Lichen

There are 1,873 species of lichen listed for the UK and more are being discovered every year! I think these must be varieties of crustose lichens as they are growing flat against the rock making up part of the stone wall along the lane.

I never realised that lichens are dual organisms made up of two or more life forms living together symbiotically. There is a fungus providing a protective living environment and a green alga making the food by fixing nitrogen through photosynthesis. Cool!