A HANDBOOK OF SOME SOUTH INDIAN GRASSES

BY RAI BAHADUR K. RANGA ACHARIYAR, M.A., L.T., Indian Agricultural Service, Agricultural College, Coimbatore, and Fellow of the Madras University

ASSISTED BY C. TADULINGA MUDALIYAR, F.L.S., Agricultural College, Coimbatore.

MADRAS: PRINTED BY THE SUPERINTENDENT, GOVERNMENT PRESS. 1921

Price, 4 rupees 8 annas



PREFACE

This book is intended to serve as a guide to the study of grasses of the plains of South India. For the past few years I have been receiving grasses for identification, almost every week, from the officers of the Agricultural and Forest Departments and others interested in grasses. The requirements of these men and the absence of a suitable book induced me to write this book.

I have included in this book about one hundred grasses of wide distribution in the plains of South India. Many of them occur also in other parts of India. The rarer grasses of the plains and those growing on the hills are omitted, with a view to deal with them separately.

The value of grasses can be realized from the fact that man can supply all his needs from them alone, and their importance in agriculture is very great, as the welfare of the cattle is dependent upon grasses. Farmers, as a rule, take no interest in them, although profitable agriculture is impossible without grasses. Very few of them can give the names of at least half a dozen grasses growing on their land. They neglect grasses, because they are common and are found everywhere. They cannot discriminate between them. To a farmer "grass is grass" and that is all he cares to trouble himself about. About grasses Robinson writes "Grass is King. It rules and governs the world. It is the very foundation of all commerce: without it the earth would be a barren waste, and cotton, gold, and commerce all dead."

In the early days when the population was very much limited and when land not brought under cultivation was extensive plenty of green grasses was upon it and pastures were numerous. So the farmer paid no attention to the grasses, and it did not matter much. But now, population has increased, unoccupied land has decreased very much and the cattle have increased in number. Consequently he has to pay more attention to grasses.

On account of the scarcity of fodder, people interested in agriculture and cattle rearing have very often imported foreign grasses and fodder plants into this country, but so far no one has succeeded in establishing any one of them on any large scale. Usually a great amount of labour and much money is spent in these attempts. If the same amount of attention is bestowed on indigenous grasses, better results can be obtained with less labour and money. There are many indigenous grasses that will yield plenty of stuff, if they are given a chance to grow. The present deterioration of grasses is mainly due to overgrazing and trampling by men and cattle.

To prove the beneficial effects which result from preventing overgrazing and trampling, Mr. G. R. Hilson, Deputy Director of Agriculture (now Cotton Expert), selected some portion of the waste land in the neighbourhood of the Farm at Hagari and closed it for men and cattle. As a result of this measure, in two years, a number of grasses and other plants were found growing on the enclosed area very well, and all of them seeded well. Of course the unenclosed areas were bare as usual.

In the preparation of this book I received considerable help from M.R.Ry. C. Tadulinga Mudaliyar Avargal, F.L.S., Assistant Lecturing and Systematic Botanist, in the description of species and I am indebted to M.R.Ry. P.S. Jivanna Rao, M.A., Teaching Assistant, for assistance in proofreading.

I have to express my deep obligation to Mr. G. A. D. Stuart, I.C.S., Director of Agriculture, for encouragement to undertake this work and to the Madras Government for ordering its publication.

For the excellence in the get up of the book I am indebted to Mr. F. L. Gilbert, Superintendent, Government Press.

K. RANGACHARI.

AGRICULTURAL COLLEGE, LAWLEY ROAD, COIMBATORE, 2nd June 1921.



CONTENTS

PAGE PREFACE iii CHAPTER I—Introduction 1 II—The vegetative organs 5 III—The inflorescence and flower 13 IV—Histology of the vegetative organs 19 V—Classification 43 VI—Panicaceae 45 VII—Oryzeae and Zoysieae 123 VIII—Andropogoneae 138 IX—Agrostideae and Chlorideae 220 X—Festucaceae and Hordeae 283 GLOSSARY 311 INDEX 315



A HANDBOOK OF SOME COMMON SOUTH INDIAN GRASSES.



CHAPTER I.

INTRODUCTION.

Grasses occupy wide tracts of land and they are evenly distributed in all parts of the world. They occur in every soil, in all kinds of situations and under all climatic conditions. In certain places grasses form a leading feature of the flora. As grasses do not like shade, they are not usually abundant within the forests either as regards the number of individuals, or of species. But in open places they do very well and sometimes whole tracts become grass-lands. Then a very great portion of the actual vegetation would consist of grasses.

On account of their almost universal distribution and their great economic value grasses are of great importance to man. And yet very few people appreciate the worth of grasses. Although several families of plants supply the wants of man, the grass family exceeds all the others in the amount and the value of its products. The grasses growing in pasture land and the cereals grown all over the world are of more value to man and his domestic animals than all the other plants taken together.

To the popular mind grasses are only herbaceous plants with narrow leaves such as the hariali, ginger grass and the kolakattai grass. But in the grass family or Gramineae the cereals, sugarcane and bamboos are also included.

Grasses are rather interesting in that they are usually successful in occupying large tracts of land to the exclusion of other plants. If we take into consideration the number of individuals of any species of grass, they will be found to out-number those of any species of any other family. Even as regards the number of species this family ranks fifth, the first four places being occupied respectively by Compositae, Leguminosae, Orchideae and Rubiaceae.

As grasses form an exceedingly natural family it is very difficult for beginners to readily distinguish them from one another.

The leaves and branches of grasses are very much alike and the flowers are so small that they are liable to be passed by unnoticed. The recognition of even our common grasses is quite a task for a botanist.

To understand the general structure of grasses and to become familiar with them it is necessary to study closely some common grasses. We shall begin our study by selecting as a type one of the species of the genus Panicum.

Panicum javanicum is an annual herb with stems radiating in all directions from a centre. The plant is fixed to the soil by a tuft of fibrous roots all springing from the bases of the stems. In addition to this crown of fibrous roots, there may be roots at the nodes of some of the prostrate branches. The stems and branches are short at first, and leaves arise on them one after the other in rapid succession. After the appearance of a fair number of leaves the stem elongates gradually and it finally ends in an inflorescence.



The stem consists of nodes and internodes. The internodes are cylindrical and somewhat flattened on the side towards the axillary bud. When young they are completely covered by the leaves and the older ones have only their lower portions covered by the leaf-sheaths. Usually they complete their growth in length very soon, but the lower portion of the internode, just above the node and enclosed by the sheath, retains its power of growth for some time.

The leaf consists of the two parts, the leaf-sheath and the leaf-blade. At the junction of these two parts there is a very thin narrow membrane with fine hairs on its free margin. This is called the ligule. (See fig. 2.)

The leaf-sheath is attached at its base to the node and it is slightly swollen just above the place of insertion. It covers the internode, one margin being inside and the other outside. The surface of the sheath is sparsely covered with long hairs springing from small tubercles. The outer margin of the sheath bears fine hairs all along its length. (See fig. 2.)

The leaf-blade is broadly lanceolate, with a tip finely drawn out. Its base is rounded and the margin wavy, especially so towards the base. On the margin towards the base long hairs are seen, and some of these arise from small tubercles. The margin has a hyaline border which is very minutely serrate. There is a distinct midrib and, on holding the leaf against the light, four or five small veins come in to view. In the spaces between these veins lie many fine veins. All the veins run parallel from the base to the apex. At the base of the blade the veins get into the leaf-sheath and therefore the sheath becomes striated. Just above the ligule and at the base of the leaf-blade there is a colourless narrow zone. This is called the collar.



As already stated the inflorescences appear at the free ends of branches. Every branch sooner or later terminates in an inflorescence which is a compound raceme. There are usually five or six racemes in the inflorescence. Each raceme has an axis, called the rachis, which bears unilaterally two rows of bud-like bodies. These bud-like bodies are the units of the inflorescence and they are called spikelets. (See fig. 3.)



The spikelets are softly hairy and are shortly stalked. The pedicels of spikelets are hairy and sometimes one or two long hairs are also found on them. Each of these spikelets consists of four green membranous structures called glumes. The first two glumes are unequal, the first being very small. The second and the third glumes are broadly ovate-oblong with acute tips. Both are of the same height and texture, but the second is 7-nerved and the third 5-nerved. The fourth glume is membranous when young, but later on it becomes thick, coriaceous and rugose at the surface. Just opposite to the fourth glume there is a flat structure with two nerves, similar to the glume in texture. This is called the palea. The fourth glume and its palea adhere together by their margins. Inside the fourth glume and between it and the palea there are three stamens and an ovary with two styles ending in feathery stigmas. Just in front of the ovary and outside the stamens two very small scale-like bodies are found. These are the lodicules. They are fleshy and well developed in flowers that are about to open. In the spikelet there is only one full flower. The third glume contains no flower in it, but occasionally there may be in its axil three stamens. The first two glumes are always empty and so they are called empty glumes. (See fig. 4.) In mature spikelets the grain which is free is enclosed by the fourth glume and its palea.



CHAPTER II.

THE VEGETATIVE ORGANS.

Grasses vary very much in their habit. Some grasses grow erect forming tufts and others form cushions with the branches creeping along the ground. (See figs. 5 and 6.) We usually find all intermediate stages from the erect to the prostrate habit. Underground stems such as stolons and rhizomes occur in some grasses. Grasses of one particular species generally retain the same habit but this does not always hold good. For example Tragus racemosus grows with all its branches quite prostrate in a poor, dry, open soil. If, on the other hand, this happens to grow in rich soils, or amidst other plants or grasses, it assumes an erect, somewhat tufted habit. Andropogon contortus and Andropogon pertusus are other grasses with a tendency for variation in habit. Plants that are usually small often attain large dimensions under favourable conditions of growth. Ordinarily the grass Panicum javanicum grows only to 1 or 2 feet. (See fig. 1.) The same plant in a good rich soil grew to about 6 feet in four months. (See fig. 7.)



