the Cell-wall 30 C. Products of the Growth in Thickness and Surface of the Cell- ... walls . . . . ... ... V. The Origin of Cells . . , . . . . 32 42 PART II. Tissues and Simple Organs. A. Structure of Tissues and Simple Organs 45 B. Differentiation of Tissues according to Structure and Func- ... tion (Physiological Anatomy of Simple Organs) .... Differences of Functions and Their Enumeration 49 49 SPECIAL FUNCTIONS : I. The Function of Formative Tissues (Meristem and Cambium) . 51 II. Structure and Function of the Epidermal Tissue-system . . 53 III. Function of Mechanical Tissues 63 vii Vlll TABLE OF CONTENTS, IV. The Function of the Conducting System ...... Consideration of the Conducting System in Itself and in Its Relation to the Mechanical System (a) The Various Cell-forms (b) The Laticiferous Tissue (c) The Stem-structure of Mosses and Vascular Cryptogams . .......... (d) The Stem of Monocotyledons, Dicotyledons, and Gymnosperms (e) Growth in Thickness among Dicotyledons and Monocotyledons by Means of the Cambium (/) Abnormal Structure of Stems (g) The Structure of Roots (h) Anatomy of the Transition-zone between the Stem and the Root ...... (0 The Special Physiology of the Movements of Food-substances and Water in Plants a. Conduction of Albumen P. Conduction of Carbohydrates y. Conduction of Water .... Protective Sheath or Endoderm. (Concluding Chapter to the Three Foregoing Ones on Special Functions.) V. Protection of the Meristematic Areas of the Plant-body . . (a) The Protection for the Terminal Meristematic Areas of the Plant-body a. Protection of the Root-tip ft. The Protection of the Stem-apex .... y. Protection of the Leaf-tip (b) Protection for Areas of Intercalary Growth VI. Food-substances Derived from the Atmosphere. Assimilation of Carbon in Green Organs (a) The Structural Principles of the Assimilating System . . (b) Movements and Changes in Form of Chlorophyll-bodies . (c) The Chemistry and Physiology of Chlorophyll . . . VII. The Function of Aeration (a) The Structure and Function of Breathing-pores (Stomata) (ft) Lenticels VIII. The Function of Roots . . . . . . . . (a) Subterranean Roots . . (b) Aerial Roots IX. The Appropriation of Assimilated Food-substances . . . (a) Condition of Seeds before the Beginning of Assimilation . ............... (b) Nutrition of Saprophytes and Parasites (c) Symbiosis ... (d) Insectivorous Plants . X. The Storing and Function of Reserve Material . (a) Storing of Water ..... The (ft) Storing of Starch and Other Food-substances, Espe- cially the Albuminous Substances XI. Secretion PAGE 70 70 70 76 78 80 87 94 95 98 99 99 101 103 112 115 115 115 118 119 119 122 123 128 128 132 135 138 139 139 140 141 142 143 145 148 150 150 151 152 TABLE OF CONTENTS. ix PART III. Organs and Systems of Organs. I. The Morphological and Physiological Relations of Organs . A. The Principal Forms of Organs B. Modification of Organs (a) Modification of Stem and Root . . . . . . (b) Modification of the Phyllome Critical Observations on the Distinction of Organs . . . C. The Complex Organ : Shoot D. Metamorphosis and Correlation II. Origin and Position of Lateral Organs and the Causes for Their Definitive Position ...... A. Spiral Arrangement of Leaves. Theories of Phyllotaxy . . B. The Determination of a Divergence ... C. The Mechanical Theory of Phyllotaxy and the Idealistic Conception of Nature III. Difference in the Power of Development of the Members of ... Equal Morphological Value. Classification of Organ-systems A. Inflorescence . (a) Racemose Inflorescence . . (b) Pauiculose Inflorescence . - > (0) Cicinnose Inflorescence . B. Rank and Succession of Shoots PAGE 155 155 157 157 159 163 165 167 168 171 174 175 179 181 182 182 182 183 PAKT IV. Reproduction. .... Introduction 185 I. Reproduction among Cryptogams . ... 188 A. Forms of Reproduction among Algae 192 B. Forms of Reproduction among Fungi 194 II. A Comparative Study of Reproduction and Alternation of Generation in Mosses, Vascular Cryptogams, and Phanero- gams 200 Gymnosperms and Angiosperms . III. The Phanerogamic Flower . . .... . . . . . . V . 210 213 ... A. Calyx, Corolla, Nectaries. The Flower as a Whole ... B. The Stamens and Pollen-grains . . .. . . 214 223 C. The Gyncecium. The Ovule with the Embryo-sac before and after Fertilization . 227 IY. The Morphology and Physiology of the Seed and Fruit of Phanerogams * 231 Germination . -. . . . 237 V. The General Physiology of Reproduction 238 A. Agents in Fertilization. Cross-pollination. Self-pollination . 