Herbs, annual, cespitose, with fibrous roots. Culms trigonous, 4-25(-35) cm, glabrous. Leaves flat, 5-20 cm × 1.5-3 mm. Inflorescences: heads ± digitate, 12-22 mm diam.; rays 3-6, 1-6 cm; bracts 1-4, ± horizontal, flat, 1.5-15 cm × 1.5-3 mm. Spikelets 6-12, oblong-lanceoloid, compressed, 5-10 × 2.8-3.2 mm; floral scales 8-28, closely imbricate, stramineous to light brown or clear (marginal band bright red, spikelet thus appearing dark margined), laterally ribless, oblong to ovate, 2.5-3 × 1.6-1.9 mm. Flowers: stamens 2(-3); anthers 0.3 mm, connective apex reddish, subulate, 0.1-0.2 mm; styles 0.3-0.5 mm; stigmas 2.2-3.1 mm. Achenes brown, network of ridges forming isodiametric or square cells, sessile or stipitate, obovoid to ovoid, 1-1.2 × 0.5-0.6 mm, stipe, if present, 0.1 mm, apex obtuse, apiculate, surfaces minutely punctate. Fruiting summer. Emergent shorelines, in sandy, peaty, or slightly brackish areas (though seldom where disturbed); 0-600 m; N.B., N.S., Ont., Que.; Conn., Del., Ill., Ind., Iowa, Maine, Md., Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Y., Pa., R.I., Vt., Va.