Some grasses are annual while others are perennial. It is often difficult to determine whether a certain grass is annual or perennial. But by examining the shoot-system this can be ascertained easily. In an annual all the stems and branches usually end in inflorescences and they will all be of the same year. If, on the other hand, both young leafy branches and old branches ending in inflorescences are found mixed, it must be a perennial grass. The presence of the remains of old leaves, underground stolons and rhizomes is also evidence showing the perennial character of the plant.

Grasses are eminently adapted to occupy completely large areas of land. They are also capable of very rapid extension over large areas, on account of the production of stolons, rhizomes and the formation of adventitious roots.

The root-system.—The root-system of grasses is very striking in its character. In most grasses, especially in erect ones, several roots all of about the same diameter arise in a dense tuft from nearly the same level and from the lower-most nodes of the stems. The roots are all thin and fibrous in the vast majority of these plants, and they are tough and wiry only in a few cases such as in the case of the roots of Pennisetum cenchroides, P. Alopecuros, Ischaemum pilosum and Andropogon Schoenanthus.

On a close examination it will become evident that all the roots of a grass plant are adventitious. Inasmuch as the growth of the primary root is soon overtaken by other roots growing from the stem, all the roots happen to be of the same size. Roots arise from the nodes just above the insertion of the leaf, and they grow piercing the leaf-sheath.



Grasses in which stolons and prostrate branches occur have, in addition to the usual radiating crown of roots at the base, aerial roots growing out of the upper nodes of the branches and fixing them to the soil. Such roots become supporting or prop roots and are particularly conspicuous in several stout tall grasses such as Andropogon Sorghum, Zea Mays and Pennisetum typhoideum. (See figs. 8 and 9.)

All the roots bear branch-roots which originate from the inner portion of the mother roots in the usual manner. The character and the extent of the development of the root-system is to a large extent dependent upon the nature of the soil and its moisture content. In light dry soils roots remain generally stunted and in well drained rich soils they attain their maximum development. In clayey soils roots penetrate only to short distances. When the soil is rich and sandy roots go deeper and extend in all directions. The root-systems of most grasses are superficial and so are best adapted for surface-feeding.



The shoot-system.—The shoot-system varies with the duration of the life of the plant. In annual grasses stems are in most cases erect and even if they are not entirely so they become erect at the time of flowering. They are attached to the soil by a tuft of fibrous roots arising from the base of the stems. But in perennials in addition to erect branches, creeping branches, stolons and rhizomes may occur.



The stem is either cylindrical or compressed and consists of nodes and internodes. In most grasses the internodes are usually hollow, the cavity being lined by the remains of the original pith cells. However, there are also grasses in which the stems remain solid throughout. In many grasses the basal portions of stems are more leafy and the internodes are short, but in the upper portions the internodes become longer separating the leaves one from the other.

In young shoots the leaves grow much faster than the internodes and consequently internodes remain small, and leaves become very conspicuous. The youngest portions of the shoots are by this means always well protected by the surrounding leaf-sheaths. As soon as leaves have grown fully, the internodes begin to elongate rapidly separating the leaves. At first growth in length takes place throughout its length in the internode and when it gets older this elongation ceases. But, however, the lower portion of the internode close to the node and which is enclosed by the leaf-sheath retains its power of growth for a considerable time.

Branches arise from the axils of leaves and when a considerable number of the axillary buds, especially from the lower nodes, develop into branches the plant becomes tufted in habit. In most grasses branches grow upwards through the sheath and emerge at its mouth as aerial branches. Such branches are called intravaginal branches or stems. But in some grasses axillary buds, instead of growing straight up through the sheath, pierce the leaf-sheath, come out and then they grow out as branches. This may be seen in the underground stolons of Panicum repens and in the ordinary aerial branches of Arundo Donax. Branches that pierce through the sheaths are called extravaginal branches. (See fig. 10.)



The nodes are in most cases very conspicuous and they are often found swollen. However, it must be remembered that the enlargement at the node is not due to the increase in size of the actual node, but due to growth in thickness of the base of the leaf-sheath. (See fig. 11-3.) Nodes may be pale or coloured, glabrous, hairy or bearded with long hairs. When the stem is erect the nodes are short and of uniform size all round. But, if the stem is bent down or tipped over by accident, the nodes begin to grow longer on the lower side until a curvature sufficient to bring the stem to the erect position is formed and then it ceases to grow.

As already noted some perennial grasses have creeping stems and stolons, while others may have rhizomes. The grass Cynodon dactylon develops several underground stolons which are covered with white scale leaves and whose terminal buds are hard and sharp so that they may be able to make their way through the soil. The rhizomes when continuous and elongated are usually sympodia formed by the lower portions of the aerial shoots. The aerial shoot comes into the air and its lower portion is continued by a branch arising from a lower leaf axil beneath the soil.

The leaf.—Leaves are two-ranked and alternate, and very often they become crowded at the lower portions of the shoots so as to form basal tufts, though they are farther apart in the upper portions of these shoots. Three distinct kinds of leaves are met with in grasses. First, we have the fully formed foliage leaves so characteristic of grasses. These are most conspicuous and are formed in large numbers.

The other two kinds of leaves are neither so conspicuous nor so numerous as the foliage leaves. At the base of shoots occur abortive leaves which are really rudimentary sheaths. These are called scales. The third kind of leaf is a modified structure called the prophyll or prophyllum. (See fig. 12.) It is the first leaf occurring in every branch on the side next to the main shoot and it is a two-keeled membranous structure resembling somewhat the palea found in the spikelets of grasses. The portion of the prophyll between the keels is concave due to the pressure of the main stem, while the sides beyond the keels bend forward clasping the stem.



The ordinary foliage leaves of grasses consist of the two parts, the flat expanded upper portion called the blade and the lower part called the sheath that encircles the stem above the node from which it arises. The leaf-sheaths usually fit close to the stem, but they may also be loose or even inflated. Though the leaf-sheath surrounds the internode like a tube, it is not a closed tube. It is really a flat structure rolled firmly round the stem with one edge overlapping the other. In most cases it is cylindrical and it may be compressed in a few cases. Occasionally it may have a prominent ridge or keel down its back. The sheath may be glabrous or hairy, smooth or striate externally, and the outer margin is often ciliate. In a few grasses the sheaths become coloured especially below or on the side exposed to the sun.



The ligule is a structure peculiar to grasses and it varies very much. In some grasses it is a distinct membrane narrow or broad, with an even, truncate or erose margin, or finely ciliate. Very often it is only a line or fringe of hairs, whilst in some it may be entirely absent as in the leaves of Panicum colonum. When it is a membrane it may be broad and oblong, ovate and obtuse, or lanceolate and acute. (See fig. 13.) The function of the ligule is probably to facilitate the shedding of water which may run down the leaf, and thus lessen the danger of rotting of the stem which is sure to follow, if the water were to find its way into the interior of the sheath. Sometimes, in addition to the ligule, other appendages may be present in grass leaves as in Oryza sativa. Such outgrowths are called auricles or auricular outgrowths. (See fig. 13.)

The leaf-blade is well developed in the foliage leaves and in most cases it follows directly on the sheath. But in bamboos and some species of Ischaemum there occurs a short petiole or stalk between the leaf-blade and the sheath. The sheath corresponds morphologically to the leaf base of a leaf of other flowering plants.



In grasses the leaf-blades usually grow more in length than in any other direction and there is no limit to the length they may attain. Some grasses have very short leaves, others very long ones. The leaf-blade in most grasses is more or less of some elongated form, such as linear, linear-lanceolate, lanceolate, etc. (See fig. 14.) In a few grasses the leaf-blade is ovate, but this is a rare condition. Therefore, in noting the general shape of the leaf-blade the relation of the length to the breadth, the amount of tapering towards the apex and base and the nature of the apex should be considered.

The veins in the leaf-blade can usually be seen on holding the leaf up to the light. All the veins run parallel. In most cases the midrib is prominent and in some cases there may be also a distinct keel. Amongst the veins running through the leaf-blade some are large and prominent, while others are small and not conspicuous. On account of this disparity, very often, ridges and furrows become prominent on the upper or lower, or on both the surfaces of the leaf-blades. Generally the two surfaces of the leaf-blade are distinct, and they may be glabrous or hairy. In most grasses the surfaces are rough or scabrid to the touch owing to the presence of regular rows of exceedingly fine sharp pointed minute hairs.

The apex of the blade is generally sharp and pointed, acute or acuminate, or sometimes it may be drawn to a very fine point by gradual tapering. Blunt or obtuse tips are not altogether absent, but it is not a common feature. The leaf-blades in Panicum colonum and in some species of Andropogon are rounded or obtuse at the apex.

The margins of the leaf-blade are somewhat hyaline and they may be perfectly even or cut into serrations of fine teeth in various ways. (See fig. 15.) In addition to these minute teeth, there may be long or short cilia. Sometimes the margins are glandular as in Eragrostis Willdenoviana and Eragrostis major.

The base of the leaf may be narrower, broader than, or about the same as the breadth of the leaf-sheath. It may be rounded, amplexicaul or narrowed. At the base and just above the ligular region there will always be a white distinct zone in the lamina of all grasses called the collar. This collar varies in length and breadth according to the species of grass.



