Lecanora sulphurea

A thick, cructose lichen, cracked-areolate, greenish to grey-yellow in colour. Apothecia initially immersed but eventually emerge, with discs that vary in colour and shape, but mostly greenish or blackish.

Found on nutrient-rich siliceous rocks and walls. It is also parasitic on Tephromela and Lecanora species. Common and widespread.