Lichen

I came across this lichen on a hedge today and it struck me how colourful it was. Like fungi, it is fascinating stuff.
There are many different types, and Wikipedia says: 'A lichen is a composite organism that arises from algae and/or cyanobacteria living among filaments of a fungus in a symbiotic relationship. The combined life form has properties that are very different from the properties of its component organisms.

- but you knew all that already didn't you?