This lichen is on the bark of a tree in our yard. Lichens take on stronger colors when they are wet, as this one was.
I leafed through my book Lichens of North America, by Brodo, Sharnoff, and Sharnoff. It is a huge, coffee-table book with great photos of lichens–highly recommended if you can find a copy. I was a little intimidated by the diversity of the group, however, and gave up in my attempts to identify this one.
You can post photos of lichens on http://mushroomobserver.org/observer/intro and you may get an ID.
Thanks. I was not aware of that site–it looks pretty useful.
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