Order: Lecanorales       Family: Physciaceae Species: Buellia aethalea Growth type crustose. Photos: On acidic rock. Ballingeary area, Cork, SW Ireland. Thick or thin, mosaic-forming areolate thallus, often less than 2cm diameter with black prothallus. Areoles pale to dark grey, sometimes tinged brownish. Abundant immersed apothecia with small black discs. Pycnidia are rare. Often a pioneer species, common on acidic rocks, pebbles and dry stone walls. Chemical reactions are variable. Sometimes negative, otherwise K+/- yellow going red, C-, P+/- yellow-orange, UV-. Similar: Buellia stellulata, whitish thallus, K+ persistent yellow B. ocellata, greenish-yellow thallus, C+ yellow Verrucaria fuscella, chemical reactions negative.

Buellia aethalea. August 2009 and December 2008