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POPP SL SIGCSE SLPS ELS SPL LEELA LOOT ES A PE OE SEL ETSI TTT PN PIES POPOL ES ELE CLE CEE CER ECL ELA DO CEL ER OCE ERE SY wchedhe ti doco tdecthetonde Docingonth Sect Dag goe on Sent ok Aan aot th teyHe ESbTe sa thy! sf tt eee te ee etn Oe tt a atin en on on en | CAMBRIDGE BIOLOGICAL SERIES. GENERAL Epitor:—Arruur E. Saipiey, M.A. FELLOW AND TUTOR OF CHRIST'S COLLEGE, CAMBRIDGE. GRASSES. Zondon: OC. J. CLAY anv SONS, CAMBRIDGE UNIVERSITY PRESS WAREHOUSE, AVE MARIA LANE, AND H. K. LEWIS, 136, GOWER STREET, W.C. Glasgow: 50, WELLINGTON STREET. Leipsig: F. A. BROCKHAUS. few Work: THE MACMILLAN COMPANY. Bombay and Calcutta: MACMILLAN AND CO., Lop. [All Rights reserved.] GRASSES A HANDBOOK FOR USE IN THE FIELD AND LABORATORY. BY H. MARSHALL WARD, S8c.D., F-.B.S. FELLOW OF SIDNEY SUSSEX COLLEGE, HONORARY FELLOW OF CHRIST’S COLLEGE AND PROFESSOR OF BOTANY IN THE UNIVERSITY OF CAMBRIDGE. BRARY NEW YORK BOTANICAL GARDEN, CAMBRIDGE: AT THE UNIVERSITY PRESS. 1901 Cambridge : PRINTED BY J. AND C. F. CLAY, AT THE UNIVERSITY PRESS. PREFACE. eens HE following pages have been written in the hope that they may be used in the field and in the laboratory with specimens of our ordinary grasses in the hand. Most of the exercises involved demand exact study by means of a good hand-lens, a mode of investigation far too much neglected in modern teaching. The book is not intended to be a complete manual of grasses, but to be an account of our common native species, SO arranged that the student may learn how to closely observe and deal with the distinctive characters of these remarkable plants when such problems as the botanical analysis of a meadow or pasture, of hay, of weeds, or of “seed” grasses are presented, as well as when investigating questions of more abstract scientific nature. I have not hesitated, however, to introduce general statements on the biology and physiological peculiarities of grasses where such may serve the purpose of interesting the. reader in the wider botanical bearings of the subject, though several reasons may be urged against extending this part of the theme in a book intended to be portable, and of direct practical use to students in the field. I have pleasure in expressing my thanks to Mr R. H. Biffen for carefully testing the classification of “seeds” on pp. 185—174, and to him and to Mr Shipley for kindly ~jooking over the proofs; also to Mr Lewton-Brain, who Shas tested the classification of leaf-sections put forward on ope: 72—82, and prepared the drawings for Figs. 21—28. _. That errors are entirely absent from such a work as his is perhaps too much to expect: I hope they are ew, and that readers will oblige me with any corrections v1 PREFACE they may find necessary or advantageous for the better working of the tables, The lst of the chief authorities referred to, which students who desire to proceed further with the study of grasses should consult, is given at the end. I have pleasure in acknowledging my indebtedness to the following works for illustrations which are inserted by permission of the several publishers :—Stebler’s Forage Plants (published by Nutt & Co.), Nobbe’s Handbuch der Samenkunde (Wiegandt, Hempel and Parey, Berlin), Harz’s Landwirthschaftliche Samenkunde (Paul Parey, Berlin), Strasburger and Noll’s Text-Book of Botany (Macmillan & Co.), Figuier’s Vegetable World (Cassell & Co.), Lubbock’s Flowers, Fruits and Seeds (Macmillan & Co.), Kerner’s Natural History of Plants (Blackie & Son), and Oliver’s First Book of Indian Botany (Macmillan & Co.). It is impossible to avoid the question of variation in work of this kind, and students will without doubt come across instances—especially in such genera as Agropyrum, Festuca, Agrostis and Bromus—of small variations which show how impossible it is to fit the facts of living organisms into the rigid frames of classification. It may possibly be urged that this invalidates all attempts at such classifications: the same argument applies to all our systems, though it is perhaps less disastrous to the best Natural Systems which attempt to take in large groups of facts, than to artificial systems selected for special purposes. Perhaps something useful may be learned by showing more clearly where and how grasses vary, and I hope that the application to them of these preliminary tests may elucidate more facts as we proceed. a) Mi OW, CAMBRIDGE, April, 1901. CONTENTS. CHAPTER I. PAGE THE VEGETATIVE ORGANS ; / 4 : A ; ; 1 CHAPTER Uk THE VEGETATIVE ORGANS (continued) . : : wee le CHAP DE Eehue GRASSES CLASSIFIED ACCORDING TO THEIR VEGETATIVE CHARACTERS P : : : E : , é foe es) CHAPIER inh. ANATOMY AND HISTOLOGY ; , : : ° : .* 162 CHAPTER V. GRASSES CLASSIFIED ACCORDING TO THE ANATOMICAL CHARAC- TERS OF THE LEAF . J ; : ; 3 : ; Wen Vill CONTENTS CHAPTER VI. PAGE GRASSES IN FLOWER : : : ; ; : , . . 26 OCOHAPTER VU. GRASSES GROUPED ACCORDING TO THEIR FLOWERS AND In- FLORESCENCES . ; é ; ; : : : : 99 CHAPTER ViLk THe FrRuIT AND SEED. ; : ; : ; : .. 8 (CEU ek xe CLASSIFICATION OF GRASSES BY THE “SEEDS” (GRAINS) . 135 BIBLIOGRAPHY . é : : : ; : : : pew (5 INDEX, GLOSSARY AND List oF SYNONYMS. . dhe CHAPTER I. THE VEGETATIVE ORGANS. THAT grasses are interesting and important plants is a fact recognised by botanists all the world over, yet it would appear that people in general can hardly have appreciated either their interest or their importance ' seeing how few popular works have been published concerning their structure and properties. Apart from their almost universal distribution, and quite apart from the fascinating interest attaching to those extraordinary tropical giants, the Bamboos, West Indian Sugar-cane, the huge Reed-grasses of Africa, the Pampas-grasses of South America; and from the utilitarian value of the cereals—Maize, Rice, Wheat and other corn, &c.