Culms obtusely trigonous in cross section, 45-100(-160) cm, smooth. Leaves: ligules 3-12 mm, mostly longer than wide; blades yellowish or light green, widest leaves 1.8-6 mm wide, smooth or sometimes papillose, especially distally. Inflorescences (3-)5-30(-45) cm; proximal (1-)2-3 spikes pistillate, erect or the proximal spreading, aggregated or the proximal sometimes remote, ovoid to short-cylindric. Pistillate scales ovate, 1/3-2/3 as long as perigynia, apex acute to acuminate. Anthers 2.3-5.1 mm. Perigynia spreading or the proximal somewhat reflexed, yellowish green, 22-34-veined, inflated, ovate to narrowly ovate, 6.4-10.7 × 2-3.5 mm, 2.6-3.9 times as long as wide, apex contracted; beak 1.3-3 mm. Achenes 2.8-3.6 × 1.6-2.2 mm.

Fruiting spring-early summer. Wet savannas, wet open forests, seeps, stream banks, often in shallow water, in sandy or peaty, acidic soils; 0-200 m; Ala., Fla., Ga., La., Miss., N.C., S.C.