Family: Arthoniaceae Species: Arthonia graphidicola Growth type lichenicolous. Photographs on Graphis inustuloides (Graphina anguina). Commeen West, Co. Cork, SW Ireland. Scattered red to dark brown, rounded, elongate or fleck-like apothecia develop below the bark then erupt through host thallus. Spores 2-3 septate, upper cells enlarged, (13-)14-17 × 4.5-5.5 µm, initially smooth and colourless, becoming brown and warted. Micrographs below. Occurs on the thallus of Graphis scripta sens lat. and Graphis inustuloides, most frequently recorded in woodland in oceanic areas Similar: Arthonia 'phaeographidicola' (undescribed) has been found on Phaeographis smithii and P.dendritica

Micrographs



Arthonia graphidicola. June 2025