Description: This species has discs (0.1–0.35mm diam.) that grow directly on the thallus of Physcia species, in particular P. adscendens and P. dubia. They occur in groups, black and rounded with one-septate spores and red-brown internal pigments which turn K+ olive. Spot test reactions are negative. In Ireland, the species has been recorded in Counties Galway and Fermanagh

Key Identification Features:

• Discs in groups, black, convex; spores one-septate, hypothecium red-brown
• On Physcia adscendens or P. dubia.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Arthonia epiphyscia at iNaturalist World Species Observations database.