Description: This very rare black-fruited Caloplaca colonises siliceous rock and is the only of its kind to do so in Ireland; it could be easily overlooked for a small species of Buellia or Lecidea. The very dark, cracked thallus has convex discs which, though black when dry, turn dark rust-red if wetted. In Ireland, most old records originate from the north-east coast. It occurs on base-rich schistose rocks.

Key Identification Features:

• Thallus almost black; discs convex, black, but becoming dark rust red when wet
• Very like a species of Lecidea; basic, schistose rocks mainly.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Caloplaca concilians at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Caloplaca concilians at iNaturalist World Species Observations database.