Lepraria impossibilis

Lepraria impossibilis is a species of leprose lichen in the family Stereocaulaceae. It forms a powdery to membranous thallus with a well-defined margin and distinctive secondary metabolites, including lecanoric acid and pannaric acid 6-methylester. The species is morphologically similar to Lepraria cupressicola and L. vouauxii but can be distinguished by its chemical composition. Lepraria impossibilis grows on tree bark, mosses, and soil-covered rocks, occurring in forested and open habitats across South and Central America, including El Salvador, Bolivia, Chile, and Peru, as well as in Iran....read more on Wikipedia.