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Parmelina tiliacea is a common, widely distributed species in south-western Europe, easily identifiable by morphology and much used as an air pollution bioindicator in many regions. A molecular phylogenetic survey of samples from many geographical areas, using Maximum Parsimony and Bayesian inference of nuITS and mtLSU rDNA regions, revealed a group of samples geographically restricted to a small region of the Iberian Peninsula and genetically separated from the other P. tiliacea specimens studied. These samples are morphologically indistinguishable from P. tiliacea, apart from subtle anatomical characters in the ascomata (hyphae of the exciple and ascospore width), which are frequently absent. Although geographically different, the two taxa occupy similar habitats and are even sympatric in some areas, indicating that they do not exchange genetic material. This previously overlooked, and apparently endemic lineage, is described as P. cryptotiliacea sp. nov., and the name Lichen tiliaceus is epitypified by a sequenced specimen to fix the application of Parmelina tiliacea to the widespread genotype. A second unexpected result was the discovery that the morphologically distinct P. pastillifera was nested within P. tiliacea. These two cases stress the need to use molecular tools to elucidate species concepts even within widespread morphologically well-characterized macrolichens. Such investigations are necessary to improve our understanding and estimation of biodiversity, and to facilitate the development of sound biodiversity conservation strategies for lichens. [ABSTRACT FROM AUTHOR]

This study focuses on European Usnea species with sorediate shrubby thalli, with the aim to evaluate the morphological and chemical separation of species in the light of molecular data. Twenty-two Usnea species, including widely distributed taxa such as U. diplotypus, U. fulvoreagens, U. glabrescens, U. lapponica, U. subfloridana, U. substerilis and U. 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 section Usnea that are difficult to determine by traditional characters form a group of closely related but still genetically distinct entities, except U. diplotypus and U. substerilis which appear to be polyphyletic. The branch lengths differed largely between two parts of the ITS tree (sections Usnea and Ceratinae). Usnea intermedia is proposed as the sexually reproducing counterpart for the sorediate U. lapponica. Additionally, some new chemotypes of Usnea species were determined. [ABSTRACT FROM AUTHOR]