Perennials, (7-)20-30(-40+) cm (rhizomes exfoliating).
Herbage densely lanate-tomentose, glabrescent (especially on adaxial faces of leaves).
Stems single.
Leaves mostly basal; petiolate; blades narrowly obovate, (2-)3-7(-10) × 1-2(-3+) cm, bases tapered, margins subentire to denticulate (cauline leaves bractlike).
Heads 1(-3).
Calyculi of (1-)5-8+ linear to filiform bractlets (lengths
1 / 3 -
3 / 4 phyllaries).
Phyllaries ± 21, 8-12 mm, tips greenish (with white bristles).
Ray florets ± 13; corolla laminae usually 8-10 mm (sometimes tubular, unexpanded, heads then perhaps technically disciform).
Cypselae hairy. Flowering summer. In duff, rocky woodlands, especially in pine-dominated areas; 2000-3000 m; Ariz., N.Mex.; Mexico (Chihuahua, Durango). Plants of
Senecio actinella with relatively small proximal leaves similar to basal leaves and adaxial leaf faces early glabrate have been recognized as var.
mogollonicus; the distinction is difficult to maintain. Receptacles in
Senecio actinella are sometimes insect-infested.