Blepharostoma trichophyllum was found to be a species collectiva formed by several strongly genetically different species. The taxonomic diversity in the group is the possible result of radiation in early stages; then, these taxa likely survived for a long time in similar environmental conditions, which resulted in stasis. Presently, the existing taxa are similar one to another and may be morphologically distinguished with difficulties. The most taxonomically valuable morphological characteristics include oil bodies and cells in the leaf segment features. The most diverse genotypes (the vast majority of which are treated here as distinct species) were found in amphi-Pacific Asia, which may reflect the evolutionary history of the genus or may be the consequence of more profound sampling in the macro-region in comparison with other parts of the Holarctic.
Keywords: Blepharostoma; East Asia; ITS1-2 nrDNA; Pacific Asia; molecular phylogenetics; stasis; trnL–F cpDNA.