Dirina massiliensis Durieu & Mont.

A species with a thick white thallus that reacts red with C+ due to the content of lecanoric acid. Populations in warm areas are often fertile, but those in central Europe usually reproduce vegetatively (grey soralia on the thallus surface). The lichen grows on overhanging or horizontal surfaces of calcareous rocks from lowlands to lower mountains. The centre of its European distribution is on the Atlantic coast and in the Mediterranean, but in areas with calcareous rocks, it is not rare even in the central part of the continent. In the Czech Republic, D. massiliensis occurs in most of the larger karst areas and rarely also in other localities.

Ascomycota → Arthoniomycetes → Arthoniales → Roccellaceae → Dirina