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.

FNA 2006, Wiggins 1964, Kearney and Peebles 1969

Duration: Perennial Nativity: Native Lifeform: Subshrub General: Erect or ascendingly branched perennial from woody taproots, 20-100 cm, herbage glabrous or with tufts of white hairs in leaf axils; stems smooth, unevenly reddish with a more or less deciduous cortex. Leaves: Alternate, evenly distributed, petiolate or sessile, with blades lanceolate to lance-linear, 3-10 cm long, 1-2 cm wide, tapered bases or auriculate, margins unevenly dentate to subentire, smaller leaves have expanded bases which are truncate to cordate and more or less clasping. Flowers: Usually 4-12 flowers in corymbose cymes, radiate, 10-12 mm high, campanulate involucres with small bracts around the calyx, 3-5, linear to subulate; phyllaries 21, 5-8 mm, tips often with minute black dots; 12-18 ray flowers, rays 8-10 mm long, 1.5-2.5 mm wide, spreading but soon curled downward. Fruits: Hairy cypselae, 2.5-3 mm long, subcylindric, weakly 8-10 ribbed and minutely puberulent with short, stiff, ascending, grayish hairs. Ecology: Found on dry hillsides and rock slopes, usually among shrubs from 1,500-3,500 ft (457-1067 m); flowers February-May. Notes: Distinguished by the petiolate to sessile leaves, lanceolate to lance-linear; bases of middle leaves expanding, clasping. The axillary tuft of hair is key. Ethnobotany: Unknown, but other species in this genus has other uses. Etymology: Senecio is from senex, old man, which refers to the gray hairs on the seeds, while lemmonii is named for John Gill Lemmon (1832-1908) an American botanical collector. Synonyms: Senecio decorticans Editor: SBuckley, 2010