Plants cespitose; rhizomes long. Culms trigonous in cross section, 30–85 cm, scabrous angled distally. Leaves: basal sheaths reddish purple; ligules as wide as to longer than wide; blades light green, glabrous, flat to W-shaped, widest leaves 1.8–4.3(–5) mm wide. Inflorescences 8–30 cm; proximal bract (3–)9–35 cm, mostly equaling or exceeding inflorescence; proximal 1–3 spikes pistillate, erect or, sometimes, the proximal spreading, cylindric; terminal 1–3 spikes staminate. Pistillate scales narrowly ovate, 3.5–5.2 × 1.1–2.1 mm, shorter than perigynia, margins entire, apex obtuse to acute, awnless. Perigynia ascending to spreading, often green or straw colored, strongly 9–12-veined, veins running into beak, lance-ovate, 5.9–10.2 × 2.4–3.3 mm, apex contracted; beak 2.4–4.2(–4.8) mm, bidentate, finely scabrous at least near tip and on teeth, teeth straight, to 0.5–1.4 mm. Stigmas 3. Achenes brown, symmetric, not indented, trigonous, smooth.

Fruiting May–Aug. Acidic soil of bogs and boggy meadows, open swamp forests, peaty or sandy pond and lakeshores, seeps; 0–1100 m; N.S.; Ark., Conn., Del., Ga., Maine, Md., Mass., N.J., N.Y., N.C., R.I., Tenn., Va.