Description from Flora of China
Annual or perennial, often glandular particularly on the leaf sheaths and inflorescence. Leaf blades mostly flat, sometimes rolled, rarely pungent; ligule a line of hairs or sometimes membranous. Inflorescence an open, contracted, spiciform or glomerate panicle, very rarely of racemes on a central axis. Spikelets 2- to many-flowered, laterally compressed, orbicular to vermiform, variously disarticulating. Glumes unequal, deciduous or persistent, 1(–3)-veined. Lemmas membranous to coriaceous, keeled or rounded, glabrous to asperulous or rarely hairy, 3-veined or the veins sometimes very faint and occasionally suppressed, apex entire, obtuse to acuminate, rarely mucronate. Palea keels sometimes winged or ciliate. Stamens 2 or 3. Fruit mostly globose, ellipsoid, or rectangular-prismatic, usually a caryopsis but sometimes the pericarp free.
About 350 species: tropics and subtropics throughout the world; 32 species (11 endemic, one introduced) in China.
(Authors: Chen Shouliang (陈守良); Paul M. Peterson)