In young shoots all the leaf-blades are usually found folded at the terminal portions. In most cases the leaf-blade is rolled up inwards from one end to the other so that one margin is inside and the other outside. This folding is termed convolute. This is the kind of folding that is found in most grasses. However, there are some grasses such as Eleusine aegyptiaca and Chloris barbata, in which the folding is different. In these grasses the laminas are folded flat on their midribs so that each half of the blade is folded flat on the other, the inner surfaces being in contact. The leaves are said to be conduplicate in this case. When the leaves are conduplicate the shoots are more or less compressed. (See fig. 16.)



CHAPTER III.

THE INFLORESCENCE AND FLOWER.

The flowers of grasses are reduced to their essential organs, the stamens and the pistil. The flowers are aggregated together on distinct shoots constituting the inflorescence of grasses. Sooner or later all the branches of a grass-plant terminate in inflorescences which usually stand far above the foliage leaves. As in other flowering plants, in grasses also different forms of inflorescence are met with. But in grasses the unit of the inflorescence is the spikelet and not the flower.

The forms of inflorescence usually met with are the spike, raceme and panicle. When the spikelets are sessile or borne directly along an elongated axis as in Enteropogon melicoides the inflorescence is a spike. If the spikelets borne by the axis are all stalked, however short the pedicels may be, it is a raceme. It must, however, be remembered that true spikes are very rare. An inflorescence may appear to be a spike, but on a close examination it will be seen to consist of spikelets more or less pedicelled. Such an inflorescence, strictly speaking, is a spiciform raceme. The branches of the inflorescence in Paspalum scrobiculatum or Panicum javanicum are racemes and the whole inflorescence is a compound raceme. The inflorescence is a panicle when the spikelets are borne on secondary, tertiary or further subdivided branches. Panicles differ very much in appearance according to the relative length and stoutness of the branches. In Eragrostis tremula the panicle is very diffuse, in Eragrostis Willdenoviana less so. The panicle in Sporobolus coromandelianus is pyramidal and the branches are all verticillate, the lower being longer than the upper. The branches of a panicle are usually loose, spreading or drooping in most grasses. But in some species of grasses such as Pennisetum Alopecuros and Setaria glauca, the paniculate inflorescences become so contracted that the pedicels and the short branches are hidden and the inflorescence appears to be a spike. Such inflorescences as these are called spiciform panicles. The inflorescences in several species of Andropogon consist of racemes so much modified as to appear exactly like a spike. What looks like a spike in these cases consists of a jointed axis and each joint bears a pair of spikelets, one sessile and the other pedicelled.

The name rachis is given to the axis of the spike, raceme and panicle, whether the axis is the main one or of the branch. The rachis of the inflorescence is usually cylindrical. In some grasses it is zigzag as in Pennisetum cenchroides. It is very much flattened in Paspalum scrobiculatum, but somewhat trigonous in Digitaria sanguinalis. In very many grasses the rachis is continuous, but in a few cases it consists of internodes or joints which disarticulate at maturity. Many species of Andropogon have such jointed rachises. Sometimes the joints become greatly thickened and the surface hollowed out, the spikelets fitting in the cavities as in Rottboellia and Manisuris.

In panicles, especially when they are diffuse, the primary branches may be disposed irregularly or in verticils on the main axis. For example in the panicle of Eragrostis Willdenoviana, the branches are irregularly disposed, whereas in Sporobolus coromandelianus the branches are verticillate. In both these grasses fleshy cushions are developed in the axils of the branches. These swellings help to spread out the branches especially at the time of anthesis. The branches at the top spread out earlier than those below.

Sometimes at the base of the rachises, main or secondary, glandular streaks are seen as in the rachises of Sporobolus coromandelianus. These glands secrete a viscid juice at the time of anthesis.



The spikelet may be considered as a specialised branch consisting of a short axis, the rachilla bearing a series of modified bracts, the glumes, the lower pair being empty but the others bearing flowers in their axils. The glumes are two-ranked and imbricating. As a type for the spikelet that of an Eragrostis or Dinebra may be chosen. (See fig. 17.) In this spikelet the rachilla bears a number of glumes alternating and imbricating. The first two glumes at the base of the spikelet do not bear any flowers and so these two glumes are usually called empty glumes. This is the case in almost all the species of grasses. The third and the subsequent glumes are regularly arranged on the slender rachilla alternately in two rows. In the axils of each of these glumes there is a flower, except perhaps in the topmost glume. The flower is usually enclosed by the glume and another structure found opposite the glume and differing very much from the glume. This is the palea. It is attached to the axis of the flower and its back is towards the rachilla. Generally there are two nerves in a palea and its margins are enclosed within those of the glume. The palea is homologous with the prophyllum which it very much resembles. The prophyllum is usually found in the branches of grasses, but it is not confined to grasses alone. It occurs in the branches of some species of Commelina.

The spikelets vary very much in their structure. The spikelets in grasses of several genera consist of only four glumes. As usual the first two glumes are empty and the remaining two are flower-bearing glumes. Both these glumes may have perfect flowers as in Isachne or the terminal one may contain a perfect flower, the lower having either a staminate flower or only a palea. Very often the spikelets are unisexual and the male and female spikelets may be on the same plant as in Coix Lachryma-Jobi and Polytoca barbata, or they may be on different plants as in Spinifex squarrosus.

The glumes of a spikelet are really modified bracts and some differentiate the flowering glumes from the empty ones, by giving them different names. The first two empty glumes are called glumes by all agrostologists. Some in Europe call the flowering glume lower palea to distinguish it from the real palea which they call the upper palea. Some American Authors have recently adopted for the flowering glume the term lemma introduced by Piper.

Considerable variation is met with in the case of the empty glumes. Generally they are unequal, the first being smaller. Very often the first glume becomes very small and it may be altogether absent. In some species of Panicum the first glume is very small, in Digitaria it is very minute and in Paspalum and Eriochloa it is entirely suppressed. The flowering glumes are generally uniform when there are many. In the spikelet having only four glumes the fourth glume differs from the others mainly in texture. Instead of being thin and herbaceous it becomes rigid and hard, smooth or rugose externally as in Panicum. Flowering glumes instead of being like empty glumes, become very thin, shorter and hyaline in Andropogon. Sometimes the flowering glumes are awned. All of them may be awned as in Chloris or only the fourth glume as in Andropogon.

The palea is fairly uniform in its structure in many grasses, but it is also subject to variation. It becomes shorter in some and is absent in others. Instead of having two nerves, it may have one and rarely more than two. The palea can easily be distinguished from the glume, because its insertion in the spikelet is different from that of the glume.



The lodicules are small organs and they are the vestiges of the perianth. In most grasses there are only two, but in Ochlandra and other bamboos we meet with three lodicules. There are also some species with many lodicules. In shape they are mostly of some form referable to the cuneate form. They are of somewhat elongated form in Aristida and Chloris. The function of the lodicules seems to be to separate the glume and its palea so as to enable the stamens to come out and hang freely at the time of anthesis. So it is only at the time of the opening of the flowers that the lodicules are at their best. Then they are fairly large, fleshy and thick and conspicuous. In the bud stage they are usually small and after the opening of the flower they shrivel up and are inconspicuous. There are also species of grasses in which the lodicules are not found.

The stamens are three in number in the majority of grasses and six are met with in Leersia, Hygrorhiza and Bamboos. Each stamen consists of a very delicate long filament and an anther basifixed to the filament. But as the anthers are long and the connective is reduced to its minimum, they appear as if versatile when the stamens are out. When there are three stamens one stands in front of the flowering glumes and the other two in front of the palea, one opposite each edge of the palea. The relative positions of the parts of the floret are shown in the floral diagrams. (See figs. 18 and 19.)



The pistil consists of an ovary and two styles ending in plumose stigmas. The ovary is 1-celled and 1-ovuled. It is one carpelled according to the views of Hackel and his followers and there are also some who consider it as 3-carpelled because of the occurrence of three styles in the pistil of some bamboos.

The rachilla is usually well developed and elongated in many-flowered spikelets, while in 1-flowered spikelets it remains very small so that the flower appears to be terminal. It often extends beyond the insertion of the terminal flower and its glume, and then lies hidden appressed to the palea. This may be seen in the spikelets of the species of Cynodon. This prolonged rachilla sometimes bears a minute glume, which is of course rudimentary. Usually the glumes are rather close together on the rachilla so that the internodes are very short; but in some grasses, as in Dinebra arabica, the glumes are rather distant and so the internodes are somewhat longer and conspicuous. In some species of Panicum the rachilla is jointed to the pedicel below the empty glumes, whereas it is articulated just above these glumes in Chloris barbata. Sometimes the rachilla is articulated between the flowers. This is the case in the spikelet of Dinebra arabica.

Pollination in most grasses is brought about by wind, though in a few cases self-pollination occurs. The terminal position of the inflorescence, its protrusion far above the level of the foliage leaves, the swinging and dangling anthers, the abundance of non-sticking pollen and the plumose stigmas are all intended to facilitate pollination by wind. Furthermore the stamens and the stigmas do not mature at the same time. In some grasses the stamens mature earlier, (protandry) while in others the stigmas protrude long before the stamens (protogyny). As the result of the pollination the ovary developes into a dry 1-seeded indehiscent fruit. The seed fills the cavity fully and the pericarp fuses with the seed-coat and so they are inseparable. Such a fruit is termed a caryopsis or grain. Though in the vast majority of grasses the pericarp is inseparable, in a few cases it is free from the seed-coat as in Sporobolus indicus and Eleusine indica.



The caryopsis consists of an embryo on one side at the base and the endosperm occupies the remaining portion. The embryo can be made out on the side of the grain facing the glume, as it is outlined as an oval area. On the other face of the grain which is towards the palea, the hilum is seen at the base. The grain varies in shape considerably. It may be rounded, oval, ellipsoidal, narrow and cylindrical, oblong terete or furrowed. There is considerable variation as regards the colour also.

