Annual, up to 3 ft. high. Culms erect or subgeniculate, somewhat slender, 3-noded, smooth, collapsing and deeply sulcate when dry, simple or sparingly branched, uppermost internode long-exserted, the others soon bared by the sheaths slipping off. Leaf-sheaths rather loose, thin, finely striate, subherbaceous, finely hirsute or all or at least the uppermost glabrous except at the dark broad (2 lin.) hispidly bearded nodes; ligules membranous, truncate, crenulate, up to 2 lin. long; blades linear, long-tapering to a fine point, 3–4 in. by 1 1/2–2 lin., flat, flaccid, green, glabrous or sparingly hairy, margins cartilaginous, scaberulous towards the tips, otherwise smooth, midrib very slender, pale, primary lateral nerves up to 6 on each side, slightly raised above. Racemes very numerous, usually over 20, sessile, fastigiate on a slender angular common axis up to 3 in. long, overtopping it by 2–3 in., mostly solitary and bearing spikelets from the base or from near it, very slender, mostly suberect, rarely spreading, up to 4 rarely 5 in. long, flexuous, loose, pale green or tinged with purple; rhachis filiform, triquetrous, 1/10– 1/7 lin. wide, with scattered very fine long spreading hairs in the lower part, internodes about 1 lin. long, angles very finely marginate, scaberulous; pedicels 2-nate, finely filiform, very unequal, the longer 2/3 lin. long, angular, minutely scaberulous. Spikelets loosely appressed, hardly imbricate even when young, oblong to oblong-lanceolate, acute, about 2/3– 3/4 lin. by 1/4 lin., apparently glabrous. Lower glume a minute hyaline scale or 0; upper oblong, acute, as long as the spikelet, very thin, finely 5-nerved, with 4 very fine lines of hairs (the space inside the submarginal nerve glabrous), hairs very delicate with recurved or circinate tips, 1/10 lin. long. Lower floret: valve very thin, corresponding in shape and size to the spikelet, prominently but finely 7-nerved, nerves equidistant, with a delicate appressed fringe of hairs along the margins and a fine often imperfect line between the 2 inner lateral nerves (of each half) or there sometimes quite glabrous; valvule and lodicules microscopic. Upper floret lanceolate-oblong, acutely acuminate, as long as the spikelet, pale olive- or greyish-green, thinly chartaceous, margins of valve at length distant. Anthers 1/2 lin. long. Grain ellipsoid, white, 1/2 lin. long.
