I remember when swimming hats used to look a bit like this! The subtle shades of colour in these lichen really caught my eye. Lichens are a symbiotic relationship between a fungus and an alga. They are classified as crustose (crusty), foliose (leafy) or fruticose (shrubby). The slightly greener lichen in the middle could be a fruticose lichen called Dotted Ramalina or maybe Cladonia Perforata. The flatter one could be a Parmalia of some type – Saxatilis maybe. I really could do with some advice to help me develop my knowledge of these fascinating life forms which go largely unnoticed.