Japan Flora: Slender green perennial; culms 50-80 cm. long, with retrorsely pilose nodes; leaf-blades thin, broadly linear, flat, 15-25 cm. long, 8-12 mm. wide, abruptly 3-acuminate, scabrous; ligules 1-1.5 mm. long; panicles 10-20 cm. long, partly or at length wholly exserted, sometimes wholly inclosed within the sheath, the branches single, slender, spreading, loosely spiculose; spikelets oblong, flat, whitish green, rather acute, 4.5-6 mm. long, 1.5-2 mm. wide, bristly ciliate, loosely short-setose on nerves; stamens 3, the anthers linear, to 1.5 mm. in chasmogamic flowers, minute in the cleistogamic. Aug.-Oct. Wet places. 

Hokkaido, Honshu, Shikoku, Kyushu; common. Widely distributed in temperate regions.

var. japonica Hack. Spikelets linear-oblong, short-ciliate, green, 5-6.6 mm. long, about 1.5 mm. wide; leaf-blades not ciliate. Aug.-Oct. Wet places; Hokkaido (sw. distr.), Honshu, Shikoku, Kyu­shu; rather common.             

f. latifolia (Honda) Ohwi. A larger phase of var. japonica with leaves 10-25 mm. wide, and panicles 20-30 cm. long. Kyushu.