Rhizome creeping. Culms tufted, stout, trigonous, 60-100 cm tall. Leaves shorter than culm, blades widely linear, 6-10 mm wide, flat, margins slightly revolute. Involucral bracts leaflike, lower 3 surpassing inflorescence. Spikes numerous, usually 10-30, 2-4 from axil of involucral bract; upper 3-6 spikes male, sometimes some becoming androgynous and bearing several female flowers at base, cylindric or clavate, 1.5-5.5 cm, with slender, scabrous peduncles 1-12 cm, pendent. Female glumes pale brown or ferruginous, elliptic-lanceolate or lanceolate, 3-3.8 mm, green 3-veined costa excurrent into a mucro. Utricles brown-green with brown-purple flecks, shorter than glume, elliptic or ovate, biconvex, 2.5-3 mm, 4-6-veined, base stipitate, apex abruptly contracted into a short beak, orifice entire. Nutlets dark castaneous, tightly enveloped, oblong, ca. 2 mm; style base not thickened, curved; stigmas 2. Fl. and fr. Jun-Sep.

Margins of wet places; 1000-1800 m. Heilongjiang, Jilin [Korea, Russia (Far East)].