Buellia aethalea (Ach.) Th. Fr.

A relatively conspicuous Buellia species characterised by small black apothecia immersed in the light grey crustose thallus. There are more similar species of Buellia with immersed apothecia which differ subtly in secondary metabolites and whose identification is not always easy, but B. aethalea is by far the most abundant one.

It grows on acidic, rarely also basic, siliceous and volcanic rocks, typically on sun-exposed rocks in a company of common lichens Circinaria caesiocinerea, Lecidea fuscoatra and Rhizocarpon distinctum. It often occurs in pioneer communities or on very hard acidic rocks, otherwise species-poor. Buellia aethalea is distributed from lowlands to mountains across the whole Czech Republic but avoids alpine zones. In Europe, it is a common lichen as well.

Ascomycota → Lecanoromycetes → Caliciales → Caliciaceae → Buellia