Description: This lichen is only encountered on sheltered acid rocks by the sea where it inhabits dry shady underhangs. It is mosaic-forming with a thin, white thallus which scratches orange-yellow and there are numerous minute grey discs (about the same size as those of Enterographa crassa) that show up better when wetted with the tip of a finger. The thallus is C- which is sufficient to separate it from its companion species, many of which are C + red. Maritime. Throughout Ireland, but less common in the east.

Key Identification Features:

• Mosaic-forming, maritime, dry underhang species with a white, scurfy thallus and tiny inconspicuous discs
• Thallus scratches orange-yellow with a fingernail and is C (fresh bleach) negative.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Roccellographa circumscripta at iNaturalist World Species Observations database.