Plants with basal sheaths of previous year persistent as linear fibers. Culms to 80 cm × 4 mm, scabrous. Leaves: sheaths all with blades, fronts smooth, red spotted, indistinctly linearly veined, apex hyaline, colorless, fragile, convex, entire; ligules rounded, 5 mm, free limb to 0.5 mm; blades dark green, not epistomic, to 60 cm × 7 mm. Inflorescences densely spicate, elongated, cylindric, with 8–12 branches, 2–4 × 1.5 cm; proximal internode to 0.5 mm; proximal bracts setaceous, apparent. Scales coppery with hyaline margins. Perigynia pale brown, coppery distally, faintly 3–5-veined or veinless abaxially, veinless adaxially, to 4 × 1.7 mm, base not distended proximally, rounded; stipe to 0.2 mm; beak to 2 mm, serrulate. Achenes circular, 1.5 × 1.3 mm; stalk to 0.15 mm; persistent style base cylindric. 2n = 68.
Phenology: Fruiting Jul.
Habitat: Seasonally saturated soils in wet meadows, openings in alluvial woods, stream banks, particularly on calcareous substrates
Elevation: 0–1500 m
Man., N.S., Ont., Que., Sask., Conn., Del., D.C., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., N.J., N.Y., N.Dak., Ohio, Pa., Vt., Wis.
Morphologically Carex alopecoidea is most similar to C. conjuncta; it differs in the smooth sheath fronts and the abaxial veins faint or absent.