in War Department [U.S.], Pacif. Railr. Rep. 4(5): 111. 1857.
Perennials, (20–)40–80(–120) cm (caudices fibrous-rooted). Herbage usually floccose-tomentose to glabrescent, sometimes glabrous. Stems single or loosely clustered. Leaves progressively reduced distally; petiolate (proximal); blades ovate to lanceolate, 7–15 × (1–)2–5 cm, bases contracted or tapered, margins subentire or serrate to dentate (mid and distal leaves similar, sessile, bractlike, often clasping). Heads nodding (especially when young), (1–)3–12(–20) in racemiform or paniculiform arrays (terminal heads often largest). Calyculi of 4–10 linear bractlets (lengths mostly 1/3–1/2 phyllaries, sometimes 1 or 2 equaling phyllaries). Phyllaries ± 13 or ± 21, 6–12 mm, tips green. Ray florets 0. Cypselae glabrous. 2n = 40.
Ariz., Colo., N.Mex., Utah, Wyo., s Rocky Mountains and adjacent areas of the United States.
Varieties 2 (2 in the flora).
The two varieties of Senecio bigelovii are distinguished by morphologic tendencies and by geography.
|1||Herbage glabrous or nearly so (at flowering); blades of proximal leaves often abruptly contracted or at least obtuse at bases; mid and distal leaves clasping; phyllaries mostly 13, 6–8+ mm||Senecio bigelovii var. bigelovii|
|1||Herbage often floccose-tomentose, especially among heads and on abaxial faces of leaves; blades of proximal leaves usually tapered to petioles; mid and distal leaves weakly, if at all, clasping; phyllaries mostly 21, (7–)8–12 mm||Senecio bigelovii var. hallii|