Lace Lichen (Ramalina menziesii)

I mistakenly assumed this was Old Man's Beard (Usnia sp.) but it turns out it is another lichen in a different genus. In fact it is the official state lichen of California best identified by the "fish-net" pattern evident in this photo. It apparently likes to grow on dead or dying trees which allow it to photosynthesize more easily than it would on living trees. However it does not damage or harm the trees in any way. Special thanks to JJ Johnson and Jennifer Rycenga for assistance with the identification.