ANALYSIS OF ENDEMISM OF THE XEROPHILOUS FLORA IN THE RUSSIAN CAUCASUS

Abstract

The aim of our research is to study the endemics of the xerophilous flora of the Russian Caucasus in connection with the matter of knowing the genesis.Methods. The study is based on the field research expeditions.Findings. The presence of endemic species in flora is an indicator of its originality, and the degree of originality is determined by the extent of the endemic species. In general, according to our geographic analysis, the number of endemic species in xerophilous flora of the Russian Caucasus accounts for 32% (326 species), of which 25% of all endemic species have natural habitats within entire Caucasus, 66% are widespread in the Greater Caucasus, and 9% in the Pre-Caucasian region.Conclusion. Endemic species of xerophytes of the flora, in their overwhelming majority, are euxerophytes, and most steno-endemics also belong to this group of xerophytes. In a systematic aspect, the leading family, containing the largest number of endemic species, is Asteraceae (in percentage terms - Lamiaceae) and Jurinea is a leading genus (in percentage terms - Psephellus). In relation to the substrate, calcixerophytes are the dominants and most saturated endemics in quantitative terms are the belt of mountain xerophytes. The predominant biomes are hemicryptophytes; as compared with the number of biomorphes, among chamaephytes there is the biggest quantity of endemics