Pertusaria corallina

Pertusaria corallina

Observation - Pertusaria corallina - UK and Ireland. Description: Crustose lichen on drystane dyke. Possibly sterile? Any ID, please? Edit: title changed in line with Synganum's ID - thanks.

Crustose lichen on drystane dyke. Possibly sterile? Any ID, please?
Edit: title changed in line with Synganum's ID - thanks.