Subshrubs (monocarpic?), (10-)20-100 cm (taproots woody). Herbage glabrous or with tufts of white hairs in leaf axils. Stems usually 1 (branching distally, unevenly reddish, usually somewhat lax). Leaves evenly distributed; petiolate (proximal) or sessile; blades lanceolate to lance-linear, 3-10+ × (0.5-)1-2 cm, bases tapered (or auriculate), margins (sometimes revolute) unevenly dentate to subentire (mid and distal leaves similar, smaller, bases expanded, ± truncate to cordate, clasping). Heads 4-12 in loose, corymbiform arrays. Calyculi of 3-5+ linear to subulate bractlets (to 1.5 mm). Phyllaries ± 21, (4-)5-8 mm, tips often with minute black dots. Ray florets usually ± 8 or ± 13, rarely 0; corolla laminae 8-10 mm. Cypselae hairy. Flowering late winter-early summer. Rocky sites in deserts; 500-1000 m; Ariz.; Mexico. Some young or depauperate specimens of Senecio lemmonii from northern Mexico resemble S. californicus, which occurs farther to the west in California and Baja California. Whether or not there is a relationship between the two is undetermined.

References: J.C. Hickman, ed. The Jepson Manual.W.B. McDougal. Seed plants of Northern Arizona.Kearney & Peebles. Arizona Flora. ASU specimens.