Japan Flora: Plant very densely tufted; culms 30-50 cm. long, firm, slender, scabrous; leaf-blades 1-1.5 mm. wide, firm, glaucous- green, conduplicate, the basal sheaths rigid, bladeless, chestnut­brown, lustrous, fibrous-reticulate; spikes 2 or 3, on the apical part of the culm, the terminal staminate, linear, 2-3 cm. long, the others pistillate, nearly globose, approximate, 5-10 mm. long, sessile, the bracts usually scalelike, short, not sheathing; pistillate scales ovate-oblong, dark purplish brown, obtuse; perigynia slightly broader than the scales, ellipsoidal, 3-3.5 mm. long, compressed-trigonous, cinereous-glaucous, densely papillose, several-nerved, abruptly short-beaked, the apex dark brown; stigmas 3, relatively thick.  May-July. Wet boggy places and high moors. 

Honshu (n. and centr.), Kyushu. Korea and e. Siberia.