Introduction

PRESENTED TO THE UNIVERSITY OF TORONTO BY A. . ^^^ A STUDENTS' TEXT-BOOK OF BOTANY A STUDENTS' TEXT-BOOK OF BOTANY ^O ^/r 5 i<7lA SYDNEY H. VINES M.A., D.Sc., F.R.S. Fellow of Magdalen College and Sherardian Professor of Botany in the University of Oxford ; formerly Fellow of Christ 's College and Reader in Botany in the University of Cambridge ; Fellow of the University of London (FIRST HALF.) WITH 279 ILLUSTRATIONS SWAN SONNENSCHEIN & CO. NEW YORK: MACMILLAN & CO. 1894 BUTLER & TANNER, THE SELWOOU PRINTING WORKS, FROME, AND LONDON. P BE FACE". WHEN, some few years ago, it became necessary to revise the English Edition of the late Prof. Prantl's Lehrbtich der Botanik, it appeared to me that the requirements of English students would be more satisfactorily met if the scope of the work were so extended that, whilst retaining all that has made it of value to beginners, it might be more useful to those engaged in the advanced study of the science. With this object in view, the number of pages has been doubled by additions to all four parts of the book, but more especially to Part III. dealing with the Classification of Plants. Though the form of Prof. Prantl's book is still retained, and here and there paragraphs from the English edition have been inserted, the present is essentially a new and distinct work for which I alone am responsible, and, consequently, on the title-page of which my name alone appears. I would most gratefully acknowledge the assistance which I have received from my friend Dr. D. H. Scott, Honorary Superintendent of the Jodrell Laboratory, Royal Gardens, Kew, who has kindly read the proofs, and has furnished me with many valuable suggestions and criti- cisms. The usefulness of the book is enhanced by the incorporation of a number of additional illustrations : most my of these are placed at disposal by- the publishers, from their English edition of Prof. Strasburger's Practical Botany, a few are taken from various other sources which are duly acknowledged. S. H. V. January, 1894. EKRATA. Page 25), line 6 from bottom, Marsilia should be spelt Marsilea throughout. ,, 61 ,,17 ,, top, for tranverse read transverse. ,, 67 5 bottom, for Mucorini read Mucorinas. ,, 69 ,,16 , f the bracket should follow the word inline. ,, 117 14 ,, for mother-eels read mother-cells. ,, 4 ,, for mother-ces read mother-cells. 127 3 top, for Schizeaccte read Schizasaceae. ,, 173 ,, 14 ,, top, for other read outer. ,, 176 ,, 2 ,, bottom, for protohploem read protophloem. ,, 276 ,, 9 top, for asocarp read ascocarp. CONTENTS. Introductory PART I. MORPHOLOGY. PAGE , . . 1 CHAPTER I. GENERAL MORPHOLOGY. 1. The Segmentation of the Body 2. Symmetry of the Body and of the Members . .. 3. The Development of the Body and of the Members . 4. Arrangement of Lateral Members on a Common Axis . 5. The Mutual Relations of Dissimilar Secondary Members 6. Branch-Systems 7. Cohesion and Adhesion . . . . ; 5 . . ' . 7 . . .13 ... . . . 23 31 32 . . .36 CHAPTER II. THE SPECIAL MORPHOLOGY OF THE MEMBERS. 8. TheThallus 9. The Thalloid Shoot A. VEGETATIVE ORGANS. '. ...... 37 38 10. The Leafy Shoot 38 11. The Stem . ' . 44 12. The Leaf . . . . 45 .','-. 13. The Root . . . . 61 14. Hairs and Emergences . . 64 B. REPRODUCTIVE ORGANS. 15. Reproduction 16. General Morphology of the Asexual Reproductive Organs 17. General Morphology of the Sexual Reproductive Organs 18. Apospory and Apogamy 19. The Fruit .,..;;" 20. The Seed . . .',.'. . . ; ., . . . 67 ... . . .70 80 .87 ' . . .88 . . . 88 PART ILTIIE INTIMATE STRUCTURE OF PLANTS. (ANATOMY AND HISTOLOGY). ~~ 21. Introductory . . . . . . ,.. . . . .- . . 89 CHAPTER I. THE CELL. 22. The Structure and Form of the Cell 93 23. The Protoplasm 95 ,24. The Cell-Wall 103 25. Cell-Contents . 108 26. Cell-Formation 114 vii Vl'ii CONTENTS. CHAPTER II. THE TISSUES. 27. The Connexion of the Cells 28. Intercellular Spaces 29. Forms of Tissue . . .."',. . 30. General Morphology of the Tissue-Systems 31. The Primary Tegumentary Tissue 32. The Fundamental Tissue-System 33. The Vascular Tissue- System .... 34. Histology of the Development of Secondary Members . . . 35. The Formation of Secondary Tissue . . 36. Formation of Tissue in consequence of Injury . . .. . PAGE 128 .130 .131 144 .153 159 170 .184 . 1^1 . 213 PART III. THE CLASSIFICATION OF PLANTS. Introductory . . . . . . . . . . 216 ' GEOUP I. THALLOPHYTA . . . . -^ , '. . Class I. Algae ... Sub-Class I. Cyanophyceae (Phycochromacese) . ,,.,.. Order 1. ChroococcaceaB . . - . ,, 2. Nostocaceae . '. . .''.'. 3. Oscillariaceae . . . . 4. Rivulariaceae .220 221 . 231 . 233 .233 .233 233 ,, 5. Scytonemacese 233 ' Sub-Class II. Chlorophyceae .. . . . . .. .234 Series I. Protococcoideae . .' . . . . . 