LIFE FORMS OF SALIX L. GENUS TYPES IN RUSSIA

Background. In view of addressing the vital issue of mankind to preserve biodiversity of species, the study of the polyvariety of life forms (biomorphs) of plants belonging to specific systematic groups is one of the most significant problems in botany. The taxa characterized by a significant variety of their life forms are of particular interest. These include the Salix L. genus being one of the largest and most difficult in a systematic way. To date, the most extensively studied species are the following: xylorhizome and creeping shrubs, and suffruticous willows in the Arctic, Hypo-Arctic, South Urals, North-East and Far East of Russia [3, 5–17, 19–24]. However, the types of willows in the European part of Russia spread in the coniferous forests of the temperate zone of the Northern hemisphere, i.e., temperate and boreal species of the two Salix and Vetrix Dum. subgenera, are not completely studied from the standpoint of biomorphology to date. The goal of research is to specify the life-forms of the boreal species of Salix and Vetrix willow subgenera and analyze the diversity of life forms of species of the Salix genus growing on the territory of Russia. Materials and methods. The article deals with the analysis of works on life forms of willows growing in Russia and covering the area from the European part to the Extreme North. The existing types of life forms are given in the single system and supplemented with a new life form. Results. Due to the polyvariety of the development, the species are characterized by not one but several life forms. Depending on the environmental conditions of the studied species of willows, different authors identified 22 life forms, 11 of which are present in boreal species, among which “semi-aquatic long-xylorithic scrub” was specified for the first time. Conclusion. Parallel series in variability of life forms of the willows species were outlined and the missing link in these series – semi-aquatic long-xylorithic scrub – was described. From the total number of the studied species of the Salix genus growing on the territory of Russia, the share of shrubs is 58 %, trees – 17 %, subshrubs – 25 %