The current view of the geographical ranges of lichens is often distorted by overly narrow or overly broad applications of names and by insufficient survey of most regions of the world. Here we present several cases where species of Teloschistaceae formerly thought to be limited to rather small territories in the western or eastern parts of Eurasia are in fact widespread in northern Eurasia. We support our findings with ITS nrDNA data in several new trees showing relationships in the genera Athallia, Calogaya, Caloplaca, Flavoplaca and Gyalolechia. The widespread species have little in common, except that most of them reproduce both sexually and asexually, and we discuss the possible influence of the combined reproduction on geographical range. Calogaya bryochrysion, Calogaya saxicola, Gyalolechia epiphyta and Gyalolechia ussuriensis are new combinations. Calogaya alaskensis is a younger synonym for C. bryochrysion. The generally arctic-alpine Calogaya bryochrysion also occurs on the bark of solitary trees in dry parts of the Altai Mountains. The Australian Flavoplaca cranfieldii is a younger synonym of F. flavocitrina. Gyalolechia epiphyta has been described numerous times, from different regions and substrata, as Caloplaca juniperi, C. laricina, C. tarani, Gyalolechia arizonica and G. juniperina. The name Gyalolechia xanthostigmoidea has recently been used for G. epiphyta, but it represents a distinct taxon. Gyalolechia ussuriensis is closely related to and morphologically indistinguishable from G. persimilis, but they have a different ecology and distribution and we regard them as distinct species. Caloplaca juniperina Tomin is lectotypified.

Delimiting species boundaries among closely related lineages often requires a range of independent data sets and analytical approaches. Similar to other organismal groups, robust species circumscriptions in fungi are increasingly investigated within an empirical framework. Here we attempt to delimit species boundaries in a closely related clade of lichen-forming fungi endemic to Asia, the Hypogymnia hypotrypa group (Parmeliaceae). In the current classification, the Hypogymnia hypotrypa group includes two species: H. hypotrypa and H. flavida, which are separated based on distinctive reproductive modes, the former producing soredia but absent in the latter. We reexamined the relationship between these two species using phenotypic characters and molecular sequence data (ITS, GPD, and MCM7 sequences) to address species boundaries in this group. In addition to morphological investigations, we used Bayesian clustering to identify potential genetic groups in the H. hypotrypa/H. flavida clade. We also used a variety of empirical, sequence-based species delimitation approaches, including: the “Automatic Barcode Gap Discovery” (ABGD), the Poisson tree process model (PTP), the General Mixed Yule Coalescent (GMYC), and the multispecies coalescent approach BPP. Different species delimitation scenarios were compared using Bayes factors delimitation analysis, in addition to comparisons of pairwise genetic distances, pairwise fixation indices (FST). The majority of the species delimitation analyses implemented in this study failed to support H. hypotrypa and H. flavida as distinct lineages, as did the Bayesian clustering analysis. However, strong support for the evolutionary independence of H. hypotrypa and H. flavida was inferred using BPP and further supported by Bayes factor delimitation. In spite of rigorous morphological comparisons and a wide range of sequence-based approaches to delimit species, species boundaries in the H. hypotrypa group remain uncertain. This study reveals the potential limitations of relying on distinct reproductive strategies as diagnostic taxonomic characters for Hypogymnia and also the challenges of using popular sequence-based species delimitation methods in groups with recent diversification histories.

Aim Contemporary species’ distributions are shaped by both geography and historical events, such as extinction, diversification in specific areas and long‐distance dispersals. In the most diverse family of lichen‐forming fungi, Parmeliaceae, the Hypogymnioid clade, is an example of an evolutionary lineage comprised of species occurring in temperate to subpolar regions in both hemispheres. Here, we elucidate the timing of diversification events and the impact of historical events on the species distribution in this lineage. Location Worldwide. Taxon Genera Arctoparmelia, Brodoa, Hypogymnia and Pseudevernia (Parmeliaceae). Methods Our sampling focused on the most diverse genus of the clade, Hypogymnia, including c. 70% of the described species. We reconstructed phylogenetic relationships using a multi‐locus data set, estimated divergence times, and inferred ancestral distributions. Results Our analyses suggest that the ancestor of the Hypogymnioid clade occurred in the Holarctic. In each of the four genera, all recovered as monophyletic here, diversification have occurred largely during the Miocene and Pliocene. A number of currently accepted species did not form monophyletic groups, especially in cases where specimens were collected from distinct geographic areas, with multiple, distinct clades corresponding to the geographic region of origin. Our results suggest that only a very few species in the Hypogymnioid clade have cosmopolitan distributions, all of which reproduces using vegetative propagules including both symbiotic partners. Main conclusions While the diversification occurred predominantly in the Northern Hemisphere during the Miocene, a long‐distance dispersal event from the Northern to the Southern Hemisphere, resulted in diversification of a clade of species largely restricted to the Southern Hemisphere. Similar to other groups in this diverse family, our study highlights the need for re‐evaluation of species boundaries among members of the Hypogymnioid clade.