Ignatova, E.A., A.V. Fedorova, O.I. Kuznetsova & M.S. Ignatov. 2018. Taxonomy of THE Plagiothecium laetum complex (Plagiotheciaceae, Bryophyta) in Russia

Arctoa (2019) 28: 28–45

doi: 10.15298/arctoa.28.05

A revision of the complex of Plagiothecium laetum and related species revealed a neglected species in East Europe, with some localities in Russian Far East, Plagiothecium rossicum. It differs from West European and North American P. laetum in sequences of both nuclear ITS and chloroplast rpl16 and in morphology. Plants identical with West European P. laetum occur in Russia only in the Black Sea coastal area of Caucasus and one locality in lowland European Russia (Kaluga Province). Asiatic plants characterized by abruptly tapered leaves with more or less piliferous acumen are referred to P. svalbardense, which therefore appeared to be a common plant throughout Siberia and Russian Far East. Plagiothecium curvifolium is also distinct from P. rossicum, in both DNA sequence and morphology; it is not confirmed by molecular markers in Russia east of the Urals.