Order: Arthoniales       Family: Arthoniaceae Species: Arthonia parietinaria # Growth type lichenicolous Photos: Drinagh area, Co. Cork, SW Ireland on Xanthoria parietina The black convex apothecia are usually in clusters of 10-50. Asci 8-spored, spores hyaline, 1-septate, (9-)10-12(-13) x (3-)4-5(-6) µm with the upper cell usually broader and slightly shorter than the lower. Microscope photographs below. Occurs on thallus and apothecia of Xanthoria parietina. Similar: Arthonia molendoi on Calogaya spp. (Caloplaca s.l.). Now thought probably not occurring on Xanthoria spp.

Microscope photographs



Arthonia parietinaria. 2011