—everyone must be struck by the significance of the enormous tracts of land covered by grasses in all parts of the world, the Prairies of North America and the Savannahs of the South, the Steppes of Russia and Siberia, and the extensive tracts of meadow and pasture- land in Europe being but a few examples. W. i! 2 NUMBERS AND USES [CH. Although in the actual number of species the Grass family is by no means the largest in the vegetable kingdom, for there are far more Composites or Orchids, the curious sign of success in the struggle for existence comes out in grasses in that the number of individuals far transcends those of any other group, and that they have taken possession of all parts of the earth’s surface. Some species are cosmopolitan—e.g. our common Reed, Arundo Phragmites; while others—e.g. several of our native species of Festuca and Poa—are equally common in both hemispheres. On the whole the Tropics afford most species and fewest individuals, and the temperate regions most individuals. Considering their multifarious uses as fodder and food, for brewing, weaving, building and a thousand other purposes, it 1s perhaps not too much to say that if every other species of plant were displaced by grasses of all kinds—as many indeed gradually are—man would still be able to supply his chief needs from them. The profound significance of the grass-carpet of the earth, however, comes out most clearly when we realise the enormous amounts of energy daily stored uj in the countless myriads of green blades as they fix their carbon. By decomposing the carbon-dioxide of the air in their chlorophyll apparatus by the action of the radiant energy of the sun, they build up starches and sugars and other plant-substances, which are then consumed and turned into flesh by our cattle and sheep and other herbivorous animals, and so furnish us with food. The whole theory of agriculture turns on this pivot, and the by no means 1] ORIGIN OF THE WORD GRASS 5) small modicum of truth in such sayings as “All flesh is grass,” and that the man who can make two blades of grass grow where one grew before deserves well of his country, obtains a larger significance when it is realised that the only real gain of wealth is that represented by the storage of energy from without which comes to us by the action of green leaves waving in the sunshine. The true Grasses, comprising the Natural Order Graminaceze—also written Gramineze—are often popularly confounded with other herbs which possess narrow green ribbon-like leaves, or even with plants of very different aspects—e.y. Cotton-grass (Hriophorum) and other Sedges, and the names Rib-grass (Plantago), Knot-grass (Poly- gonum), Scorpion-grass (Myosotis) and Sea-grass (Zostera), as well as the general usage of the word grass to signify all kinds of leguminous and other hay-plants in agri- culture, point to the wider use of the word in former times. This has been explained by the use of the words gaers, gres, gyrs, and grass in the old herbals to indicate any kind of small herbage. In view of the importance of our British grasses in agriculture, I have here put together some results of observation and reading in the hope that they may aid students in recognising easily our ordinary agricultural and wild grasses. During several years of work in the fields, principally directed at first to the study of the parasitic fungi on grasses, and subsequently to that of the importance of grasses in forestry and agriculture, and to the variations they exhibit, the need of some guide to the identification of a grass at any time of the year, 1—2 + GENERAL CHARACTERISTICS [CH. whether in flower or not, forced itself on the attention, and although a botanist naturally turns to a good Flora when he has the grass in flower, as the best and quickest way of ascertaining the species, it soon became evident that much may be done by the study of the leaves and vegetative parts of most grasses. Indeed some are recog- nisable at a glance by certain characters well known to continental observers: in the case of others the matter is more difficult, and perhaps with a few it is impossible to be certain of the species from such characters only. Nevertheless, while the best means for the deter- mination of species are always in the floral characters so well worked up in the Floras of Hooker, Bentham and others, there is unquestionably much value in the characters of the vegetative organs also, as the works of Jessen, Lund, Stebler, Vesque and others abroad, and Sinclair, Parnell, Sowerby and others in this country attest. Almost the only plants confounded with true grasses by the ordinary observer are the sedges and a few rushes. Apart from the very different floral structures, there are two or three easily discoverable marks for distinguishing all our grasses from other plants (Fig. 1). The first 1s their leaves are arranged in two rows, alternately, up the stems; and the second that their stems are circular or flattened in section, or if of some other shape they are never triangular and solid? (Figs. 6 and 7). Moreover the leaves are always of some elongated shape, and without 1 Some foreign grasses (Andropogon, Panicum, &c.) have solid stems, and in Psamma and some others the lower parts may be solid. 1] SHEATH 5 leaf-stalks', but pass below into a sheath, which runs some way down the stem and is nearly always perceptibly split Fig. 1. A plant of Oat (Avena), an example of a typical grass, showing tufted habit and loose paniculate inflorescence (reduced). Figuier. 1 Leaf-stalks occur in tropical Bamboos. 