Hypotrachyna appalachensis

Hypotrachyna appalachensis is a species of blue-gray to gray foliose lichen in the family Parmeliaceae.[1][2] It can be found growing in eastern North America in the southern Appalachian Mountains.[1] The species grows on the bark or wood of trees, specifically hardwood trees, either on the tree's trunk or base.[1] Its name was chosen due to its distribution being entirely restricted to the Appalachian Mountains.[1] The species was originally thought to be Hypotrachyna minarum, which it is morphologically identical to, until molecular data showed H. appalachensis consistently produced higher concentrations of 4,5-di-O-methylhiascic acid.[1] As a result, H. appalachensis can only be distinguished with certainty from H. minarum by using TLC, which can detect this molecular difference.[1]