Arnica cana

Arnica cana Greene, Ottawa Nat. 15: 282. 1902
Arnica foliosa incana A. Gray, Am. Nat. 8: 214. 1874.
Arnica denudata canescens Greene, Pittonia 3: 105. 1896.
Arnica incana Greene, Pittonia 4: 169. 1900. Not .4. incana Pers. 1807.
Rootstock long, creeping; stem 2-10 dm. high, striate, white-floccose or glabrate below, especially if growing in water; stem-leaves 5-12 pairs, the lower petioled, with the bases of the petioles connate-sheathing, the upper sessile; lower leaf-blades lanceolate or oblanceolate, 4-10 cm. long, 1-3 cm. wide, white-floccose on both sides, entire or denticulate, the upper leaves lanceolate; heads 1-5; peduncles 3-7 cm. long; involucre broadly turbinate, about 1 cm. high, 1.5-2 cm. broad, white-floccose; bracts about 15, linear or linear-lanceolate, acutish; rayflowers 15-18, the ligules 12-15 mm. long, about 4 mm. wide; disk-corollas 7 mm. long; achenes 5 mm. long, short-hirsute and usually also glandular-granuliferous ; pappus-bristles straw-colored, 7 mm. long, barbellate.
Type locality: Lake Tahoe, California.
Distribution': Mountains of Nevada, California, and Oregon.