6 DIMENSIONS [CH. (Figs. 8—13). Further, the stems themselves are usually terete, and distinctly hollow except at the swollen nodes, and only branch low down at the surface of the ground or below it’. All our native grasses are herbaceous, and none of them attain very large dimensions. In the following lists I term those small which average about 6—18 inches in the height of the tufts, whereas those over 3 feet high may be termed large, the tufts being regarded as in flower. The sizes cannot be given very accurately, and starved specimens are frequently found dwarfed, but in most cases these averages are not far wrong for the species freely growing as ordinarily met with, and in some cases are useful. I have omitted the rare species throughout, and in the annexed lists have added the popular names. LARGE GRASSES. (Over 3 feet.) Milium effusum (Millet-grass). Digraphis arundinacea (Reed-grass). Aira cespitosa (Tufted Hair-grass). Arrhenatherum avenaceum (False Oat). Elymus arenarius (Lyme-grass). Bromus asper (Hairy Brome). B. giganteus (Tall Brome). Festuca elatior (Meadow Fescue). F. sylvatica (Reed Fescue). Glyceria aquatica (Reed Sweet-grass). G, fluitans (Floating Sweet-grass). Arundo Phragmites (Common Reed). 1 Tropical Bamboos branch in the upper parts and are woody. Dinochloa and Olyra are climbing grasses. MEDIUM AND SMALL GRASSES MEDIUM GRASSES. (1—3 feet.) Phleum pratense (Timothy). Avena pratensis (Perennial Oat-grass). Anthoxanthum odoratum (Sweet Vernal). Alopecurus agrestis (Slender Foxtail). A. pratensis (Meadow Foxtaii). Agrostis alba (Fiorin). Psamma arenaria (Sea Mat-grass). Avena flavescens (Yellow Oat-grass). Holcus lanatus (Yorkshire Fog). Hordeum sylvaticum (Wood Barley). H. pratense (Meadow Barley). Agropyrum repens (Couch-grass). A. caninum (Fibrous Twitch), Lolium italicum (Italian Rye-grass). Brackypodium sylvaticum (Wood False-Brome). B. pinnatum (Heath False-Brome). Bromus erectus (Upright Brome). B. sterilis (Barren Brome). B. arvensis (Field Brome). Festuca ovina (var. rubra, &c.). Sheep’s Fescue. F. elatior (var. pratensis). Meadow Fescue. Dactylis glomerata (Cock’s-foot). Cynosurus cristatus (Crested Dog’s-tail). Poa pratensis (Meadow-grass). P. trivialis (Rough stalked Meadow-grass). P. nemoralis (Wood Poa). Molinia cerulea (Flying Bent). Melica nutans (Mountain Melick). M. uniflora (Wood Melick). SMALL GRASSES. (6—18 inches.) Phleum arenarium (Sand Cat’s-tail). Alopecurus geniculatus (Marsh Foxtail). Agrostis canina (Brown Bent). Aira flexuosa (Wavy Hair-grass). 8 ROOTS AND STOLONS [CH. Aira canescens (Grey Hair-grass). A. precor (Early Hair-grass). A. caryophyllea (Silvery Hair-grass). Nardus stricta (Moor Mat-grass). Hordeum murinum (Wall Barley). H. maritimum (Sea Barley). Lolium perenne (Rye-grass). L. temulentum (Darnel). Bromus arvensis (var. mollis). Field Brome. Festuca ovina (Sheep’s Fescue). F. Myurus (Rat’s-tail Fescue). Briza media (Quaking-grass). Poa maritima (Sea Poa). P. annua (Annual Meadow-grass). P. compressa (Flattened Meadow-grass). P. alpina (Alpine Poa). P. bulbosa (Bulbous Poa). Triodia decumbens (Heath-grass). Keleria cristata (Crested Keeleria). The roots of our grasses are almost always thin and fibrous and are adventitious from the nodes, frequently forming radiating crowns round the base and easily pulled up, and usually broken in the process; but in the case of a few moor grasses—especially Nardus (Fig. 2) and Molinia—the roots are so tough and thick (stringy) as to resist breakage very efficiently. In stoloniferous grasses a similar difficulty of removal may be caused in a slighter degree by the underground stems. In a few cases, e.g. Alopecurus bulbosus (Fig. 3), Poa bulbosa, Phlewm pratense and P. Behmeri, Arrhenatherum avenaceum, and to a slighter extent in Poa alpina and one or two others, the lowermost internodes and sheaths of the stems may be swollen and stored with food-materials, and a sort of tuber or bulb results; this is especially apt to occur in dry sandy 1] TUFTED AND BULBOUS GRASSES 9 Fig. 2. Nardus stricta. Plant showing tufted habit, and simple spikate inflores- Fig. 3. Alopecurus geniculatus, var. cence, with pointed spike- bulbosus. Plant (reduced) showing lets all turned towards one habit, bulbous shoots and cylin- side (secund) on the ra- drical spike-like inflorescences chis (reduced). Note also (Foxtail type). Notice the in- the bristle-like (setaceous) flated sheaths, and the ‘‘kneed”’ leaves at length reflexed. lower parts of the ascending stems. Parnell. Parnell. 10 DURATION OF LIFE [CH. soils. In old lawns, pastures, &c., the roots of Poa annua and others may have nodules on them due to the presence of certain small Nematode worms, Heterodera. Grasses are annual, biennial, or perennial, and it is often of importance to know which. The point may usually be determined by examining the shoots. If all the shoots have flowering stems in them, and are evidently of the current year, the grass is an annual; but if any shoots have leaves only, it is either biennial or perennial: to determine which is not always easy, but in perennial grasses there will generally be evident remains of older leaf-bases and shoots, and if there are distinct under- ground stolons or creeping rhizomes as well the point may be considered decided, and the grass is perennial, as is the case with most of our important species. If all the shoots are barren, the grass is a biennial in its first year of growth: if all have Howering stems in them, but show traces of old leaf-bases of the previous year, then the grass is a biennial in its second year. The proof of biennial character is not always easy, however, and a few grasses may be either annual or biennial, or biennial or perennial, according to conditions—e.g. species of Hordeum, Bromus, &c. In the following lists I have given the duration of the principal grasses, where the character is especially important. ANNUALS. Phleum arenarium. Lolium temulentum. Aira precon. Festuca Myurus. A. caryophyllea. Briza minor. Hordeum murinum. Poa rigida. H. maritimum. P. annua. 