Plants with basal sheaths of previous year not persistent. Culms to 80 cm × 2 mm, scabrous throughout. Leaves: sheaths all with blades, fronts smooth, lacking spots, veinless, apex yellow, thickened, truncate, cartilaginous, entire; ligules acute, 5 mm, free limb to 0.5 mm; blades yellow-green, epistomic, to 60 cm × 6 mm, papillose adaxially (25X). Inflorescences densely spicate, cylindric, elongate, with 6-15 distinguishable branches, 3-6 × 1.5 cm; proximal internode to 10 mm; proximal bracts setaceous, apparent. Scales hyaline. Perigynia pale brown, red-brown distally, with red-brown veins, 10-12-veined abaxially, 7-veined adaxially, to 6 × 2.6 mm, base slightly distended proximally, cordate; stipe to 0.2 mm; beak to 2.5 mm, margins serrulate. Achenes ovate, 2 × 1.3 mm; stalk to 0.3 mm; persistent style base cylindric, 0.3 mm. 2n = 46. Fruiting May-Jun. Seasonally saturated or inundated soils in wet meadows, marshes, edges of tidal marshes, swamps, or alluvial bottomlands, particularly on calcareous substrates; 0-1500 m; Ont.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Md., Mass., Mich., Minn., Mo., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Va., W.Va., Wis. Carex laevivaginata is readily distinguished from all other species in the section by the thickened, yellow sheath apex and the papillose, epistomic leaves.
From Flora of Indiana (1940) by Charles C. Deam
Infrequent in wet ravines, swamps, swales in woods and on muddy banks of creeks.
Much like no. 34 [Carex stipata Willd.]; sheaths not cross-corrugated, not prolonged, the mouth distinctly concave and thickened; spike shorter and less compound, 2-5 נ1-1.5 cm, green or somewhat stramineous at maturity; perigynia 4.9-6.2 (avg 5.2) mm, usually less than a third as wide. Wet woods; Mass. to Mich. and Minn., s. to n. Fla., Ala., and Mo.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.