Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Rocky soil in seeps or springs, cliffs, or riverbanks, from middle elevations to the alpine.
Flowers: July-September
Origin: Native
Growth Duration: Perennial
Conservation Status: Not of concern
Pollination: Apomixis, bumblebees, butterflies
Densely tufted perennial, often in large patches, from a short rhizome; many sterile, leafy stems; flowering stems leafy, 3-6 dm. high.
Leaves opposite, 5-7 pairs, the lower sheathing, with reduced blade; other leaves nearly sessile, only slightly reduced upward, lanceolate or lance-elliptic with a pointed tip, entire, 5-12 cm. long and 1-2 cm. wide; no basal leaves.
Heads several to many; involucre 7-10 mm. high, the bracts sharply pointed; rays 8-13, yellow, pistillate, 1-2 cm. long; disk flowers yellow; pappus tawny, barbellate.
Achenes glandular and hairy or sub-glabrous.
PNW Herbaria: Specimen records of Arnica longifolia in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Arnica longifolia checklist entry
OregonFlora: Arnica longifolia information
E-Flora BC: Arnica longifolia atlas page
CalPhotos: Arnica longifolia photos