Japan Flora: Gla­brous, soft annual; culms tufted, erect, smooth, 10-40 cm. long, from a branching, ascending or decumbent base; leaf­blades linear, 4-10 cm. long, 2-4 mm. wide, glabrous; ligules very short, hyaline; sheaths rather short, glabrous; panicles spikelike, long-exserted, erect, cylindric, 1-6 cm. long, pale green, 4-6 mm. across, densely flowered, the axis smooth; pedicels short, slightly dilated and concave at apex; spikelets about 3 mm. long, acute, numerous, narrowly conical-ovoid, slightly oblique, often sparsely white-pilose; first glume ovate, about half as long as the spikelet, the second longer, narrowly ovate-oblong, prominently several-nerved; sterile lemma slightly shorter, not inflated at base; fertile lemma crustaceous, lus­trous, narrowly ovoid-oblong, rather acute, pale yellow, about 1.5 mm. long. Aug.-Oct. Wet paddy fields and river­banks. 

Honshu, Shikoku, Kyushu; common.  India, China, Malaysia, Korea, Ryukyus, Formosa, and Australia.

var. oryzetorum (Makino) Ohwi Culms erect, 30-60 cm. long; leaves 10-20 cm. long, 3-6 mm. wide; spike purplish, 3-12 cm. long, erect, densely flowered. Paddy fields and along river­banks; Honshu, Shikoku, Kyushu; common. Ryukyus, For­mosa, and China.