Description from Flora of China
Annual. Culms slender, tufted, erect or slightly decumbent at the base, 15–100 cm tall. Leaf sheaths smooth; leaf blades linear, flat, 3–20 × 0.1–0.5 cm, adaxial surface papillose, apex acuminate; ligule ca. 0.5 mm. Panicle very slender, densely spikelike, 2–20 × 0.2–0.5 cm, axis glabrous. Spikelets purple, ovate-elliptic, slightly curved, laterally compressed, 1.5–2 mm, glabrous or pilose, acute or subobtuse; lower glume 1/2–2/3 spikelet length, 3–5-veined; upper glume 7–9-veined; lower lemma with a small palea; upper lemma slightly shorter than spikelet. Fl. and fr. winter. 2n = 36.
Moist places and shallow water, rice fields. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Xizang, Yunnan [India, Indonesia, Laos, Malaysia, Myanmar, Nepal, New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; Africa, Australia, Pacific Islands].