A review of the genus Glyphomitrium Brid. (Rhabdoweisiaceae, Bryophyta) in the Russian Far East

ABSTRACT Introduction The diversity of the moss genus Glyphomitrium Brid. is concentrated in East Asia. Its range extends to the southern part of the Russian Far East, where its species are rather widespread in hemiboreal coniferous forests. However, the species to which Russian specimens should be assigned remains unclear. Methods A morphological survey was conducted, along with a molecular phylogenetic study based on the plastid trnS–trnF and nuclear ITS regions. Of the three lineages identified, two were investigated using species distribution modelling. Key results For two of three revealed lineages, the use of the names Glyphomitrium crispifolium Nog. (previously considered to be a rare Japanese endemiс) and G. humillimum (Mitt.) Card. are suggested, whereas the third one, which combines excurrent costae of stem leaves and subulate acumina of the perichaetial leaves, is described as a new species, G. ambiguum Fedosov. In Russia, G. crispifolium is mostly associated with the cooler and more humid climate of hemiboreal forests, whereas G. ambiguum occurs in drier conditions in broadleaved forests. Although the niches of G. crispifolium and G. ambiguum were assessed as being rather similar, their ranges overlap weakly. Conclusions Our results suggest the presence of three species of Glyphomitrium at the northern limit of its distribution in Asia. Results of niche distribution modelling show that the two species’ distributions depend on different predictors, and thus this tool appeared helpful for integrative taxonomic purposes. By contrast, the results of the niche similarity/divergence test were inconclusive.