Plants densely cespitose. Culms 40-100 cm; vegetative culms conspicuous, with spreading leaf blades evenly along stem. Leaves: sheaths adaxially green-veined to within 3 mm of collar, adaxially firm, summits usually brown tinged, U- or V-shaped, thick; distal ligules to 2 mm; blades 7-12 per fertile culm, 12-25 cm × 3-5 mm. Inflorescences open at least proximally, brown, (4-)5-9 cm × 10-20 mm; proximal internode (4-)5-15 mm; 2d internode (3-)5-11 mm; proximal bracts scalelike. Spikes 5-12, distant, distinct, lanceoloid, 12-28 × 3.5-7 mm, bases tapered, apex acute. Pistillate scales white-hyaline or pale brown with pale brown midstripe, oblong-ovate, 4-5 mm, 1/2 length of and narrower than perigynia, apex acute. Perigynia appressed-erect, pale brown, conspicuously 5-7-veined abaxially, conspicuously 3-7-veined adaxially, lanceolate, flat to plano-convex, 6-9 × (1.5-) 2-2.5 mm, 0.3 mm thick, margin flat, including wing 0.2-0.4 mm wide; beak tip flat, ciliate-serrulate, abaxial suture inconspicuous, distance from beak tip to achene 3.1-4.5 mm. Achenes elongate-oblong, 2-2.7 × 0.8-0.9 mm, 0.3 mm thick. 2n = 80. Fruiting early-mid summer. Moist to wet, deciduous flood plains, lowland woods, and thickets; 100-400 m; Ont.; Ark., Ill., Ind., Iowa, Kans., Ky., Mich., Minn., Mo., Ohio, Okla., Tenn., Wis.
Cespitose, with numerous very leafy sterile stems; fertile stems stout, 5-10 dm; main lvs 3-5 mm wide; sheaths ventrally green-veined almost to the summit; spikes 5-10, gynaecandrous, fusiform, pointed at both ends, 15-25 נ4-6 mm, closely aggregated into a dense cluster 4-8 cm; pistillate scales lanceolate, half as long as the perigynia, pale brown with hyaline margins; perigynia appressed, lanceolate, thin, 6.5-10 mm, 3-4 times as long as wide, finely nerved on both sides, gradually tapering to the flat, serrulate, deeply bidentate beak half as long as the body; achene lenticular, 2-2.5 mm, less than 1 mm wide. Low woods, wet meadows, and river-bottomlands; O. and Ky. to Mich., Minn., Man., Kans., and Okla.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.