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Abstract: The role of different sources of water (rain, dew and water vapor) has been investigated under natural conditions in order to explain the activity and the distribution patterns of Teloschistes lacunosus (Rupr.) Sav. in the Tabernas Desert (Almeria, Spain). This field work was carried out at two neighboring sites: a pediment where T. lacunosus is well developed and an east-facing slope where only few small thalli are developed. Diurnal courses of photosynthetic activity were assessed by the use of chlorophyll a fluorescence measurements, at each site for a total of 12 days distributed among different seasons over the year. Microclimatic data (thallus temperature, relative humidity (RH) and light intensity) were recorded continuously for a period of 1 year including all the days on which fluorescence measurements were made. Dried T. lacunosus in its natural habitat only became photosynthetically active after re-hydration with liquid water (dew or rain). In contact with an atmosphere of high RH (higher than 90%) but without dew condensation, thalli were not able to obtain sufficient water to become physiologically active. The microclimatic study showed notably differences between the two studied expositions. After dawn, thalli from the east-facing slope were exposed to higher temperatures and light intensity (PPFD) levels than thalli from the pediment. This was reflected in the length of time that the air remained saturated and the lichen remained wet and active. The high incident PPFD and the resultant increased temperatures at the east-facing slope led to short dew duration and, therefore to shorter periods of morning photosynthetic activity than on the pediment as fluorescence measurements showed. Additionally, the microclimatic differences between the two sites indicated a high frequency of dew fall events on the thalli from the pediment. The time periods of thallus dew imbibition vary strongly with the exposure of the lichens. [Copyright &y& Elsevier]

Abstract: Sections of apothecia were used to study the internal morphology of ascospores in the largest monophyletic clade within Parmeliaceae composed of Xanthoparmelia and related genera. The results were compared with fertile representative species of most other parmelioid clades. All the Xanthoparmelia species had spores with a single smooth vacuole, which was peanut-shaped, with different degrees of constriction in the equatorial plane. This differs from the ellipsoid vacuole of other parmelioids. In the Xanthoparmelia clade, sexual reproduction seems much more common than in other parmelioids. Thus, we suggest that the presence of this unique spore morphology might contribute to the evolutionary success of this monophyletic group. Further, the discovery of this useful ascospore character demonstrates that detailed ascospore morphological studies significantly enhance molecular phylogenetic analyses. Ascospore features may be more taxonomically significant in Parmeliaceae than hitherto considered. [Copyright &y& Elsevier]

Abstract: The phylogenetic position of Trypetheliaceae was studied using partial sequences of the mtSSU and nuLSU rDNA of 100 and 110 ascomycetes, respectively, including 48 newly obtained sequences. Our analysis confirms Trypetheliaceae as monophyletic and places the family in Dothideomycetes. Pyrenulaceae, which were previously classified with Trypetheliaceae in Pyrenulales or Melanommatales, are supported as belonging to Chaetothyriomycetes. Monophyly of Pyrenulales, including Trypetheliaceae is rejected using three independent test methods. Monophyly of Arthopyreniaceae plus Trypetheliaceae, the two families including lichen-forming fungi in Dothideomycetes, is also rejected, as well as a placement of Trypetheliaceae in Pleosporales (incl. Melanommatales). [Copyright &y& Elsevier]

Abstract: A phylogenetic and taxonomic study of the Physconia distorta morphotype complex was undertaken using ITS nu-rDNA as a molecular marker to re-evaluate this group. The analysis incorporated several samples of European P. distorta and also of American and European populations, recently named as P. americana. The phylogenetic analysis revealed that P. distorta and the European population of P. americana form two monophyletic and partially sympatric species and that both are distinct from the American species P. americana. Because differences in upper cortex anatomy had been used in establishing P. americana as distinct from P. distorta, the anatomy of the upper cortex was restudied in all three of these taxa, and notable differences were revealed. Our study confirmed that the upper cortex of P. distorta is prosoplectenchymatous with thick hyphal cell walls and narrow lumina, and that American specimens of P. americana have a typical paraplectenchymatous upper cortex. The cortex anatomy of both of these looks essentially the same in both longitudinal and transverse sections. Conversely, the European specimens that have been called P. americana are different from both of these. The cells of the upper cortex are rather thin walled, and in transverse lobe sections the cortex closely resembles a paraplectenchyma. However, in longitudinal lobe sections these thin walled cells can be seen to be elongate and ramified, obviously hyphal in nature, and better meeting the criteria of a prosoplectenchyma. The results confirmed the evolutionary pattern and taxonomic assessment of the anatomy of the upper cortex in the genus Physconia and revealed a common undescribed species (P. thorstenii sp. nov.) that can be added to the North African and Southern Euro-Asiatic lichen flora. [Copyright &y& Elsevier]