A crustose species with a thick, smooth and cracked, light grey thallus and a grey-black prothallus when it meets other thalli of this species. The apothecia have a pinkish buff disc that is white pruinose, and becomes contorted when mature.
Thallus: C-, K+ yellow. Medulla: UV+ yellow. Disc: C+ yellow, UV+ pale orange
In Scotland, Lecanora rupicola has a mainly coastal, lowland and eastern distribution where is it common on well-lit siliceous rocks, including gravestones. BLS distribution map
scottishlichens.co.uk 