Arnica louisiana

Arnica louisiana Farr, Ottawa Nat. 20: 109. 1906
Rootstock branched; stem 7-20 cm. high, glandular-puberulent and sometimes with a fewscattered hairs; leaves of the offsets oblanceolate, 3-5 cm. long, tapering below into a short petiole, sparingly denticulate, glandular-puberulent on both sides, ciliolate on the margins; basal leaves small, often scale-like; stem-leaves usually 2 pairs, near the base, the lowest lanceelliptic, with short-petioles, acute, 4-5 cm. long, the second lanceolate and sessile, the third pair, if present, much reduced; heads usually solitary, rarely 3, nodding; involucre turbinate, 1012 mm. high, 12-15 mm. broad, glandular-puberulent, villous at the base and with scattered hairs on the bracts; bracts about 12, lance-linear, acuminate, dark-purple, the inner with greenish margins; ray-flowers about 10, the ligules 12-15 mm. long, 4-5 mm. wide, 5-7-nerved, 2or 3-toothed ; disk-corollas 7 mm. long; anthers yellow; achenes strongly striate, glabrous or with a few scattered hairs; pappus-bristles 7-8 mm. long, white, barbellate.
Tvpk locality: Slopes of Ml. Fairview at Lake Louise, Alberta.
Distkihi tion: Rocky Mountains of Alberta and eastern British Columbia.