New name: Myriolecis crenulata
A crustose species with an immersed but scurvy thallus that is pale grey when on hard limestone. The apothecia may be grouped but are more usually scattered. They have a brown to bluish, and persistently pruinose, flat disc. The margin is crenulate and inrolled and has a translucent appearance.
Thallus: C-, K-, UV-
In Scotland, Lecanora crenulata has a scattered, mainly coastal distribution, where it is found on calcareous rock, including limestone gravestones, and manmade substrata like cement and mortar. BLS distribution map
scottishlichens.co.uk 