Plants 30-120 cm. Leaves: proximal and mid blades serrate to undulate-serrate, glabrous or sparsely hairy; distal blades glabrous or sparsely hairy. Heads 20-150(-300+) per plant. Peduncles 1-3.5 cm, projecting terminal heads barely beyond foliage. Involucres 4-8 × 4-8 mm. Ray florets 7-13; corollas yellow, 2.6-4.8 × 1.6-3.9 mm. Disc florets 120-300+; corollas 1.2-1.6 mm, lobes (4-)5. Pappi (0.2-)0.3-0.4(-0.5) mm. 2n = 26.

Flowering (Feb-)Jun-Jul(-Nov). Sandy or clay soils, ditches, washes, around ponds and lakes, along streams; 0-1500 m; Ariz., N.Mex., Okla., Tex.; Mexico (Coahuila, Nuevo León, and Tamaulipas).