Rhizocarpaceae

Rhizocarpaceae is a family of lichen-forming fungi; together with the family Sporastatiaceae it constitutes the order Rhizocarpales in the Ascomycota, class Lecanoromycetes. These lichens are primarily rock-dwellers that form thin, paint-like crusts tightly attached to stone surfaces, though some species grow as small scales or radiating rosettes. The family includes five genera found mainly in cool to cold regions around the world, where they colonize exposed siliceous and basic rocks in sunny locations. Most species reproduce through small black disc-shaped fruiting bodies that sit flush with or slightly above the crusty surface, and they often contain distinctive chemical compounds that help with identification....read more on Wikipedia.