A crustose lichen that forms thick, yellow-grey to bright yellow-green thalli that can be warted or cracked, and that often is limited by a black prothallus that is also visible in the cracks. Apothecia are usually present and immersed. When young, they are pale yellow or concolorous with the thallus, but they become convex and irregular in shape, and black with a pale grey pruina.
Thallus: C-, K+- yellow-brown, UV+ dull orange
In Scotland, Lecanora sulphurea has a mainly coastal and lowland distribution where it is found on exposed, nutrient-rich siliceous coastal rocks and gravestones. BLS distribution map
When young, Lecanora sulphurea is often found parasitically on Tephromela atra.
scottishlichens.co.uk 