Plants densely cespitose. Culms (9-)16-60 cm. Leaves: sheath adaxially white-hyaline, summits usually U-shaped, rarely prolonged to 3 mm beyond collar; distal ligules 0.5-2.5(-3) mm; blades 2-6 per fertile culm, (4-)8-18 cm × (1.7-)2-3.6(-4) mm. Inflorescences stiffly erect, dense, brown or dark brown, 0.9-2.1 cm × 10-15(-18.5) mm; proximal internode 1.5-3.7(-4.8) mm; 2d internode 1-3 mm; proximal bracts scalelike or bristlelike, shorter than inflorescences. Spikes (3-)5-9, densely aggregated, ± individually indistinct, ovoid to broadly ovoid, 5.5-10.5 × 4-7 mm, base rounded to acute or tapered, apex truncate to tapered. Pistillate scales gold to brown, often reddish, sometimes with whitish or gold midstripe, ovate to broadly ovate, 2.7-3.5(-4) mm, shorter or longer and usually narrower than perigynia, margin, white-hyaline usually conspicuous, 0.03-0.25 mm wide, apex usually obtuse. Perigynia appressed-ascending to ascending-spreading, straw colored, gold, red-brown, or coppery, conspicuously 0-7(-11)-veined abaxially, conspicuously 0-3-veined adaxially, narrowly to broadly ovate, plano-convex to biconvex, occasionally ± flat around achene, 3.5-4.5 × (1.1-)1.3-2 mm, 0.4-0.5 mm thick, margin flat, including wing 0.2-0.5 mm wide, darker than perigynium body, ciliate-serrulate at least on distal body, pithlike tissue usually present in proximal perigynium walls in U-shape around achene, glossy metallic sheen; beak white, golden brown, red-brown, brown, or dark brown, usually white-hyaline at tip, cylindric, unwinged, ± entire for (0.4-)0.5-0.6(-0.9) mm, abaxial suture usually white, conspicuous, distance from beak tip to achene (1.2-)1.6-2.4 mm. Achenes usually elliptic, (1.2-)1.4-1.9 × 0.85-1.1 mm, 0.35-0.5 mm thick. 2n = 86.

Fruiting summer-early fall. Mountain lake and river shores, moist meadows and slopes, bogs, and other wet areas, disturbed areas; 0-3300 m; Greenland; Alta., B.C., Nfld. and Labr. (Labr.), N.W.T., Que., Yukon; Alaska, Colo., Mont., Wyo.; South America (Chile to Tierra del Fuego); Europe (Finland, Iceland, Norway, n Sweden).