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.
Fig. 79.—Eriochloa polystachya.
1. A portion of the branch; 2, 3 and 4. the first, second and the third glume, respectively; 4a. back view of the third glume; 5. palea of the third glume; 6. lodicules, stamens and the ovary; 7. grain.
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.