Subshrubs or shrubs, (30-)40-120+ cm (taproots forming woody crowns). Herbage glabrous or ± lanate-tomentose. Stems usually multiple (little branched, arching-erect). Leaves ± evenly distributed; sessile or obscurely petiolate; blades narrowly linear to filiform (or pinnatifid, the segments linear to filiform), 3-10(-12) cm, bases ± linear, ultimate margins entire or remotely toothed (fascicles of smaller leaves sometimes borne in axils of larger leaves). Heads (1-)3-10(-20+) in corymbiform or subcorymbiform clusters, often gathered in larger, showy arrays (involucres campanulate or cylindric). Calyculi usually of 3-5+ bractlets (lengths often to ¹ / 2 + phyllaries), sometimes 0. Phyllaries ± 13 or ± 21+, 5-10(-12) mm, tips green or minutely black. Ray florets usually ± 8 or ± 13, sometimes ± 21; corolla laminae 10-15(-20) mm (mostly yellow, sometimes ochroleucous). Cypselae hairy. 2n = 40. The varieties of Senecio flaccidus are distinguished by morphologic tendencies and geography. The species occurs southward to central Mexico; a sound under­standing of the infraspecific taxonomy must await revisionary studies that include the Mexican plants.

Plant: Shrub to 1.5 m, ± taprooted, arching-branched above; herbage grey-green from woolly hairs; stems generally 1-few per rosettes Leaves: leaves alternate, crowded, entire to pinnatisect, the lobes narrowly linear INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads radiate, 3-10(20) per cluster; main phyllaries ± 13, sometimes 21, 5-10+ mm; outer phyllaries ± prominent Flowers: Ray flowers 8(13); ligules 10-20 mm, ± yellow; Disk flowers < 40; corolla generally ± yellow; style tips truncate to obtuse, generally hair-tufted Fruit: achenes, soft-hairy, cylindric; ribs shallow, often stiff-hairy; pappus of thin, minutely barbed deciduous bristles ± = fruit body Misc: Dry, rocky or sandy sites; < 2000 m. Notes: Stigma lobes truncate-obtuse in shape.Leaf shape is linear-filiform. References: Kearney & Peebles; Arizona Flora. McDougall; Seed plants of Northern Arizona. Hickman, ed.; The Jepson Manual. ASU specimans