Abstract
This article presents the results of a study on the biological diversity of vegetation and species composition of birch forests in the protected area «Sogrovsky Reserve» located in the northernmost part of the North Kazakhstan region. A floral analysis of higher plants has been compiled and carried out.As a result of the study of the species composition of the flora of the Sogrovsky reserve, we identified and identified 241 plant species belonging to 176 genera from 63 families. At the same time, 235 species were classified as vascular angiosperms.The leading families in terms of the number of species include 156 species of plants, which is 63.63% of the species composition of the entire flora of the Sogrovsky reserve. The following families are large: Asteraceae (34 species), Rosaceae (21 species), Fabaceae (19 species), Poaceae (13 species), Caryophyllaceae (10 species), Lamiaceae (9 species) and others.The genera of plants that are large in number of species are: Artemisia (5 species, 9.43%), Silene, Thalictrum, Ranunculus, Astragalus, Plantago, Galatella have 4 species each (7.54%).