MOSS FLORA OF ULAKHAN-CHISTAI RANGE AND ITS SURROUNDINGS (MOMSKY DISTRICT, EAST YAKUTIA)

Moss flora of the Ulakhan-Chistai Range is studied. The range is situated within Obruchev chain of mountain ranges of Chersky System, forming a watershed between Nera and Moma Rivers (Indigirka River basin, Eastern Yakutia). The studied area, mainly in the valley of Tirekhtyakh Creek, was at 64°42'–65°11.5' latitude and 145°32'–146°45' longitude. The annotated list of mosses includes 325 species, which is the highest number among the local floras of Yakutia. It is apparently caused by a great variety of habitats: calcareous and acid rocks (marble, siltstone, mudstone, sandstone, slate, granite, rhyolite, etc.), larch forests, alder and Siberian pine thickets, various tundra communities in alpine belt and on aufeis glades, mires, lake shores, willow stands in flood valleys, disturbed habitats, places of reindeer and horse grazing, etc. Wet marble cliffs, especially near waterfalls, have numerous populations of Andreaeobryum macrosporum. Other interesting records in the area include three species of Mielichhoferia and Coscinodon hartzii, four species of Meesia, five species of Tetraplodon, four species of Splachnum, two species of Tayloria, seven species of Didymodon, five species of Tortella, 16 species of Schistidium, and 23 species of Sphagnum. In one locality Tetraphis pellucida was collected, with is very rare in Yakutia, and at base of steep dry slope to Tirekhtyakh Creek Hilpertia velenovskyi was found.