Lecanora hafelliana

Lecanora hafelliana is a species of corticolous (bark-dwelling), crustose lichen in the family Lecanoraceae. It was described in 2011 from specimens collected in South Korea, where it commonly grows on the bark of various broadleaved trees including maples, birches, and oaks. The lichen forms a well-developed greyish crust with abundant small, yellowish-brown to reddish-brown circular fruiting bodies that have thick, pale rims. It is found in the temperate mountains of Northeast Asia, ranging from South Korea into northeastern China at elevations between 680–1,660 metres....read more on Wikipedia.