Contr. U.S. Natl. Herb. 16: 190. 1913.
Plants 50–100+ cm (perennating bases ± erect, internodes not winged). Leaves all or mostly opposite (distal sometimes alternate); blades ovate-deltate to lance-elliptic, 3–8(–11) × 1–4(–6) cm, bases subtruncate to cuneate, margins coarsely toothed to subentire, apices acute to attenuate, faces ± hirsutulous to scabrellous. Heads borne singly or 2–6 in loose, corymbiform arrays. Involucres ± hemispheric, 8–10 mm diam. Phyllaries 12–16 in 2 series, ± erect, linear to lance-ovate or lance-linear, 4–7 mm. Ray florets 13; laminae 9–12+ mm. Disc florets 60–100+; corollas yellow. Cypselae dark brown, obovate, 4–5 mm, faces glabrous; pappi 0–0.5 mm.
Phenology: Flowering (Aug–)Sep(–Nov).
Habitat: Rocky slopes, limestone
Elevation: 1500–2100 m
N.Mex., Tex., Mexico (Coahuila).