Plants loosely cespitose; rhizomes long, slender. Culms ± erect, weak, 10-50 cm. Leaves: sheaths pale brown abaxially, inner band hyaline, concave at summit; ligules as long as wide; blades pale green, flat or channeled, 5-15 cm × 0.5-2 mm. Inflorescences erect, ovoid or suborbicular, 0.6-1.2 cm × 4-9 mm; proximal bracts scalelike, sometimes bristlelike, shorter than inflorescences. Spikes 2-4, gynecandrous, closely approximate, containing 3-15 perigynia, short-oblong, 4-9 × 3-6 mm. Pistillate scales white-hyaline with green, 3-veined center, ovate, subequal to perigynia, apex obtuse. Perigynia appressed-ascending, gray-green, obscurely few-veined, obovate-elliptic, 3-3.5 × 1.5-1.75 mm, subcoriaceous; beak absent or nearly so. Achenes pale brown, oblong-elliptic, 1.5-2 × 1.25(-1.5) mm, glossy. 2n = 58.

Fruiting May-Aug. Mires, especially sphagnum bogs, wet woodlands, lowlands; 0-1400 m; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., Ont., P.E.I., Que., Sask., Yukon; Alaska, Colo., Maine, Mass., Mich., Minn., Mont., Ohio, N.Y., Vt., Wis.; n Eurasia.