Plants cespitose; rhizomes appearing elongate in old clumps. Culms uniformly slender, 40-80 cm; vegetative culms few, inconspicuous, usually fewer than 15 leaves, not strikingly 3-ranked. Leaves: sheaths adaxially conspicuously green-veined nearly to collar, narrow hyaline band or sharp Y-shaped region at collar, adaxially firm, summits U-shaped; distal ligules 1.6-3.3 mm; blades 2-5 per fertile culm, 12-18 cm × 1.5-2.5 mm. Inflorescences stiffly erect, dense to slightly open, brown, 1.5-3(-3.5) cm × 6-14 mm; proximal internode 2-12 mm; 2d internode 2-7 mm; proximal bracts scalelike, often with bristletips shorter than or equaling inflorescences. Spikes 2-5, distant, distinct, ovoid, 7-12 × 4-7 mm, base rounded or short-acute, apex acute. Pistillate scales reddish brown, 1-veined midstripe sometimes pale, broadly lanceolate, 2.7-3.6 mm, shorter and narrower than perigynia, apex firm, acute to acuminate. Perigynia 15-80 in larger spikes, appressed, usually golden brown, conspicuously 6-9-veined abaxially, inconspicuously veined adaxially, diamond shaped, flat except over achene, 4-5 × 2-2.8 mm, 0.4-0.5 mm thick, base subacute or acute, margin flat, including wing 0.6-0.9 mm wide, smooth; beak apprressed, golden brown at tip, flat, 0.7-1.6(-1.8) mm, 2/5+ length of body, ciliate-serrulate, abaxial suture with hyaline, golden brown margin, distance from beak tip to achene 2-3 mm. Achenes elliptic to ovate, 1.5-1.7 × 0.8-1.1 mm, 0.3-0.4 mm thick. 2n = 72.
Fruiting early summer. Calcareous fens and seeps, shores, swales; 100-600 m; Ont.; Ark., Ill., Ind., Iowa, Mich., Minn., Mo., Ohio, Tex., Va., Wis., W.Va.
Tufted, aphyllopodic, 3-7 dm; main lvs 2-3 mm wide, shorter or longer than the stem, their sheaths ventrally green-veined almost to the summit, with only a short hyaline area; spikes 2-5, gynaecandrous, ovoid, 7-12 mm, sessile, distinct but closely aggregated into an ovoid or short-oblong infl; pistillate scales shorter and narrower than the perigynia, yellowish-brown with pale midnerve and narrow hyaline margins, acute to cuspidate; perigynia numerous, appressed, prominently distended over the achene, 3.9-5.1 נ2.1-2.6 mm, 1.8-2.4 times as long as wide, broadest at a third to two-fifths their length, the broad body straight-tapered to the base, faintly nerved dorsally, nerveless or nearly so ventrally, abruptly contracted to the flat, serrulate beak; achene lenticular, 1.5 נ1 mm. Swamps and moist or wet meadows and shores, calciphile; s. Ont. to w. Va., s. Minn., and Mo.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.