238 X TABLE OF CONTENTS. B. Fertile Seeds. Hybridization. Apogaray . . . C. Variability, Constancy, Heredity . D. Special Creation and the So-called Theory of Natural Descent . Appendix: The Life-period of Plants PAGE 241 243 244 250 PART Y. The General Chemistry and Physics of Plant-life. I. Chemical Physiology 252 Selection 257 The Cyclic Course of Food-substances 258 II. The Physiology of Growth 253 A. Active and Passive Growth 261 B. The Results of Unequal Growth 261 (a) Tissue-tension 262 (V) Curvatures 263 (c) Torsions 264 C. Molecular Organization of Plant-structures 266 III. Temperature, Light, Gravity, and Other Factors in Their Re- lation to Plant-life 268 A. Effects of Temperature 268 .... (a) Production of Warmth and Cold (b) The Effect of Temperature upon Plant-life 268 269 B. Effect of Light 270 (a) Production of Light 270 ......... (b) Influence of Light upon Plant-life C. Influence of Gravity 271 275 D. Electricity, Moisture, Water- currents, Radiating Heat . . 276 IT. The Physiology of Plant-movements 277 A. Classification of Movements according to Cause. The Outward ........ Manifestation of Some Movements 277 B. Hygroscopic Movements 278 C. Autonomous Movements 279 D. Irritable Movements 280 Mimosa 280 Behavior of Tendrils. Conduction of Stimuli. The Function of Irritable Movements 281 E. The Physiology of Twining 283 PART VI. Classification of Plants. Taxonomy . . 286 ALPHABETICAL INDEX 293 COMPENDIUM OF GENEEAL BOTANY, DIVISIONS OF SCIENTIFIC BOTANY AND GENEKAL CONSIDEEATIONS. THE two domains of plant study are MOEPHOLOGY and PHYSI- OLOGY. Morphology treats of the substance of the vegetable kingdom. Physiology treats of the forces or energies bound up with the plant-substance or which manifest themselves with it. Plant-functions, as we know them in the light of morphology and physiology, are not only proper adjustments to the environment, but above all fulfill the requirements of plant-life and are therefore life-functions. To define the term life, even only in its application to the plant kingdom, is impossible. Science can, however, proceed more and more into the order of things, to know more clearly the properties of matter and the harmonious manifestations of force. In spite of this progress we cannot approach any nearer the solution of the " life-problem." Processes of a chemical and physical nature are the most that we are able to see in this order of things and this knowledge distinguishes the scientist from the layman who sees the order less clearly. The earnest investigator who has concluded to believe by faith finds the answer to the "why" of this order in the words " wonder of creation." To the one who is not so inclined this "why" becomes a darkness which grows denser in propor- tion as he sees more clearly the order in which chemical and physical processes are combined as they are in plant-life. Life manifests itself in certain chemical and physical processes, and in so far as physics and chemistry are concerned in life-processes there is a " physics and chemistry of plant-life." Plant-physiology may be designated by the expression " physics and chemistry of plant- 2 DIVISIONS OF SCIENTIFIC BOTANY life," but always in the sense that the exactness of the knowledge of life-manifestations adds nothing to the causal mechanical explanation of "life" itself. To morphology in the above sense belongs the description of the form, size, arrangement, and outer and inner numerical relations of the plant-body ; therefore anatomy is a part of morphology in the wider sense. Usually, however, anatomy (inner form-relations) is distinguished from morphology in a narrower sense (outer formrelations). Thus limited, morphology forms one of the fundamental principles underlying our present system of classification. A Let us now return to the two main divisions of our science. few examples will make clear to the novice how morphology may be distinguished from physiology, but that a complete and compre- hensive knowledge of the plant necessitates a combination of the two. "When an investigation has for its purpose the explanation of the cause of development of the woody cell-wall, then it concerns itself with a function, in this special case a function of nutrition ; this is therefore physiology. If one makes a microscopic compari- son of one wood with another and seeks to find the similarities or dissimilarities of the tissues, then no functions are involved and the study is morphology (anatomical morphology). If one seeks to find the relation of anatomical differences to the environment (as a rule this relation is considered from a teleological standpoint), then we must of necessity concern ourselves with physiological processes. If we seek after the conditions which cause plants to turn green, then the study is purely physiological : we are solely concerned with energies. If, with the aid of the highest magnifications, the finest structure of chromoplastids (chlorophyll bodies) is studied in order to describe them more correctly, we are concerned only with morphology. Development, for example, embryology, belongs to morphology. To study, describe, and represent graphically, the successive stages of embryonic development lies wholly in the domain of morphology. If one, however, makes a study of the wall of the ovum in order to determine experimentally what forces eventually determine the position of the first septum, then we are again in the domain of physiology. If a minute description is given of the various cell-forms found in the stem, where, for example, the thick-walled cells occur, the form of the thickenings, etc., then we are concerned with morphology. If, however, one seeks for the significance of this or that cell- AND GENERAL CONSIDERATIONS. 