How I ended up photographing lichens is a convoluted story that started with poor weather for my planned day and finished with taking pictures of moss. I didn't know much about them to be honest and it looks like they would be a study all on their own.
To start with, I wasn't sure what a lichen was. Turns out it isn't just one thing. It's a symbiosis between algae and fungi. And it's far from being the flat crust it appears. These photo shows something that looks more at home in a coral reef or a Science Fiction novel.
And amazingly it isn't just greeny grey. This one has tiny red "flowers" that weren't visible even on close inspection. To give an idea of scale, the photo covers 13mm of rock surface from top to bottom.
Lichens are very sensitive to pollution and only survive in clean fresh air. A good sign for this site on the edge of the peak district close to Sheffield.