摘要
This paper presents the results of systematic, ecopathological, and chorological studies of the diversity of the subnival belt （zone） flora of the Caucasus Mountains, peculiarity of altitudinal distribution, endemism and florogenesis. Comparative analysis of the diversity of the subnival flora on different types of stone and at different altitudes in various parts of the Caucasus has been made. It is based on field investigation and on literature research. 226 species, 96 genera and 35 families were recorded in the subnival belt of the Caucasus within a range of 2,800 （2,900）-4,000 m a.s.l. Among these 117 species or 51% are common endemics of the Greater Caucasus and Caucasus. It is proved that floristic elements of different origin （authochronic and aloctonic） and age （Miocene-Pliocene and Pleistocene） contributed to the florogenesis of the subnival belt of the Caucasus. The Caucasian, the Eu-Caucasian, the Eastern Asian, the Minor Asian, the Dagestan-lranian, the Caucasia-European groups plaied an important role in the florogenesis. Criophilic evolution on the of the some plants was related to oreophytizacion during formation of the Caucasus mountains （in the second half of the Tertiary）, as well as the glaciations scale. Species composition and coenotic role are different in various parts of the Caucasus and within each part. This is conditioned by the different hypsometry of various parts of the Caucasus, the character of glatiations, edaphic and climatic conditions, lythological diversity. Compared with the Greater Caucasus, the relative floristic poverty of the Lesser Caucasus is due to low elevations and extensive rather recent vulcanism.
