Bull. Torrey Bot. Club 25: 122, plate 331, figs. 1, 2. 1898.
Perennials, (15–) 20–45 (–60) cm (caudices erect or weakly spreading). Herbage nearly always glaucous, glabrous. Stems single or clustered. Leaves (thickish and turgid) progressively reduced distally; petiolate; blades ovate or obovate to lanceolate, 4–9 (–15+) × 1.5–3 (–4+) cm, bases tapered, margins wavy or subentire (often with callous denticles; mid and distal leaves sessile, bractlike). Heads (3–) 8–24+ in corymbiform arrays. Calyculi of 1–3+ oblong to lance-linear bractlets (less than 3 mm). Phyllaries ± 13 (± 21), 6–9 mm, tips green to brownish (not blackened). Ray-florets 8–10; corolla laminae 4–10 mm. Cypselae glabrous. 2n = 40.
Phenology: Flowering spring–summer.
Habitat: Damp or drying sites, often in rocky, moderately disturbed sites
Elevation: 2000–3500 m
Ariz., Colo., N.Mex., Tex., Mexico
Senecio wootonii reaches its southern limit in Coahuila and Chihuahua, Mexico; farther south, it is replaced by S. toluccanus de Candolle, a similar, larger, more robust species.