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.