236 Order 1. PleurococcaceaB . 2. Protococcacete . . ..... ... . . . 236 236 ^ ...... ' - Series II. Volvocoideffi . . . . . . . ,237 Order 1. Chlamydomonadaceae 237 ... 2. Volvocaceae Series III. Siphonoideae Order 1. Siphonacete . . . 2. Cladophoraceas . . ,, 3. Hydrodictyaceae . . . , .. . . .,'- . . . . . . . . 237 . 238 . 238 .241 . 242 Series IV. Confervoidesa Order 1. Conjugatae . . . . . .... . . 24'3 244 2. Ulothrichaceas . . ...... . . 246 3. Cbaetophoraceae . . . ... . . 247 4. Ulvaceae 5. CEdogoniaceae . . . V^. .' . .248 .248 6. Coleocha3tacea3 -Series V. Charoideaa . 249 . .251 - Order 1. Characeaa Sub-Class III. Phaeophycc-83 . Order 1. Syngeneticas ....... . . . ' %' . 251 .255 . 257 2. Diatomaceae Series (a). Phaeosporeae . . ... . . . 258 . 258 OrderS. Ectocarpaceae . ' - . f ./ . ... 259 CONTENTS. ix Order 4. Encceliaceas . , ,, 5. Laminariaceas PAGB 259 259 6. Cutleriaceae 259 Series (6). PhaeogamaB Order 7. Tilopteridaceae 262 262 ,, ,8. Dictyotaceae 9. Fucaceae Sub- Class IV. Rhodophyceae . . 262 ' . . 266 . .267 Series I. Nemalionince . . 272 Order 1. Helminthocladiaceas 272 2. Lemaneaceag 272 ,, 3. Gelidiaceae 272 Series II. Gigartininae . 272 Order 4. Gigartinaceae 272 ........ 5. Rhodophyllidaceae . . . . . . 272 Series III. Rhodymeninae 272 Order 6. Sphaerococcaceae 272 ,, 7. Rhodymeniaceae 272 ,, 8. Delesseriaceae 272 ,, 9. Bonnemaisoniaceae 272 10. Rhodomelaceae . 272 ,, 11. Ceramiaceae 272 Series IV. Cryptoneminas . 272 Order 12. Glceosiphoniaceae 272 13. GrateloupiaceaB 272 14. Dumontiaceas 272 ,, 15. Nemastomaceee 272 16. Rhizophyllidaceae 272 ,, 17. Squamariaceaa . 272 18. CorallinaceaB 272 Series V. Porphyrinaa Order 19. Bangiaceae . .' , 272 272 Class II. Fungi 273 Sub- Class I. Schizomycetes 280 II. Myxomycetes IIL Phycomycetes Section A. Zygomycetes Order 1. ChytridiaceaB . . 283 285 285 285 2. Mucorinae 287 3. Entomophthoraceao 289 Section B. Oomycetes ....... Order 1. Ancylistaceae ....... 2. Peronosporacefe .290 290 291 3. Saprolegniaceae . 293 Sub-Class IV. Ascomycetes 294 Order 1. Gymnoasceae . 300 2. Pyrenomycetes 301 3. Discomycetes 302 ^Sub-Class V. ^Ecidiomycetes 303 . Order 1. Uredineae . 303 CONTENTS. Order 2. Ustilagineffi . . . ;./. PAOK .308 Stib-Class VI. Basidiomycetes * .310 Series I. Protobasidioinycetes . 315 ,, II. Autobasidiomycetes 315 ....... Order 1. Hymenomycetes 315 ,, 2. Gasteromycetes 317 Subsidiary Group. Lichenes 319 GROUP II. BBYOPHYTA (MUSCINE^) 324 Class III. Hepaticae (Liverworts) 333 Order 1. Marchantiaceae 336 2. Jungermanniaceae . . . . . . 343 ,, 3. Anthocerotaceae 352 Class IV. Musci (Mosses) 354 Order 1. Sphagnaceae 363 2. Andreaeaceae r. 365 ,, : 3. Archidiaceae 366 4. BryineaB 367 GBOUP III. PTEBIDOPHYTA (VASCULAB CBYPTOGAMS) . . 372 ^ Class V. Filicinae 381 Sub-Class. Eusporangiatae 381 Homosporeae. Order 1. Opbioglossaceae 381 2. Marattiaceaa . . . . . . .383 Heterosporeae. 3. Isoetaceae . ., Sub-Class. Leptosporangiatae Homosporeae (Filices) Order 1. Hymenophyllaceae ___ 2. Polypodiaceae 3. Cyatheaceae 4. Gleicheniacete 384 388 388 404 404 405 405 5. Schizaeaceae . . 406 ,, 6. Osmundaceae Heterosporeae (Hydropterideae) .... 406 406 ,, 7. Salviniaceae 415 8. Marsileaceac 415 Class VI. Equisetinae . . . . . . . . .416 Order 1. Equisetaceae . . '. : . . . . 416 Class VII. Lycopod'mae . . * . . - . . . .421 Sub- Class. Homosporeae . . -. 421 Order 1. Lycopodiacea; . 421 2. Psilotaceae . '. .' 425 .: Sub-Class. Heterosporeae ^ Order 3. Selaginellaceao . ... . . 426 .426 PAKT I. MORPHOLOGY. Introductory. The province of morphology is the study of the form of the body of plants, including the development of the body, the segmentation of the body into members, and the form and mutual relations of the members, as also the intimate structure (Anatomy and Histology) of the body and its members in so far as structure throws light upon the morphology of any part of the body. It is an essentially comparative study : it classifies into categories the members of a plant, or those of various plants, according to their morphological nature, that is, according to the mode and relations of their development. Each category consists of homologous members; of members, that is, which essentially agree in the mode and relations of their development ; or, in other words, which are more or less nearly equivalent morphologically, because they are of common descent. There are various degrees of Homology, that is, of morphological relationship. General homnlogy exists between homologous members when the one is not the precise equivalent of the other ; for instance, the sporogonium of a Moss is generally homologous with a Fern-plant ; and again, the sporangium of Lyco- podium, being borne singly on a sporophyll, is