1] ANNUALS AND PERENNIALS 4 which may become biennial or perennial. Alopecurus geniculatus. Hordeum pratense. Lolium perenne. L. italicum (may be perennial). Bromus asper (may be perennial). B. sterilis. B. arvensis (may be perennial). Holeus lanatus. H. mollis. Nardus. Hordeum sylvaticum. Agropyrum. Brachypodium. Bromus erectus. B. giganteus. Festuca ovina. F. elatior. F. sylvatica. Dactylis. Cynosurus cristatus. Briza media. Milium. Anthoxanthum. Digraphis. Phleum pratense. Alopecurus pratensis. Agrostis alba. A. canina. PERENNIALS. Psamma. Awa cespitosa. A. flexuosa. A, canescens. Avena pratensis. A. flavescens. Arrhenatherum. Glyceria aquatica. G. fluitans. Poa maritina. P. compressa. P. pratensis. P. trivialis. P. nemoralis. P. alpina. P. bulbosa. Molinia. Melica. Triodia. Keleria. Arundo. The rhizome of a perennial grass is continued sym- podially by means of buds branching from the lowermost joints of the flowering shoots, and some importance is attached to the mode of spreading of these lateral sprout- 12 BRANCHING [CH. ing shoots. The buds always arise in the axils of the lower leaf-sheaths—i.e. they are intra-vaginal. If they remain intra-vaginal during further growth, the shoots are forced upwards and only tufts (Fig. 2) are formed, except in so far as such shoots may fall prostrate on the surface of the ground later, and throw out roots from their nodes, and so act as runners or offsets, or put out a few roots &c. as they ascend through the soil. But in many cases the buds soon burst through the leaf-sheaths, and develope as extra-vaginal shoots, and may then run _ horizontally as underground stolons. Only creeping grasses of these latter kinds can rapidly cover large areas!: the grasses v 2 eS = = te QW i f SIN) LISS De BTA SZ Tae yO Pr LE DN ee 3 \ . < ~ J ad ™~ A — jE SSS ee oe a) zC AEN —. SS Vea ) —_— ay — — = Le. J . ( — Fig. 4. Catabrosa aquatica. Plant showing the creeping habit, rooting nodes, and paniculate inflorescence (reduced). Parnell. 1 Except, of course, in cases of virgin ground rapidly occupied by the seedlings. 1] STOLONIFEROUS GRASSES 13 with intra-vaginal shoots only can only make tufts or “tussocks.” Several peculiarities in the habits of grasses depend on these facts. The following are the most important creeping, or stoloniferous species, contrasted with the much more common tufted and the far rarer grasses with runners above ground (Fig. 4). Some of these (Hlymus, Psamma, &c.) are of great importance as sand-binders. With intra-vaginal branches only. Lolium—slightly stoloniferous. Festuca elatior— slightly stoloniferous. Avena flavescens—slightly stoloniferous. Phleum pratense—no stolons, but may be bulbous. Dactylis—no stolons. Festuca ovina-—no stolons. Poa alpina—no stolons. Cynosurus—no stolons. With extra-vaginal shoots. Arrhenatherum—short stolons, sometimes bulbous. Holcus lanatus—creeping. Alopecurus pratensis—long stolons. Anthoxanthum—slightly stoloniferous. Agrostis alba (var. stolonifera)—long stolons and runners. Digraphis—long stolons. Poa pratensis—long stolons. P. trivialis—runners only. Festuca heterophylla, Lam.—a variety of F. ovina with slight stolons. F.. rubra (Linn.)—a variety of /. ovina with long stolons. Bromus erectus—no stolons. B. inermis—long stolons. 14 CREEPING AND TUFTED GRASSES [CH. Creeping below ground and truly stoloniferous. oO fo) Agropyrum. Bromus erectus (slightly). Elymus. Festuca ovina (var. rubra, Linn.). Psamma. fF’. elatior (slightly). Poa pratensis. Briza (slightly). P. compressa. Glyceria. Agrostis alba (var. stolonifera). Poa maritima. Alopecurus pratensis. Melica, Brachypodium (slightly). Arundo. Tufted Grasses. Milium. Festuca sylvatica. Agrostis alba (on downs, &c.). F, Myurus. Aira cespitosa. Dactylis. A. flexuosa. Cynosurus. A. canescens. Poa rigida. A. precox. P. annua. A. caryophyllea. P. trivialis. Avena pratensis (slightly creeping). P. nemoralis. Arrhenatherum. P. alpina. Nardus (Fig. 2). P. bulbosa. Hordeum sylvaticum. Molinia. Lolium. ; Triodia. Bromus. Keleria. Festuca ovina (except some varieties). Creeping above ground (with runners). Holcus lanatus. Alopecurus geniculatus. Agrostis alba (var. stolonifera). Hordeum pratense (slightly). H. murinum (slightly). Catabrosa (Fig. 4). Cynodon (Fig. 5). Hackel has pointed out that a distinction must be drawn between the true nodes of the culm, and the swellings 1] SHOOTS AND NODES 15 often found at the base of the sheaths themselves over these: the latter are often former are inconspicuous—e.g. most species of Agrostis, Avena, Festuca, &c. The nodes are of importance in the description of a few species only—e.g. they are usually dark coloured in certain Poas such as P. compressa and P. nemoralis ; they are sharply bent in Alope- curus geniculatus, and may be so in other species if “layed” by wind, rank growth, We. A point of considerable classi- ficatory value is the shape of the transverse section of the shoot, which is correlated with the mode of folding up of the young leaf- blades. In most grasses the blades are convolute—i.e. rolled up lke the paper of a cigarette, one edge over the other—and the section of the shoot is round (Fig. 7). conspicuous when the 4 7 Fig. 5. Cynodon Dactylon. Plant (reduced) showing creeping and stolonifer- ous habit, and peculiar inflorescence of digitate spikes. Parnell. In some cases, however, the leaves are conduplicate—te. each half of the lamina is folded flat on the other, the upper sides being turned face to face inwards, with the mid-rib as the hinge—and in this case the shoots are more or less compressed (Fig. 6). 16 SHOOT-SECTIONS [CcHAt In these latter cases the transverse section may be elliptical—e.g. Poa pratensis and P. alpina, Briza, &c., | Fig. 6. Dactylis glomerata. Fig. 7. Digraphis arundinacea. Trans- Transverse section of a verse section of a leaf-shoot (x5). leaf-shoot ( x 5). A, con- A, sheath. 