The embryo consists of an axis and a scutellum. The axis, which is differentiated into the plumule directed upward and the radicle downward, is small and straight and it is covered more or less by the edges of the scutellum. The scutellum is attached to the axis at about its middle and its outer surface is in contact with the endosperm. This is an important organ as its function is to absorb nourishment from the endosperm during germination. The scutellum is considered to represent the first leaf or cotyledon. The endosperm consists mostly of starch. Just outside the endosperm and within the epidermis lies a layer of cells containing much proteid substance. This layer is called the aleurone layer. (See fig. 21.) As an illustration of the caryopsis, the grain of Andropogon Sorghum may be studied. All the structural details are shown in fig. 20 which is a longitudinal section of the grain.

The primary axis of the embryo is enclosed by a closed sheath both above and below. The sheath which envelopes the radicle is called coleorhiza and that of the plumule, pileole or germ-sheath.



CHAPTER IV.

HISTOLOGY OF THE VEGETATIVE ORGANS.

The shoots and roots of grasses conform in their internal structure to the monocotyledonous type. In all grasses numerous threads are found running longitudinally within the stem and some of these pass into the leaves, at the nodes, and run as nerves in the blades of the leaves. These threads are the vascular bundles. The rest of the tissue of the stem and leaves consists of thin-walled parenchymatous cells of different sorts.

The general structure of these bundles is more or less the same in all grasses. A vascular bundle consists of only xylem and phloem, without the cambium, and so no secondary thickening can take place in the stems of grasses. Such bundles as these are called closed vascular bundles to distinguish them from the dicotyledonous type of vascular bundles which are called open vascular bundles on account of the existence of the cambium.



The component parts and elements of which the vascular bundles in grasses are composed may be learnt by studying the transverse and longitudinal sections of these bundles in any grass. The cross and longitudinal sections of a vascular bundle of the stem of Pennisetum cenchroides, are shown in figs. 22 and 23. In the figure of the transverse section the two large cavities indicated by the number 3 and the two small circular cavities with thick walls lying between the larger ones and indicated by the numbers 1 and 2 are the chief elements of the xylem.

By looking at the longitudinal section it is obvious that these elements are really vessels, the larger being pitted and the smaller annular and spiral vessels. These vessels together with the numerous small thick-walled cells lying between the pitted vessels constitute the xylem. Just above the xylem there is a group of large and small thin-walled cells. This is the phloem and it consists of sieve tubes and thin-walled cells. All round the xylem and the phloem there are many thick-walled cells. These are really fibres forming the bundle-sheath. On account of this bundle-sheath the bundles are called fibro-vascular bundles.



Structure of the stem.—The stem of a grass consists of a mass of parenchymatous cells with a number of fibro-vascular bundles imbedded in it, and it is covered externally by a protective layer of cells, the epidermis. The stem is usually solid in all grasses in the young stage, but as it matures the internodes become hollow in many grasses and they remain solid in a few. In the internodes the fibro-vascular bundles run longitudinally and are parallel, but in the nodes they run in all directions and form a net work from which emerge a few bundles to enter the leaves. So far as the broad general features are concerned, the stems of many grasses are more or less similar in structure. However, when we take into consideration the arrangement of bundles, the development and arrangement of sclerenchyma, every species of grass has its own special characteristics. And these are so striking and constant that it may be possible to identify the species from these characters alone.

We may take as a type the stem of Rottboellia exaltata. This stem is somewhat semi-circular in transverse section and it is almost straight and flat in the front (the side towards the axillary bud). The peripheral portion of the stem becomes somewhat rigid and thick due to the aggregation of vascular bundles, some small and others large. The outermost series of bundles consisting of small and larger bundles are in contact with the layers of the cells lying just beneath the epidermis and these cells are also thick-walled. A few are away from these being separated by three or four layers of cells from the peripheral bundles. In all these vascular bundles the bundle-sheath is very strongly developed all round and is very much developed especially at the sides. It is this great development of sclerenchyma that makes the outer portion of the cortex hard. Within the ground tissue are found a number of vascular bundles scattered more or less uniformly. These bundles have no continuous bundle-sheaths but have instead groups of fibres at the sides and in front of the phloem. The cavities near the annular vessels are somewhat larger and conspicuous in these bundles.



The epidermal cells are all thickened very much and the outer layer is cutinized and impregnated with silica. This is the case in the epidermis of the stems and leaves of most grasses. (See fig. 24.)

In order to give a general idea of the variations in the structure of the stem in grasses a few examples are chosen and the details of the structure of the stems of these grasses are dealt with here.



The stem of Pennisetum cenchroides is somewhat round in outline in the transverse section with a slight curvature in the front. The vascular bundles are rather numerous and irregularly scattered all over the ground tissue. The peripheral bundles are not so close to the periphery of the stem as in Rottboellia exaltata. These are separated from the epidermis by several layers of parenchymatous cells. Further, these peripheral bundles are all imbedded in a continuous sclerenchymatous band which runs round the stem in the form of a ring. The epidermal cells as well as the layer of cells in immediate contact with it are thick-walled. In the vascular bundles of the ground tissue the bundle-sheath is rather prominent and the phloem portion is well developed. (See figs. 25 and 26.)



In the stem of Eriochloa polystachya, all the vascular bundles are more or less peripheral in position leaving a wide area of parenchymatous cells in the centre. The outline of the stem in cross section is rotund or ovate-rotund with the front side somewhat flattened and straight. The epidermal cells alone are thickened. A well developed continuous ring of sclerenchyma is present and this is connected with the epidermal layer at short intervals by means of short sclerenchymatous bands. So the parenchymatous cells of the cortex lying outside the sclerenchymatous ring are divided into small isolated areas. There are three series of vascular bundles.



One series consists of small bundles lying inside the sclerenchyma ring at the base of each of the connecting bands. The second series is made up of large vascular bundles imbedded in the ring so as to bulge out inside the ring. The vascular bundles of the third series are found just away from the ring and separated from it by a few layers of parenchymatous cells. (See figs. 27 and 28.)



Another stem in which the vascular bundles are more or less peripheral in position and enclosing a wide parenchyma is that of Setaria glauca. In the transverse section of the stem the outline is ovate, laterally compressed, obtusely keeled at the back and somewhat concave in the front. The sclerenchymatous band is narrow and continuous and very close to the epidermis, being separated from it only by two or three layers of thin-walled cells. The epidermal cells alone are thickened. As to the vascular bundles there are three sets. One set of bundles lying just outside the sclerenchymatous ring consists of small ones connecting the ring with the epidermis. Just inside the sclerenchymatous ring lies a series of bundles which are connected with it. Still inside, at some distance from the sclerenchymatous band, are seen vascular bundles forming a row and enclosing a large space of the ground tissue consisting of only parenchyma. (See figs. 29 and 30.)



The stem of Panicum ramosum is semi-circular and somewhat flat on one side. The epidermal cells alone are thickened. There is a broad well developed continuous band of sclerenchyma, which is connected at regular intervals with the epidermis by small vascular bundles. Another row of vascular bundles lies just inside the sclerenchymatous ring and each of these bundles is in contact with the band. Away from the ring lie a number of bundles forming a series disposed in two irregular rings around a broad portion of the ground tissue. (See figs. 31 and 32.)



The stem of the grass Andropogon caricosus is oval in outline, the front being flat. The epidermal cells and those below and in contact with them are thick-walled. The sclerenchymatous ring though present is very narrow and not very conspicuous. It consists of one or two layers of cells connecting a few vascular bundles forming the outermost set. There is a series of vascular bundles inside the ring which surrounds a large area of the ground tissue. Two isolated bundles, one in front and another at the back of the ground tissue, are found. The cells of the ground tissue lying just inside the vascular bundles are all very much thickened. (See figs. 33 and 34.)



The stems of Panicum Isachne and Eragrostis interrupta are hollow. The stem of the former is circular in outline in cross section, though wavy. There is a sclerenchymatous ring close to the epidermis but separated from it by a few layers of parenchyma. One set of bundles is imbedded in the band, and another set just touches the inner border of it. A third series is disposed around a fairly large amount of ground tissue, which may or may not have a cavity in the centre. The stem of Eragrostis interrupta has more or less the same structure, but the cortex has air spaces here and there. Other minor differences may be seen on referring to figs. 35 and 36.



The stems of grasses growing in wet or marshy situations differ in structure from those detailed above. As examples the stems of Panicum flavidum, Panicum colonum, Panicum Crus-galli and Panicum fluitans may be considered. The stem of Panicum flavidum is broadly ovate in cross section with a flat front and is more or less solid, though occasionally the parenchymatous cells in the centre get broken. Two rows of vascular bundles surround a fairly large amount of parenchymatous cells of the ground tissue. There is a continuous ring of sclerenchyma separated from the epidermis by a fairly broad cortex. The cortex has a number of fairly large air-cavities separated by bands of parenchymatous cells. Within the sclerenchymatous band lie small vascular bundles at regular intervals just towards the cortex. A few isolated bundles are in contact with the inner border. (See figs. 37 and 38.)

The stems of Panicum colonum, Panicum stagninum and Panicum Crus-galli have in their centre in the ground tissue stellate cells with air-cavities. This part is surrounded by a fairly broad portion of parenchymatous cells in which are imbedded two rows of bundles. Outside these bundles runs round the stem a narrow sclerenchymatous band with a few bundles in it of which some touch it inside and others outside. Two bundles are found by themselves in the tissue of stellate cells. In Panicum Crus-galli three or four bundles are met with amidst the stellate cells.



