Reichlingia leopoldii

Reichlingia leopoldii is a species of lichen-forming fungus (a lichenised hyphomycete) in the family Arthoniaceae. It forms greyish-green patches up to several centimetres across on hard siliceous rocks such as basalt, often in sheltered overhangs and crevices. The fungus reproduces asexually through distinctive chocolate-brown, branched spores that develop on the thallus surface, and no sexual reproductive structures are known. In continental Europe the species is rare and scattered, occurring mainly on the bark of veteran oaks in long-established woodlands from the Netherlands and Belgium eastward to Poland, Lithuania and Russia. In Britain it is known only from a few rock localities in eastern Scotland, while elsewhere it has been recorded from primeval beech forests in the Carpathians....read more on Wikipedia.