Arnica columbiana

Arnica columbiana A. Nels. Bot. Gaz. 30: 200. S 1900
Arnica multiflora Greene. Pittonia 4: 162. D 1900. Arnica laclucina Greene. Ottawa Nat. 23: 214. 1910.
Rootstock branched; stem 2-4 dm. high, striate, glabrous below, glandular-puberulent above; leaves of the offsets long-petioled, the petioles 3-5 cm. long; blades ovate, thin, not prominently 3-ribbed, sharply dentate, 2-5 cm. long, acute, glabrous beneath, somewhat glandular-granuliferous and sometimes with a few hairs above ; basal leaves similar but smaller ; stem-leaves usually 3 pairs, the lowest pair similar to the leaves of the offsets, with marginal petioles, the second with more rhombic-lanceolate blades and decidedly winged petioles, the uppermost deltoid-lanceolate, sessile, acuminate; those of the branches narrowly lanceolate; heads 3-12, cymose; ultimate peduncles 3-8 cm. long; involucre turbinate, about 1 cm. high and broad, glandular-puberulent and sometimes with a few hairs; bracts about 12, linearlanceolate, acute; ray-flowers S-12, the ligules 12-15 mm. long, 3 mm. wide, slightly 3-toothed; disk-corollas 6-6.5 mm. long; achenes more or less glandular-granuliferous, rarely with a few hairs; pappus-bristles white, 6 mm. long, barbellate.
Type locality : Columbia Falls, Montana. Distribution: Alberta and British Columbia to Wyoming.