Parmelioid lichens are a diverse and ubiquitous group of foliose lichens. Generic delimitation in parmelioid lichens has been in a state of flux since the late 1960s with the segregation of the large, heterogeneous genus Parmelia into numerous smaller genera. Recent molecular phylogenetic studies have demonstrated that some of these new genera were monophyletic, some were not, and others, previously believed to be unrelated, fell within single monophyletic groups, indicating the need for a revision of the generic delimitations. This study aims to give an overview of current knowledge of the major clades of all parmelioid lichens. For this, we assembled a dataset of 762 specimens, including 31 of 33 currently accepted parmelioid genera (and 63 of 84 accepted genera of Parmeliaceae). We performed maximum likelihood and Bayesian analyses of combined datasets including two, three and four loci. Based on these phylogenies and the correlation of morphological and chemical characters that characterize monophyletic groups, we accept 27 genera within nine main clades. We re‐circumscribe several genera and reduce Parmelaria to synonymy with Parmotrema. Emodomelanelia Divakar & A. Crespo is described as a new genus (type: E. masonii). Nipponoparmelia (Kurok.) K.H. Moon, Y. Ohmura & Kashiw. ex A. Crespo & al. is elevated to generic rank and 15 new combinations are proposed (in the genera Flavoparmelia, Parmotrema, Myelochroa, Melanelixia and Nipponoparmelia). A short discussion of the accepted genera is provided and remaining challenges and areas requiring additional taxon sampling are identified.

Morphological and phylogenetic relationships of the worldwide Mediterranean lichen forming fungus, Parmelina quercina , have been studied. Specimens from western Europe, western North America and southern Australia were analysed using molecular data (nuITS rDNA, nuLSU rDNA and mtSSU rDNA) and selected morphological features (upper cortex maculae, scanning electron microscopy examination of the epicortex, ascospores and conidia shape and size, and amphithecial retrorse rhizines). The results conclusively reveal that: (1) there is not one single species but four separate species in the Mediterranean or sub Mediterranean areas of the world. Parmelina quercina and Parmelina carporrhizans (Euroasiatic species), Parmelina coleae sp. nov. (North America) and Parmelina elixia sp. nov. (Australia);(2) largely debated P. carporrhizans is not a synonym of P. quercina but supported as a valid species circumscribed to Macaronesic relict sites; (3) the geographical isolation of the Australian population is correlated with a large genetic distance; (4) morphological characters (ascospores and conidial variability and thallus epicortex) correlate with the phylogenetic hypothesis; (5) the new or revalidated species within Parmelina quercina are not cryptic species but morphologically recognizable taxa.

The first molecular phylogenetic study on a range of Punctelia species is reported, focussing on specimens growing in the Iberian Peninsula. Material of seven species was included in the analysis. Forty sequences were generated from nuITS and mtSSU rDNA in 20 specimens, and the resultant majority rule consensus tree from the combined analyses shows four major clades. Punctelia ulophylla is confirmed as a distinct species, P. reddenda is basal to P. borreri, and P. perreticulata groups with P. subrudecta. Samples identified as P. rudecta from the Canary Islands and China occupy different basal positions; the complex merits further study. Punctelia borreri and P. subrudecta are mainly coastal in the Iberian Peninsula, but are now reported from the central plateau for the first time; newly colonizing thalli have been found in a park in Madrid which is regularly spray-watered and where sulphur dioxide levels have fallen over the last two decades.

The new species Lepraria santosii Argüello & Crespo is described from the Canary Islands. It is characterized by a crustose to subsquamulose thallus with slightly raised rim and the presence of atranorin and the stictic acid chemosyndrome. It is currently known from Tenerife (Canary Islands), where it grows on soil over basaltic rocks in the laurel forest. Twelve new sequences of the ITS region from this species and L. isidiata were obtained and analysed with sequences downloaded from GenBank. Maximum parsimony and Bayesian analyses suggest that Lepraria santosii is closely related to L. isidiata. The latter name is here lectotypified and the characters for the distinction of the two species from similar taxa are discussed.

Argüello et al. (2007) found that Parmelina quercina, as circumscribed by Hale (1976), comprised four phylogenetic species which could also be distinguished by morphological features and also had different distributions: P. carporrhizans (usually rhizinate apothecia, and distinct effigurate maculae; oceanic Europe and Macaronesia), P. coleae (usually rhizinate apothecia, narrow ascospores, and fenestrate maculae; North America), P. elixia (non-rhizinate apothecia, larger ascospores, smaller conidia, and not or faintly maculate; Australia), and P. quercina (apothecia rhizinate or not, and less distinct more rounded maculae; continental Europe).