Arnica louiseana var. illiamnae (Rydberg) Maguire

Arnica louiseana var. illiamnae (Rydberg) Maguire is a synonym sensu Downie & Denford, 1988 of:

Arnica griscomii subsp. frigida (C.A. Meyer ex Iljin) S.J. Wolf, an accepted subspecies name sensu FNA Ed. Comm., 2006c.