Tetraphidaceae. Genus Tetrodontium
1. Flagelliform shoots absent —
1. T. ovatum
This species is known in Russia in the Altai Mountains, SW Yakutia and Khabarovsk Territory. It grows on acidic rocks in shaded, wet habitats. All previous Russian records of T. brownianum belong to this species.
— Flagelliform shoots present —
2. T. repandum
This species is known from only a few localities in the northern areas of European Russia, Siberia and along the Pacific coast. It grows on acidic rocks, especially in cracks and on overhanging ledges.