Plants with basal sheaths of previous year persistent, entire. Culms to 90 cm × 5 mm, scabrous. Leaves: sheaths all with blades, fronts smooth, red spotted, indistinctly linearly veined, apex red-brown, membranous, truncate, minutely ciliate; ligules rounded, 2 mm, free limb to 0.5 mm; blades glaucous, not epistomic, to 90 cm × 12 mm. Inflorescences densely spicate, cylindric, elongate, with 15-25 distinguishable branches, 10-20 × 6 cm; proximal internode to 10 mm; proximal bracts setaceous, apparent. Scales hyaline. Perigynia pale brown, red-brown distally, 10-12-veined abaxially, 5-veined adaxially, to 8 mm, body to 1.2 mm wide, base to 2.2 mm wide, base distended proximally forming disk, cordate; stipe to 0.9 mm; beak to 4.5 mm, mouth deeper abaxially, serrulate, apical teeth somewhat spreading. Achenes ovate, 2.5 × 1.4 mm; stalk to 0.2 mm; persistent style base cylindric, 0.3 mm. 2n = 52. Fruiting May-Aug. Seasonally saturated or inundated soils in wet meadows, marshes, swamps, alluvial bottomlands; 0-1000 m; Ont.; Ala., Ark., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Mich., Minn., Mo., Nebr., N.C., Okla., Ohio, S.C., Tenn., Tex., Va., W.Va. Primarily a species of the Mississippi drainage, Carex crus-corvi also occurs along the coastal plain.
From Flora of Indiana (1940) by Charles C. Deam
Frequent in southern Indiana in low open woods, especially flat pin oak woods; occasional in northern Indiana on borders of ponds in woods. Reported from Lake County by Peattie and by Pepoon but no specimens from the county could be located.
Stems very stout, densely clustered, 4-8 dm, sharply triangular and narrowly winged, shorter than the lvs; main lvs 5-10 mm wide; sheaths thin and truncate at the mouth, not corrugated; infl ovoid to cylindric, 8-18 cm, the lower branches ±separate, to 5 cm, the upper shorter and contiguous; scales triangular-ovate, equaling or shorter than the body of the perigynium; perigynia divaricate, 5.6-8.2 mm, dilated at base into a suborbicular spongy disk 1.5-2.5 mm wide, the body ovate, planoconvex, narrower than the disk, sharply nerved dorsally, obscurely nerved or nerveless ventrally, the beak much longer than the body, deeply bidentate. Swampy woods and meadows throughout the Gulf states and n. in the interior to Ind., s. Ont., s. Mich., and s. Minn. (C. bayardii Fernald, a form with the perigynium-base scarcely nerved)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.