Phylogenetic relations of European shrubby taxa of the genusUsnea
AbstractThis study focuses on EuropeanUsneaspecies with sorediate shrubby thalli, with the aim to evaluate the morphological and chemical separation of species in the light of molecular data. Twenty-twoUsneaspecies, including widely distributed taxa such asU. diplotypus, U. fulvoreagens, U. glabrescens, U. lapponica, U. subfloridana, U. substerilisandU. wasmuthii, were included in the study using Bayesian and maximum parsimony analyses of nuclear ITS and beta-tubulin sequences. The analyses showed that: 1) most taxa that are morphologically well delimited are also distinct by means of molecular characters, 2) shrubby taxa in the sectionUsneathat are difficult to determine by traditional characters form a group of closely related but still genetically distinct entities, exceptU. diplotypusandU. substeriliswhich appear to be polyphyletic. The branch lengths differed largely between two parts of the ITS tree (sectionsUsneaandCeratinae).Usnea intermediais proposed as the sexually reproducing counterpart for the sorediateU. lapponica. Additionally, some new chemotypes ofUsneaspecies were determined.