Plants colonial; rhizomes long-creeping. Culms central, trigonous, 10-40(-50) cm, smooth, base with remains of previous year´s leaves. Leaves: basal sheaths straw colored to dark brown, the youngest tinged reddish purple, apex of inner band glabrous; ligules 0.8-1.6 mm; blades M-shaped distally, channeled proximally; 2-5.5 mm wide, glabrous. Inflorescences 8-25 cm; peduncle of terminal spike 0.7-3 cm; proximal 2-4 spikes pistillate or, sometimes, androgynous, erect; terminal 1-3 spikes staminate. Pistillate scales ovate, apex otuse to acute, glabrous or scabrous-margined apically. Perigynia ascending, 12-20-veined, ovoid, 3.5-5.5 × 1.6-2.2 mm, pubescent; beak hyaline, 1.2-1.7 mm, ciliate, bidentulate, teeth straight, 0.2-0.6 mm.

Fruiting Jun-Sep. Dry, sandy, gravelly or rocky meadows, shores, other open habitats; 1400-2000 m; Calif., Oreg., Wash.