The cortex outside the band of sclerenchyma is full of air-cavities, small and large. In Panicum colonum the outline of the stem is ellipsoidal with the front quite flat, and the cortex is narrow at the sides and very broad in front and at the back. The sclerenchymatous ring is circular in outline. The stem of Panicum Crus-galli is broadly ovoid and the cortex is uniformly broad. The epidermal cells as well as the lower cells are thickened in the stems of Panicum fluitans and Panicum Crus-galli, but in the stems of Panicum colonum and Panicum flavidum the epidermis alone is thickened. In the cortical portion outside the sclerenchymatous band, small vascular bundles occur in the stems of Panicum colonum, Panicum Crus-galli and Panicum fluitans. (See figs. 39, 40, 42 and 43.)



The stem of Panicum fluitans is round in outline in the transverse section and has a large cavity. Just close to the cavity and separated from it by only one or two parenchymatous cells are found vascular bundles forming a series. Outside this series of bundles lies a sclerenchymatous band which is wavy, following the lower edges of the large air-cavities. One series of bundles is connected with this sclerenchymatous ring. The air-cavities are large and uniform and are separated by bands of parenchymatous cells. In each of these bands lies a vascular bundle on the upper side near the periphery. Sometimes we find, especially in young stages, diaphragms of stellulate cells stretched across the air-cavities. Later as the stem matures these disappear and the cavities become conspicuous. (See figs. 42 and 43.)

Structure of the root.—As already stated, the roots of grasses conform to the monocotyledonous type, but the variations met with in their structure are not so great as in the case of the stem. The root-tips are protected by root-caps, and the actual tip of the root is very distinct in the roots of all grasses and it can be seen very clearly in a longitudinal section of the root. The actual tip of the root is sharply distinct from the root-cap as there are two distinct sets of cells, one giving rise to the root-tip and the other to the root-cap.

The young root-tips are always free from root-hairs, and they are confined to the portions behind the root-tips. The extent of the root-hair region will vary according to the vigour and development of the roots and the nature of the soil. The root-hairs are mere protrusions of the cells of the outermost layer of the cortex of the root and this layer is called the piliferous layer.



To learn the structure of the roots of grasses we may select as types the roots of Pennisetum cenchroides and Andropogon Sorghum and consider their structural details. In the transverse sections of these roots we find a fairly broad cortex consisting of thin-walled parenchymatous cells more or less regularly arranged. (See figs. 44 and 45.) Just below the piliferous layer two or three layers of thick-walled cells are seen. In the roots of Andropogon Sorghum these thick-walled cells are very conspicuous as they consist of several layers. These layers of thick-walled cells constitute the exodermis. (See fig. 46.) The innermost layer of cells of the cortex is called the endodermis and it becomes conspicuous on account of the thickening in the lateral and inner walls of the cells of this layer. (See figs. 44 and 47.)



The rest of the root forming the central core is the stele and at its periphery there is a single layer of cells called the pericycle. The arrangement of the xylem and the phloem is different from that of the stem. They lie side by side on different radii, and not one behind the other on the same radius as in the stem. The number of xylem groups is fairly large and the development of the xylem is from the pericycle towards the centre of the stele. (See figs. 44 and 45.) The parenchymatous cells in the centre of the stele become thick-walled in older roots.

Structure of the leaf.—The structure of the leaf of grasses is quite characteristic of the family. In every leaf a number of vascular bundles, some small and others large, pass from the base to the apex. Externally the leaf is covered on both the sides by the epidermis. The spaces existing between the vascular bundles and the epidermis are filled with parenchymatous cells. The larger vascular bundles consist of xylem and phloem surrounded by a bundle sheath of a single layer of cells. In the smaller bundles the xylem is very much reduced. Around every vascular bundle there is a single row of somewhat large cells densely packed with large chloroplasts, the chlorophyllous layer. The vascular bundles are strengthened by fibres, on both the sides in the case of larger bundles and on only one side in small bundles.



For a detailed study of the structure of the leaves of grasses the leaf of the grass Panicum javanicum may be chosen. In a transverse section of this leaf, the vascular bundles are very conspicuous. The larger bundles are normal in every way, while in the smaller ones the xylem elements are considerably reduced. Around every one of the vascular bundles there is a single row of large cells containing large chlorophyll grains (the chlorophyllous layer). In a well developed large vascular bundle the chlorophyllous layer is open below just close to the sclerenchymatous band. On both sides of the larger vascular bundle there are bands of sclerenchyma. In the case of smaller bundles some are strengthened by sclerenchyma on the lower side and others have none. The spaces between the bundles are occupied by thin-walled parenchymatous cells containing small chlorophyll grains.



The lower epidermis of the leaf in the transverse section is even and consists of small and large round cells. The upper epidermis is slightly wavy and it is made up of some small round cells alternating with groups of larger cells. The epidermal cells lying over sclerenchyma and the smaller vascular bundles are small and round, while those lying over the furrows between the vascular bundles are large and are called motor or bulliform cells. The presence of motor cells is a characteristic feature of the leaves of many grasses.

The continuity of both the upper and the lower epidermis is interrupted by the stomata. Air-cavities are seen below these stomata. The arrangement of the stomata, the shape of the guard cells and the characteristics of the epidermal cells become clear on examining a piece of epidermis. (See figs. 49 and 50.)

The structure of the leaf of Panicum javanicum may be taken as typical of the structure of the leaves of most grasses. The leaves of Eriochloa polystachya, Cynodon and Paspalums are very much like the leaves of Panicum javanicum in their internal structure.

Considerable amount of variation, however, occurs in the leaves of grasses especially as regards the arrangement of fibres and motor cells.



Every large primary vascular bundle in the leaves of many grasses possesses sclerenchymatous bands both above and below. The other vascular bundles may have bands of sclerenchyma on both sides or on one side only or none. For example, in the leaves of Panicum repens both the primary and secondary bundles are provided with sclerenchyma on both the sides, while those of the third order may have it on one side or not. The hyaline margin of this leaf and of the leaves of other grasses consists entirely of sclerenchyma. (See fig. 53.)



All the vascular bundles in the leaves of Aristida setacea have broad sclerenchymatous bands on both the sides. Besides these bands arranged like a girder above and below each bundle, there are on the lower side bands of sclerenchyma. So the sclerenchyma becomes almost continuous on the lower side.



The sclerenchyma lying on the lower side of the primary bundles are contiguous with the bundle, while those above are separated from the bundle by the chlorophyllous layer. (See fig. 55.) In the case of secondary and tertiary bundles the sclerenchymatous bands lying on the lower side are in contact with the chlorophyllous layer, whereas the upper bands are either in contact with this layer or separated from it by a few parenchymatous cells.

All the vascular bundles in the leaves of Eragrostis Willdenoviana are provided with sclerenchyma on both the sides. The lower band of the primary vascular bundles is continuous with the vascular bundle, the chlorophyllous layer being open below. The upper bands of the primary and the lower bands of the secondary vascular bundles just touch the chlorophyllous layer. In the secondary bundles the sclerenchyma band above is separated from the chlorophyllous layer by two layers of parenchyma. In the case of the leaves of Panicum flavidum, P. colonum, P. fluitans and Pennisetum cenchroides the sclerenchyma is separated from the chlorophyllous layer by layers of parenchyma.



Even from the few examples dealt with above, it is obvious that the range of variation of sclerenchyma in leaves is very great. In the leaves of Aristida setacea there is a considerable amount of sclerenchyma whilst in some leaves such as those of Panicum colonum, P. flavidum and Panicum fluitans the sclerenchyma is reduced to its minimum.



In the leaves of grasses growing in dry situations the development of sclerenchyma is generally very considerable. The grass Aristida setacea is a good example of a xerophytic grass. The sea-shore grass Spinifex squarrosus is another example of the same kind. But in the leaves of this grass, the development of sclerenchyma is not very considerable, but there is a great development of parenchymatous cells free from chlorophyll within the leaf, the chlorophyll bearing cells being confined to the upper and the lower surfaces of the leaves.



The upper and the lower surfaces of the leaves of many grasses are more or less even, but in the case of a few grasses the upper surface consists of ridges and furrows, instead of being even. In the leaves of Panicum repens and Eragrostis Willdenoviana the upper surface is wavy and consists of shallow furrows and slightly raised ridges. But in the leaves of Aristida setacea and Panicum fluitans the furrows are deeper and the ridges are more prominent. In Aristida setacea the ridges are flat-topped and they are rounded with broad furrows in Panicum fluitans.



The epidermis covering the leaves consists of elongated cells with plane or sinuous walls, various kinds of short cells intercalated between the ends of long cells, motor-cells and stomata. Hairs of different sorts occur as outgrowths of the epidermis. The roughness of the surface of the leaves of grasses is due to the presence of very minute short hairs borne by the epidermis. In most cases these short hairs are found in regular rows. Although the epidermis is more or less even in the leaves of several grasses such as Panicum repens, P. flavidum and Eriochloa polystachya, it is wavy or undulating in the leaves of a few grasses. For example, the upper epidermis in the leaves of Panicum fluitans is undulating as it follows the contour of the ridges and furrows.

The epidermal cells have even surfaces in the leaves of most grasses but in some they bulge out. In the leaves of Panicum flavidum the cells of the lower epidermis are quite even, whilst those of the upper epidermis bulge out. The cells of both the upper and the lower epidermis are distinctly bulging out in the leaves of Panicum colonum. In Panicum fluitans the cells of the upper epidermis bulge out so much as to form distinct papillae.

The free surface of the epidermis is more or less cutinised in the leaves of all grasses. In some leaves the cuticle is very thick and even papillate as in the leaves of Aristida setacea and Panicum repens whilst in others it is very thin, as in the leaves of Panicum colonum and P. fluitans. Cutinisation is rather prominent in the leaves of grasses growing under dry conditions and it is less pronounced in mesophytic grasses.



