Rare and noteworthy boreal lichens from the Altai Mountains (South Siberia, Russia)

Based on field trips between 1995-2007, rare and noteworthy lichens from the Altai Mountains in southern Siberia are described. Bacidia zerovii Oxner is recognized as a synonym of Scoliciosporum chlorococcum (Graewe ex Stenh.) Vezda. Lecidea brenneri H. Magn. is lectotypified and synonymized with Lecania cyrtellina (Nyl.) Sandst. The new combination Puttea exsequens (Nyl.) Printzen & Davydov is introduced for Lecidea exsequens Nyl. and is the oldest validly published name for Lecidea gibberosa sensu Th. Fr. non Ach. Of the 33 species reported here, five species - Lecania croatica, Lecanora pseudosarcopidoides, Lecidea, L. sanguineoatra, Puttea exsequens and Rimularia fuscosora are new for Asia and Russia, Buellia arborea is new to Asia, Lecanora farinaria is new to Russia, Caloplaca herbidella, C. sorocarpa, Fellhanera subtilis, Lecidea pullata, and Pertusaria coccodes are new to Siberia. Several species are reported as new to West or South Siberia. Most corticolous lichen species display a more or less circumboreal distribution and also occur in Europe and North America.