Two asexual reproductive strategies of the common lichen Pseudevernia furfuracea are described. Although the species propagates mainly by isidia, some specimens also show the development of soralia. Morphological, chemical and molecular analyses were performed on three such sorediate specimens from the Canary Islands, Morocco and Turkey. Maximum parsimony, maximum likelihood and Bayesian analyses indicate that: a) sorediate samples represent only a morphological variant of the reproductive mode and b) the separation of taxa (at species level or below) on the basis of their containing either olivetoric acid or physodic and oxyphysodic acids is not appropriate. In addition, a phylogenetic reconstruction of the genus Pseudevernia is presented for the first time. The tree shows two sister monophyletic clades, one containing American species (P. intensa, P. cladonia, P. consocians), and the second encompassing the P. furfuracea samples (including sorediate specimens). The biological and taxonomic significance of soralia in sorediate samples is discussed.

Phylogenetic relationships among the hypothetical species pairs Lobaria kurokawae / L. retigera and L. pseudopulmonaria / L. isidiosa were investigated based on TLC techniques and the phylogenetic analysis of the internal transcribed spacers (ITS) nrDNA. Results of TLC demonstrate that L. retigera and L. kurokawae can be chemically distinguished from L. isidiosa and L. pseudopulmonaria by the absence of retigeranic acid. Parsimony analysis of 18 specimens shows two monophyletic clades – a L.retigera lineage and a L. isidiosa lineage—both including their apotheciate counterparts. Unlike the original hypothesis of species pairs, our study reveals transitions from isidiate morphs that have the potential to rarely form apothecia, towards apotheciate morphs that produce no vegetative propagules.

ITS rDNA sequence data shows that Diploicia and Diplotomma species form a monophyletic clade distinct from other Buellia species. This indicates that Diplotomma merits acceptance as a genus, and suggests that Diploicia should be treated as a synonym of Diplotomma, the earlier name. The data also shows Diploicia subcanescens, considered the fertile counterpart in a species pair with D. canescens, is nested within D. canescens and should be treated as a synonym despite reported chemical differences. In addition, the molecular data support the distinctness of Diplotomma rivas-martinezii, a species restricted to gypsum rocks in Spain, from the widespread D. venustum, which grows on calcareous rocks. Aposymbiotic cultures suggest that D. rivas-martinezii also differs from D. venustum in its germination and isolation success rates. One new combination is made: Diplotomnta pulverulenta (Anzi) D. Hawksw. (syn. Abrothallus pulverulentus Anzi) for the lichenicolous species previously known as Buellia pulverulenta.