As regards size, the epidermal cells overlying the sclerenchyma are small and those lying over parenchyma are larger. Amongst the larger cells some may be motor-cells. The stomata occur in regular rows between the vascular bundles and they are quite characteristic of grasses. They are more or less similar in structure in all grasses. In the leaves of many grasses stomata are found in both the upper and the lower epidermis and they are confined to the lower epidermis in a few grasses only.

The motor-cells vary very much both as regards their shape and position. In some leaves as in the leaves of the grass Panicum flavidum the motor-cells are confined to the midrib on the upper surface.

The epidermal cells of this leaf are large and uniformly round. (See figs. 66 and 67.)



In the case of most grasses the motor-cells are found in groups of three, four or five between the vascular bundles. The central motor-cell is usually the largest and it is somewhat obovate in shape in a transverse section of the leaf. In the leaves of Panicum javanicum and Eriochloa polystachya there are three or four motor cells in the group and the group consists of four, five or rarely six motor cells in the leaves of Eragrostis Willdenoviana. When there are distinct furrows between ridges these cells lie in the furrows and they are many in number. In the leaves of Panicum repens there are five to seven motor-cells in the furrows and the single row of cells stretched between the motor-cells and the lower epidermis in the furrow consists of more or less clear cells with sparsely scattered small chlorophyll grains. (See fig. 52.) The motor-cells occupying the furrows in the leaves of Aristida setacea are more in number than in Panicum repens and are of a different shape. All the cells lying in the furrow between the motor-cells and the sclerenchyma are clear cells free from chlorophyll grains.

Although the motor-cells differ in shape from the ordinary epidermal cells in most grasses, there are, however, a few grasses in which the motor-cells do not differ very much from the epidermal cells except in size. For example, in the leaves of Panicum colonum the motor-cells are just like the ordinary epidermal cells in shape but are larger. (See fig. 64.)

Motor-cells are usually confined to the upper epidermis, but they may also be found in the lower epidermis. In the leaves of Pennisetum cenchroides motor-cells are found in both the upper and the lower epidermis, the group in the upper epidermis alternating with that in the lower.



CHAPTER V.

CLASSIFICATION.

The family Gramineae is usually divided into two series taking into consideration the presence or absence of a joint in the pedicel or rachis, the number of flowers in the spikelet and the position of the fertile flower. All the species in which there is a joint just below the spikelet, in the pedicel, in the rachis, or at the base of a cluster of spikelets come under one series Panicaceae. The spikelets of the grasses coming under this series, when mature, fall away singly by themselves, or with their pedicels, or in groups with portions of the rachis. The spikelets are all similar and consist of usually four glumes. Each spikelet contains a single perfect flower and sometimes in addition a staminate flower just below the perfect flower. In this series the tendency for imperfection is always confined to the lower flowers, the terminal flower alone being perfect. For inclusion under this series the grass plant should have both the characters, articulation and position of the flower as mentioned above.

The second series Poaceae includes those grasses in which the spikelets are one to many-flowered and continuous with their pedicels. But the rachilla of the spikelet may be jointed just above the empty glumes or between the flowering glumes. The complete flower is the lowest and the tendency for imperfection is in the upper flowers.

Of the two series the Panicaceae appears to be more highly developed than the Poaceae.

KEY TO TRIBES.

Series I.—Panicaceae.

A. Rachis of inflorescence not jointed.

Spikelets 2-flowered; upper flower bisexual and lower male or neuter; the first glume the smallest I. Paniceae.

Spikelets 1-flowered;

Spikelets articulate on their pedicels and falling away from them; flowers bisexual and usually with six stamens II. Oryzeae.

Spikelets falling away with their pedicels; flowers bisexual or rarely imperfect III. Zoysieae.

B. Rachis of inflorescence usually jointed.

Spikelets usually binate (3-nate at the top), pairs of spikelets alike or dissimilar; empty glumes larger and the flowering glumes smaller, hyaline, the fourth glume awned or reduced to an awn IV. Andropogoneae.

Series II.—Poaceae.

A. Rachilla produced or not beyond the flowering glume.

Spikelets 1-flowered, with three glumes; first and second empty, third flowering and awned; rachilla jointed V. Agrostideae.

Spikelets 1- or more-flowered, biseriate and secund on an inarticulate spike or on the spiciform branches of a slender panicle; flowers all or the lower only bisexual VI. Chlorideae.

B. Rachilla produced beyond the uppermost flowering glume and articulate.

Spikelets 2- or more-flowered, pedicelled, rarely sessile, in effuse, contracted or rarely spiciform panicles VII. Festucaceae.

Spikelets 1- or more-flowered, sessile, 1- to 2- or more-seriate on the rachis of a simple spike, or partially sunk in cavities of the same. Glumes awned or not, first and second glumes are opposite or subcollateral, persistent or separately deciduous; first glume minute or absent VIII. Hordeae.



CHAPTER VI.

Series I—Panicaceae.

TRIBE I—PANICEAE.

This is a fairly large and important tribe flourishing mostly in the warm regions and the tropics. It is very well represented in South India and fifteen genera are met with.

The inflorescence varies very much within this tribe and consists of spikes, racemes and panicles. The spikelets are usually four-glumed and contain one terminal perfect flower and a staminate or neutral flower below. But in the genus Isachne both the flowers are perfect. In some grasses the spikelets contain only staminate or pistillate flowers. In Coix and Polytoca the plant bears both male and female spikelets in the same inflorescence, but in Zea on the same plant they occur as distinct inflorescences. The littoral grass Spinifex is dioecious.

The first glume of the spikelet is the smallest. In Panicum it is nearly two-thirds or less than the third glume. It is very small in Digitaria and entirely suppressed in Paspalum. In Eriochloa it is reduced to a minute ridge lying just close to the swollen ring-like joint of the rachilla. The second and the third glumes are more or less equal and similar in texture. The fourth glume becomes firm and rigid along with its palea and usually encloses the grain.

The pedicel is jointed in some genera and in others it is continuous with the spikelet and not jointed. When mature the spikelets fall away either by themselves, singly with their pedicels or in groups with portions of rachis, according to the position of the joint. Bristles (branchlets) are often found on the pedicels. In Setaria a few are borne by the pedicels. The bristles form a regular involucre at the base of a group of spikelets in Pennisetum, and in Cenchrus these become united at the base into a mass forming a kind of burr around the spikelets.

KEY TO THE GENERA.

A. Spikelets articulate on their pedicels.

B. Spikelets without involucels.

C. Spikelets dorsally flattened, awnless.

Inflorescence racemed; glumes three; nerves of second glume five or less, side nerves curved 1. Paspalum.

Inflorescence digitate; glumes three with a minute glume; nerves of second glume five to seven, straight and prominent 2. Digitaria.

Inflorescence panicled; glumes three with a thickening at the base of the spikelet 3. Eriochloa.

Inflorescence racemed or paniculate; glumes four, first two glumes unequal 4. Panicum.

Inflorescence panicled, branches of panicle produced beyond the uppermost spikelet; glumes four, the first being minute and hyaline 5. Chamaeraphis.

Spikelets unisexual and dioecious 6. Spinifex.

CC. Spikelets awned.

Glumes four, second glume broadly fimbriate with hairs; palea of the third glume short and deeply cleft, fourth glume awned 7. Axonopus.

BB. Spikelets involucellate 8. Setaria.

AA. Spikelets not jointed but continuous.

Spikelets in involucelled deciduous fascicles.

Involucre of bristles free 9. Pennisetum.

Involucre of bristles united 10. Cenchrus.



1. Paspalum, L.

These are annuals or perennials. The spikelets are plano-convex, orbicular to oblong, obtuse, secund, 2-ranked on the flattened or triquetrous rachis of the spike-like branches of a raceme, one-flowered and falling off entire from the very short or obscure pedicels. There are three glumes, all more or less equal and similar. The first and the second glumes are membranous, alike and as long as the third, the second glume is usually epaleate and occasionally with a minute palea. The third glume is chartaceous to sub-coriaceous and paleate. Lodicules are two and small. Stamens are three. The styles are slender and distinct with plumose stigmas exserted at the top of the spikelet. Grain is tightly enclosed in the third glume and its palea.



Paspalum scrobiculatum, L.

This is an annual grass, with stems tufted on very short rhizomes, erect or very shortly bent at base, glabrous, bifariously leafy and varying in height from 1 to 3 feet or more.

Leaf-sheaths are compressed, glabrous, loose, keeled, mouth hairy or not. The ligule is a short thin membrane. The nodes are glabrous.

The leaf-blade is linear-lanceolate, finely acuminate, keeled with a distinct midrib, and with very minutely serrulate margins, 6 to 18 inches by 1/12 to 1/3 inch.

The inflorescence consists of 2 to 5 sessile alternate spikes, usually distant and spreading and varying in length from 1 to 8 inches; the rachis is flattened and winged.

The spikelets are either orbicular or ovate-oblong, as broad as the rachis, glabrous, closely imbricating in two rows (rarely in three or four rows), sessile or rarely geminate on a common pedicel.

There are three glumes. The first glume is concave, 3- to 5-nerved (rarely 3- to 7-nerved). The second glume is flat, 5-nerved, with two strong sub-marginal nerves, sometimes with shallow transverse pits along the margins. The third glume is thickly coriaceous, brownish, shining, minutely striolate, margins roundly incurved throughout its length, paleate; the palea is similar to the glume in structure and colour, margins strongly inflexed and with two broad membranous auricles almost overlapping just below the middle. There are three stamens. The stigmas are white both when young and while fading. The style branches are diverging widely and then straight. There are two oblong cuneate fleshy lodicules.