3B, convolute leaves. duplicate leaf-blade. B, Compare Fig. 14. Stebler. sheath. Stebler. or more flattened and linear-oblong—e.g. Glyceria flui- tans—with the flattened sides straight, or the section is oval but pointed more or less at each end owing to pro- jecting keels and leaf-edges, and the form is naviculate— e.g. Glyceria aquatica, Dactylis (Fig. 6)—or, the sides being less flattened, more or less rhomboidal as in Poa trivialis. In Melica the leaves are convolute and the shoot-section quadrangular. Flat, and usually sharp-edged shoots. Dactylis glomerata (Fig. 6). Poa trivialis, P. annua, P. pratensis, P. conypressa, P. maritima, and P. alpina. Glyceria aquatica and G. fluitans. Avena pubescens. Lolium perenne. CHAPTER II. THE VEGETATIVE ORGANS (continued). THE leaves of all our grasses consist of the blade, which passes directly into the sheath, without any petiole or leaf-stalk (Fig. 1). The sheath is usually obviously split, and so rolled round the internode that one edge overlaps the other, but in the following grasses the sheath is either quite entire, or only slit a short way down, the two edges being fused as it were for the greater part of its length. Sheath more or less entire. Glyceria aquatica and G. fluitans. Melica uniflora and M. nutans. Dactylis glomerata. Poa trivialis (Fig. 8), P. pratensis, P. alpina. Sesleria cerulea. Bromus (all the species). Briza media and B. minor. In some cases—e.g. Arrhenatherum, Bromus asper, and Holcus lanatus—the sheath is marked with a more or less Ww. Z 18 SHEATH AND LIGULE [CH. prominent ridge down its back, due to the continuation of the keel of the leaf. The sheath may also be glabrous or hairy, and grooved or not. A few grasses are so apt to develope characteristic colours in their sheaths, especially below, that they may often be recognised in winter by this peculiarity. Sheaths coloured. Lolivm—all red. Holcus—red with purple veins. Festuca elatior—red. Cynosurus—y ellow. Alopecurus pratensis, and A. agrestis—violet-brown, «ce. Festuca ovina, var. rubra—red. Fig. 8. Poatrivialis. Fig. 9. Alopecurus Fig.10. Avena flavescens. A, base of blade. pratensis. A, base Lettering as before B, ligule. (C, of blade. B, ligule. (x2). Note the split sheath. D, culm C, sheath. Slight- sheath, the hairs and (x about 3). ly magnified. ridges. Stebler. At the junction of the blade with the sheath there is in most cases a delicate membranous upgrowth of the former, more or less appressed to the stem, and called the Ligule (Figs. 8—13). Its use is probably to facilitate the shedding II] LIGULE AND LAMINA 19 of water which has run down the leaf, and so lessen the danger of rotting between the sheath and stem: possibly the shelves and ears commonly met with at the base of the lamina (Fig. 12) aid in the same process. This ligule may be long or short, acute or obtuse, toothed or entire, or it may be reduced to a mere line, or tuft of hairs, or even be obsolete, and is of considerable value in classification— e.g. the ligule is obsolete or wanting in Melica, Festuca ovina, F. Myurus, F. elatior, Keleria and Panicum. It is represented by a tuft of hairs in Molina, Triodia and Arundo. Fig.11. Lolium perenne. Fig.12. Festuca elatior, Fig. 13. Festuca A, base of lamina, var. pratensis. A, ovina. Fig. 31. Diagram of a spikelet Fig. 32. Diagram of a spikelet of of Wheat dissected ( x about Anthoxanthum dissected (x about 5) showing—from below up- 8), and showing—from below wards—the two glumes, two upwards—two outer and two pale, two lodicules, three (awned) inner glumes, two pale, stamens, and the ovary of two stamens, and the ovary. the typical grass. Oliver. There are no lodicules. Oliver. On looking at the total inflorescence of the Nardus we see that we have a number of spikelets seated on the sides of an axis: this is then a spike of spikelets, or, shortly, a Spike’ (Fig. 5). Mibora and Lepturus afford other ex- amples. In Panicum, Cynodon (Fig. 2) and Spartina we have groups of such spikes. 1 Strictly speaking a spike is an axis bearing sessile flowers—not sessile spikelets: in Grasses, however, the conventional abbreviated term is sanctioned by long usage. The same applies to the panicle, &c. 88 TYPES OF INFLORESCENCE [ CH. The Poa inflorescence is, however, different. It con- sists of a loose branched system of spikelets. Botanists term such a loosely branching system, where each branch ends in a flower, a panicle: here then we have a panicle of spikelets, or, shortly, a Panicle. Azra, Agrostis, Ca- lamagrostis, Avena, Catabrosa (Fig. 4) and many others afford further examples. In Dactylis we have a condition of affairs between the two extremes given: the inflorescence is not so close a spike as Nardus, and not so open a panicle as Poa—it is rather a spike-like panicle, partaking of the nature of both. A special type of this (Foxtail) occurring in certain grasses—e.g. Phleum, Alopecurus, Phalaris and Lagurus, —is so characteristic as to be worth noting (Fig. 3). There is also another aspect of these inflorescences which is not without interest as showing how diagnostic characters may be obtained from purely external features, easily observed in the field. We have seen that in Nardus the spikelets are arranged on one side only of the rachis, or main axis, so that about three quarters of the circumference of the latter is bare; whereas in Lolium—with which Agropyrum and Brachypodium agree in this respect—the spikelets are on opposite sides, leaving the intervening two quarters, 1e. half its surface, of the circumference of the axis naked. In Cynosurus and the simpler forms of Dactylis, we find the spikelets crowded round about three quarters of the surface of the rachis, leaving the fourth quarter naked; and, finally, in Phlewm, Alopecurus, Hordeum, and Anthoxanthum the spikelets cover the entire surface. VI] BARREN AND FERTILE FLOWERS 