Perennials (possibly biennials), (10-)20-70 cm (caudices buttonlike, roots fleshy-fibrous). Herbage arachnose, loosely tomentose, or villous (hairs crisped, jointed), glabrescent. Stems single. Leaves progressively reduced distally; ± petiolate; blades elliptic, lanceolate, linear, oblanceolate, rounded-deltate, or suborbiculate, 6-25 × 1-6 cm, bases ± tapered or truncate to cordate, margins entire or ± dentate (distal leaves sessile, bractlike). Heads 6-20(-40+) in corymbiform arrays (peduncle of terminal head often shorter than others). Calyculi of 1-5+ linear to filiform bractlets (seldom more than 2 mm). Phyllaries usually ± 13 or ± 21, rarely ± 8, (4-)5-12(-15) mm, tips usually black, sometimes green. Ray florets usually ± 8 or ± 13, sometimes 0; corolla laminae 6-15(-20) mm (usually yellow, ochroleucous to white in one variety). Cypselae usually glabrous, sometimes hirtellous (mostly on angles). 2n = 40, 80. The varieties of Senecio integerrimus are distinguished by morphology and geography.