This grass flourishes all over the Presidency in moist places, such as, bunds of wet lands, edges of ponds and lakes and in marshy land. There are two forms of this grass, one with round and another with ovate oblong spikelets. They also vary in the size of the spikelets—some forms have small spikelets and others large. Sometimes the spikelets show variation in the number of glumes.

This grass is also cultivated for its grain. In cultivated forms the spikelets are larger and the whole plant grows bigger. It is grown both in wet and dry land.

Distribution.—Throughout India (wild and also cultivated).



2. Digitaria, Rich.

Annuals or perennials. The spikelets are lanceolate, 2- to 3-nate, in digitate or racemose spikes, jointed on the pedicels but not thickened at the base, 1-flowered. There are usually four dissimilar glumes in the spikelet. The first glume is hyaline very minute, sometimes absent in the same species. The second glume is membranous, 1- to 5-nerved or nerveless. The third glume is membranous, almost equal to the fourth, usually 7- to 9-nerved, the nerves being straight, close, parallel and prominent, with a minute palea or without a palea. The fourth glume is chartaceous or sub-chartaceous, usually 3-nerved and paleate; palea is equal to and similar to the fourth glume, 2-nerved. Lodicules are two, small, broadly cuneate. Stamens are three. Styles are distinct with plumose stigmas exserted laterally near the apex of the spikelet. Grain is enclosed in the fourth glume and its palea.

KEY TO THE SPECIES.

Spikelets 1/10 inch or more.

Spikes usually few, spikelets bearded 1. D. sanguinalis. Var. ciliaris.

Spikelets not bearded 2. Do. Var. extensum.

Spikes usually many; spikelets spreading 3. Do. Var. Griffithii.

Spikelets less than 1/10 inch.

Spikes narrowly winged; spikelets subsilky with slender (not clavellate) hairs 4. D. longiflora.



Digitaria sanguinalis, Scop.

Var. ciliaris.

This is an annual grass either with erect tall stems or long prostrate stems, varying in length from 1 to 3 feet or more.

The leaf-sheath is herbaceous, loose and glabrous. The ligule is a distinct membrane. The nodes are glabrous.

The leaf-blade is linear-lanceolate or linear, flat, glabrous or very sparsely hairy, varying in length from 2 to 5 or 6 inches and in breadth from 1/6 to 1/3 inch.

The spikes are usually few, 2 to 6, 3 to 6 inches long, with a triquetrous, narrowly winged rachis.

The spikelets are oblong, acute, binate, one pedicel being shorter than the other, usually appressed to the rachis and not spreading.



There are four glumes including the minute glume. The first glume is a very minute scale. The second glume is about half as long as the third glume, membranous, usually 3-nerved and sometimes 3- to 5-nerved, distinctly ciliate. The third glume is oblong-lanceolate, acute, membranous, 3- to 5-nerved, sparingly hairy in the lower spikelet and densely bearded with soft spreading hairs in the upper spikelet. The fourth glume is lanceolate, or oblong-lanceolate, acute, somewhat chartaceous, paleate; palea is like the glume in texture. Anthers are pale yellow. Stigmas are white. There are two small cuneate lodicules.

This is an excellent fodder grass. It grows well in all kinds of soils, rich or poor, and is very common in dry fields brought under cultivation.

Distribution.—Throughout India.

Digitaria sanguinalis, Scop.

Var. Griffithii.

This is an annual with stems ascending from a prostrate or geniculate base, glabrous and varying in length from 1 to 3 feet.

The leaf-sheath is glabrous, thinly herbaceous and loose. The ligule is a distinct membrane and the nodes are glabrous.

The leaf-blade is linear or linear-lanceolate, flat, acuminate, varying in length from 2 inches to 12 inches and in breadth 1/6 to 1/3 inch.

The inflorescence is of several slender spikes, usually drooping, 2 to 4 inches; the rachis is filiform and trigonous.

The spikelets are linear-lanceolate, solitary or in distant pairs, glabrous or ciliate, pedicelled and when binate the upper pedicel often longer than the spikelets, usually spreading and not appressed to the rachis.



There are four glumes. The first glume is a minute scale. The second glume is shorter than the third and narrower, 5-nerved, ciliate, acute or sometimes with two fine teeth. The third glume is oblong-lanceolate, acute, 5-nerved (rarely 3-nerved), ciliate on the nerves. The fourth glume is lanceolate, acute, sub-chartaceous, paleate; palea is like the glume in texture. Anthers are yellow and stigmas are white. Lodicules are two and small.

This seems to be a good fodder grass. It grows in all kinds of soils. It is not so common in the plains as on the hills, though it occurs in the plains at the base of the hills.

Distribution.—Throughout India.



Digitaria sanguinalis, Scop.

Var. extensum.

This grass is an annual with stems ascending from a prostrate or geniculate, rooting branched base, greenish or purplish, glabrous and varying in length from 1 to 2-1/2 feet.

The leaf-sheath is thin, herbaceous, rather loose, keeled and glabrous. The ligule is a distinct membrane, truncate, rarely irregularly toothed. The nodes are glabrous.

The leaf-blade is linear-lanceolate, acuminate, flat when mature and convolute when young, glabrous, 1 to 12 inches long and 1/6 to 1/3 inch broad, the margin is very closely and finely serrate, the midrib is prominent with three or four main veins on each side.

The inflorescence consists of a few or many spikes, corymbosely arranged on a short angular slightly rough axis, erect or spreading, 1-1/2 to 4 inches long, the lowest ones in whorls of two to four; the rachis is nearly triquetrous, laterally winged, base thickened and with a few long white hairs; the peduncle is cylindric, smooth, 6 to 12 inches long.



The spikelets are oblong-lanceolate, acute, about 1/10 inch long, binate, one pedicelled and the other subsessile, the pedicel is angular, about 1/2 to 2/3 the length of the spikelet.

There are three glumes in the spikelet corresponding to the second, third and fourth glumes of a Panicum, the first glume being obsolete. The first glume is membranous, ovate-lanceolate, acute, about 1/3 the length of the spikelet or very much less, 3-nerved, densely ciliate along the margins and silkily hairy between the nerves. The second glume is greenish, oblong lanceolate, acute, ciliate along the margins and with fine appressed silky hairs between the lateral nerves, 5-nerved, palea is very minute or absent. The third glume is oblong, sub-acuminate, a little shorter than the second glume, 3-nerved, sub-chartaceous, paleate; palea is similar to the glume in texture. Anthers are pale yellow with a tinge of purple. Stigmas are white. Lodicules are two, minute and cuneate.

This is an excellent fodder grass and is very much liked by cattle. It grows very rapidly and is found in cultivated fields and in somewhat rich loamy soils.

Distribution.—Throughout the Presidency in the plains and low hills.



Digitaria longiflora, Pers.

This is a perennial grass with short underground branches covered with scales. Stems are many, tufted, slender, creeping and rooting, or ascending and suberect, simple or branched, 6 to 20 inches long and leafy and leaves bifarious and divaricate.

Leaf-sheaths are hairy or glabrous, compressed, keeled. The ligule is a short membrane. Nodes are glabrous.

Leaf-blades are broadly lanceolate or linear-lanceolate, acute, spreading, flat, or in short-leaved forms, stiff and pungent, 1 to 2 inches long (rarely also 5 inches long), glabrous above and below, ciliate at the margins towards the base, and with a very minutely serrate hyaline margin.

The inflorescence consists of two to four terminal spikes with a slender, long, hairy or glabrous peduncle. The spikes are slender, erect or spreading with fine winged glabrous rachis.

The spikelets are small, 1/20 to 1/14 inch, geminate, one short and the other long pedicelled, appressed to the rachis, elliptic, silky with slender crisped hairs, pale green or purplish.



There are three glumes with a rudimentary first glume. The first glume is very minute and hyaline. The second glume is as long as the third, membranous, 5-nerved (rarely 3- to 7-nerved), silkily hairy. The third glume is similar to the second and usually 7-nerved (rarely 3- to 5-nerved). The fourth glume is sub-chartaceous, ovate-oblong, paleate, slightly shorter than the third glume, pale brown, smooth. There are two small lodicules. Styles are long and purple.

This grass grows in cultivated dry fields. It seems to like a sandy loamy soil.

Distribution.—Throughout India.



3. Eriochloa, H. B. & K.

These are annuals or perennials. Leaves are flat. The inflorescence is a raceme or a panicle. Spikelets are one-flowered, borne unilaterally on the branches, and the base is thickened and jointed on the top of a short pedicel. The spikelet has three glumes. The first and the second glumes are subequal, membranous. The third glume is apiculate, hardened in fruit. The lodicules are small and truncate. There are three stamens with linear anthers. Styles are two free, with plumose stigmas. The grain is oblong, free within the hardened glume and its palea.



Eriochloa polystachya, H. B. & K.

This grass is a densely tufted perennial, varying in height from 2 to 3 feet, with a short creeping root-stock. Stems are slender, or stout, simple and branching, ascending from a short creeping and rooting base, glabrous, slightly channelled on one side.

The leaf-sheath is glabrous, green or partly purplish, striate, loose, mouth and margins above sometimes pubescent. The ligule is a short villous ridge. Nodes are perfectly glabrous.

The leaf-blade is flat, linear or linear-lanceolate, acuminate, glabrous on both sides, with a slender or prominent midrib, veins more or less uniform, 2 to 10 inches long and 1/6 to 1/3 inch wide, convolute when young. Sometimes the blade is purplish below.

