Phylliscaceae

The Phylliscaceae are a family of lichen-forming ascomycete fungi placed in the order Lichinales (class Lichinomycetes). Members are mostly small cyanolichens that form thin crusts tightly attached to rock, or minute, scale-like rosettes. These lichens are typically found growing on rocks in sunny, dry locations where they form small, crusty patches or tiny leaf-like scales. They partner with cyanobacteria instead of green algae, which helps them survive in harsh, drought-prone environments where other lichens cannot establish....read more on Wikipedia.