Senecio eurycephalus Torrey & A. Gray, Mem. Amer. Acad. Arts, n. s. 4: 109. 1849

Perennials, 20–50+ cm, taprooted (caudices branched, ascending to erect, woody). Stems 1 or, usually, multiple, clustered, densely tomentose to glabrescent. Basal leaves (soon withering), petiolate; blades lyrate (lateral lobes 2–6+ pairs), ovate, obovate, or spatulate, 70–100+ × 20–30+ mm, bases tapering, ultimate margins irregularly and coarsely serrate-dentate. Cauline leaves gradually reduced (± petiolate, proximal and mid similar to basal, terminal lobes smaller than laterals; distal sessile, incised). Heads 5–20+ in open or compact (rarely), cymiform arrays. Peduncles bracteate, sparsely to densely lanate-tomentose. Calyculi inconspicuous (bractlets tomentose). Phyllaries 13 or 21, green (tips sometimes yellow), 8–10+ mm, densely tomentose proximally, glabrescent distally. Ray florets 8 or 13; corolla laminae 10–15 mm. Disc florets 35–50+; corolla tubes 3.5–4.5 mm, limbs 2.5–3.5 mm. Cypselae 1–1.5 mm, glabrous; pappi 6–7 mm. 2n = 46.

Varieties 2 (2 in the flora): w United States.