Arnica grandifolia

Arnica grandifolia Greene, Pittonia 4: 172. 1900
Rootstock long, horizontal; stem 3-5 dm. high, striate, glabrous or sparingly villous beneath, glandular-puberulent and slightly villous in the inflorescence; leaves of the offsets and the basal leaves long-petioled, the petioles of the former often 1 cm. long or more ; blades rounded-cordate, 5-7 cm. long and nearly as wide, thin, coarsely dentate, sparingly villous on both sides; basal leaves similar but smaller; stem-leaves usually 3 pairs, the lowest pair with petioles 5-9 cm. long, the blades cordate with deep narrow basal sinuses, coarsely, saliently, and usually doubly serrate, 8-13 cm. long, 6-9 cm. wide, the middle pair smaller, ovate, with short winged petioles, the uppermost pair much reduced and sessile; heads 1-3; involucre broadly turbinate, about 12 mm. high and 2 cm. broad, sparingly villous and glandular-puberulent; bracts 12-15, broadly obovate, acuminate; ray-flowers 10-13, the ligules about 2 cm. long, 4 mm. wide; disk-corollas 9 mm. long; achenes 6 mm. long, striate, sparingly hirsute; pappusbristles white, 8 mm. long, barbellate. Closely related to A. cordifolia.
Type LOCALITY: Bridger Pass, Montana.
I >t-TKiBt tion: Montana. Alberta, and British Columbia.