Plants 50-70+ cm (robust). Basal leaves: petiole lengths 1-1.5 times blades; blades broadly lanceolate to subhastate, 40-80+ × 30-40+ mm, margins sharply dentate. Heads 12-20 in open, corymbiform to cymiform arrays. Phyllaries 7-8 mm. 2n = 40, 44, 80.

Flowering early Jul-mid Aug. Damp stream banks, wet meadows, open, wet woodlands; 900-2400 m; Alta., B.C., Sask.; Calif., Idaho, Mont., Nev., Oreg., Wash., Wyo.

Plants of var. pseudaurea are much larger and more robust than those of the other two varieties and are distributed throughout the northern Rocky Mountains, the Cascades, and the northern Sierra Nevada, and the Jarbridge and Ruby mountains of Elko County, Nevada. Variety pseudaurea is the most abundant of the three varieties and is seldom confused with any other species.

Stems solitary or few from a simple or weakly branched, short, mostly erect or ascending rhizome-caudex with many fibrous roots; basal lf- blades mostly 2-4 נ1-2 cm, seldom larger, ovate to broadly lanceolate, subcordate to subtruncate at base, rather bluntly toothed, normally held erect, at right angles to the ground; otherwise much like no. 14 [Senecio aureus L.]; 2n=46. Moist prairies and other open places; widespread in the w. cordillera, e. to s. Man., w. Minn., and nw. Mo. May-July. Ours is var. semicordatus (Mack. & Bush) T. M. Barkley.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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