3 form in the service of plant-life, then again we are concerned with a force effect which is bound to a specially constituted plant-sub- stance and is therefore physiology. Throughout the arrangement of this book a strong effort is made to adhere as strictly as possible to the combination of such methods of investigation as have just been indicated. However, some attention must be given to the didactic uses of the book. Due regard shall be given to a proper summarizing. In its entirety we have adopted that disposition of subject-matter which SCHWENDENEK has so efficiently tested and found useful in the academic course of study. His arrangement is as follows : I. The cell. II. Tissues. A. Structure of tissues and simple organs. B. Differentiation of tissues (physiological anatomy of simple organs). III. Systems of organs. IV. Reproduction. V. General chemistry and physics ofplant-life. VI. System ofplant classification. PAET I. THE CELL I. INTEODUCTIOK The organisms which we designate as plants, though variable, have one thing in common : they are either single cells or cell- complexes. There is, so to speak, only one element in plants, and that is the cell. Every plant consists of at least one cell. Omitting for the present the embryonic conditions of the cell, it may be defined as, for the most part, a microscopic closed vesicle consisting of wall or covering and contents (large cells, as those of Gossypium species, 6 cm. long ; medium-sized cells, as those of elder- We pith). must distinguish between younger and older stages of the cell. At first an apparently homogeneous, mucous, tenacious substance plasm, protoplasm fills the entire cell-cavity (lumen] and is enclosed by the cell-wall (membrane]. The components of the cell-contents designated by the collective noun "plasm" are albumi- noid substances and hence contain besides carbon, hydrogen, oxygen, also nitrogen, sulphur, and sometimes phosphorus. Its mucous consist- ency is noticeable by its spontaneous escape from openings of the cell- wall (swarm-spore formation of algse, etc.). Gradually there appear differentiations in the apparently homogeneous plasm. Spherical particles filled with a watery substance vacuoles 1 are distinguish- able from the more dense contents ; the latter, the true plasm, are of different kinds, not homogeneous, as a superficial examination would indicate. Tlieplasmic utricle, which is of special importance, shall 1 According to more recent investigation (WENT) the "vacuoles" originate from pre-existing ones. (The conclusions of this investigator are generally conceded to be erroneous. Trans.) 4 THE CELL. first claim our attention. The water-bearing cavities (vacuoles) in- crease more and more in size and subsequently come in contact and become flattened by mutual pressure. Finally they are separated only by thin plasmic membranes and threads ; when these break the vacuoles flow together to form one. The plasm then lines the inner surface of the cell- wall as a membrane which is usually very thin, but which is never absent from the liv- ing cell. This membrane is called the primordial utricle or plasmic utricle. On account of its frequently immeasurable thinness it is invisible as long as it is in contact with the cell- wall. If by artificial means the plasmic utricle can be caused to separate from the wall by contraction, then this is looked upon as giving evidence that it was a living cell. (Compare Fig. 10 The cell-wall and the plasmic utricle, the two coverings of the cell con- tents, differ (1) chemically, in that the primordial utri- cle being a part of the plasm is an albuminoid substance, while the cell-wall belongs fl to the group of carbohy- drates and contains there- fore C, H, and O, the latter in the proportion to form ' * oun parenchyma-cell of Zea Mays. A normal; 5, plasmolyced. m, membrane; p and h < protoplasmic utricle; n, nucleus; s, cell-lumen witb ^p. (After prank.) water (H2 O) ; (2) physically, in that the cell-wall is highly elastic with but little extensibility, while the plasmic utricle is very ex- tensible and only slightly elastic. To this must be added a second physical difference, that of diosmosis. The physical differences are 6 COMPENDIUM OF GENERAL BOTANY. of such great importance that they will be more fully treated in Chapter II. The formation of the plasmic utricle is, as has been indicated, not the only differentiation product