Culms 7-31 cm. Leaf blades involute, bristlelike, 3-21 cm × 0.2-1 mm. Inflorescences: proximal bract sheaths 2.5-8 mm; pistillate spikes 3-7 × 1.5-6 mm; staminate spikes 3-10 × 0.5-1.5 mm, inconspicuous. Scales: pistillate scales white-hyaline, with green or brown midvein, ovate to ovate-circular, 1-2 × 0.7-1.4 mm, shorter than or equaling perigynia; staminate scales, white-hyaline, with broad hyaline margins, elliptic-oblanceolate, 2.6-4 × 0.7-2 mm, apex obtuse or subacute. Anthers 1.3-1.8 mm. Perigynia light green becoming dark brown and glossy, 1.5-2.2 × 0.7-1.1 mm; beak 0.2-0.4(-0.5) mm. Achenes ellipsoid-obovoid. Fruiting late spring-mid summer. Usually in conifer or mixed forests, occasionally fens, stable dunes and alvar, on neutral or calcareous substrates; 0-2000 m; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Ont., Que., Sask., Yukon; Ala., Alaska, Ark., Conn., Ill., Ind., Iowa, Ky., Maine, Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Pa., S.C., S.Dak., Tenn., Vt., Va., W.Va., Wis.; c Mexico.