Rhizome obliquely ascending, stoloniferous; stolons slender, clothed with red-brown leaf sheaths. Culms loosely tufted, 20-60 cm tall, slender, triquetrous, slightly scabrous on upper part, red-brown and bladeless sheathed at base; sheaths at membranous part usually disintegrating into reticulate fibers. Leaves equaling or slightly shorter than culm, blades 1-2 mm wide, rather soft, glabrous, margins revolute, upper margin scabrous; sheaths rather long, hispidulous adaxially. Lower involucral bracts leaflike, linear, shorter than inflorescence, nearly not sheathed, upper involucral bracts scalelike, not sheathed. Spikes 3 or 4, male spike and uppermost female spike approximate, remaining spikes remote; terminal spike male, linear, 1-2 cm, subsessile; lateral spikes female, oblong, ovate, or subglobose, 0.5-1.2 cm, few flowered; lowermost spike very shortly pedunculate, upper ones sessile. Female glumes yellow-brown at middle, ovate, ca. 2 mm, membranous, 3-veined, sometimes 2 lateral veins indistinct, margins yellowish white, apex obtuse, muticous. Utricles green-brown, obliquely patent, longer than glume, broadly obovate or broadly elliptic, trigonous, 2.5-3 mm, membranous, densely hispidulous, many veined, base broadly cuneate, apex abruptly contracted into a short beak, orifice emarginate. Nutlets dark brown, tightly enveloped, obovate or broadly obovate, trigonous, 1.8-2 mm, apex mucronate; style base not thickened; stigmas 3. Fl. and fr. Jun-Aug.

The stems and leaves of this species are good pasture for sheep, cows, and horses.

Grasslands on mountain slopes, wet places in forests, swamps. Heilongjiang, Jilin, Nei Mongol [Japan, Korea, Russia; Europe].