Ignatova, E.A., O.I. Kuznetsova,
N.R. Shafigullina, V.E. Fedosov
& M.S. Ignatov. 2020. The genus
Pylaisia (Pylaisiaceae,
Bryophyta) in Russia
Arctoa (2020) 29: 135–178
doi: 10.15298/arctoa.29.11
The genus Pylaisia
is revised for the Russian moss flora basing on morphological and molecular phylogenetic studies of nuclear ITS and IGS
markers and plastid trnL-F. The main
subdivision of the genus in the obtained phylogeny splits it into two clades. The first clade includes
species with the endostome totally adherent to exostome; it is represented in Russia only by P. stereodontoides that is related to North American P.
intricata and more southern East Asian P. cristata. The second clade
includes a rather well supported clade composed of
species with endostomes rather strongly adherent to exostome (P. brotheri, P. condensata, P. obtusa, P. subcircinata), that is nested in a polytomy
of species with endostomes either free or only a
little adherent to exostomes. The latter polytomy includes P. polyantha,
P. curviramea, P. steerei,
P. coreana, P. bezgodovii
sp. nov., and P. camurifolia (= ‘Asiatic P. falcata’). Asian P. condensata
differs from the North American P. selwynii,
thus they may not be considered as synonymous, as it was usually assumed. A
complicated diversity is found within P. polyantha
s.l. in TCS network of
ITS haplotypes: a group of European and North
American haplotypes is the most isolated; mainly
Siberian group of haplotypes is moderately delimited
whereas the Far Eastern haplotypes form a
reticulation with P. steerei and P. curviramea, and also a small-sized
plants with free endostomes of P. polyantha-group. The latter form a moderately
supported clade in IGS
based trees and has morphological distinctions, allowing its resurrection as a
separate East Asian species, P. coreana. One Genbank accession from Alaska
referred to P. selwynii is deeply nested in P.
obtusa, thus we presume that the latter species occurs
in North America.