A crustose, widespreading species with a dark bluish grey thallus that is cracked to areolate and often densely covered in small, granular isidia that give the surface a rough appearance. Apothecia have yellow to orange discs and a thick irregular and often granular margin.
Thallus and isidia: K+ pale violet or K-. Disc: K+ purple
In Scotland, Caloplaca chlorina has a mainly eastern lowland distribution where it is common on the flat tops of limestone memorials and damp or shaded siliceous rocks. BLS distribution map
scottishlichens.co.uk 