Japan Flora: Rhi­zomes tufted; the neck thickly covered with dark brown fibers; culms slender, 20-50 cm. long, nearly glabrous; leaf­blades elongate, 2-3 mm. wide; spikes 2 or 3, erect, approxi­mate, the terminal staminate, clavate, 1-1.5 cm. long, the lateral pistillate, ovoid to oblong, 5-15 mm. long, the upper ones nearly sessile, the lowest bract setaceous, short-sheathing; pistillate scales oblong, brown, obtuse or rounded; perigynia slightly longer than the scales, about 3 mm. long, obliquely spreading, obovoid, faintly nerved, hispidulous, abruptly very short-beaked, 2-toothed at apex; stigmas 3, short. May-July. Sunny fields or open woods; Hokkaido, Honshu (n. distr.). e. Siberia, Sakhalin, s.  Kuriles, and Korea.

var. rostrata (Maxim.) Ohwi. Rhizomes tufted and creeping; leaves elongate and much overtopping the culms after flowering. May-July. Wet grassy places; Honshu (n. and centr. distr.), Kyushu (n. distr.).  e. Siberia and Korea.