Plants cespitose; rhizomes short. Culms central, trigonous, 45-130 cm, smooth. Leaves: basal sheaths reddish purple tinged, pubescent; ligules 3-17 mm; blades green, M-shaped, 4-9 mm wide, pubescent on both blade surfaces and apex of inner band of distalmost sheaths. Inflorescences 4-17 cm; proximal 3-4(-5) spikes pistillate, ascending; distal spikes erect; terminal spike staminate. Pistillate scales lanceolate to ovate, apex acute, pubescent abaxially, ciliate. Perigynia ascending to spreading, greenish to brown, sometimes purplish tinged on beak, prominently 2-ribbed and faintly 6-10-veined, broadly ovoid, 2.3-3.7 × 1.2-1.8 mm, pubescent; beak 0.4-1 mm, ± hyaline, friable, ± irregularly bidentulate or erose, ciliate.

Fruiting Jun-Aug. Moist to wet meadows and open forests, lakeshores, stream banks; 1200-2600 m; Calif.