Perennials, 10–30(–40) cm (perennating bases subrhizomatous, spreading, sometimes knotty-woody). Herbage (often purple-tinged) glabrous. Stems clustered (arching upward to semiprostrate). Leaves evenly distributed or smaller and fewer distally (somewhat stiffish-succulent when fresh, proximalmost and distalmost often smaller, bractlike); petiolate; blades ovate or obovate to oblanceolate, 2–5(–7) × 1–3(–4) cm, bases ± truncate to tapered, margins laciniate to dentate or subentire. Heads 1–5+. Calyculi 0 or of 1–5+ usually lance-deltate to linear, sometimes foliaceous, bractlets (lengths mostly 1/5–1/2 phyllaries). Phyllaries (± 8) ± 13 (± 21), 5–12 mm, tips green or brownish. Ray florets ± 8; corolla laminae 8–12 mm. Cypselae glabrous or strigose-hirtellous, at least on angles. 2n = 40, 40+, 80.
Alta., B.C., Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.
Varieties 4 (4 in the flora).
The varieties are distinguished by morphologic tendencies plus their geographic ranges.
|1||Plants (10–)25–40 cm; stems straight or gently arching upward; leaves often to 7 × 3 cm, bases of larger ones weakly clasping; phyllaries (9–)10–12 mm||Senecio fremontii var. blitoides|
|1||Plants 10–20+ cm; stems usually arching upward; leaves usually smaller than 4 × 2 cm, bases not clasping; phyllaries 5–10 mm||> 2|
|2||Leaf margins notably laciniate or laciniate-toothed (segments sometimes also toothed)||Senecio fremontii var. inexpectatus|
|2||Leaf margins toothed or subentire||> 3|
|3||Leaves smaller and fewer distally; phyllaries 5–7(–8) mm||Senecio fremontii var. occidentalis|
|3||Leaves ± equally developed along stems; phyllaries (7–)8–10 mm||Senecio fremontii var. fremontii|