Melanelixia fuliginosa

Melanelixia fuliginosa is a species of foliose lichen in the family Parmeliaceae, commonly found growing on siliceous rocks in humid, temperate regions of Europe and possibly parts of Asia. It forms dark brown to blackish rosettes up to 15 cm in diameter with small overlapping lobes that bear numerous tiny, cylindrical outgrowths (isidia) on their surface. The lichen primarily reproduces by vegetative means when these isidia break off and establish new colonies. Originally described by French botanist Jean Étienne Duby in 1830 as a variety of another lichen, it has undergone several taxonomic changes, being assigned to various genera including Parmelia and Melanelia before its current classification in Melanelixia in 2004. Although historically thought to occur in North America, recent studies suggest true M. fuliginosa may be restricted to Europe, with North American specimens now identified as the closely related Melanelixia glabratula, which prefers bark rather than rock substrates.......read more on Wikipedia.