Taxonomic diversity of Brassicaceae in the Samara-Ulyanovsk Volga Region

In the flora of the Samara-Ulyanovsk Volga region, the Brassicaceae family is one of the leading ones. It is of interest to study the composition of the genera of this family at the level of the territory of the entire Samara-Ulyanovsk Volga region, as well as the physiographic regions included in it. It helps to understand whether there are local features in the composition of the cruciferous flora and what they are. Two natural zones are distinguished in the study area: forest-steppe and steppe; four provinces and 15 physical-geographic regions. In this paper, we consider in more detail 7 floras, they are described most fully. All of them are located in the forest-steppe zone. In the spectra of flora families of the considered physiographic regions, the Brassicaceae family is located on the 4^th–5^th place. In the spectrum of the adventive fraction of the flora, it rises to the 2^nd–3^rd position, and in the native fraction it falls to the 7^th–9^th place. The composition of the complete flora of cruciferous plants throughout the territory of the Samara-Ulyanovsk Volga region contains 40 genera and 89 species. It is not possible to unambiguously single out the head part in the generic spectrum, concentrating in itself a significant part of the flora species of this family. The most numerous genera are Rorippa, Lepidium and Alyssum. The species representation of these genera, as well as those of slightly smaller weight (Cardamine, Erysimum and Sisymbrium), does not differ in the considered physiographic regions. An exception is the genus Alyssum, whose representatives are confined to limestone and chalk substrates, which are not common in all areas. The Brassicaceae family has a fairly wide ecological spectrum; it includes species that grow in different ecotopes.