Pectenia

Pectenia is a genus of lichen-forming fungi in the family Pannariaceae. It comprises four species. The genus was established in 2014 when DNA studies showed that a group of thick, bluish-grey lichens previously classified in the genus Degelia actually represented a separate evolutionary lineage. Pectenia species are characterized by their rigid, scallop-like surface texture and circular growth pattern. These lichens are found primarily in Atlantic-influenced regions of Europe and North Africa, with one species also occurring in northeastern North America. The genus partners with cyanobacteria from the genus Nostoc and produces abundant brown fruiting bodies on the lichen surface....read more on Wikipedia.