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. Flowering spring-summer. Damp or drying sites, often in rocky, moderately disturbed sites; 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.
FNA 2006, Kearney and Peebles 1969, McDougall 1973
Duration: Perennial Nativity: Native Lifeform: Subshrub General: Herbaceous perennials, to 50 cm tall, stems 1-several, herbage glabrous and somewhat glaucous, with shrubby or branched rhizomes. Leaves: Alternate or basal, thickish and turgid, the basal leaves obovate to oblong or oblanceolate, 2-15 cm long, margins entire to sinuate-dentate, borne on winged petioles, cauline leaves greatly reduced, entire to toothed or lyrate-pinnatifid, short-petioled or sessile and clasping. Flowers: Heads radiate, rays yellow, 8-10, pistillate, 7-8 mm long, the disk flowers yellow, involucres campanulate, row of bracts around outer calyx of 1-3 or more oblong to lance-linear bractlets, these less than 3 mm long, phyllaries 7-9 mm long, glabrous, equal, narrow, sub-herbaceous with green to brownish (but not black) acute to acuminate tips, the heads in groups of 8-24 or more, borne in corymbiform arrays. Fruits: Achenes terete, ribbed, and glabrous. Pappus of numerous, soft, white, capillary bristles. Ecology: Found in damp or drying sites, often in rocky, moderately disturbed sites and coniferous forests, from 6,000-11,500 ft (1829-3505 m); flowering May-September. Distribution: Arizona, Colorado, New Mexico, Texas; Mexico. Notes: Look to the radiate heads and glabrous and somewhat glacuous stems to help identify this species. Ethnobotany: Unknown, but other species in the genera have uses. Etymology: Senecio is from senex, old man, which refers to the gray hairs on the seeds, while wootonii is named for Elmer Otis Wooton (1865-1945) curator of the National Herbarium in 1910. Synonyms: Senecio anacletus, Senecio microdontus, Senecio toluccanus var. microdontus Editor: LCrumbacher 2011