Dendriscosticta

Dendriscosticta is a genus of foliose lichens in the family Peltigeraceae. The genus contains ten species that grow primarily on tree bark and branches across much of the Northern Hemisphere. Species are divided into two main groups based on their chemistry and geography: an Eastern Hemisphere lineage that produces gyrophoric acid and a mostly Western Hemisphere lineage that typically lacks this compound. These lichens often develop small outgrowths (isidia or phyllidia) on their upper surface and can form special structures harbouring cyanobacteria. ...read more on Wikipedia.