<p>This paper considers the problem of geographic links between the urban flora of steppe zone of Ukraine on the example of the industrial agglomeration Donetsk-Makeyevka, in comparison with urban flora of Kherson and Kirovograd. We presented the detailed description of special features of the composition of geographic elements of the agglomeration flora. It strongly reflects the characteristic features of steppe urban flora, because its territory is affected by the anthropogenic influence at large extend. The spectrum of geographic ranges of species from the agglomeration Donetsk-Makeyevka urban flora numbers 6 types, 12 classes and 130 groups of ranges. The urban flora is both represented by species with wide and local ranges, endemics, that point to its significant heterogeneity. However, compared to the flora of Kherson and Kirovograd, the role of holarctic type of ranges in the agglomeration flora (375 species compared to 400 and 522 species, respectively) is reduced in favor of the polyregional type, reflecting active adventization processes. The holarctic class itself is represented by 150 species (16.7%). It far exceeds the number of species of this class in the regional flora (9.2%), since nearly a half of their number in the observed flora is adventive species. Second place by the number of species in the holarctic class belongs to the European and North American group (13; 1.5%). Apart from this, seven more groups of the class, comprising 1-3 species each, are connected with North America. The polyregional type is represented to a large extent by the species of ruderal habitats. The total number of species of this type is 199. The palaearctic class includes the greatest number of ranges of species from the agglomeration urban flora (31); it consists of 175 species (19.5%), that is less than such index for regional flora (27.3%). The European and Old Mediterranean transition type comprises 97 species (10.8%), that is less than in other urban flora of steppe zone (128; 13.3% in Kherson and 171; 18.0% in Kirovograd). The Nomadic type numbers 132 species (14.7%). One more species – Verbascum marschallianum Ivanina et Tzvelev – is related to the Nomadic and European transition type. The Nomadic and Old Mediterranean transition type includes 93 species (10.4%). This all suggests heterogeneity of urban flora of steppe zone of Ukraine due to their wide geographic connections. On the one hand, they have features of regional flora, which was formed under the great influence of Old Mediterranean flora and has a significant number of narrow-range and endemic species. On the other hand, under the impact of urbanization one can observe the reduction of the role of ranges of the Nomadic type and the enhanced role of the polyregional type due to the significant number of adventive species.</p><p> </p>
Welded Construction Design of Transition Fittings from Metal Pipes to Plastic Pipes
