In a moment of boredom I wrote a short note on some of the lichens on a concrete post:
It might help others trying to make sense of urban lichens (not that I am sure that urban lichens do make sense).
Thanks for the notes on this node, well worth a look.
Speaking of urban lichens not making sense. when I first arrived at OU 20 years ago there were no usneas on the trees (that I noticed), then one or two small ones developed but now they have vanished. Is this because the levels of air pollution have increased again from the major road with much increased traffic or have they been used by birds to build nests or what.