generally homologous with all the sporangia, collectively, borne on a sporopbyll of an Osmunda. Special homology exists between two homologous members when the one is the precise equivalent of the other. When this is true in detail, the special homology is said to be complete : for instance, the foliage-leaves, the perianth-leaves, and the sporophylls of a Phanerogam are ah* specially homologous, they all belong to the one category, leaves ; but complete special homology can only exist between the members of each sub-division of the category, between foliage-leaf and foliage-leaf, perianth-leaf and perianth-leaf, and so on. The special homology is incomplete when the members compared present differences in detail ; thus between foliage-leaves, perianth-leaves, and sporophylls there exists incomplete special homology ; or again, the sporangia of eusporangiate plants are incom- pletely homologous with those of leptosporangiate plants. Members may have 'both their general and their special homologies ; thus whilst the sporangium of a Lycopodium is generally homologous with all the sporangia on the sporophyll of an Osmunda, it is specially homologous with each individual sporangium. Homologous members are termed the homologues of each other. Morphology does not, however, include the consideration of the v. s. B. B 2 PART I. THE MORPHOLOGY OF PLANTS. functions of the various members of the body, except in so far as the form or other morphological characters of any member may be affected by special adaptation to the performance of some particular function. For instance, foliage-leaves and sporophylls are specially homologous ; but their special homology is incomplete on account of the differences in form, due to special adaptation to their functions, which they respectively present. In this case essentially similar members come to differ widely : in other cases, essentially dissimilar members come to resemble each other. For instance, tendrils are climbing-organs, and are all much alike ; but they may be of very different morphological value ; either modified branches, or leaves, or parts of leaves. Tendrils, therefore, are not all homologous ; but they are all analogous, that is, whatever their morphological value may be, they are modified in the same direction for the performance of the same function. Similarly the flattened stem-segments of Opuntia, and the phylloclades of Euscus, are the analogues of foliage-leaves ; and again, the subterranean shoots of Psilotum, and the submerged leaves of Salvinia, being absorbent organs, are the analo- gues of roots and of each other. From the purely morphological standpoint of development and mutual relation, the various parts of a plant are regarded as members of the body ; whilst from the physiological standpoint of function, they are considered as organs of the body, each being specially adapted for the performance of some particular kind of work. The more clearly the members of the body are marked off from each other, and the greater the variety of them, the higher is the degree of morphological differentiation which the body pre- sents ; similarly, the more special the adaptation of the organs, and the greater the variety of them, the more complete is the physiological differentiation, or the division of the physiological labour, of the body. A remarkable fact in the general morphology of plants, is that they are more or less polymorphic : that is to say, a plant assumes, as a rule, at least two different forms in the course of its life- history. Most commonly it presents but two forms which, while they may differ more or less widely in form and structure, differ essentially in that the one, termed the sporophyte, bears asexual reproductive organs which produce certain asexual reproductive cells, termed spores, each of which is capable by itself of giving rise to a new organism ; whilst the other, the gametophyte, bears sexual reproductive organs, which, as a rule, produce sexual repro- ductive cells, termed gametes, which, though each is by itself in- capable of giving rise to a new organism, yet by their fusion in INTRODUCTORY. 