Senecio canus Hook.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Several-stemmed perennial 1–4 dm from a ± branched caudex, often with an evident short taproot; herbage ± strongly white-tomentose, often less so in age, the upper surfaces of the lvs sometimes glabrate; basal and lowermost cauline lvs ± tufted, from narrowly oblanceolate to broadly elliptic or subovate, the blade mostly 1–4 or 5 cm × 4–30(–45) mm, entire to irregularly subpinnately lobed, borne on a short or elongate petiole; middle and upper lvs few, strongly and progressively reduced, becoming bract-like; heads several; invol 4–8 mm; rays mostly 6–13 mm; achenes glabrous; 2n=46, 92, 138. Dry, open often rocky places; widespread in the w. cordillera, and e. to Minn. May–July.