Thanks Jean - great starting points! It sounds like the medium is similar to what is used to grow moss. The Irish site has some very interesting pictures of lichens,
Yes, Sandy, I see more of it from branches that drop out of trees, but there are several colonies on rocks around my yard. I even have some growing on the side of my pickup near the rear view mirrors on a rough surface (plastic?). The truck sits under the same tree that has lichen on fallen branches.