89 In the first (Vardus) and third examples (Cynosurus, Dactylis) where the spikelets are turned to one side, the inflorescence is said to be secund. The next point to notice is that not every grass has so many as two fertile flowers and one barren one in its spikelet, as the Oat has. A spikelet may have one (Phleum), two (Aira) or three (Avena) or more (Poa) fertile flowers, and no barren ones or several, the number of flowers being counted by the number of pairs of pales found inside the pair of glumes. Moreover every flower is not necessarily fertile (e.g. Arrhenatherum, Holcus) and several grasses have one or more flowers in each spikelet containing stamens only—male flowers—while others may have ovaries only—female flowers. In some exotics the male and female flowers are on different parts of the same plant (Maize) or even on different plants (Gynerium), an arrangement not met with in our grasses. Accordingly, it is of importance in determining a grass to discover how many flowers the spikelet contains, and whether any are male only, or barren, &c., as well as to make out the character of its inflorescence. In the following lists I have brought together some of the chief points with illustrative examples. SPIKELETS with only one perfect flower (without rudimentary ones), Psamma. Phleum. Milium. Hordeum. Nardus. Agrostis. Alopecurus. And species of the rare grasses Calamagrostis, Muibora, 90 SPIKELETS AND [CH. Lepturus, Spartina, Cynodon, Gastridium, Lagurus, Poly- pogon, Leersia. SPIKELETS with one perfect flower and one or more male or rudimentary ones. Digraphis. Holeus. Anthoxanthun. Arrhenatherum. And the rare genera Hierochloe and Panicum. SPIKELETS with at least two perfect flowers. Molinia. Triodia. Arundo. Sesleria. Avena. Keleria. Aira (some species). Melica (one species). Bromus. Briza. Cynosurus. Poa trivialis, Dactylis. Catabrosa. SPIKELETS with at least three perfect flowers and usually more. Elymus. - Festuca. Agropyrum. Poa. Brachypodium. Glyceria. Lolium. INFLORESCENCE, a spike of single spikelets. Agropyrum. Lolium. Brachypodium. Nardus. And varieties of Festuca Myurus and F. loliacea, &c. INFLORESCENCE, a spike of pairs or tufts of three or more spikelets. Elymus (pairs). Cynosurus (clusters). Hordeum (threes). INFLORESCENCE, a cylindrical closely tufted spike-like panicle. Phleum. Psamma. Alopecurus. Anthoxanthum. vi] INFLORESCENCES 91 INFLORESCENCE, a compact more or less tufted panicle. Molinia, Aira precox. Keleria. A. canescens. Triodia. Sesleria. Dactylis. And rare grasses like Polypogon, Gastridium, &c. INFLORESCENCE, a loose plume-like or branched panicle. Avena. Milium. Bromus. Agrostis. Arrhenatherum. Melica. Catabrosa. HHolcus. Aira (except A. precox and Poa (most of the species). A. canescens). Glyceria. Arundo. Briza. Digraphis. Festuca (except F. Myurus). And the rare Hierochloe. The Glumes are always present in our grasses, and rudimentary only in the rare grass Leersia; but Loliwm and Nardus have only one glume to the spikelet, and Hierochloe, Digraphis and Anthoxanthum (Fig. 32) have four or six. Our other grasses have two, but often unequal in size. In shape they are usually boat-like, pointed or obtuse (Briza) and frequently with a distinct keel (Anthoranthum, Digraphis, Phleum, &c.) or with ridges, green lines (veins) and other characteristic markings (e.g. Digraphis). The tip may be extended into a stiff long point or awn (Ag- ropyrum, Phlewm, Nardus) and the keel, ribs, and awn may have hairs or serrule on them. The rule is, how- ever, that the glumes are not awned. In texture the glumes may be herbaceous and green-brown or purple 92 AWNS [CH. (e.g. Melica) or membranous or stiff, or scarious (Le. browned, as if scorched) at the edges. In Hordeum some of the glumes are so narrow and pointed as to resemble stiff awns. In Catabrosa the glumes are trun- cate, as if bitten off at the top. The Palew are also often more or less boat-shaped, or flat ovate or oblong scales, usually more delicate than the glumes and frequently pointed, or (especially the outer pale) awned at the tip: in some cases, however, the awn springs from the middle or base of the back of the pale, and the latter may be bifid at its apex. The pale has usually a distinct middle nerve. The inner pale is com- monly the smaller and more delicate of the two, and is sometimes difficult to see. CONSPICUOUSLY AWNED GRASSES. Avena. Agropyrum canmum. Arrhenatherum (Fig. 33). Lolium temulentum. Hordeum. 7 Brachypodium sylvaticum. Bromus. Festuca Myurus. And a few rare grasses like Panicum, Polypogon, Lagurus. GRASSES WITH NO TRUE AWNS. Keleria. Poa. Milium. Glyceria. Digraphis. Catabrosa. Elymus. Molinia. Festuca (except F’. Myurus Melica. and F’. uniglumiis). Psamma. Briza. Agrostis alba. And a few rare forms like Leersia, Hierochloe, &c. v1] POLLINATION 93 GRASSES WITH INCONSPICUOUS AWNS, OR MERE POINTS, TO SOME OF THE GLUMES OR PALES. Arundo. Lolium perenne. Phleum. Brachypodium pinnatum. Alopecurus. Dactylis. Ffolcus. Cynosurus. Nardus. Sesleria. Agropyrum repens. Fig. 33. Arrhenatherum. 1 unopened and 2 open anther (x12). 3, spikelets open and exposing the stamens and stigmas; 4, the pollen escaping and being dusted on to the stigmas (x about 5). Kerner. 