Ignatova, E.A., O.I. Kuznetsova, A.V. Fedorova & M.S. Ignatov. 2026. Comments on Syntrichia caninervis and S. pseudohandelii in Russia

Arctoa (2026) 35: 108–121

doi: 10.15298/arctoa.35.10

Two species of Syntrichia—S. caninervis and S. pseudohandelii—with bistratose leaf lamina and pedicellate, branched papillae on dorsal side of costae occur in Russia. Syntrichia caninervis is sporadically distributed in European Russia in areas with limestone bedrocks, being especially frequent in its xeric south-eastern regions. In Asian Russia, it is much rarer, known from few localities in Altai, Buryatia, Taimyr, and Yakutia. Intraspecific variation of S. caninervis includes a development of rhizoidal gemmae, which is more frequent than it was thought previously, being especially regular in damaged plants. We found no differences in nrITS and cp rpl16 and atpB–rbcL between plants bearing and lacking gemmae, as well as between plants having almost completely bistratose leaf lamina and those having predominantly or even totally unistratose leaves. Syntrichia pseudohandelii occurs on Russia only in south-eastern European Russia and East Caucasus, being very rare in these areas. Molecular phylogenetic analysis of nrITS resolved S. caninervis in a clade sister to the S. ruralis complex while in the latter S. pseudohandelii clade is sister to all other species of this complex. The analysis of plastid atpB–rbcL also supports the species identity of S. pseudohandelii and its position within S. ruralis complex. Morphologically S. pseudohandelii combines features of S. ruralis s.l. and S. caninervis, and it is a well delimited species, despite more variable as it was previously thought.