Plants without conspicuous rhizomes. Culms 15-100 cm, 1.5-3 mm wide basally, 0.9-1.1 mm wide distally. Leaves: sheaths tight, green, fronts hyaline, yellow-brown and thickened at mouth; ligules to 3 mm, wider than long; blades 2.5-4 mm at widest. Inflorescences forming dense heads, with 4-8 spikes, 1-1.5 times as long as wide, 1-2 cm × 9-14 mm; proximal bracts not more than 2 cm; spikes with 8-20 ascending to spreading perigynia. Pistillate scales brownish to green-hyaline with green, 3-veined center, ovate, 2.3-3.1 × 1.2-2 mm, narrower than and as long as perigynia, apex cuspidate to short-awned. Anthers 1.1-1.7 mm. Perigynia pale green to pale brown, weakly veined or veinless abaxially, 3-4.1 × (1.7-)2-2.6 mm, margins serrulate distally; beak 0.8-1 mm, apical teeth 0.2-0.3 mm. Achenes suborbiculate, 1.5-1.7 × 1.3-1.5 mm.

Fruiting late spring-early summer. Dry grasslands, roadsides, railroads; 100-300 m; Ont.; Ala., Calif., Conn., D.C., Ga., Ill., Ind., Kans., Ky., Md., Mass., Mich., Mo., Nebr., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Tex., Va., W.Va.

Carex mesochorea is naturalized in California and is probably not native at the northern and eastern limits of its range.

Rare or local in pasture fields and on open, wooded, grassy slopes. At the Montgomery County station, on an open white oak ridge 5 miles west of New Market, it is associated with Poa pratensis, Danthonia spicata, Luzula echinata var. mesochorea, Antennaria neglecta and "reindeer moss."