Arnica coloradensis

Arnica coloradensis Rydb. Bull. Torrey Club 32: 131. 1905
Rootstock short; stem about 2 dm. high, crispvillous and glandular-puberulent; stemleaves about 3 pairs, the lower ones obovate, subsessile, 4-5 cm. long, sparingly pubescent with short crisp hairs, obtuse at the apex, the upper ovate or ovate-lanceolate, sessile, acute, more hairy and glandular-granuliferous; heads mostly solitary; peduncle 3-6 dm. long, sparingly villous and glandular-granuliferous; involucre hemispheric, about 1 cm. high and broad, villous, densely so at the base, and glandular-granuliferous; bracts about 12, broadly oblanceolate, often tinged with purple, abruptly acuminate; ray-flowers 10-12, the ligules brightyellow, 12-15 mm. long, 5-6 mm. broad, minutely toothed; disk-corollas 6 mm. long; achenes 5 mm. long, hirsute and glandular-granuliferous; pappus-bristles 6-7 mm. long, light-brown, short-plumose.
Type locality: Colorado.
Distribution: Known only from the type locality.