Description from Flora of China
Perennials. Rhizomes horizontally creeping. Culms solitary, erect, 60-120 cm tall, acutely 5-angular, glabrous except below inflorescence, basalmost node bulbously thickened. Cauline leaves with sheath 1.2-6.5 cm, tightly surrounding culm; ligule rust-colored, hyaline, truncate; leaf blade pale green, lanceolate to linear-lanceolate, 10-20 × 0.9-1.9 cm, flat, ± rigid, usually glabrous but sometimes basally pubescent, 5-veined, apex acuminate. Involucral bracts leaflike; bractlets setaceous, sheathless. Inflorescences paniculiform, with 4-20 glomerulate clusters of spikelets; glomerules single or binate, 1.5-2.5 cm wide, bearing 6-15 spikelets; peduncles single or binate, occasionally branched, white villous. Spikelets brownish green to dark brownish green at maturity, ovoid to ovoid-ellipsoid, 7-12 × ca. 3 mm, many flowered, wholly covered with woolly hairs. Glumes brown, broadly elliptic to oblong, ca. 2 mm, membranous, apical ones abaxially sparsely pilose, apex emarginate and with a 3-veined costa ending in a short recurved puberulent 0.5-0.7 mm awn. Perianth bristles brown; outer bristles absent; 3 inner bristles obovate, subsessile, gradually narrowed to base, margin ciliate, apex emarginate and with 3 prominent veins, with 1 costa usually excurrent into a short curved awn. Stamens 3; anthers oblong, 0.5-0.7 mm. Stigmas 3, as long as style. Nutlet brown at maturity, shortly stipitate, obovoid, ca. 1 mm (including stipitate base), 3-sided, base cuneate. Fl. and fr. Jun-Dec. 2n = 48, 52.
Wet grasslands, river margins, paddy fields; near sea level to 1000 m. Fujian, Guangdong, Guangxi, Hainan, Taiwan, SE Xizang, S Yunnan [Bangladesh, Cambodia, India, Indonesia, Japan (Ryukyu Islands), Laos, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; tropical Africa, America, and Australia, Pacific islands, South America].