Senecio atratus

Perennials, (20-)35-70(-80+) cm (rhizomes or caudices branched, erect to weakly creeping). Herbage floccose-tomentose to canescent, sometimes unevenly glabrescent. Stems 1-(2-5). Leaves progressively reduced distally; petiolate; blades oblong-ovate to oblanceolate, (5-)10-30 × 1.5-4(-6) cm, bases tapered, margins dentate (denticles, dark, callous; mid leaves similar, sessile, smaller; distal leaves bractlike). Heads 20-60+ in corymbiform or subpaniculiform arrays. Calyculi of 2-5 linear bractlets (lengths to ¹ / 3 phyllaries). Phyllaries (± 5) ± 8, 6-8 mm, tips black. Ray florets (± 3) ± 5; corolla laminae 5-8 mm. Cypselae glabrous. 2n = 40. (A report of 2n = 46 is presumably erroneous.)

Flowering late spring-early fall. Dry or drying, rocky or sandy sites in coniferous areas, especially sites with frequent disturbance; 2800-4000 m; Colo., N.Mex., Utah, Wyo.