Opegrapha atra

Revised name: Arthonia atra

A crustose species with a light grey or white thallus that is delimited or sometimes almost evanescent. It stands out because of the numerous, often contiguous, lirellae that are short and slit-like.

Thallus: C-, K-, UV-

Opegrapha atra is found on smooth-barked trees, in particular hazel, ash and holly, that grow in light shade. It is widespread in Scotland. BLS distribution map