Description: This lichenicolous lichen grows on Xanthoria and Caloplaca species. It forms small black convex discs (like dots) containing one-septate spores with unequal cells pinched at the septum. Previously, this species was assigned to A. epiphyscia (described elsewhere) which occurs on Physcia lichens. In Ireland, the species has a predominantly northern distribution.

Key Identification Features:

• Lichenicolous on Diploicia canescens
• Minute black discs; the one-septate spores have unequal cells.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Arthonia molendoi at iNaturalist World Species Observations database.