Ptychomitriaceae. Genus Brachydontium

1. Peristome present; stems 0.5-1.2(-2) mm long 1. B. trichodes

Found in Russia in two localities in Kamchatka: in subalpine belt, at 600-850 m a. s. l. , on lithosoil on rocky slope, and on volcanic boulder in Pinus pumila thicket.

Peristome absent; stems 3-7 mm long 2. B. olympicum
Reported from Paramushir Island, North Kuriles, on volcanic substrate on slope of Ebeko Volcano.