Japan Flora: Rhizomes short, tufted; culms 20-40 cm. long, soft^ acutely angled, 0.6-1 mm. thick, prominently scabrous on the angles; leaf-blades 2-3 mm. wide, flat, soft, thin; spike solitary, terminal, androgynous, ovoid-globose, 5-7 mm. long, 斗-5 mm. in diameter, the staminate inconspicuous, the pistillate with rather many flowers; pistillate scales ovate-elliptic, pale, some­times the lower 1 or 2 ending in a short awn; perigynia longer than the scales, 2-2.5 mm. long, spreading, broadly ovoid, slightly compressed, 3-angled, few-nerved on each side, abruptly short-beaked, with a membranous entire tip; stigmas 3, short. June-July. Wet places in mountains.

Honshu (n. and centr. distr. and Bitchu Prov.); rather rare.