Culms densely tufted, central, ascending or lax, 24-82 cm × 0.8-1.6 mm. Leaves: basal sheaths light brown to brown; sheaths green or yellow-green, 2-26 mm; blades ascending, green or yellow-green, midrib well developed abaxially, 2 lateral veins well developed adaxially, flat, 18-44 cm × 12-14 mm, blade of overwintering leaves smooth abaxially. Inflorescences: peduncles of proximal spikes 0-12 cm, arising in proximal 1/3 of culm, distal lateral spikes not exerted; peduncles of terminal spike 0-2.8 cm; bracts 8-21 × 0.5-4 mm, blade of distal lateral spike linear, narrower than spikes; widest bract blade of distalmost lateral spike 0.5-3.4 mm wide. Spikes 3(-4) per culm; lateral spikes 6-9(-15) × 4-6 mm, distal ones separate; terminal spike 11-35 × 1.8-3 mm, exceeding distal lateral spike. Pistillate scales 2-2.5 × 0.8-1.2 mm, apex acute. Staminate scales 3.2-4.2 × 1-1.2 mm, margins hyaline or brown tinged, apex acute. Anthers 3.8-4 mm. Perigynia 4-20 per spike, closely to loosely overlapping, ratio of longer lateral spike length to perigynia number 0.8-3.4, aggregated, spreading, finely, conspicuously (22-)25-32-veined, narrowly elongate ovate, 3.5-5.5 × 1.2-1.6 mm, 1.9-2.3 times as long as achene bodies; beak excurved, 0.5-1.7 mm. Achenes elongate-obovoid, 2.2-3.2 × 1-1.4 mm. 2n = 48. Fruiting spring. Wet, sandy, acidic soils, around springs, seeps, and small streams, under deciduous or mixed deciduous-evergreen forests; 0-1000 m; Ala., Conn., Del., D.C., Fla., Ga., Ky., La., Md., Miss., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Tex., Va.
Plants 3-8 dm, forming large tufts; fertile stems lax or ascending, sharply triangular but not winged, minutely roughened above; basal sheaths ±brown; largest lvs to 7 mm wide, seldom more; terminal spike staminate, 1-3.5 cm, its peduncle usually and its summit always surpassing the short (ca 5 mm), sessile, uppermost pistillate spike; pistillate spikes 2-5, 0.5-2 cm, widely separated but none basal, the lowest on a long, drooping peduncle, the upper on short, scarcely exserted peduncles; pistillate scales acute to acuminate; perigynia 4-20, closely overlapping, greenish-stramineous, 3.5-5.5 mm, finely many-nerved as well as 2-ribbed, obtusely trigonous, fusiform, long tapering to both ends, the elongate but ill-defined beak somewhat outcurved, with an oblique, entire orifice; achene trigonous; 2n=48. Wet woods and bogs, often in sandy or silty soil; Conn. to Fla., w. to s. O., Ky., Tenn., La., and se. Tex.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.