Found these on the bark of cherry blossom trees in Garry Point Park. They look some what different than those on my backyard pear tree. A fronds are much bigger. A lot of the "cups" don't look like "egg tarts", but like Danish pastry. Are these Xanthoria parietina ? and NOT X. polycarpa ? Or, the shape of the "cups" are not a diagnostic critera ?
Hi David - I agree that Xanthoria parietina is the best match: Apothecia, appressed broad lobes, wood substrate, tendency to greenish-yellow tones, habitat, granular soredia not seen. Similar species differ in some of those characters. I have not used cup shape as a diagnostic character for this and similar X. species, so I don't know of a difference, but if you noticed a consistent difference there, then it could be a useful character.
Haha, just joking. I know it could be the struggle for available space that determines the shape of each cup.