94 MORPHOLOGY OF SPIKELET [CH, As regards the flower proper, all our British grasses except Anthoxanthum (which has two only) have three stamens; but many exotic grasses have six stamens, and a few have a large number—even 40. The stamens have slender filaments and large versatile anthers, which dangle from between the paleze when the flowers are mature, scattering their clouds of fine pollen in the wind (Fig. 33). All our ordinary grasses except Nardus—where there is a simple straight hairy style—have two spreading feathery stigmatic plumes, which stand out right and left from between the palee when the pollen is flying about on the wind. (Fig. 33.) Much interesting speculation has been expended in attempting to ex- plain the morphological or theoretical significance of the parts of the spike- let of a grass. If we project the various organs on a flat surface in the form of a plan, keeping their relative positions intact, we obtain a diagram such as that shown in |. Fig. 34. Diagram of a Fig. 34. spikelet of a grass. The comparison of numerous The two glumes—g’ outer, g? inner—em- brace four flowers, of ment of the parts on the microscopic which 1 is the lower- growing point dissected out from most ang? ge most. young buds, have suggested that cases, and the study of the develop- the inner and outer glumes are bracts, or covering leaves, vi] MORPHOLOGY OF AWN 95 at the base of the true spikelet. In like manner the two pales are bracteoles which subtend the flower proper. On this assumption they can be compared with the corresponding structures in other plants; whereas any attempt to compare the palez or glumes with the sepals and petals of ordinary flowers breaks down. A curious interest attaches to the awns so often found on the backs of pale, and especially to those where the (sub-terminal) awn springs from just below the bifid apex (e.g. Avena, &c.). Hackel showed by comparison with a rolled leaf attached to its sheath and ligule (e.g. Psamma) that such an awn as that of Bromus Alopecurus attached to its palea stands in the relation of a leaf to its sheath, the part of the palea above the insertion corresponding to the ligule, the awn itself to the lamina, and the palea below its msertion to the sheath. This view is rendered the more probable by the anatomy of the awn and by the observations of Schmid, who has shown that the awns of cereals contain chlorophyll-tissue and a vascular bundle, and have stomata, and his experiments led him to con- clude that in the young condition they transpire and assimilate, and probably even contribute to the nutrition of the ripening grain. When dry and mature the awns subserve biological functions of quite another kind, and as we shall see are of importance in the distribution and sowing of the grains. (Fig. 42.) Returning to the floral diagram, we see that the two lodicules, the three stamens and the ovary still remain to 96 FLORAL DIAGRAMS [CH. be explained. Much discussion has been held regarding the lodicules. Functionally they are said to aid in the divarication of the palez when the period of anthesis arrives, and the stamens and stigmatic lobes are to be Fig. 35. Floral diagram of ordi- Fig. 36. Floral diagram of a nary grass. Each pair of Bamboo, showing six stamens, palee—i.p. inner and o.p. three inner (i.s.) and three outer palea—encloses three outer (a.s.), and three lodi- stamens (s), two lodicules (I) cules (/) in addition to the and the ovary. st, stigmatic ovary. i.p. inner and o.p. plumes. a, axis. outer palea. a, axis. exposed, by swelling and driving the valve-like palee apart. Morphologically they have been explained as representing the rudimentary perianth, here reduced to two minute scales, but in some exotic grasses (Bambusa, Stipa, &c.) three lodicules, or even more, are present. (Figs. 35, 36.) On the other hand they may be, and probably are, scales of the nature of minute bracteoles and of no significance to the flower itself. If this is so the flower of the grass is perfectly naked, v1] MORPHOLOGY OF THE FLOWER 97 and consists in the typical case of three stamens and one carpel. The development of the ovary lends no support to the view that there are two carpels: the stigmatic plumes are not separate styles. Nor does the fact that some grasses have six stamens lend support to the idea that the flower is derived from the trimerous type so common in Monocotyledons: other numbers may occur—e.g. as few as two (Anthoxanthum, Fig. 32) or even one only (Uniola, Cinna, &ec.) or as many as 20 or 40 in certain other exotic grasses. Even when three stigmatic plumes are developed, as in some Bamboos, close investigation does not confirm the view that the ovary consists of more than one carpel. We must therefore regard the flower of the grass as typically composed of one carpel and three stamens, with no perianth whatever. It is subtended by one or more bracteoles (the lodicules), and enclosed in a pair of bracteoles one higher than the other (the pale). The glumes are bracts of the partial inflorescence—the spikelet. That there are some departures from this type in detail does not invalidate the importance of the fact that most grasses conform to it. I now pass to the consideration of a grouping of our ordinary grasses according to their floral arrange- ments. The student should distinctly understand that the following notes are intended to serve as an introduction to the floral characters of our grasses, and not to replace by W. ( 98 USE OF THE FLORA [CH. VI the study of the Flora. I have dealt with this section of the subject less in detail, because our best Floras give so much information that it seemed undesirable to do more than attempt to guide the reader in the recognition of the genera and principal species by means of external features easily observed by anyone with a little care. The detailed and critical examination of species, varieties and rare forms should always be done with reference to a complete Flora. CHAPTER VII. GRASSES GROUPED ACCORDING TO THEIR FLOWERS AND INFLORESCENCES. I. GRASSES WITH ONLY ONE PERFECT FLOWER IN THE SPIKELET. (1) Inflorescence spikate *. A. Inflorescence a spike of simple spikelets. Nardus stricta, L. A tough wiry tufted moor-grass, with setaceous leaves, secund spikelets with a single rudimentary glume, and a stiff simple hairy style. (Fig. 2.) The much rarer Mibora verna about three inches or so high, and Lepturus, both with flat leaves, also come here. Certain superficial resemblances in the habit or inflorescence in Festuca Myurus and rare forms like Spartina, may occasionally cause hesitation until the spikelets are examined. B. Spike with sessile or sub-sessile tufts of three or more spikelets. (a) A spike of tufted awned spikelets, in triplets at each notch of the rachis, and one or two of each triplet barren. Hordeum. 