The inflorescence is a panicle on a long or short glabrous stalk, striate, 2 to 7 inches long, with four to fifteen erect or spreading, lax branches, the main rachis is glabrous, angular and deeply grooved. Spikes or branches are slender, alternate, 1 to 2-1/2 inches, becoming shorter upwards, thickened and puberulous at the base, and the secondary rachis is flexuous, grooved, angular, and obscurely pubescent.



The spikelets are green or purplish, ovate, lanceolate, acuminate 1/8 to 1/6 inch long, softly hairy, stalked, solitary above and binate below and then one with a long and the other with a short pedicel rising from a common short branchlet, loosely imbricate, distichous and shortly stipitate and the stipe with a purple thickening; pedicel is short, 1/24 to 1/12 inch with sometimes long deciduous hairs and the tip somewhat thickened.

There are three glumes in the spikelet. The first glume is membranous, covered densely with silky hairs, ovate-lanceolate, acuminate, tip very minutely 3-toothed with three to five fine nerves. The second glume is similar to the first glume but with a more pointed tip, faintly 3- to 5-nerved; palea is not present and if present it is very small, hyaline and empty. The third glume is shorter than the first and the second glumes, thinly coriaceous, punctate, oblong, obtuse, pale, faintly 3- to 5-nerved with a short scaberulous awn, paleate; palea is oblong, similar to the glume in texture, margin infolded. Anthers are three, linear, pale yellow. Stigmas are feathery, white when young and purple later. Lodicules are two and distinct.

This is a common succulent grass growing in large or small tufts in moist situations such as sides of water channels, rivulets and bunds of paddy fields. It is very much liked by cattle. This grass is easily recognized by the silky lanceolate spikelets which have a purple thickening at the base.

Distribution.—Plains of India and Ceylon and in all hot countries.



4. Panicum, L.

The grasses of this genus are annual or perennial and of various habits. Inflorescence is either a raceme of spikes or, a lax or contracted panicle. Spikelets are small, solitary or two to four, rarely more ranked, 1- to 2-flowered, ovoid or oblong, rounded, or dorsally or laterally compressed, falling entire with the pedicels. There are four glumes in a spikelet. The first two glumes are empty and the first glume is small (sometimes minute) and fewest nerved. The second glume is equal or very nearly equal to the third glume, oblong-ovate or lanceolate, 5- to many-nerved. The third glume is similar to the second, male or neuter, paleate or not, 3- to 9-nerved. The fourth glume is chartaceous, sometimes shortly stalked, ovate-oblong or lanceolate, hardened in the fruit, smooth or rough, bisexual, paleate; the palea is as long and of the same texture as the glume. Lodicules are cuneate or quadrate and two in number. There are three stamens and an ovary with two style branches ending in feathery stigmas. Grain is free and enclosed by the hardened fourth glume and its palea.

KEY TO THE SPECIES.

A. Inflorescence racemose of simple (rarely branched) spikes bearing secund spikelets.

I. Rachis of spikes broad and flattened.

(a) Spikelets biseriate.

Spikelets villous. 1. P. Isachne.

Spikelets glabrous.

Spikes shorter than the internodes. 2. P. flavidum.

Spikes longer than the internodes. 3. P. fluitans.

(b) Spikelets 3- to 5-seriate.

Third glume awned.

Stems stout, erect. 4. P. Crus-galli.

Stems stout, prostrate at base. 5. P. stagninum.

Third glume cuspidate.

Stems slender. 6. P. colonum.

II. Rachis of spikes narrow, filiform, terete or angular.

First glume shorter than the third.

First glume semilunate, about 1/4 of the third glume. 7. P. prostratum.

First glume 1/2 of or less than 1/2 of third glume, 5-nerved. 8. P. ramosum.

Leaf base broad or cordate.

Fourth glume shortly awned. 9. P. javanicum.

Fourth glume muticous. 10. P. distachyum.

B. Inflorescence a contracted or open panicle.

I. Panicle contracted and spike-like.

Spikelets lanceolate and first glume minute. 11. P. interruptum.

II. Panicle effuse.

Annuals; first glume nearly 3/4 of the third glume. 12. P. trypheron.

Perennials; first glume less than 1/3 of the third glume. 13. P. repens.



Panicum Isachne, Roth.

This is an annual grass usually growing in tufts with fine fibrous roots and many slender spreading branches, all of them at first creeping and horizontal, rooting at the nodes and then becoming erect and varying in length from 1 to 2 feet.

Stems are very slender, glabrous or covered with scattered hairs, purplish or pale green, and branching freely towards the base.

The leaf-sheath is shorter than the internodes, green or purplish, striate, externally hairy with scattered bulbous-based hairs, varying in length from 1/2 to 3 inches, the outer margin of the sheath is ciliate with long hairs and at the mouths sometimes long hairs are present, especially when the leaves are young. The ligule is merely a dense fringe of long hairs. Nodes are tumid, purplish, covered with long hairs.

The leaf-blade is flat but convolute when young, lanceolate or linear-lanceolate, acuminate, base rounded and margin with minute serrations. It is glabrous or occasionally hairy with scattered, tubercle-based, deciduous hairs, and varying in length from 1 to 3 inches generally (sometimes in well-grown plants it is 5 inches) and in breadth from 1/8 to 1/4 inch. The midrib is prominent though slender at the base and four veins are present on each side with five or six smaller ones between them.



The inflorescence is an erect, narrow panicle consisting of spikes varying in number from 5 to 12 and in length from 2 to 3 inches. The spikes are erect, pressed to the very slender rachis, longer than the internodes of the main rachis, stalked or sessile, mostly simple but sometimes the lower dividing into two or three branches, 1/2 to 1 inch long. The rachis of the spike is very slender, angular, flexuous, narrower than the spikelets, scaberulous with a few long cilia at the angles.

The spikelets are very small, 1/16 inch long, turned all to one side and closely packed in two rows, oblong or oval-oblong, obtuse or subacute, softly hairy, pale green or purplish, with very short pedicels which are pubescent with a few long hairs towards the thickened cupular tips.

There are four glumes in the spikelet. The first glume is very small, membranous, glabrous, broader than long, cordate or triangular, broadly but shallowly emarginate, nerveless or very obscurely 1- to 2-nerved. The second glume is pale or purplish, 5-nerved, hairy, as long as the third glume, membranous, oblong and obtuse. The third glume is pale, nearly equal to the second glume with a longitudinal depression at the back, less hairy than the second glume, 3-nerved (rarely 5-nerved also); palea is present, and it is hyaline, shorter than the glume, truncate or shallowly retuse, usually barren but occasionally with three stamens. The fourth glume is oblong, rounded, coriaceous, smooth, shining, dorsally flattened, 3- or indistinctly 5-nerved; palea is similar to the glume in texture and with folded margins. There are three stamens with yellow anthers. Lodicules are two, very small and distinct. Ovary has two styles with feathery stigmas white at first, but turning deep purple while withering.

This delicate and small grass occurs here and there as mere tufts especially in sheltered situations. It usually flourishes in black cotton soils amidst cholam (Andropogon Sorghum), although it thrives equally well in other rich soils. This is considered to be a very good fodder grass.

Distribution.—It is fairly common all over the Madras Presidency, and goes up to 3,000 or 4,000 feet. It occurs in Africa, America and Italy.



Panicum flavidum, Retz.

This plant is a tufted annual. It branches freely from the base; branches are tufted, decumbent at first but soon becoming erect, slender, glabrous, compressed and leafy, varying in length from 1 to 3 feet.

Leaves are somewhat distichous. The leaf-sheath is compressed, glabrous, sometimes with a tinge of purple, the lower ones swollen at the base and the mouth is hairy. The ligule is a fringe of hairs. Nodes are glabrous.

The leaf-blade is flat, thinly coriaceous, linear-lanceolate and acuminate, or ligulate with a rounded tip, 3 to 5 inches in length, 3/16 to 5/16 inch wide, glabrous or very thinly scaberulous, base rounded or slightly cordate with long white ciliate hairs on the small basal lobes.



The inflorescence is a raceme of spikes, 5 to 10 inches long, erect or inclined on a short or long, glabrous, strongly channelled peduncle; the main rachis is grooved, angled and scaberulous. Spikes are few or many, 1/4 to 1 inch long, erect, pressing on the rachis of the inflorescence along the groove, distant and sessile; the lower spikes are very much shorter than the internodes, but the upper equal to or longer than the internodes; the rachis of the spike is angular, flattened below, erect or slightly recurved.

The spikelets are white, in two rows on a flattened rachis, obliquely ovoid or gibbously globose, glabrous, sessile, 1/8 inch in length.

There are four glumes. The first glume is suborbicular, about half the length of the third glume, usually 3-nerved. The second glume is broadly ovate, obtuse, concave, larger than the first glume and nearly equal to or shorter than the fourth glume, 7-nerved, rarely 7- to 9-nerved, nerves are anastomosing, tip rounded. The third glume is broadly ovate or oblong, equal to or longer than the fourth glume, obtuse, 3- to 5-nerved, paleate, mostly with and rarely without stamens. The anthers are yellow and they do not open until the stigmas and anthers of the fourth glume are thrown out. Lodicules are two and conspicuous. Palea is hyaline with infolded margins. The fourth glume is coriaceous, broadly ovate, tip acutely pointed and almost cuspidate or acute, mucronate, white or brownish, reticulately minutely pitted. Anthers are three and yellow. Stigmas are purplish. Lodicules are small but conspicuous.

This grass is very common throughout the plains and grows in the bunds of paddy fields and in wet situations, and goes up to moderate elevations on the hills. Cattle eat this grass greedily and seem to like it. It is considered to be an excellent fodder.

Distribution.—In wet situations all over India ascending to 6,000 feet. Occurs also in Ceylon, Africa, Tropical Asia and Australia.