Parmotrema robustum

Parmotrema robustum is a species of corticolous (bark-dwelling), foliose lichen in the family Parmeliaceae. It can be identified by its thin, leaf-like thallus, few (or sometimes no) tiny hair-like structures (cilia) on the edges, short lobes with powdery edges, and a black underside with few root-like structures (rhizines), along with a wide brown area without these structures. It produces specific secondary metabolites (lichen products), including protocetraric acid and atranorin, and sometimes usnic and fatty acids.