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.
From Flora of Indiana (1940) by Charles C. Deam
Frequent to common in central Indiana; frequent elsewhere except in the lake and prairie areas. Its preferred habitat is on wooded alluvial banks of streams, but it is also found in low woods and on moist wooded slopes.
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.