Rhizomes 3-5 mm thick. Culms 20-100 cm × 2-5 mm. Leaf blades 3.5-8 mm wide. Spikes 1-3(-5) per culm. Spikelets 5-20 per spike. Anthers 3-4 mm.

Fruiting summer-fall (Jul-Oct). Open wet places, lake and pond margins, marshes, swamps, bogs, stream shores; 0-700 m; B.C., Man., N.B., Nfld. and Labr., N.S., Ont., P.E.I., Que.; Ala., Ark., Calif., Conn., Del., Fla., Ga., Idaho, Ill., Ind., Iowa, Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Vt., Va., Wash., W.Va., Wis., Wyo.

Generally found in sedge marshes or associated usually with some sedge on the low borders of lakes, sloughs, and ponds. It is rather frequent in the lake area, becoming rare south of it because its habitat is rare in southern Indiana.