Page author: David Giblin
Arnica longifolia
longleaf arnica, seep spring arnica, spear-leaf leopardbane
Specimens
Photos

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

Description:
General:

Densely tufted perennial, often in large patches, from a short rhizome; many sterile, leafy stems; flowering stems leafy, 3-6 dm. high.

Leaves:

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.

Flowers:

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.

Fruits:

Achenes glandular and hairy or sub-glabrous.

Accepted Name:
Arnica longifolia D.C. Eaton
Publication: Botany (Fortieth Parallel). 186. 1871.

Synonyms & Misapplications:
Arnica longifolia D.C. Eaton ssp. myriadenia (Piper) Maguire
Additional Resources:

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.

USDA Plants: Arnica longifolia information.

23 photographs:
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