Page authors: Don Knoke, David Giblin
Arnica sororia
bunch arnica, twin arnica, twin leopardbane

Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, and Wyoming.

Habitat: From low elevation prairies and grasslands to coniferous forest openings at middle elevations.

Flowers: May-July

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Apomixis, bumblebees, butterflies


Perennial from slender rhizomes, the slender stems 2-6 dm. tall


Basal leaves petiolate, the blades lanceolate, 3-12 cm. long and 1-2.5 cm. wide; cauline leaves 2-4 pair, the lower ones with short petioles, reduced upward.


Heads few; involucres 10-15 mm high, the bracts narrow, tapering from the base, pointed; disk corollas with stalked glands; pappus white

Identification Notes:

The similar Arnica fulgens has long, woolly brown hairs in the axils of the lower leaves; A sororia usually has no axillary hairs; if any are present, they are white.

Accepted Name:
Arnica sororia Greene
Publication: Ottawa Naturalist. 23: 213. 1910.

Synonyms & Misapplications:
Arnica fulgens Pursh var. sororia (Greene) G.W. Douglas & Ruyle-Douglas
Additional Resources:

PNW Herbaria: Specimen records of Arnica sororia in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Arnica sororia checklist entry.

OregonFlora: Arnica sororia information.

E-Flora BC: Arnica sororia atlas page.

CalPhotos: Arnica sororia photos.

USDA Plants: Arnica sororia information.

49 photographs:
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