Phytologia 19: 223. 1970.
Perennials, 20–40(–70) cm (densely fibrous-rooted crowns). Stems (commonly purple) erect, puberulous (hairs usually with colored crosswalls). Leaves opposite; petioles usually 0, sometimes 1–2 mm; blades ovate-lanceolate, 2–4.5 × 0.5–2.5 cm, margins shallowly serrate, abaxial faces glabrous or glabrate, gland-dotted. Heads in loose, open arrays. Peduncles 10–60 mm, puberulent. Involucres 4–5.5 mm. Phyllaries: (narrowly oblong-lanceolate) apices acute, abaxial faces sparsely hairy to glabrate. Corollas white, lobes densely hispid-villous. Cypselae sparsely and finely hispidulous. 2n = 34.
Phenology: Flowering Aug–Oct.
Habitat: Rocky slopes, mostly in pine-oak woodlands
Elevation: 1800–2800[–3300, Mexico] m