Plants cespitose; rhizomes short or inconspicuous. Culms trigonous in cross section, 40-120 cm, smooth distally. Leaves: basal sheaths reddish purple; ligules as wide to slightly longer than wide; blades dark green, flat to W-shaped, 2-5 mm wide, glabrous. Inflorescences 10-35 cm; proximal bract 25-70 cm, exceeding inflorescence; proximal (1-)2-3(-4) spikes pistillate, erect or the proximal spreading or pendent, cylindric; terminal 1-3 spikes staminate. Pistillate scales narrowly ovate, 3.9-5.2 × 1.2-2.4 mm, shorter than perigynia, margins entire, apex acute, awnless. Perigynia ascending, often green or straw colored, strongly 7-12-veined, veins running to beak, broadly elliptic, 7.5-12.5 × (4-)4.5-7 mm, apex contracted; beak 2.4-4.8 mm, smooth, bidentate, teeth straight, 0.7-1.9 mm. Stigmas 3. Achenes brown, trigonous, asymmetric, deeply indented on 1 face, smooth. Fruiting Jun-Aug. Deciduous swamp forests, thickets, often along streams or pond shores, wet meadows; 0-500 m; N.B., Ont., Que.; Conn., Ind., Maine, Md., Mich., Minn., N.Y., Ohio, Pa., Vt., Wis.