1 See note, p. 87. 7—2 100 CLASSIFICATION ACCORDING TO [CH ° No other genus of our grasses is like Hordewm. The purely superficial resemblances in the inflorescences of Polypogon, Lagurus, and Cynosurus echinatus—all extremely rare species—disappear at once on examination. In Bromus erectus the equally superficial resemblance is due to the stiff awns: the spikelet has six to twelve flowers and is stalked. It should also be noted that Hordeum sylvaticum occasionally has a rudimentary second flower in the lateral spikelets (see note p. 105). (a) A shade-grass with the central spikelet only imperfect ; staminate, or rudimentary, or en- tirely wanting. HH. sylvaticum, Huds. (8) The central spikelet is the perfect one, the two lateral barren. Growing in open land. (Gi) A perennial meadow-grass. All the glumes scabrid and bristle-like. H. pratense, Huds. (ii) Annuals with some of the glumes at least, lanceolate or broad below. * Ruderal plant, with cylindrical spikes, long awns; glumes of the central flower dilated below. H. murinum, With. ** Maritime plant, more or less glaucous, with short ovoid spikes: glumes of the central flower bristle-like. H. maritimum, With. (b) Spike cylindrical, of sessile or nearly sessile awned spikelets, densely crowded round the axis, the whole resembling a fox’s brush or cat’s tail. vit] FLORAL CHARACTERS 101 Species of Lagurus, Polypogon, Phalaris (not truly awned), Panicum (with bristles between the spikelets), and Gastridium are other British grasses approaching this type of inflorescence: they are all rare or very local. Sesleria has an ovoid spike, but the spikelets are two-flowered and not truly awned. Keleria may present resemblances, but the spikelets are very different in detail (see p. 109). (i) Awns inserted into the back of the single palea, and hair-like. Glumes connate below, keeled. Only one palea. Alopecurus. Annual corn-weed, with a long and slender spike, pointed above. Glumes almost glabrous, and connate to the middle. A. agrestis, L. ** Perennials, with shorter and stouter spikes, rounded above. Glumes connate at the base only, and obviously hairy on the keel. +t Procumbent and kneed at the nodes below. Spike 1—2 inches long. In marshy places. A. geniculatus, L. tt A meadow-grass, with erect stems, and spikes 2—3 inches or more and stouter. A. pratensis, L. The rare A. alpinus, Sm. with short ovoid spikes, about one inch long, only occurs in the Highlands. (11) Awns, when present, merely the stuff, pointed termination of the keel. Glumes free below. Palee two. 102 CLASSIFICATION ACCORDING TO [CH. * A glaucous shore plant with long creeping stolons (sand-binder). Inflorescence harsh, 5—6 inches long. Glumes tapering, simply acute. Psamma arenaria, Beauv. Elymus, a much rarer sand-binder of similar habit, may lead to confusion until the 3—4 flowered spikelets and different arrange- ment are observed. (See p. 108.) Agropyrum repens (var. junceum) is similar in habit and station, but its spikes and spikelets are very different (see p. 107). Phleum arenarium is much smaller (see below). ** Erect. Inflorescence rarely longer than three inches. Spikelets flat: glumes keeled, the keel suddenly produced into a sharp stiff awn or mucronate point. Palee two. Phleum. + Tall perennial meadow-grass. Awn bristle- like, almost as long as the nearly glabrous glume: spike long, cylindrical. P. pratense, L. tt Small, compact annual shore plant, with the glumes acute only and the keel ciliate above. Inflorescence not more than 1—1% inch long. . P. arenarium, L. The rare P. Behmeri, Schrad. has the glumes merely tapering to a sharp point ; and the rare P. alpinum, L. has a much shorter spike and glumes ciliate on the keels. The rare P. asperuwm, Jacq. has broad, shortly mucronate glumes and a longer and more slender spike. (2) Inflorescence a panicle—i.e. tufts or spreading stalked groups of spikelets are arranged on the main axis. A. Inflorescence compact and irregular; a spike of tufts (spike-like panicle). Glumes four, the inner pair awned: palee minute. Stamens two only. Anthoxanthum odoratum, L. vit] FLORAL CHARACTERS 103 The four glumes and two stamens distinguish this grass at once. Other grasses with occasionally tuft-like inflorescences—e.g. species of Agrostis, Gastridium, Atra, Dactylis, Cynosurus, Poa, Triodia, Keleria—are distinguished at once by having three stamens (Bromus occasionally has but two), only two glumes, several flowered spikelets, &c. B. Inflorescence a distinctly branched panicle, more or less loose and spreading. (a) Tall reed-lke perennials, growing in water or in marshes, with plume-like inflorescences, and silky hairs at the base of the palee. Glumes with a keel and point, but not awned. (i) Spikelets purplish: outer palea with a slender dorsal awn: basal hairs longer than the palee. Leaves narrow. Not common. Calamagrostis Epigeios, Roth. (ii) Spikelets greenish. No awns: basal hairs much shorter than the palee. Leaves broad. Common. Digraphis arundinacea, Trin. A variety of Digraphis with white stripes in the leaves is grown in gardens. Other aquatic reed-like grasses are Arundo and Glyceria aquatica : both have several flowers in the spikelet. The rare Calamagrostis lanceolata, Roth., C. stricta, Nutt. and C. strigosa, Hartm. also come here. (b) Slender grasses, not reed-like, with delicate loosely spreading panicles of small spikelets. (i) . . Fe ee ee Anbphh bn en ee ee wee 4 « toe Sete rete) é * ee ‘ e ¢ at 4 ad + it v2 « 4 ‘ 7 . z ‘ P.' «