Heads 15-60(-80); bracts linear-oblanceolate to narrowly oblanceolate or elliptic, 20-120 × 3-18 mm. Involucres 3-5 × 6-9 mm. Phyllaries oblanceolate to linear-oblanceolate, subequal, membranous margins ± narrow, 1-2.5(-3) mm wide, apices cuspidate; outer 1.5-3 × 0.4-1.5 mm, inner 2.1-4 × 0.5-1.5 mm. Cypselae obovoid, winged; pappus awns 0.6-1.4 mm, lengths ² / 3 + cypselae. 2n = 36. Flowering Aug-Sep. Wet prairies, riverbanks, sloughs; 10-500 m; Man., Sask.; Ark., Conn., Idaho, Ill., Ind., Iowa, Kans., Ky., Maine, Mass., Mich., Minn., Mo., Nebr., N.J., N.Y., N.Dak., Ohio, Okla., Oreg., R.I., S.Dak., Tenn., Wis.