Plants with basal sheaths of previous year persistent as linear fibers. Culms to 80 cm × 3.5 mm, scabrous abaxially. Leaves: sheaths all with blades, fronts rugose, red-brown spotted, veinless, apex hyaline, colorless, fragile, convex, entire; ligules rounded, 7 mm, free limb to 0.5 mm; blades not epistomic, to 75 cm × 8 mm. Inflorescences densely spicate, cylindric, elongate, with 8-12 branches, 3-7 × 2 cm; proximal internode to 15 mm. Scales hyaline. Perigynia green with green veins, 3-5-veined abaxially, veinless adaxially, to 4.5 × 2 mm, base spongy on both sides, not distended proximally, rounded; stipe to 0.3 mm; beak to 1.8 mm, serrulate. Achenes ovate, 2.2 × 1.4 mm; stalk to 0.2 mm; persistent style base cylindric. Fruiting Jun. Seasonally saturated soils in wet meadows, openings in alluvial woods, upper borders of tidal marshes, stream banks; 0-1500 m; Ala., Ark., Ill., Ind., Iowa, Kans., Md., Mich., Mo., Nebr., N.J., N.Y., Ohio, Tenn., Va., W.Va.
Stems clustered, 4-8 dm, stout but soft, 2-4 mm wide when pressed, about as long as the lvs; main lvs 5-10 mm wide; sheaths somewhat prolonged beyond the base of the blade, cross-corrugate ventrally; infl slender, 2-5 cm, compound, the lower branches distinct, the upper spikes scarcely distinguishable; scales ovate-triangular, about equaling the perigynia; perigynia green or becoming ±stramineous, flatly planoconvex, ovate, 3.5-4 mm, half as wide, rounded at the spongy base, sharply few-nerved dorsally, nerveless ventrally or with 1-3 short nerves at the base, tapering to a rough beak half as long as the body. Damp woods; N.Y. to Minn. and S.D., s. to Va. and e. Kans.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.