Lichen. I find it fascinating, and yet I know almost nothing about it.
You can find it everywhere in Cornwall. It must be down to the air quality. In the winter months the lichen that covers many of the trees and shrubs are visible. Wonderful colours and forms. So many different types. I've become a bit obsessed. So much so that I've asked for a book about lichen for Christmas. That's a long way from asking for Simon le Bon in my stocking.