Herbs, perennial, cespitose, rhizomatous. Culms trigonous, compressed, 15-75 cm × 0.5-3 mm, glabrous. Leaves 1-3, 5-30 cm × 1-2 mm. Inflorescences: spikes 1(-2), ovoid, 5-23 × 9-21 mm; rays 2-3(-4), 0-15 mm; if rays absent, head single, compact, sessile, (12-)15-20 mm diam.; bracts 2-3, horizontal to vertical, 2-14 cm × 0.5-3.5 mm. Spikelets 1-6, oblong-lanceoloid, 5-26 × 2-3 mm; floral scales 12-54, closely imbricate, laterally yellowish brown, medially pale brown, occasionally greenish, laterally 1-ribbed, medially 3-ribbed, distinctly 2-keeled basally, ovate, 1.8-2.6 × 1.4-1.7 mm, apex obtuse. Flowers: stamens 2; anthers 0.4-0.5 mm, connectives not prolonged; styles 0.3-1 mm; stigmas 0.6-0.8(-1) mm. Achenes brown, network of ridges forming isodiametric or square cells, stipitate, obovoid to ellipsoid, 1.1-1.3 × (0.5-)0.6 mm, apex acute to broadly rounded, surfaces minutely punctate or finely papillose. Fruiting summer. Marshes; 0-100 m; Ala., Fla., Ga., La., Tex.; Mexico; Central America; South America; Africa.