Hi - Awesome photo and awesome specimen! And I can see why you would go to Parmelia, but Parmelia grows much closer to the bark (appressed), and it doesn't get the really big wrinkles like the lichen in your photo; it also has a different distribution of those granules (soredia). If you go back, you'll find that the lower surface of this lichen does not have a dense cover of black hairs (rhizines) like Parmelia does.
icosahedron
2014-02-18
2014-02-18 0931
United States of America, California, Sant Rosa Memorial Park, Santa Rosa CA