Herbs, perennial, cespitose, shortly rhizomatous. Culms trigonous, (2-)25-60(-100) cm × 1-4 mm, soft (flattened in drying), glabrous. Leaves usually reduced to sheaths, occasionally with blades, flat to V-shaped, (3-)10-30 cm × (1-)2.5-5 mm. Inflorescences: heads loosely digitate; rays (5-)10-12(-15), 1-15(-20) cm; 2d order rays usually present, (1-)6-12(-25) mm; 3d order rays sometimes present, 1-6 mm; bracts 2(-3), horizontal to ascending at 30-60°, longer (3-)6-18 cm × 2-4 mm, shorter (0.5-)2.5-6.5 cm × 1-2(-3) mm. Spikelets 1-15, linear-lanceoloid, ± compressed-quadrangular, 3-18 × 1-1.6 mm; floral scales 10-20(-40), laterally reddish to greenish brown, dull, often clear-edged, medially greenish, laterally 1-ribbed, medially 1-ribbed, oblong to obovate, 1-1.5(-1.9) × 0.8-1 mm, apex mucronate, glabrous except for cluster of crystalline prickles at apex. Flowers: stamens 3; anthers 0.3-0.5 mm; styles 0.4-0.9 mm; stigmas 0.5-0.8(-1.3) mm. Achenes white or reddish brown, stipitate, globose to obovoid or ellipsoid, 0.5-0.6(-0.7) × 0.3-0.4(-0.5) mm, base nearly cuneate, stipe 0.1 × 0.1-0.2 mm, apex obtuse to acute, apiculate or entire, surfaces granular to papillose. Fruiting summer. Swales between dunes, marshes, pond shores; 0-200 m; Ala., Fla., Ga., La., Miss., N.C., S.C., Tex., Va.; Mexico; Central America; South America; Asia; Africa; Australia.

Somewhat cespitose perennial 2-7 dm; lowest cauline lvs ordinarily reduced to blade less sheaths, the uppermost either bladeless or rarely with well developed blade; bracts 2, erect or ascending, usually shorter than the infl; rays none or to 10 cm, often branched at the top; spikes short, loosely subglobose, 1-2 cm thick; spikelets to 1 cm, flattened with 5-25 fls; rachilla persistent; scales ovate or elliptic, 1-1.5 mm, 3-nerved in the center, obtuse, often red-purple; rachilla wingless; achenes obovoid-trigonous, pearly white, 0.4-0.7 mm; 2n=26. Swamps and shallow water, mostly near the coast; pantrop., n. to se. Va.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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