Аннотация:The vertical distribution of plant communities in the Gremyachaya Valley, Barguzinskii Range, was mapped. The research was focused on the study of changes of the vegetation under different climatic conditions. For comparison, the earlier published data from neighbouring valleys - Shumilikha, Bol’shoi Chivyrkui and Bol’shaya Cheremshana (all at the lake-side of Lake Baikal) were chosen. Although the area studied, the Gremyachaya Valley is situated on the opposite side of the ridge, similar plant communities were found but they showed a different pattern in their vertical distribution. Along more than a thousand meter transect 14 types of plant communities (associations) were distinguished. In the upper zone communities of mountain tundra they were abruptly replaced by a mosaic of alpine grasslands and shrub communities. The middle part of this valley was characterised by transition of non-forest to forest vegetation with various ecotone situations. Forest vegetation showed the clearest dependence on altitude, although the relation to the moisture gradient and soil conditions was also very strong. The ecological peculiarities of all habitats are briefly described. Syntaxonomy of vegetation units corresponds with the current concept of classification of Siberian vegetation following the BRAUN-BLANQUET approach.