EUPHORIA DAVIDII SUBILS (EUPHORBIACEAE) IN FLORA OF RAILWAY TRACKS OF DNIESTER BAY BAR

Abstract

Aim. Anthropogenically transformed ecotopes act as a centre for existance of many adventive species. The distribution of North-American species Euphorbia davidii subsp. Poinsettia across various continents is often attributed to the export of grain. For some time scientists have been bringing up the issue about identification of plants E. davidii in new territories, because the species is morphologically similar to E. dentata agg.
 The species E. davidii is characterised by a high invasive potential, it is a neophyte. In Ukraine the species is represented by separate localities almost throughout the country. It is related to sectors of ports, railway tracks, and abandoned lands.
 Methods. In the year 2021, by means of route method, in sectors of railway tracks of the Dniester bay bar, between the railway stops Karolina-Buhas and Soniachna (total length is up to eight kilometers) seven localities of E. davidii were distinguished; the coordinates of the locations are listed in the publication. The examined ecotopes are characterised by a crushed stone substratum, with higher temperatures, and also by specific vibrational, insolational and hydrological modes.
 Results. Both inconsiderable in number of plants localities (32 exemplars) and zones, where the number of plants reaches over 2000 are represented. The extent of habitats ranges from 2 to 20 meters. The height of particular, the most developed individuals constituted 20 cm. As a rule, in the inter-rail space there is a considerably smaller number of plants, however, they are better developed, well-branched and have more inflorescences with fruits.
 Conclusions. A number of plants from the southern slopes of the railways is typically bigger, however, the plants on the southern slopes (in comparison with the northern ones) are worse developed, branch out less and, at the time of conducting the research were represented by a smaller number of generative individuals. In sandy sectors of the bay bar adjoining the railway tracks the plants E. davidii were almost not noticed. The individuals found in the above-mentioned sectors are characterised by stunted growth, a single stem, almost did not bloom, and did not produce seeds.