The genus Melanelia was segregated from Parmelia s. l. by Esslinger (1978). A taxonomic treatment of the whole group and first distribution maps of many species were given by Esslinger (1977). Ahti (1966) dealt in-depth with the ecology and distribution of the non-sorediate and non-isidiate holarctic species. Thell (1995) combined some species formerly belonging to Cetraria to Melanelia.Recent studies considering molecular, chemical and morphological characters of 15 of the 40 Melanelia species have led to the conclusion that the genus is not monophyletic (Blanco et al., 2004), and two new genera have been proposed, circumscribing probably monophyletic groups: Melanelixia O. Blanco et al. contains eight species; M. fuliginosa, M. glabra, M. subargentifera and M. subaurifera occur in Europe. Melanohalea O. Blanco et al. contains 19 species; M. elegantula, M. exasperata, M. exasperatula, M. infumata, M. laciniatula, M. olivacea, M. septentrionalis and M. subolivacea occur in Europe and Macaronesia. According to this study, Melanelia stygia, as the type species of the genus Melanelia, has to be placed outside the parmelioid lichens, and M. disjuncta forms a further group, possibly related to some Neofuscelia species, a genus that is now placed in Xanthoparmelia. Furthermore, ABSTRACT Aim The global distribution of the European species of Melanelia Essl. (Lichenes: Parmeliaceae) was investigated in order to understand their distribution patterns against the background of ecogeographical and historical factors.Location The location of the study is global, with a local emphasis on Europe.Methods Geographical distribution and ecology of the species were investigated on the basis of herbarium studies and data from the literature as well as field observations. Distribution maps were created with ArcView GIS. The distribution patterns are expressed as three-dimensional 'areal formulas', regarding zonal distribution, altitudinal range and oceanicity, using a previously described method. The observed distribution patterns are discussed on the basis of their analogies with vascular plants and with respect to the ecogeographical vs. historical factors reflected by them.
ResultsWith the exception of one species that is endemic to Europe, all species studied occur in both northern continents. A number of species have tropicalalpine outposts, and two species occur also in extratropical zones of the southern hemisphere. Arctic and boreal distributions are circumpolar, while in the southern holarctic zones an affinity to the western sides of both northern continents is frequent.
Main conclusionsThe distribution patterns appear to be mainly determined by contemporary ecogeographical factors. Most species probably have largely filled their potential distribution, at least within the Holarctic. Thus, the geographical origin and dispersal history of a species cannot reliably be reconstructed; they can be dissimilar in different species with similar distributions.