Annuals or perennials; culms hollow or solid; erect, ascending or creeping; shoots intravaginal.
Sheaths of leaf often loose from culm; ligule well-developed, membranaceous; blades linear to lanceolate,
with broad base and acute tip, flat, soft. Inflorescence branched from all sides, composed of 2-
numerous spike-like racemes. Spikelets crowed, alternately 2-3-together along keel, unequally pedicelate
in a group, sometimes subsessile, articulate with widened tip of pedicel, dorsally compressed, linear-
lanceolate to obovate, small, 2-flowered, muticous, usually equal in from and size; lower glume
absent or very small, hyaline and veinless, rarely faintly 1-veined; upper glume very veriable in length,
thin, hyaline and veinless, rarely faintly 1-neined; lower lemma as long as spikelet, rarely shorter, 5-9-
veined; lower palea absent or very small and adnate to base of upper lemma; upper lemma as long as
spikelet or slightly shorter, papery with broadly inflexed, hyaline or pale margins, densely striate and
very finely tuberculate, often olive-green, brown or dark purple at maturity, glabrous; upper palea as
long and of same texture, 2-veined, with inflexed margins, embraced to apex by margins of upper
lemma; lodicules very small, cuneate; stamens 3; style 2, free; stigmas plumose, exserted at or near
apex. Caryopsis tightly enclosed by only slightly indurate upper palea and lemma, elliptic, dorsaly compressed,
hilum punctiform, embryo at most 1/2 as long as caryopsis.
A large genus of ca. 230 species distributed in the warmwe parts of the world; 13 species and two
varieties are found mainly on the plains of Taiwan.