Description from Flora of China
Annual or perennial, often shortly rhizomatous. Leaf blades linear, flat. Inflorescence a spikelike, cylindrical panicle, elongate to ovoid or capitate; branches short, sometimes adnate to axis, spikelets densely crowded, subsessile. Spikelets strongly laterally compressed, floret 1, disarticulating above glumes; rachilla extension present or absent; glumes equal, oblong or obovate in side view, longer than and enclosing floret, herbaceous, 3-veined, strongly keeled, keel often pectinate-ciliate, margins overlapping but not connate, apex truncate to acute, with stout mucro or short stiff awn; lemma broadly oblong or ovate, thinly membranous, dorsally convex, 3–7-veined, apex truncate to subacute, awnless or mucronate; palea slightly shorter than lemma, ciliate along keels; lodicules 2; stamens 3. Caryopsis ellipsoid to ovoid.
Sixteen species: temperate and cold regions of the N hemisphere, extending southward in America along mountain chains into Chile; four species in China.
(Authors: Lu Shenglian (卢生莲); Sylvia M. Phillips)