A comparison of molecular phylogenetic analysis (maximum parsimony and haplotype networks) with morphological approach to species taxonomy is given, revealing a probable rapid speciation in terminal Brachythecium salebrosum-clade. Within the latter, there are rather clearly morphologically delimited taxa with identical ITS, the most variable of the widely used molecular markers. Three new species are described based on morphology. A key for the species identification in Russia is given, and species delimiting characters are also discussed. Brachythecium laetum is confirmed and B. helminthocladum is reported for Russia for the first time.