3 pairs form cells, of the nature of spores, from each of which a new organism can be developed. These two forms alternate more or less regularly in different plants, the asexually-produced spores of the sporophyte giving rise to gametophytes, the sexually- produced spores of the gametophyte giving rise to sporophytes. Such a plant is dimorphic, and its life-history presents an alternation of generations, that is, an alternation of a sexual with an asexual form. A typical instance of such alternation of generations is afforded by the life- history of a Moss. The sexual generation (gametophyte) is the moss-plant bearing the sexual reproductive organs, male (antheridiurn), and female (archegonium), of which the former produces male reproductive cells (spermatozoids), the latter a single female cell (oosphere). As the result of the fusion of the male cell with the female cell (sexual process), a cell, the oospore, is produced which is the origin of the asexual generation (sporophyte) known as the mosssporogonium. The sporogonium produces spores asexually, which, on germination, each give rise to a (at least one) moss plant (gametophyte). The gametophyte is thus always developed from a spore produced asexually ; the sporophyte, from a spore produced sexually. This kind of life-history obtains in the majority of plants, but it may be complicated in various ways. Thus, the sexual generation may be represented by two distinct forms, the one male (androphyte), the other female (gynophyte). Again, in some of the lower plants, the gametophyte also gives rise asexually to spore-like reproductive cells (yonidia), which do not, however, enter into the alternation of generations, for they give rise, not to sporophytes, but to repeti- tions of the gametophyte. The sporophyte also may similarly repeat itself, though not always in exactly the same form. Further, it occasionally happens that the gametophyte does not actually produce sexual organs or cells at all, though it is essentially capable of doing so ; and successive generations of such gametophytes may be developed by means of gonidia, until at length one arises which is actually sexual. Such non- sexual gametophytes are designated poten- tial gametophytes. Without entering into detail, the general morphological rela- tions between the two generations may be briefly considered. In the case of the Moss, the morphological differentiation of the sporophyte is, on the whole, not much lower than that of the gametophyte. In the approach to morphological equality between the two generations, the Mosses occupy a central position in the vegetable kingdom. For in all plants higher in the scale than Mosses, the morphological differentiation of the sporophyte is far higher than that of the gametophyte ; whilst in plants lower than the Mosses, the gametophyte is, as a rule, more highly differentiated than the sporophyte. In other words, whereas in the higher plants, the sporophyte is the form to which the name 4 PART I. THE MORPHOLOGY OF PLANTS. has been given, and on which classification is based, in the Mosses and the plants below them, it is to the gametophyte that the name has been attached, and it is upon its characters mainly that the classification of these plants depends. At this point the question naturally arises as to the morphological relation, if any, which may exist between the members of a gametophyte and those of a sporophyte. Since, speaking generally, the morphological differentiation of the one form has proceeded along the same lines as that of the other, a certain correspondence exists between their members. For instance, a foliage-leaf of a Moss (gametophyte) corresponds to that of a Fern (sporophyte) ; for, in the forms to which these leaves respectively belong, they stand in essentially similar relations, both of development and position, to the other members of the body. But the correspondence does not amount to relationship, and cannot be regarded as constituting homology as defined above (p. 1). It is, however, permissible, to this extent, to institute comparisons between the various members, reproductive organs, etc., of the two generations. The consideration of the polymorphism of plants is a most important preliminary to the study of their morphology, inasmuch as this knowledge facilitates precision of statement, and prevents that comparison of like with unlike which has been so common in this department of Botany. For instance, since the sporophyte and the gametophyte of one and the same plant are generally very different from each other, it conduces to clearness if, when reference is made to the morphology of any plant, it be definitely stated to which form of it the reference applies. And again, it is impossible to institute sound morphological comparisons between the members of different plants unless it is clearly understood to which form, whether sporophyte or gametophyte, the members to be compared belong in each case. The most fundamental preliminary consideration is, however, this that the body of a plant consists essentially of a mass, larger or smaller, of living substance known as protoplasm. The body may consist simply and only of protoplasm, without any investing membrane to give it a determinate form (e.g. Myxomycetes) ; or it may consist of protoplasm enclosed by a membrane (e.g. Phycomycetous Fungi and Siphonaceous Algce) ; or it may consist, as is generally the case, of a mass of protoplasm segmented by partition-walls into structural units termed cells. In all these possible capes, however, the form and segmentation of the body 1.] CHAPTER I. GENERAL MORPHOLOGY. 