List of species of the genus Betula l. (family Betulaceae s.f. gray) of the Kazakhstan Altai, Saur-Manrak and the Zaysan depression

Abstract

A list of the genus Betula L. was compiled by the authors on the basis of field work carried out in 1970–2019, and also the collections of other collectors stored in the herbarium of Republican state-owned enterprises on the right of economic management “Altai Botanical Garden” (Ridder) and the Institute of Botany and Phytointroduction (Almaty). Purpose: to clarify the species composition and distribution of the genus Betula L. (family Betulaceae S.F. Gray) in the territory of Kazakhstan Altai, the Altai ridges and the Zaysan depression. As a result of the studies established the growth of 15 species and one subspecies of the genus Betula L. in the studying region. The study of herbarium samples, literature data and private collections allowed to supplement the species composition of the genus Betula L. of Kazakhstan with 7 species: B. x aurata Borkh., B. pseudopendula V. Vassil., B. falcata V. Vassil., B. x kelleriana Sukacz., B. х pseudomiddendorffii V. Vassil., B. talassica P. Pol., B. fruticosa subsp. montana M. Schemberg. Species saturation in the studied region: Central Altai – 3 species (18,8% of the total number of species); Southern Altai – 11 (68,75%); Western Altai –11 (68.75%); Kalba Altai – 6 (37,5%); Zaysan depression – 3 (18,75%); Saur-Manrak – 2 (12,5%). The average saturation index of species of the genus Betula L. in the flora of the Kazakhstan Altai and the Altai ranges is 6, which is relatively low, which indicates that family Betulaceae in the studied region is a specific element of boreal and holarctic flora. Keywords: list, genus Betula, species, Kazakhstan Altai, Saur-Manrak, Zaysan depression, distribution, occurrence.