Melanohalea olivacea

Melanohalea olivacea, the spotted camouflage lichen or spotted brown shield, is a species of brown foliose lichen in the family Parmeliaceae. It forms rounded, olive-brown to dark brown patches (rosettes) that are typically 5–8 centimetres across on tree bark, particularly on birches in boreal forests and mountain woodlands. The lichen is distinguished by small pale spots called pseudocyphellae scattered across its upper surface and a black lower surface with dark rhizines (root-like attachment threads). Originally described by Carl Linnaeus in 1753 as Lichen olivaceus, the species was moved through several genera before DNA-based phylogenetic studies in 2004 placed it in the newly created genus Melanohalea. In that genus, it is recognized as distinct from similar brown species based on both genetic data and physical characteristics. Melanohalea olivacea has an almost circumpolar distribution (around the high latitudes of the Northern Hemisphere) across the Northern Hemisphere's boreal......read more on Wikipedia.