Order: Lecanorales       Family: Physciaceae Species: Buellia stellulata Growth type crustose. Photos: On rock. Gougane Barra, Cork, SW Ireland. Left identified by John Douglass Small white to pale grey cracked thallus with a black prothallus, often forming mosaics. Immersed apothecia. Asci are 8-spored, spores brown, 1-septate, 8-15 x 5-8 µm. Micro photo below. K+ persistent yellow, C-, P+/- yellow, UV- Usually coastal on hard siliceous rocks and pebbles. Similar: Buellia aethalea. Greyer thallus, K+ yellow going red. Spores 13-18 x 6-12 µm.

Microscope photograph

Buellia stellulata. August 2009 and January 2012