Calicium viride Pers.

A lichen conspicuous by its yellow-green thallus and apothecia with brown margins. It is an epiphytic species, growing on bark (less often on wood) of several deciduous trees, infrequently also on spruce or fir. It prefers furrowed bark of older trees, where it searches for rain protected microhabitats. Typically, C. viride occurs in moister natural forests, but it may be seen also in dry oak forest, usually as a sterile crust forming yellow to blue-black pycnidia. Although rarely, this species may grow on overhanging shady rocks as well. In such cases, it may easily be mistaken for the rare C. corrynellum (see the taxon). Calicium viride is scattered from lowlands to mountains throughout the Czech Republic, often in a company of the more common C. salicinum. Recently, it has repeatedly been reported from the Šumava Mts, otherwise, only single localities are known.

Ascomycota → Lecanoromycetes → Caliciales → Caliciaceae → Calicium