Parmotrema flavescens (Kremp.) Hale, 1974
Diagnostic description:
Parmotrema flavescens is characterized by the presence of usnic acid, salazinic acid and isidia, together with the presence of only monomorphic rhizines. This combination is, as far as we know, unique in Parmotrema. Only P. neotropicum also produce isidia and has usnic acid, but is differentiated by the effigurate maculae and dimorphic rhizines.
Related species with usnic and salazinic acids are P. delicatulum and P. masonii (without propagules) and the sorediate P. mirandum, P. nylanderi and P. pectinatum.
(Spielmann 2009)