Plants densely to loosely cespitose. Rhizomes short to long, internodes 0.2-20 mm. Culms 0.5-1(-1.1) mm wide. Widest leaf blades 1.3-2.9(-3.1) mm wide. Longest inflorescences (33-)40-63(-71) mm. Perigynium beak 0.3-0.42 times as long as perigynium. 2n = 64, 66, 68. Fruiting spring-early summer. Forested flood plains, wet hardwood forests, hardwood swamps, occasionally wet meadows, marsh edges; 0-500(-1100) m; N.B., N.S., Ont., Que.; Ala., Ark., Conn., D.C., Del., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis.; c Mexico.