A review of the lichen family Parmeliaceae - history, phylogeny and current taxonomy

Parmeliaceae is the largest family of lichen-forming fungi with more than 2000 species and includes taxa with different growth forms. Morphology was widely employed to distinguish groups within this large, cosmopolitan family. In this study we test these morphology-based groupings using DNA sequence data from three nuclear and one mitochondrial marker from 120 taxa that include 59 genera and represent the morphological and chemical diversity in this lineage. Parmeliaceae is strongly supported as monophyletic and six well-supported main clades can be distinguished within the family. The relationships among them remain unresolved. The clades largely agree with the morphology-based groupings and only the placement of four of the genera studied is rejected by molecular data, while four other genera belong to clades previously unrecognised. The classification of these previously misplaced genera, however, has already been questioned by some authors based on morphological evidence. These results support morphological characters as important for the identification of monophyletic clades within Parmeliaceae.

Species of the Neuropogon group in the lichen genus Usnea have their centre of distribution in polar regions of the Southern Hemisphere. Their morphological and chemical variability is poorly understood and several asexual taxa with uncertain relationships to fertile taxa occur in the group. The species concept is controversial. A phylogenetic analysis revealed three related complexes of mainly asexual lineages arranged around three fertile Usnea species: U. aurantiaco-atra, U. trachycarpa and U. perpusilla. In this study a dataset of 80 specimens was used to resolve species circumscriptions in the U. perpusilla complex. We used a phylogenetic and a haplotype network approach based on three gene fragments (ITS, IGS and RPB1) to detect distinct lineages. To support the hypothesis that these lineages represent different species, we tested for correlation of morphological and chemical characters with hierarchical nested haplotype groups, employing statistical tests of contingency tables and analysis of variance (ANOVA). This cohesion species recognition method detected three fertile U. perpusilla lineages. We could also delimit an undescribed fertile species with yellow apothecia and a new asexual species from the High Andes. Interestingly, there is an additional bipolar species, U. lambii, which was formerly confused with U. sphacelata. The fact that U. lambii shows a geographically disjunct distribution pattern, but the genetic distances among specimens are low, points to recent long-distance dispersal.