Plants perennial; rhizomes 1-4 mm thick, soft to hard, longer internodes 3-7.5 cm, scales 5 mm, tubers absent. Culms terete or obtusely trigonous, 30-80 cm × 1-5 mm, soft to hard, not septate-nodulose, internally spongy, transverse septa incomplete; plants never forming filiform, flaccid culms. Leaves: distal leaf sheaths persistent, membranous, apex acute to acuminate, often prolonged into a slender awn to 4 mm. Spikelets not proliferous, 14-54 × 3-5.6 mm; rachilla joints without winglike remnants of floral scales; proximal scale empty, amplexicaulous, 2.5-4.9 mm; floral scales 40-180, 2-3 per mm of rachilla, stramineous to pale brown, flanks sometimes minutely dotted reddish, usually with pale to dark brown, reddish, or purplish submarginal band, obovate to suborbicular, widest in middle, 3.4-4.5(-6) × 3-4.8 mm, cartilaginous, membranous toward margins, margins broadly translucent, membranous, apex rounded. Flowers: perianth bristles 6-7, medium brown to pale brown or reddish, slender, proximally slightly flattened, subequal to unequal, mostly exceeding achene, 2-3.4 mm, smooth or sometimes finely retrorsely spinulose; anthers reddish brown, 1.7-2.5 mm; styles 3-fid. Achenes brown, biconvex, obpyriform, 2.2-2.8 × 1.3-1.9 mm, markedly sculptured at 10-15X, each face with (17-)20-24 rows of isodiametric to slightly transversely elongated cells, apex narrowed to a stout, often pale, spongy region 0.8-1.1 mm wide at base, 1/2-3/4 of achene width. Tubercles dark brown, lamelliform to pyramidal, 0.1-0.5 × 0.2-0.5 mm.

Fruiting late spring-winter. Brackish to saline marshes, shores, ditches, mostly coastal, often abundant or dominant; 0 (Florida)-600 (Arkansas, Texas) m; Ala., Ark., Fla., Ga., Miss., N.C., S.C., Tex.; Mexico; West Indies; Central America (Nicaragua).