Annual. Culms ascending from a geniculate or decumbent base, sometimes rooting at the lower nodes, 3/4–3 ft. long, slender to somewhat stout, branched, the erect portion 3–4-noded, scabrid towards the inflorescence, the remainder glabrous and smooth. Leaf-sheaths compressed and keeled, the intermediate and upper at length shorter than the internodes, glabrous or pilose along the margins, rarely all over; ligule reduced to a densely ciliate rim; blade lanceolate-linear, rounded at the base, and tapering upwards to an involute pungent tip, 2 1/2–10 in. long, 1 1/2–6 lin. wide, flat, usually rather stiff, glabrous and smooth on the lower surface except for the scabrid tip, scabrid and sparsely pilose above especially towards the base. False spike loose to rather dense, 1 1/4–4 in. long, 5–7 lin. wide, at length pale brown or tinged with green or purple; rhachis angular, flexuous, scabrid along the angles; involucres subsessile or minutely stalked, spreading, 2–3 1/2 lin. long and wide, very hard and rigid; bristles connate, retrorsely scabrid, the basal very slender, erect, up to 2 lin. long, the intermediate more rigid, spine-like and spreading, the inner (8–10) fused for half their length, pubescent, ciliolate on the margins, rigid and flattened, widened at the base, the free portion erect or with some lobes inflexed, with 1–2 green nerves on the back. Spikelets in clusters of 2–6, sessile, 2 1/4–3 lin. long, ovate, acuminate. Glumes thinly membranous, ovate, acute or obtuse; lower 1–2 lin. long, 1-nerved; upper 1 1/2–2 3/4 lin. long, 3–5-nerved, puberulous. Lower floret barren or rarely ♂: valve similar to the upper glume but 5-nerved and up to 1 1/2 lin. long; valvule linear-lanceolate, obtuse, about as long as the valve, puberulous, keels scabrid. Upper floret hermaphrodite, ovate, acuminate: valve when flattened broadly ovate, obtuse, as long as the spikelet, coriaceous, 5-nerved; valvule as long as the valve. Grain broadly elliptic, truncate, 1 1/2 lin. long.
