Caloplaca subalpina and C. thracopontica, two new saxicolous species from the Caloplaca cerina group (Teloschistales)

Caloplaca subalpina Vondrák, Šoun & Palice and C. thracopontica Vondrák & Šoun are described here as new to science. The former is a sorediate, often sterile, saxicolous species inhabiting subalpine base-rich overhanging rocks in European mountains; the latter grows on maritime cliffs of the Black Sea and is conspicuous by the lobules and pustules which are usually present on its thallus and by its apothecia which are typically large and abundant. The placing of the two species in the C. cerina group was confirmed by molecular studies using nrDNA ITS sequences. The chemosyndromes of both new species correspond to chemosyndrome A, which is in accordance with their position in the C. cerina group. A key to the saxicolous species of the C. cerina group is provided.