Arnica latifolia |
Arnica mollis |
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broadleaf arnica, mountain arnica |
cordilleran arnica, hairy arnica |
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Habit | Plants 1–5 dm; strongly rhizomatous. | Plants 2–6 dm; rhizomatous. |
Stems | usually simple, sometimes branched, glabrous to puberulent or villous. |
simple or branched, tomentose to lightly or densely villous, usually stipitate-glandular, sometimes glabrate proximally. |
Basal leaves | withering early, usually in separate sterile rosettes, petiolate. |
well developed, petiolate. |
Cauline leaves | 2–4 pairs; blades ovate, lanceolate, or elliptic, 1.5–14 cm, bases rounded to attenuate, rarely truncate or cordate; margins entire to denticulate, dentate, or serrate; veins branching laterally; tips acute; surfaces glabrous to puberulent or strigose; adaxial surfaces sometimes densely and minutely strigillose; most sessile; lower pair sometimes subsessile. |
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. |
Peduncles | glabrate or villous, sometimes glandular-puberulent at apex. |
glandular-puberulent, often pilose or villous. |
Involucres | cylindric to campanulate or hemispheric, 8–15 mm. |
broadly campanulate or hemispheric, 12–14 mm. |
Ray florets | 5–15; rays 10–28 mm, yellow. |
10–22; rays 14–24 mm, yellow. |
Disc florets | 20–90; corollas 6–10 mm, yellow. |
20–100; corollas 7–10.5 mm, yellow. |
Phyllaries | broadly or narrowly lanceolate to oblanceolate, elliptic, or linear; tips acute or acuminate; surfaces glabrous to pilose or villous, sometimes tomentulose or glandular-puberulent at bases. |
lanceolate or elliptic-lanceolate to linear; tips acute or acuminate; surfaces pilose or scabridulous, stipitate-glandular. |
Fruits | columnar-fusiform, 5–9 mm, dark brown, glabrous to glandular-puberulent; pappus bristles 5–7 mm, white, barbellate. |
columnar-fusiform, 5–8 mm; brownish black; hirsute; pappus bristles 3–6 mm; brownish, plumose. |
Heads | radiate. |
radiate. |
2n | =38, 76. |
=38, 57, 76, 95, 114, 133, 152. |
Arnica latifolia |
Arnica mollis |
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Distribution | ||
Discussion | Coniferous forests, meadows, shrublands, cliffs, rocky talus, clearcuts, roadsides. Flowering May–Sep. 300–2300 m. BW, Casc, CR, ECas, Owy, Sisk. CA, ID, WA; north to AK, northeast to Alberta, east to WY, southeast to NM. Native. |
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. |
Source | Flora of Oregon, volume 2, page 185 Kenton Chambers |
Flora of Oregon, volume 2, page 185 Kenton Chambers |
Sibling taxa | ||
Synonyms | Arnica latifolia var. latifolia | |
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