Ignatova, E.A., A.V. Fedorova, O.I.
Kuznetsova & M.S. Ignatov. 2018. Taxonomy
of THE Plagiothecium laetum
complex (Plagiotheciaceae, Bryophyta)
Arctoa (2019) 28: 28–45
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.