5 is determined by the protoplasm ; for the cell-walls, of which, in many cases, the body largely consists, and which give to it its form, are developed from and by the protoplasm. Hence the study of the morphology of plants is the study of the processes and results of the formative activity of their protoplasm ; and these are to be traced both in the variety of form presented by different plants, and in the various stages in the development of anyone individual plant. CHAPTER I. GENERAL MORPHOLOGY. 1. The Segmentation of the Body. The body of a plant may be either segmented into members, or unsegmented. The members of a segmented body may either be all similar, or they may be similar and dissimilar. Segmentation into similar members is termed branching. When the body is unsegmented, or segmented only into similar A members (i.e. branched), it is termed a thallus. plant of this constitution is termed a Thallophyte. The primary segmentation of the body into dissimilar members A consists in the differentiation of shoot and root. plant of this constitution is termed a Cormophyte. The Root is usually segmented, but only into similar members : it occasionally gives rise to (adventitious) shoots. The Shoot may be either unsegmented, or segmented into A similar or dissimilar members. shoot which is either unseg- mented, or segmented only into similar members, is termed a A thalloid shoot. shoot which is segmented into dissimilar members presents an axial member, the stem, bearing dissimilar lateral members, the leaves ; stem and leaf may be further seg- mented into similar members, that is, be branched ; such a shoot is termed a leafy shoot. Though the ideas of shoot and root are correlative, the one involving the other, yet there are cases in which the body consists of shoot only, the root being suppressed ; as in the gametophyte of Mosses ; in the sporophyte of Salviuia and Psilotum among Vascular Cryptogams ; and in Utricularia, Epipogou, and Corallorhiza among Phanerogams. In many plants no root is developed until after the stem and leaves have begun to appear. The shoot, in these cases, is recognized as such, and is distinguished from a thallus, by being differentiated into stem and leaves. 6 PART 1. THE MORPHOLOGY OF PLANTS. [ 1. Three main types of morphological constitution may be dis- tinguished: 1. The body is a thallus. 2. The body consists of root and thalloid shoot (two dissimilar members) . 3. The body consists of root and leafy shoot (three dissimilar members). These members frequently bear others of secondary morpho- logical importance, such as hairs, prickles, and reproductive organs. In highly organised plants the members can, as a rule, be readily distinguished from each other ; but in some cases there is difficulty in distinguishing between leaves and branches of the stem, between leaves and hairs or prickles, between roots and branches of the stem, etc. This difficulty is especially great in the study of less highly organised forms (e.g. gametophytes of Algae, Muscineae, and Pteridophyta), in which, whilst there is a certain degree of morphological differentiation, it is insufficient to obviously indicate the morphological nature of the members. In such doubtful cases an investigation of the development, relations, and structure of the member in question is the only method of arriving at a conclusion as to its morphological nature. For the principal members of the plant, stem, leaf, root, occupy certain definite relative positions and present a general co-ordination of structure, and are thus distinguishable from appendages such as hairs, etc. Moreover, their relative positions serve to distinguish them from each other; and though co-ordinate in structure, that is, presenting a corresponding degree of complexity of internal structure, yet they generally present distinguishing peculiarities in the details. The morphological characteristics of the principal members are briefly these : The shoot bears the true (spore-producing) reproductive organs. It is frequently differentiated into stem and leaf. The stem is the axial member of the shoot, and bears the leaves. The leaf is the lateral member of the shoot ; it is borne upon the stem, but usually differs from it in form and details of structure, though stem and leaf are co-ordinate in structure. The ideas of stem and leaf are correlative, the one involving the other ; nevertheless, in some cases (e.g. Kuscus,