Growing on Amelanchier. Cf clavipes, based on key and description in "The Genus Gymnosporangium in Western Canada" (Parmelee, 1970). Spore mass was bright orange, the Aecia peridium tissue is lacerate, and is mature in July (Parmelee noted spore mass was mature in this species mid-July). Picture 1 and 2 are not magnified. Picture 3 is magnified to 80x with a compound microscope. Picture 4 is magnified to 200x. Picture 5 is magnified to 800x. Picture 6 is magnified to 40x using a dissecting microscope to show overal shape of Aecia.