Here we consider the coenotic distribution of 23 species of the genus Sphagnum and their relation to prime ecological factors in Pinezhsky Strict Nature Reserve (Arkhangelsk Region, north of European Russia). Ecologo-coenotic analysis was performed on the basis of 584 relevés, which cover the entire range of habitats. The relevés were systematized and processed by multivariate techniques. The species ecological optima and distribution among habitats as a whole were determined by calculating the species’ phytocoenotic signifi cance in groups of associations and groups of habitats. It was found that widespread (or frequently occurring) species are the most eurytopic and are characterized by the highest phytocoenotic signifi cance in one or more habitats. Species that occur sporadically have average phytocenotic indices and are less eurytropic. Rare species are stenotopic with low values of phytocoenotic signifi cance. Sixteen species among 23 occur both in boggy forests and in open bogs. Six species (Sphagnum papillosum, S. rubellum, S.majus, S.lindbergii, S.jensenii, S. balticum) are associated only with bogs and S. wulfi anum occurs only in boggy forests. Fens and poor fens have the highest value of Sphagnum species diversity. Bogs and boggy forests have a somewhat lower diversity. Rich fens and wet herbaceous forests are characterized by the lowest value of Sphagnum diversity. Cluster analysis made it possible to sort the 23 Sphagnum species into 6 groups which differ in their relation to environmental factors (humidity, trophicity, nitrogen richness, acidity, shading). It was shown by using cluster analysis and ANOVA that Sphagnum species diff erentiate ecological space fi rst of all by richness and secondly by humidity. We specified Tsyganov’s ecological indexes for all the considered species in the northern taiga subzone of European Russia.