Trematodon laetevirens Hakelier & J.-P. Frahm and T. brevicollis Hornsch. (Bruchiaceae, Bryophyta) in Russia

Trematodonl laetevirens Hakelier & J.-P. Frahm is here added to the Russian bryoflora based on records from the Khibiny Mts. (Murmansk Region, North-West Russia), Anadyr’ River Basin (Chukotka Autonomous Region) and the Ushkovsky volcano (Kamchatka Peninsula). The Khibiny moss population, earlier defined as T. brevicollis Hornsch., is attributed to T. laetevirens. We reaffirmed that the East Sayan samples belong to T. brevicollis, so, currently only one locality of T. brevicollis is known in Russia. The revision of T. longicollis Michx. samples from the Kamchatka Peninsula, and Kunashir Island (the Kuril Islands) confirmed their affiliation to this species, despite some deviations in morphological features. The taxonomical concepts inferred from variation in morphological traits are supported by for the first molecular-phylogenetic analyses of the genus Trematodon based on the nucleotide sequence data of ITS2 nrDNA and trnL-F cpDNA. At present, four species of the genus Trematodon Michx. are known from Russia: T. ambiguus (Hedw.) Hornsch., T. brevicollis, T. laetevirens and T. longicollis. A key to Russian Trematodon species is provided.