perennial; culms erect from a geniculate or prostrate base, or floating, terete, up to 15 ft. high, in tall specimens very robust, as thick below as the middle finger or thicker, often with whorls of long roots from the submerged nodes, sheathed all along or some of the internodes at length exserted, many-noded; sheaths striate, smooth, glabrous, rarely hispid, terete; ligule a fringe of hairs; blades linear from a rather broad and rounded, or from a slightly attenuate and decurrent base, long tapering to a fine point, 1–2 ft. by 3–12 lin., flat, firm, glabrous, often more or less glaucous, smooth above, scabrid below in the upper part, margins cartilaginous, spinulous or scabrid, or smooth below, midrib usually broad, whitish; panicle erect, rarely nodding, usually linear-oblong, dense, 1/2–1 ft. long, facing all sides or sometimes subsecund; axis stout, 3–4-angular, sulcate, hispidulous or glabrous and smooth except the scabrid angles, usually with a fringe of hairs at the nodes; branches very many, some solitary, others 2-nate or fascicled, the lowest distant, the others rather close, suberect, strict or flexuous, rarely nodding, 1–3 in. long, forming moderately dense simple or subsimple spikes; rhachis slender, triquetrous, hispidulous, or glabrous; pedicels fascicled, very short, tips discoid; spikelets ovoid, cuspidate, 1 1/2–2 lin. long, greenish or variegated with purple; glumes herbaceous-membranous; lower broadly ovate, clasping at the base, acute, about 1/2 the length of the spikelet, 5-nerved, margins scabrid or ciliate; upper glume ovate to ovate-oblong, shortly acuminate, very concave, scarcely shorter than the spikelet, 5–7-nerved, minutely and rigidly pubescent or subglabrous between the scabrid or spinulous nerves; lower floret ♂; valve similar to the upper glume, flat on the back; pale oblong, subacuminate, keels scabrid; anthers 1/2–1 lin. long; hermaphrodite floret usually elliptic, rarely oblong, cuspidate, 1 1/2–2 lin. long, straw-coloured, smooth; valve coriaceous, 5-nerved. null
