Description: Parasitic on the soil-dwelling lichen Baeomyces rufus, A. grisea is easily identified by its dark grey-green colour which gives the host a sickly appearance. It is not uncommon to find it with pimple-like pycnidia only. It occurs wherever the host is found, such as on exposed soil over siliceous rocks, most commonly in hilly areas. In Ireland: Brandon Mountains, County Kerry and Comeragh Mountains, Waterford.

Key Identification Features:

• On Baeomyces rufus it stands out as a grey-green discolouration of the thallus
• Discs to 0.5mm diam. with thick margin; pycnidia black.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Arthrorhaphis grisea at iNaturalist World Species Observations database.