Snow Arnica

Arnica mendenhallii Rydberg, sp. now
Rootstock ascending; stem 2-4 dm. high, striate, glabrous below, sparingly villous and
puberulent above; basal leaves small, oblanceolate; stem-leaves about 3 pairs, the lowest pair
broadly oblanceolate, 5-ribbed, 6-9 cm. long, usually denticulate, glabrous or nearly so on both
sides, ciliolate on the margins; the middle pair lanceolate and the uppermost lance-linear and
reduced; heads solitary, slightly nodding or erect; involucre turbinate, 15 mm. high and 2-2.5
cm. broad, densely white-villous at the base, glabrate on the upper part of the bracts, the
latter 18-25, lance-linear, acute or acuminate; ray-flowers 7-12, the ligules light-yellow,
strongly 4—7 nerved, 2-2.5 cm. long, 5-7 mm. wide; disk-corollas 8 mm. long; achenes sparingly
hairy' or glabrate; pappus-bristles 7 mm. long, white, barbellate.
Type collected on Old Man's Creek, a branch of Koyukuk River, July 8, 1901, II'. C. Mendenhall (U. S. Nat. Herb, no 377409).
Distribution: Yukon district of Alaska.