The xanthones are generally tropical (I have no idea why!), interesting to see an arctic species with it.

Discussion with Jason Hollinger led me to Oliver Gilbert’s (very good, in my opinion) book “Lichens”, which has a color plate (not so good, in my opinion) captioned, ""The rare arctic-maritime species Lecanora straminea growing on a bird cliff, Flannan Isles." This moved me to acquire some fresh C to confirm the specimen as C+orange, which it is (see newly posted photo).

Brodo (2001) – “There are many other [than L. muralis] lobed species of Lecanora, especially in the west. Some of them contain xanthones in the cortex and either react C+ orange or are fluorescent in long-wave ultraviolet light. One example is L. stamina, which often accompanies L. murals on bird rocks along the west coast.”

It is still listed as available from Bruce McCune –
http://people.oregonstate.edu/~mccuneb/books.htm

I have a preliminary copy in Word format that Trevor reviewed, but not the final, and certainly not an updated copy!