Plants 2–6 dm; rhizomatous.
Stems simple or branched, tomentose to lightly or densely villous, usually stipitate-glandular, sometimes glabrate proximally.
Basal leaves well developed; petiolate.
Cauline leaves 2–4 pairs, distal pairs more developed than proximal; blades ovate to broadly or narrowly lanceolate, 3–15 cm, bases attenuate to cordate, margins entire or denticulate, veins branching laterally, tips usually acute, surfaces glabrous or villous, often glandular-puberulent; sessile or lower pair short-petiolate.
Heads radiate.
Peduncles glandular-puberulent, often pilose or villous.
involucres broadly campanulate or hemispheric, 12–14 mm.
Phyllaries lanceolate or elliptic-lanceolate to linear, tips acute or acuminate, surfaces pilose or scabridulous, stipitate-glandular.
Ray florets 10–22; rays 14–24 mm, yellow.
Disc florets 20–100; corollas 7–10.5 mm, yellow.
Fruits columnar-fusiform, 5–8 mm, brownish black, hirsute; pappus bristles 3–6 mm, brownish, plumose.
2n=38, 57, 76, 95, 114, 133, 152.
Moist coniferous forests, meadows, streambanks, bogs, cliffs, rocky slopes. Flowering Jun–Sep. 1000–3000 m. BR, BW, Casc, ECas, Lava, Owy. CA, ID, NV, WA; north to British Columbia, AK, northeast to Alberta, east to WY, southeast to CO. Native.
as described under Arnica mollis
Plants 15-70 cm. Stems (forming clumps) simple or branched among heads. Leaves (2-)3(-4) pairs, mostly cauline (basal sometimes present); petiolate (petioles relatively short, broad-winged) or subsessile; blades broadly elliptic, lance-elliptic, or narrowly to broadly lanceolate, 4-20 × 1-4 cm, margins entire or irregularly denticulate, apices acute, faces sparsely to moderately hairy (hairs relatively short to long, stipitate glands or soft, silky). Heads 1 or 3-7. Involucres hemispheric to campanulate. Phyllaries 10-22, usually broadly lanceolate, rarely narrowly lanceolate or oblanceolate. Ray florets 10-22; corollas yellow. Disc florets: corollas yellow; anthers yellow. Cypselae grayish brown to black, 4-8 mm, mostly stipitate-glandular, sparsely hirsutulous (hairs white to brownish, simple or bifid); pappi tawny, bristles plumose (with deep, amberlike deposits). 2n = 38, 57, 76, 95, 114, 133, 152.Flowering Jun-Sep. Moist meadows and conifer forests, stream banks, late snow-melt areas, montane to subalpine; 1000-4000 m; Alta., B.C., N.W.T., Yukon; Alaska, Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.