Protoparmelia hypotremella Herk, Spier & V. Wirth

An epiphytic, or epixylic, Protoparmelia species. It usually forms light grey to brownish sterile crusts on the bark, or wood, of deciduous trees in open forests, tree avenues or solitary trees. It is quite toxitolerant, with subatlantic distribution. In western Europe, P. hypotremella is commonly found in urbanized landscapes. In the Czech Republic, there are only sparse records from forests at lower elevations, more rarely also in the montane belt. It is probably more common but overlooked. In the field the species is recognizable thanks to quite conspicuous parasymbiotic fungi (Sphinctrina anglica, Tremella wirthii) associated to P. hypotremella. However, they may also grow on a related species P. oleagina. The two species are distinguished based on small morphological differences, distribution and ecological preferences (P. oleagina has a boreal distribution and more commonly occurs on wood, especially on pines). Their distinction is problematic and deserves a detailed study.

Ascomycota → Lecanoromycetes → Lecanorales → Parmeliaceae → Protoparmelia