Description from Flora of China
Annuals or perennials, with rhizomes or stolons. Basal leaf sheaths rounded or keeled; leaf blades linear, flat or folded; ligule a short ciliolate membrane. Inflorescence of racemes, digitate or occasionally in 2 or more whorls; spikelets shortly pedicelled or subsessile, closely imbricate, biseriate. Spikelets laterally compressed, florets 2–4, lowermost fertile, successive florets male or sterile and progressively reduced, disarticulating above glumes; glumes unequal, usually shorter than florets, lanceolate, membranous, 1-veined, acuminate to an awn-point; callus bearded; lemma of fertile floret keeled, lanceolate to obovate, cartilaginous to leathery, usually ciliate on margins and keel, apex entire or emarginate, subapically mucronate or awned; palea as long as lemma; subsequent florets similar to fertile floret or of different shape or vestigial. Caryopsis ellipsoid to subterete, pericarp free though sometimes reluctantly so. x = 10.
About 55 species: tropical and warm-temperate regions throughout the world; five species (one introduced) in China.
(Authors: Sun Bixing (孙必兴 Sun Bi-sin); Sylvia M. Phillips)