A Handbook Of Some Common South Indian Grasses: 8-Oryzeæ And Zoysieæ
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Tribes Ii And Iii—Oryzeæ And Zoysieæ
Oryzeæ
Oryzeæ is a very small tribe with a few genera, which usually flourish in marshes. The spikelets are in panicles, 1-flowered and the flower is usually perfect. In Oryza there are three glumes, the first two being very minute, and there is only a single glume in Leersia and Hygrorhiza. There are usually six stamens. The palea becomes firm in texture like the glume instead of remaining hyaline, and so it is often mistaken for a glume. The spikelets are jointed on their pedicels and fall away from them.
Not floating; spikelet not awned 11. Leersia.
Floating; spikelets awned 12. Hygrorhiza.
Zoysieæ
Zoysieæ is another small tribe with half a dozen genera. The inflorescence is either a spike-like raceme or a spiciform panicle. The spikelets are solitary in Perotis, binate in Tragus and grouped in Trachys. There is usually a complete flower in a spikelet and the glumes are membranous. Mature spikelets are deciduous with their pedicels singly in Perotis and in clusters in others.
Spikelets fascicled unilaterally on a broad rachis, 4-glumed, glumes not echinate 13. Trachys.
Spikelets binate and all round the rachis, 3-glumed, glumes echinate 14. Tragus.
Spikelets single, awned and 3-glumed 15. Perotis.
11. Leersia, Sw.
These are tall perennial marsh grasses. The inflorescence is usually a more or less contracted panicle with very slender branches. The spikelets are compressed and consist of only one glume bearing a perfect flower. The solitary flowering glume is chartaceous, awnless, 3- to 5-nerved, the lateral nerves forming the thickened margin of the glume. The palea is narrow, linear-lanceolate, as long as the glume, 3-nerved, rigid, dorsally ciliate, and with hyaline margins. Lodicules are two. Stamens are usually six in number. Styles are short, with plumose stigmas and laterally exserted. Grain is ovoid or oblong, compressed, free within the glume and its palea.
Leersia hexandra, Sw.
This is a slender perennial marsh-grass with stems rooting in the mud and with flexuous floating branches, sending up erect or ascending, weak and slender leafy branches, 2 to 4 feet high.
The leaf-sheath is smooth, glabrous, with eciliate margins. The ligule is a short obliquely truncate or two-lobed membrane. Nodes are hairy with deflexed hairs.
The leaf-blade is flat, narrow, linear, tapering to a fine point, suberect and rather rigid, glabrous and with a narrow base, varying in length from 3 to 10 inches and 1/8 to 1/3 inch in breadth.
The inflorescence is an oblong laxly branched, narrow pedunculate panicle, 2 to 4 inches long.
The spikelets are all 1-flowered and 1-glumed, articulate on the pedicels above the rudimentary glumes, strongly laterally compressed. The glume is about 1/6 inch long, ovate-oblong, somewhat boat-shaped, acute and shortly mucronate, strongly keeled, ciliate on the keel and margins, 5-nerved, the lateral nerves forming a thickened margin; palea is as long as the glume, linear-lanceolate, subacute, rigid with membranous margins. Stamens are six and there are two small lodicules. The first two glumes are reduced to an obscure hyaline rim.
This marsh-grass is found in marshy places such as ditches and channels in paddy fields, ponds and tanks.
Distribution.—It is found all over India and Ceylon; also in Africa, America and Australia.
12. Hygrorhiza, Nees
. These are floating glabrous grasses with stems diffusely branching and profusely rooting at the nodes. The inflorescence is a panicle. The spikelets are 1-flowered, with a solitary flowering glume only. The flowering glume is awned, strongly 5-nerved, nerves scabrid and ciliate, the lateral nerves being marginal. Palea is 3-nerved, narrow acuminate with a ciliate keel. Lodicules are suborbicular. There are six stamens with long slender anthers. Styles are free with plumose stigmas, laterally exserted. Grain is oblong, narrowed at the base, obtuse, free within the glume and its palea.
Hygrorhiza aristata, Nees.
This is a floating aquatic grass. Stems are spongy, branching diffusely, 1 foot long, with feathery whorled roots in dense masses at the nodes; branches are short, erect and leafy.
The leaf-sheath is smooth, inflated, compressed, with ciliate margins. The ligule is a narrow membrane. Nodes have whorls of roots.
The leaf-blade is linear or ovate-lanceolate, obtuse, glabrous, glaucous beneath, base rounded or subcordate, 1 to 3 inches long and 1/2 to 3/4 inch broad. The inflorescence is a panicle, 2 inches long and broad, somewhat triangular in outline; the rachis and the branches are stiff, slender and smooth, the lower branches are a little deflexed.
