Three
species of Dicranum with fragile leaves were usually recognized in
Russia: D. fragilifolium, D. tauricum and D. viride. However,
our revision based on morphology and nrITS sequences reveals that two more
species were overlooked. Collections from the Russian Far East, including both
mainland and the Kuril Islands, usually treated as D. viride were found
to be different from the european D. viride, thus supporting the
resurrection of D. hakkodense Cardot that was synonymised with D.
viride and not accepted for a long time as a distinct species. In addition
to the resurrection of D. hakkodense, its distributional range is much
expanded. One more species, Dicranum pacificum sp. nov. was revealed
among the collections from Kamchatka, Sakhalin and the Kuril Islands. It is
clearly separated from the superficially similar D. fragilifolium,
although probably not closely related to it. Phylogenetic analysis reveals that
the group of Dicranum with fragile leaves is not monophyletic.