Japan Flora: Culms 20-50 cm. long, tufted, acutely angled, scabrous; leaf-blades 2-3(-5) mm. wide, soft, flat, bright green, scabrous; spike solitary, androgynous, narrowly oblong, 1.5-4 cm. long, the pistillate many-flowered, longer than to nearly as long as the staminate; pistillate scales ovate, acute, pale, the midrib green; perigynia nearly twice as long as the scales, 5-6 mm. long, suberect, ovate, 3-angled, light green, weakly many-nerved, thinly membranous, gradually long-beaked, obliquely truncate and hyaline at tip; stigmas 3.  Apr.-June. Wet places along streams in low mountains;

Hokkaido, Honshu, Shikoku, Kyushu; common.  s. Kuriles(?)