Description from Flora of China
Perennial, tufted, stoloniferous or rhizomatous. Leaves mostly basal, leaf blades linear, flat or folded; ligule short, membranous. Inflorescence a single terminal raceme; raceme strongly flattened, spikelets overlapping along one side, disarticulating very tardily; rachis internodes narrowly clavate, nodes ciliate (in China), base truncate, sometimes with a low central peg. Sessile spikelet longer than rachis internode; lower glume elliptic-ovate to oblong, papery to leathery, 5–9-veined, marginally 2-keeled, keels pectinately spiny, often winged at apex; upper glume 3-veined, keeled along midvein, otherwise almost flat, often narrowly winged on lower keel; lower floret staminate, palea present; upper floret bisexual, upper lemma entire, awnless. Pedicelled spikelet absent or represented by a small bristle; pedicel free from and longer than adjacent internode, subulate to narrowly ovoid or leaflike.
This genus is easily recognizable by its distinctive inflorescence. The solitary, terminal, 1-sided raceme of closely overlapping spikelets does not break up readily into segments, and most species have spikelets with conspicuous, long spines along their margins.
Eleven species: India to SE Asia and Australia; five species in China.
(Authors: Sun Bixing (孙必兴 Sun Bi-sin); Sylvia M. Phillips)