The spikelets are very narrow, sessile or pedicellate, articulated on the pedicel, 1-flowered and 1-glumed. The glume is about 3/8 inch long (excluding the awn) and the awn is as long as the glume or slightly longer, lanceolate, with five strong nerves and the lateral ones forming thickened margins; the palea is as long as the glume. Stamens are six and lodicules two.
Found in ponds and tanks.
Distribution.—All over India and Ceylon.
13. Trachys, Pers.
These are softly, villous, diffuse annual grasses. The inflorescence consists of usually two (rarely three) divaricating spikes on a long peduncle. The rachis is herbaceous, broad flexuous, jointed and bearing at each joint a solitary globose cluster of two or three perfect 1-flowered glabrous spikelets surrounded by many short spinescent glumes of imperfect ones. The perfect spikelets are 4-glumed and the glumes are very unequal.
The first glume is minute, tooth-like, nerveless. The second glume is long, linear-lanceolate, membranous, very acute, strongly 3- to 5-nerved. The third glume is the largest, obliquely ovate, or obovate-oblong, cuspidately acuminate, rigidly coriaceous, 9- to many-nerved, paleate or not, empty.
The fourth glume is shorter and narrower than the lower one, linear-oblong, acuminate, chartaceous, smooth, dorsally convex, with incurved margins, bearing a bisexual flower, paleate, palea is hyaline as long as the glume, and the margins are inflexed below the middle. Lodicules are very minute or wanting. There are three stamens. The styles are very long with slender stigmas, exserted at the top of the glume. The grain is oblong, compressed, free within the glume and its palea.
Trachys mucronata, Pers.
This is a diffusely branching, softly villous annual grass. The stems are many from the root, 16 to 18 inches long, ascending or decumbent and prostrate, leafy, glabrous, rooting freely at the lower nodes, especially when procumbent.
The leaf-sheaths are loose, inflated, hairy or rarely glabrous. The ligule is a thin membrane, or a ridge of fine closely set hairs. Nodes are villous.
The leaf-blade is linear-lanceolate to ovate-lanceolate acuminate, flaccid, softly villous on both the surfaces, margins often crisped, base rounded, 2 to 6 inches by 1/4 to 1/2 inch.
The inflorescence consists of a long or short, slender, shining peduncle bearing two or three rigid, flattened, flexuous, jointed spikes, the rachis is broad, herbaceous, with a flat, broad, closely nerved wing on both the sides and with a distinct flat midrib and jointed, each joint bears on the under surface at the articulation, a solitary, globose cluster of two to three perfect 1-flowered glabrous spikelets surrounded by many short spinescent glumes of imperfect ones. The spikes vary in length from 1 to 2 inches and in breadth from 1/10 to 1/6 inch and are glabrous.
The clusters of spikelets are about 1/4 inch in diameter, often partially sunk, in a concavity of the rachis; the perfect spikelets are 1/5 to 1/4 inch long and the imperfect are shorter.
In the perfect spikelet there are four very unequal glumes. The first glume is minute, tooth-like, triangular or lanceolate, acute, nerveless, 1/16 to 1/12 inch long. The second glume is elongate, linear-lanceolate, acute, sometimes ciliate below the middle, membranous, narrower than the third glume, hyaline, strongly 3-nerved, 1/16 by 1/6 inch. The third glume is 1/5 by 1/8 inch the largest in the spikelet, broadly and obliquely ovate or obovate, cuspidately acute, with nine to many green nerves, paleate; the palea is very small, about 1/20 inch long, oblong, hyaline and rigidly coriaceous. The fourth glume is much narrower and shorter than the third glume, linear oblong, acuminate, chartaceous, smooth, dorsally convex, with incurved margins, bisexual and paleate; the palea is as long as the glume, acuminate, hyaline, the margins inflexed below the middle, ovate, acute.
Lodicules are minute or absent. Stamens are three with linear anthers. Styles are very long with slender stigmas. The grain is oblong, compressed.
This grass grows abundantly in cultivated dry fields and in the sand near the sea-shore and it is easily recognized by the clusters of spikelets in the spike.
Distribution.—The Deccan Peninsula—both in the interior and on the sea coast.
