Buellia disciformis (Fr.) Mudd

A member of the genus Buellia with a grey-white thin thallus and sessile black apothecia. The species may be confused, for example, with the common Lecidella elaeochroma. It resembles also the rarer B. erubescens, from which it differs in larger spores with characteristically decoloured ends, numerous oil droplets in hymenium and lack of norstictic acid in the thallus.

Buellia disciformis grows on smooth bark of deciduous wooden plants, in the Czech Republic mainly on the beech and hornbeam. It prefers a humid environment and its centre of distribution is in scree forests and beechwoods. Its occurrence at lower elevations is often restricted to climatically suitable river valleys. The species is widespread in Europe, in some localities even very abundant. In the Czech Republic, the lichen has been recorded in many regions from lowlands to mountains but it is usually sparse in its localities.

Ascomycota → Lecanoromycetes → Caliciales → Caliciaceae → Buellia