Annuals or perennials; culms hollow, ribbed, glabrous. Leaves often with tubercle-based hairs; ligule a fringe of hairs or obsolete; blades lanceolate or linear-lanceolate, acute, often prominently nerved. Inflorescence an open or contracted panicle, sometimes very small, branched on all sides, the apex rigid. Spikelets globose, always muticous, 2-flowered; rachilla articulated above glumes; glumes tardily deciduous, often separate, herbaceous, nearly equal, as long as spikelet or slightly shorter; lemmas differing in texture or equal in texture, distinctly spaced; lower lemma as firm as upper lemma, and convex, or less firm and scarcely convex, reaching as far as upper lemma or distinctly farther; upper lemma shorter, strongly convex, firm; stamens in staminate or bisexual florets 3, the anther linear; ovary glabrous; the styles 2, free, the stigma plumose, exserted apically, purple. Caryopsis plano-convex, free, enclosed between palea and lemma.
About 60 species distributed in the tropical and subtropical regions of the world.
Eight species, mainly growing at medium elevations in moist place, are found in Taiwan.