14. Tragus, Haller.
These are annual or perennial grasses, with erect or prostrate stems. Inflorescence is a spiciform raceme, bearing the spikelets in clusters of 2 to 4. The spikelets are 1-flowered and usually with two glumes. Sometimes a very minute hyaline lower glume is present. The first glume is thickly coriaceous, 5-ribbed, oblong-lanceolate, and ribs with long recurved spines. The second glume is oblong or oblong-lanceolate, apiculate, chartaceous, 3-nerved and with a perfect flower; palea is as long as the glume, 2-nerved. Lodicules are broad, cuneate and fleshy. There are three stamens. Styles are slender and distinct, with narrow stigmas exserted from the top of the glume. Grain is oblong to ellipsoidal free within the glume and its palea.
Tragus Racemosus, Scop.
This plant is a perennial with tufted prostrate or erect stems, rooting at the nodes freely and densely leafy. The flowering branches are erect or geniculately ascending and varies from a few inches to about a foot.
The leaf-sheath is short, pale, glabrous, somewhat compressed, striate, equitant below and upper are longer, terete and green. The ligule is only a ridge of short, fine hairs. Nodes are glabrous. The leaf-blade is convolute when young, ovate or ovate-lanceolate, variable from 1/4 to 2 inches long and 1/10 to 1/6 inch wide, acuminate, flat or somewhat wavy, glabrous on both the surfaces, rigidly pungent, densely crowded and distichously imbricate in the lower part of the stem, base is amplexicaul, and the margin is distantly serrate and rigidly ciliate.
The inflorescence is a spike-like terminal panicle varying in length from 3/4 to 2 inches; the rachis is wavy, slender, angular or grooved, pubescent, the peduncle is striate, pubescent and enclosed by the leaf-sheath.
The spikelets are arranged in groups of two, facing each other and appearing like a single spikelet with two equal echinate glumes, sessile, or obscurely pedicelled on very short, tumid, pubescent branches.
There are two (rarely three) glumes in the spikelet. The first glume is very minute, hyaline, obtuse and it is very often not present. The second glume is about 1/8 inch, ovate-lanceolate, acuminate, strongly 3-ribbed with rows of stout, spreading hooked spines along the ribs and encloses a single floret.
The margins of this glume are membranous and somewhat scaberulous. The third glume is about 1/12 inch, oblong lanceolate, membranous minutely hairy, 3-nerved and finely pointed at the apex; the palea is as long as the glume, hyaline, 2-nerved, lanceolate, subacute and irregularly toothed at the apex. Stamens are three, with slender [Pg 134]filaments, anthers are short, broad and pale yellow. The style branches are pale and feathery. Lodicules are two, fleshy and cuneate or subquadrate. The grain is free inside the glume and the palea, linear oblong, slightly compressed and pale brown, the embryo occupies about 1/3 the length of the grain.
This is one of the commonest grasses growing everywhere in tufts with usually prostrate branches. In some situations the branches are erect.
Distribution.—Plains of India throughout and Ceylon. It is found in all the warm regions of the world.
15. Perotis, Ait.
These are slender annual or perennial grasses with short broad leaves. Inflorescence is a spike or spiciform raceme. The spikelets are 1-flowered, sessile or shortly pedicelled and jointed. There are three glumes in the spikelet. The first and the second glumes are empty, subequal, narrowly linear with a strong midrib which is produced into a long capillary awn. The third glume is very small, hyaline, lanceolate, acute, 1-nerved and with a perfect flower; palea is small, narrow, hyaline and nerveless. Stamens are three with short anthers. Styles are short and united at the base with very short stigmas. The grain is long and narrow, longer than the flowering glume.
Perotis latifolia, Ait
This grass is an annual with slender leafy stems, branching at the base, prostrate at first and then geniculately ascending, terminating in inflorescences and varying in length from 3 to 15 inches.
The leaf-sheaths are glabrous, usually all short except the one next to the inflorescence which is two or three times as long as the lower sheaths. The nodes are purple and glabrous.
The leaf-blade is short, 1 to 1-1/4 inches long, ovate or lanceolate, cordate at base, acute and glabrous on both the surfaces; the margin is minutely serrate, rigidly ciliate and with a very narrow hyaline border.
The inflorescence is a slender, crinite, spike-like raceme, 1 to 8 inches long, with a finely scabrid main rachis.
The spikelets are narrow linear 1/12 to 1/8 inch or longer, purple, shortly pedicelled and 1-flowered, pedicels are short with a hyaline swelling on the upper side at the base.
There are three glumes. The first and the second glumes are empty, narrow-linear, purple, scabrid, 1-nerved and awned; awns are capillary, varying in length from 1/3 to 1/2 inch. The third glume is very minute with very small palea. There are three stamens and two small lodicules. Styles are somewhat shorter. The grain is long and cylindric.
This grass grows in open waste places and in dry fields all over the Presidency.
Distribution.—Throughout India.
