Four new species of Bacidia s.s. (Ramalinaceae, Lecanorales) in the Russian Far East

The molecular phylogeny of Bacidia s.s. in the Russian Far East was investigated using 62 nucleotide sequences from the ITS nrDNA region, 22 of which were newly obtained. Phylogenetic reconstructions employed Bayesian inference and maximum likelihood searches using MrBayes and RAxML. In addition, ITS2 secondary structures added further support using Compensatory Base Changes. As a result of morphological and phylogenetic studies, four new species of Bacidia are described. Bacidia areolata sp. nov. belongs to the suffusa group. It was collected once in Khabarovskiy Krai, the Russian Far East, on the bark of Acer tegmentosum and is closely related to B. suffusa but differs in having a smooth, cracked to areolate thallus and shorter spores. Bacidia elongata sp. nov. is a member of the fraxinea group and is similar to B. fraxinea but differs in having a wide zone of cells with enlarged lumina along the edge of the exciple. In fact, this zone of enlarged cells, in combination with its overall habit, places it morphologically close to B. suffusa, B. millegrana and B. campalea. Bacidia kurilensis sp. nov. is a basal member of the laurocerasi group and closely related to B. biatorina, B. heterochroa, B. laurocerasi and B. salazarensis. However, the combination of a granular thallus, large black apothecia and a green hue in the upper part of the exciple edge as well as in the epihymenium sets it apart from the species mentioned above. Bacidia sachalinensis sp. nov. resolves as a strongly supported member of the polychroa group and is known from a single locality in Sakhalin, the Russian Far East. Its thallus structure and apothecium colour are variable, which is typical for the polychroa group, but it differs from B. polychroa by having shorter spores with fewer septa and a mainly smooth to areolate thallus.