in A. Gray et al., Syn. Fl. N. Amer. ed. 2, 1(2): 454. 1886.
Subshrubs or shrubs, (20–) 40–150 cm (taproots woody). Herbage sparsely hairy, unevenly glabrate (usually with persistent tomentum in leaf-axils and on abaxial leaf faces). Stems usually multiple (arching upwards). Leaves evenly distributed (proximal withering before flowering); sessile or obscurely petiolate; blades ± oblong or elliptic, (4–) 6–10 (–12) × 1.5–3 cm (1–2-pinnatifid, lobes ± linear, 1–2 mm wide), bases ± linear, ultimate margins entire. Heads 4–12 in cymiform arrays (involucres campanulate, 8–15 mm diam.). Calyculi 0 or of 1–3+ (inconspicuous) bractlets. Phyllaries (± 13) ± 21, (5–) 6–8 mm, tips minutely black. Ray-florets ± 13; corolla laminae 8–10 mm. Cypselae hairy. 2n = 40.
Phenology: Flowering spring.
Habitat: Ocean bluffs, open hillsides
Elevation: 0–500 m
Calif., Mexico (Baja California)
Of conservation concern.
Senecio lyonii is known from the Channel Islands (off the coast of southern California) and south.