Order: Arthoniales       Family: Arthoniaceae Species: Arthonia radiata Growth type crustose. Photos: Ballingeary area, Co. Cork, SW Ireland. Immersed small white, pale-grey or olive-brown tinged thallus often surrounded by brown line. Crowded, black, rounded or star-shaped apothecia, not pruinose, only slightly raised. Asci are 8-spored, spores 3-septate, the upper cell not enlarged, 15-20 x 5-7 µm. Microscope photographs below. A pioneer species that is very common on smooth-barked shrubs and trees throughout Ireland. Chemical reactions negative.

Micro photographs



Arthonia radiata Ballingeary, Co. Cork. 2009