Lophozia excisa var. succulenta (≡ Lophoziopsis excisa var. succulenta) is a synonym of Lophozia svalbardensis. This conclusion is based on morphological investigation and a subsequent molecular-genetic study which revealed an absence of variability amon nucleotide sequences of ITS1-2 nrDNA and trnL-F cpDNA in specimens from Arctic Alaska, west Siberian Arctic and Svalbard. Lophozia svalbardensis is reported for the first time for continental North America, Greenland and Siberia based on revised data on the distribution of Lophozia excisa var. succulenta. An expanded description of Lophozia svalbardensis, its variation, differentiation and photomicrographs of specimens from the Seward and Gydanskiy peninsulas are provided. The variability of pigmentation pattern, cell walls, perianth structure and gemmae is described.

Representative specimens examined: Norway, Svalbard, Nordaustlandet, Gustav V Land, Murchisonfjorden, south– east slope on north–west coast of Nordvika Bay, 80°03′13″N, 18°48′26″E, 196 m a.s.l., bank of lake, rock field, on covered by bryophytes nonsorted circles among crushed rocks, 17 Aug 2007, Konstantinova N.A. & A.N. Savchenko K135-3-07 (isotype of L. svalbardensis, LE); Denmark, West Greenland, Agpat [Appat Island], R.M. Schuster & K. Damsholt 66-1465 (C, paratype of L. excisa var. succulenta); Russia, West Siberia, Yamal Peninsula, Neromoyakha watershed slope, on bare soil among Solarina crocea, 20 Jul 1990, V. Golubkov (LE); GYDANSKIY PENINSULA, cotton grassdwarf shrub-moss tundra, 71.9082°N, 78.6625°E, on loamy wet soil, 2017, E. I. Troeva G2-4 (LE); USA, Alaska, Seward Peninsula, Southern Killeak Lake, lake shore, ca 66°20′N, 164°08′E, on bare ground, 24 Jul 1992, Potemkin 92-90-04 (LE).

To provide a molecular comparison with DNA data from the type specimen of L. svalbardensis (GenBank accession numbers MW298768 and MW297149) the ITS1-2 nrDNA and trnL-F cpDNA sequences were produced for the two abovecited specimens (Potemkin 92-90-04 from Alaska and Troeva G2-4 from Gydanskiy Peninsula). The procedures of DNA extraction and amplification followed protocols described in Konstantinova et al. (2020). Obtained sequences were assembled and aligned in BioEdit ver. 7.0.1 (Hall 1999). The molecular variability of the tested samples was evaluated as the value of p-distances for both ITS1-2 and trnL-F in Mega ver. 5.1 (Tamura et al. 2011).