Japan Flora: Tufted perennial; culms erect, 30-80 cm. long, firm, glabrous; leaves chiefly radical, the blades firm, linear, 20-60 cm. long, 1.5-5 mm. wide, loosely involute or with involute margins, gradually acuminate, glabrous or with short hairs above; sheaths white-hairy near the summit; ligule a ring of short hairs; panicles narrow and rather spike­like, rarely slightly interrupted, erect, 15-40 cm. long, 5-10 mm. wide, the branches numerous, appressed, densely spiculose; spikelets 2-2.5 mm. long, at first lanceolate, obovate when mature, lustrous, pale lead-green; glumes unequal, the first ovate, obtuse, 1/4-1/3 as long as the spikelet, the second broadly lanceolate, rather obtuse, 1-1.5 mm. long, 1/2-2/3 as long as the spikelet; lemma narrowly ovate, 2-2.2 mm. long, the nerve faint, smooth, obtuse; stamens 3; anthers 0.5-0.7 mm. long, pale yellow. Sept-Nov. Waste grounds, riverbanks, and sunny places in lowlands; Honshu, Shikoku, Kyushu; very common. Warmer parts of Asia and Australia. 

var. purpureosuffusus Ohwi. Plant larger with an elongate inflorescence and pale reddish purple spikelet. Grows with the typical phase.