The phylogenetic relationships of 16 species of Parmelia s. str. are presented based on sequences of nuITS rDNA from 56 specimens, and β-tubulin gene sequences from 29 collections. Parmelia serrana sp. nov. a Mediterranean species morphologically very close to P. saxatilis is described. Parmelia ernstiae is the sister-group to P. saxatilis s. str., and a further undescribed North American species of the P. saxatilis complex may require recognition. The isidiate P. squarrosa is closely allied to the sorediate P. sulcata, which is paraphyletic. Japanese samples of P. cochleata form a monophyletic group but too few collections of these were studied to reach firm conclusions regarding their relationships. An epitype is selected for the lectotype of Lichen saxatilis to unequivocally fix the application of that epithet.

Parmelia barrenoae is described as new to science in the P. sulcata complex on the basis of morphological and molecular data. The new species is superficially similar to P. sulcata but differs in having simple rhizines whereas the other species of the complex have squarrose rhizines. Nuclear ITS rDNA and partial β-tubulin gene sequences have been used as molecular markers. In the phylogenetic analysis, P. sulcata falls into four well supported clades, one of them corresponds to the morphotype that is described here as a new taxon. Six samples of the new taxon from different locations on the Iberian Peninsula form a strongly supported monophyletic group.