T. flagellaris
This
species has a classical Beringian distribution: Alaska in North
America and Japan, China, and Korea in Asia. In the Russian Far East
it is very common in the Pacific Islands, Kamchatka and in the
southern part of the Far East mainland. It grows abundantly on the
bases of tree trunks, rotten logs and stumps. When flagellae are
present the species is immediately recognizable because no other
similar regional species has flagellae. When flagellae are absent T. flagellaris can be
recognized by the presence of arcuate shoots with ± complanate,
rigid, intensely yellowish-green leaves. This intense
yellowish-green color is often associated with mammillose or
papillose leaf cells.
— Leaf
margins unbordered or indistinctly bordered, with simple teeth;
plants without flagellae 2
2. Leaves
strongly incurved to contorted when dry; leaf margins indistinctly
bordered by one or two rows of large, pellucid cells; leaf cells
mamillose and papillose 2. T. microphylla
This
East Asian species is known in the Russian Far Åast from only a few
localities in north temperate mixed forests. It grows on cliffs. The
presence of strongly curved leaves and much smaller plants than
those of T. ussuriensis are
helpful in recognizing it in the field.
— Leaves
appressed to slightly flexuose when dry; leaf margins unbordered;
leaf cells smooth or slightly bulging 3. T. ussuriensis
Trachycystis
ussuriensis is common
in the southern part of the Russian Far East and southern Siberia. It occurs disjunctly more to the north in Central Yakutia and
Chukotka. It is also known from the Caucasus, where itis a rare species. Grows on rock outcrops and soil, occasionally forming continuous
carpets on river gravel bars. The strongly curved, tumid shoots of
T. ussuriensis
resemble those of Thamnobryum
species, but plants of Thamnobryum
are strongly branched, while sterile shoots of Trachycystis
are mostly unbranched.