[Arnicas and Leopardbanes: The Genus Arnica in the Columbia River Gorge of Oregon and Washington]

Bunch Arnica, Foothills Arnica, Twin Arnica, Twin Leopardbane

Arnica sororia

Synonym: Arnica fulgens var. sororia

Involucral bracts of Bunch Arnica, Foothills Arnica, Twin Arnica, Twin Leopardbane: Arnica sororia (Synonym: Arnica fulgens var. sororia)

Involucral bracts of what appears to be twin arnica as seen in vernally moist swales at Brooks Memorial State Park, Klickitat County, Washington..........May 24, 2015.

Bunch Arnica, Foothills Arnica, Twin Arnica, Twin Leopardbane: Arnica sororia (Synonym: Arnica fulgens var. sororia)

Basal or lower stem leaves of Bunch Arnica, Foothills Arnica, Twin Arnica, Twin Leopardbane: Arnica sororia (Synonym: Arnica fulgens var. sororia) - Bunch Arnica, Foothills Arnica, Twin Arnica, Twin Leopardbane: Arnica sororia (Synonym: Arnica fulgens var. sororia)

Involucral bracts of what appears to be twin arnica as seen in vernally moist swales at Brooks Memorial State Park, Klickitat County, Washington..........May 24, 2015. No tufts of brownish hairs were observed in the leaf axils of the basal leaves, so this is probably not Arnica fulgens.
Paul Slichter