of the plasm. In the entire plasmic body one can distinguish a fundamental substance (" cytoplasm" from ^uros", cavity, cell) and inclusions formed within this fundamental substance. These inclusions are of two kinds, (A) living and (B) dead. Tho plasmic utricle and threads constitute the cytoplasm. The living inclusions are the nucleus, the chromatophores, and the fertilizing elements, made up chiefly of nuclear substance and having a reproductive function. Of the dead substances formed from the plasmic body the most important are protein- grains, protein-crystals, starch-grains, crystals (of fat, salts, organic acids, etc.), oil-globules, and tannin. The term " " chromatophores includes three substances: chlorophyll bodies, color-granules, and colorless starch-builders. These bodies are considered collectively because they are either the bearers of color-substances or are formed out of such to be again converted into chromoplastids. (STRAS- BURGER, SCHIMPER.) The space not occupied by the above-mentioned solid constitu- ents is filled with a watery fluid, the cell-sap (sometimes having color-substances in solution). It is important to bear in mind that within the living cell gas accumulates only in very small quantities. No bubbles are ever rapidly formed. The reaction of cytoplasm is usually alkaline or neutral. In the living cell, cytoplasm has the property of reducing very dilute alka- line silver-nitrate solutions. (Low and BOKORNI.) In the cytoplasm an outer hyaline layer (hyaloplasm) and a more granular internal layer (polioplasm) may be noticed. According to REINKE the plasmodia of Aethelium septicum contain 73$ of water, and judging from the mucous nature of other forms of cytoplasm we may con- clude that they also contain a high percentage of water. To plasm in general, especially its important structures, as nucleus and chloro- plastids, one no longer ascribes 1 homogeneity. Careful microscopic examinations reveal a reticulated (spongy) structure of plasm. (SCHMITZ, BUTSCHLI, and others.) A All life-processes of the cell take place within the plasm. 1 I would especially recommend WIESNER'S Elementarstructur, 1892. Trans. THE CELL. 7 cell without plasm does not grow, does not take in food, does not live. There is no mechanics of plasm ; cell-life is still wrapt in obscurity. Direct observation shows that plasm gives rise to the cell-wall, as in the case of 1 Stigeoclonium.. The plasmic utricle contracts, escapes from the opening in the cell-wall, and in time surrounds itself with a new wall. To trace a phenomenon back to- plasm is as a rule the present limit of our ability. II. PRIMORDIAL UTRICLE AND CELL-WALL IN THEIR MUTUAL RELATIONSHIP. TURGOR. PLASMOLYSIS. The primordial utricle is usually of immeasurable thinness. In order to represent it in a figure such cells or portions of cells are selected in which it is of perceptible thickness as it lies in contact with the cell-wall. As a rule it can be made visible only by causing it to separate from the cell-wall either through causes inherent in the cell itself or by artificial means. When this plasmic contraction is artificially induced it is recognized as "plasmoly- sis." The phenomenon of plasmolysis can be explained only from the inherently different properties of the cell- wall and primordial utricle. It is at once evident that the endosmotic properties of the bladder of an animal filled with a solution of some salt cannot be compared with a living cell. It can only be compared with a dead cell- wall. If a living cell with cell-sap (ex., hair-cell of petal of Tradescantia) of a given concentration is placed in distilled water, then the endosmotic flow of water through cell-wall and primordial utricle into the cell is greater than the outflow of cell-fluid. The endosmotic substances within the cell attract the water, which therefore increases the cell volume. The limit of this increase is determined by the cell- wall because it is less extensible than the primordial utricle, although much more elastic. (Elasticity is that force which replaces dis- placed molecules. It is very great in the cell-wall and very small in the plasmic utricle.) The cell-wall is therefore a hindrance to the excessive expansion of the primordial utricle. Action induces reaction : the cell-sap which exerts a given pressure upon the cellwall in turn receives an equal pressure. This mutual pressure of cell-sap upon cell- wall and cell-wall upon cell-sap is called N 1 Studied by AGE LI. 8 COMPENDIUM OF GENERAL BOTANY. " l Turgor" Sometimes the cell-wall cannot resist the expansive force of the continually expanding primordial utricle, and as a result the wall will rupture, which indeed sometimes happens in nature. If the utricle is not ruptured at the same time, then it may expand to the limit of resistance and finally rupture. Let us now suppose an inverse case. Let there be a more highly