Plants 25-70 cm. Leaves: proximal blades usually irregularly toothed or lobed; mid and distal leaves usually entire. Heads 20-50. Peduncles 3-14 cm. Involucres 7-11 × 8-12(-13) mm. Ray florets 13-17; corollas 6.3-15(-19) × 2.2-5.5(-8.7) mm. Disc florets 250-500(-700+). Cypselae 0.7-1 mm; pappi 0.1-0.3(-0.4) mm. 2n = 26.

Flowering (Feb-)Mar-Jun(-Sep). Calcareous soils, ditches, washes, along streams; 300-1900 m; Tex.; Mexico (Coahuila, Nuevo León, San Luis Potosí, Tamaulipas).