Fungi Outer Hebrides

Family: Rocellaceae

Opegrapha atra Pers.

Type: Crustose

Widespread but easily confused with other graphid lichens. Thallus creamy but can look quite green with algae present. Crowded lirellate apothecia

Smith, C.W. et al. editors (2009) The Lichens of Great Britain and Irelandd
Dobson, F.S. (2018) Lichens: an Illustrated Guide to the British and Irish Species