Often confused with C. teicholyta this species has a thin white to pale grey thallus with some scattered grey soredia. Look for it in brick, concrete and cement structures. It is often a pioneer species, unmistakable when fertile. In Ireland, it has been recorded from Counties Galway and Dublin.

Key characteristics

• Like C. teicholyta but with a thin white to grey mottled thallus; often with grey soredia present
• Concrete, brick, cement and calcareous rock.

Original text submitted by Vince J. Giavarini