Description: Sometimes confused with C. ceracea and C. crenularia, C. arenaria grows on nutrient-rich siliceous rocks, especially slate and basalt, frequently spreading over other lichens. This species has an immersed thallus, small, red-orange, flat-shaped discs with a persistent proper margin. In Ireland: Counties Cork and Antrim only.

Key Identification Features:

• Thallus, not obvious; discs, small, red-orange, spreading to other lichens; spore septum narrow
• On nutrient-rich, siliceous rock, especially basalt and slate.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Rufoplaca arenaria at iNaturalist World Species Observations database.