Annuals or perennials; culms erect or ascending and often rooting at base, hollow. Blades flat or inrolled, margins involute. Inflorescence composed of many slender spike-like racemes, placed on all side of main axis. Spikelets alternate, usually crowded on abaxial side of rachis, sessile to shortly pedicelled, laterally compressed, one broad side appressed to rachis, 1-several-flowered, awnless; rachilla produced or not, articulate below lemmas, joints usually stipitate, glabrous or very short-hairy; glumes persistent, convex-keeled, thinly membranous, 1-nerved; lower glume usually shorter than spikelet; upper glume larger; lemmas broadly ovate, blunt or acute, strongly convex to conduplicate, 3-nerved, lateral nerves marginal; palea as long or slightly shorter, 2-nerved; lodicules 2, minute; stamens 3, the anthers very small; styles 2, free, short, the stigmas plumose, laterally exserted. Caryopsis, free, oblong, smooth , or rugose, hilum-side grooved, the other side more or less keeled, the hilum punctiform, basal; embryo 1/3 as long as the caryopsis.
About 27 species distributed in tropical and subtropical regions.
Two species are commonly found in Taiwan.
