Japan Flora: Soft perennial; culms 20-70 cm. long, erect from a long, creeping base with sterile ascending innovations; leaf­blades thin, flat, 10-30 cm. long, 3-6 mm. wide, nearly smooth, glaucescent above, short-acuminate; ligules 4-7 mm. long, nar­rowly deltoid; panicles linear, 10-30 cm. long, partly enclosed within the uppermost leaf-sheath, with 5 to 20 spikelets, the branches geminate, strongly unequal, appressed to the axis, smooth; spikelets 25-50 mm. long, pale green, 9- to 15-flowered, short-pedicelled; glumes unequal, 1-nerved, lanceolate, rather acute, the lower about 2 mm., the upper 4-5 mm. long; lemmas lanceolate, minntely scabrous, 7-9 mm. long, 7-nerved, with short, parallel veinlets between the nerves; palea 0.7-1 mm. longer than the lemma, bicuspidate; caryopsis 3-4 mm. long. May-June. Ponds, paddy fields.

Honshu, Shikoku, Kyu­shu; common. Korea, Ryukyus, China, and N. America.