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.
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.