Japan Flora: Slender to rather stout perennial; culms erect from an ascending base, 80-120 cm. long; leaf-blades flat, somewhat membranous, 30-60 cm. long, 3-7(니0〉mm. wide; sheaths terete; ligules short, truncate; panicles lanceolate to ovate, 15-40 cm. long; spikelets narrowly oblong, 5-7 mm. long, 3- to 6-flowered, pale green, sometimes tinged pale purple; glumes oblong, obtuse, weakly 1-nerved, the 1st about 1 mm. long, the 2d 1.5-2 mm. long; lemmas ovate, obtuse, about 2.2 mm. long, 7-nerved; palea with conspicuously curved keels, slightly inflated below. May-June. Ponds and river­ banks.

Hokkaido, Honshu, Shikoku, Kyushu; common. Korea.