Description from Flora of China
Perennial or annual, sometimes with scaly rhizomes. Leaf blades usually linear; ligule very short, membranous, a dense fringe of long hairs behind at base of blade. Panicle open or contracted, usually with simple racemelike primary branches; central axis smooth, scabrid or hispid on angles; spikelets paired; pedicels unequal, briefly connate. Spikelets with 2 florets, lanceolate to ovate, gaping, often purplish; lower floret staminate or barren, upper floret bisexual; rachilla disarticulating between florets; glumes unequal, upper as long as spikelet, often caudate, lower shorter, acute to caudate; lower lemma similar in texture to upper glume, often persistent, smooth, 3–5-veined, awnless, its palea hyaline; upper lemma terete, smaller than the lower, firmer in texture, scaberulous, apex entire or 2-toothed, often awned, rarely awnless, occasionally lateral teeth also awned; awn usually geniculate with brown twisted column, sometimes caducous; palea margins sometimes auriculate; callus short, rounded, bearded. x = 7.
About 60 species: tropical and subtropical regions, but mainly in Asia; 20 species (eight endemic) in China.
(Authors: Sun Bixing (孙必兴 Sun Bi-sin); Sylvia M. Phillips)