Culms compressed, 2-5 times as wide as thick, 0.5-1.8 mm wide. Distal leaf sheaths without tooth. 2n = 24. Fruiting late spring-winter. Damp soil to shallow water of seasonally wet seeps and depressions in calcareous grasslands, meadows, limestone and dolomite barrens, glades, fens, ditches, waste places; 0-2100 m; Ont., Que.; Ala., Ark., Colo., D.C., Ill., Ind., Iowa, Kans., Ky., Md., Mich., Minn., Miss., Mo., Nebr., N.Y., Ohio, Pa., S.Dak., Tenn., Va., W.Va., Wis.