Culms to 120 cm × 3 mm. Leaf blades green, to 60 cm × 10 mm. Inflorescences to 10 × 3 cm. Perigynia 4-5 × 2 mm; beak to 2.5 mm. 2n = 48 (Japan), 52.

Fruiting Jun-Aug. Seasonally saturated or inundated soils in wet meadows, marshes, edges of tidal marshes, swamps, alluvial bottomlands; 0-1700 m; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr., N.S., Ont., P.E.I., Que., Sask.; Alaska, Ariz., Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; e Asia.

From Flora of Indiana (1940) by Charles C. Deam

Very common in wet habitats throughout Indiana. It is usually found on borders of ponds and streams and in low woods, roadside ditches, swamps, marshes, bogs, and woodland swales.

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Indiana Coefficient of Conservatism: 2

Wetland Indicator Status: OBL