Description: This lichen should be searched for along siliceous rocky coasts in sheltered openings and caves in cliffs, often below overhanging rocks that may support bird colonies. It is easily recognised on account of the dense, deep orange, finger-like isidia which appear granular from above. Discs are scarce. C. britannica is similar but is a paler yellow colour, with tiny, unevenly rounded isidia covering the compressed radiating lobes often independently forming little heaps. In Ireland: north coast and south-west.

Key Identification Features:

• Thallus of deep orange finger-like isidia forming small or extensive sheet-like patches
• In massive cliff hollows below overhanging rocks; typically found on remote stretches of siliceous rocky coasts, especially along the western seaboard where large bird colonies are common.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Caloplaca littorea at iNaturalist World Species Observations database.