Plants densely cespitose. Culms 9-30(-40) cm. Leaves: sheaths adaxially white-hyaline, sometimes cross-corrugate adaxially, summits usually U-shaped, sometimes prolonged to 3 mm beyond collar; distal ligules 0.3-2 mm; blades 3-4(-5) per fertile culm, 3-16 cm × 1.5-4 mm. Inflorescences dense, dark brown, green and brown, or gold, 1.1-2.1 cm × 13-18 mm; proximal internode 1-2.5(-3.4) mm; 2d internode 0.5-2 mm; proximal bracts scalelike, shorter than inflorescences. Spikes 5-7(-9), aggregated, individually indistinct broadly ovoid, 6.5-10 × 4.5-8 mm, base and apex usually rounded. Pistillate scales reddish or coppery to dark brown, sometimes with whitish or pale gold midstripe, narrowly ovate to ovate, 3-4.8 mm, shorter and narrower than perigynia, apex acute to obtuse. Perigynia ascending to ascending-spreading, light brown to coppery or dark brown, conspicuously 0-3(-8)-veined adaxially, lance-ovate to broadly ovate, flat except over achene, 4-6.5 × 1.5-2.6 mm, 0.3-0.5 mm thick, margin flat, including wing 0.3-0.6(-0.8) mm wide, ciliate-serrulate at least on distal body; beak dark brown to black, white-hyaline at tip, cylindric, unwinged, at least 1 mm, ± entire for 0.3-0.6 mm, abaxial suture inconspicuous or with conspicuous white margin, distance from beak tip to achene (2.3-)2.6-3.8 mm. Achenes elliptic or ovate, (1.2-)1.4-1.8 × 0.8-1.1(-1.3) mm, 0.3-0.45 mm thick. 2n = 82.
Fruiting summer. Rocky or gravelly subalpine to alpine meadows, slopes, stream banks; 1700-4300 m; Alta., B.C.; Calif., Colo., Idaho, Mont., Oreg., Utah, Wash., Wyo.