Orthotrichum
holmenii
Lewinsky-Haapasaari is found in Russia for the first time, in European Arctic
(Adzva River, Nenetzky Autonomous District) and Siberian Subarctic (Maimecha
River, the southern Taimyr). Previously the species was known only from the
type locality in Kazakhstan, vicinity of Alma-Ata, 3400 km and 3000-3400 km
from the new localities. The description, illustrations and differentiation
from similar species are provided. Orthotrichum holmenii differs from
other species of the genus by the combination of naked calyptra,
exserted, distinctly ribbed capsules with stomata slightly to moderately
covered by subsidiary cells, exostome teeth reflexed when dry and not paired
when old, and 16 long papillose endostome segments.