Stems usually slender, sometimes stout , glabrous or hairy in lines. Leaf blades linear-lanceolate to lanceolate, distal cauline margins entire . Heads congested on lateral branches of arrays, often developing on short peduncles along most of the branch, usually not subtended by large foliaceous bracts. Involucres 3-4 mm. Phyllaries: outer 1.8-3.4 × ca. 0.4, inner 3.5-3.7 × 0.4-0.5 mm, outer ¹ / 3 - ² / 3 length of inner. Ray florets 22-24; corollas white, laminae 3.9-5.8 mm. Disc florets 20-23; corollas 2.8-3.1 mm, limbs 1.6-1.8 mm, lobes 0.5-0.7 mm. Cypselae 0.6-0.8 mm; pappi 2.9-3.3 mm. 2n = 48, 64. Flowering Jul-Oct. Bottomlands, along streams; 10-400 m; Ont., Que.; Ark., Ill., Ind., Iowa, Kans., Ky., Mich., Mo., Nebr., N.Y., Ohio, Okla., Pa., Vt.