Main taxonomical flora parameters of the Samara-Ulyanovsk Volga region (family spectrum)

An analysis of the spectrum of flora families helps to designate a number of parameters for its taxonomic characteristics (quantitative and qualitative), which depend on the geographical location. In this paper we aim to determine the values of these parameters for the Samara-Ulyanovsk Volga region. Such data is important for characterizing the flora, as well as assessing the degree of completeness of the floristic sample. The determination of the taxonomic parameters of the floras of the Samara-Ulyanovsk Volga region was carried out using the lists of higher vascular plants. The source material for the floras of the regions was the lists compiled in individual geographical points. This material forms the basis of the FD SUR database. With the help of the functional algorithms of this database, the necessary combination of them and the construction of family spectra were carried out. The ranges of absolute and relative parameters are determined for the complete floras of the areas under consideration. In the head parts of the spectra of families, we distinguish five leading families: Asteraceae, Poaceae, Fabaceae, Rosaceae, and Brassicaceae. The remaining five families of the top ten are represented by the following: Caryophyllaceae, Lamiaceae, Scrophulariaceae, Apiaceae, and Cyperaceae. The Chenopodiaceae family is in the top ten in all areas belonging to the steppe province. In the spectrum of native flora, the order of families varies more than their composition. The list of the first four families remains unchanged; the Cyperaceae family should be considered the fifth leading family. For the adventive fraction, a common feature is the presence of the Asteraceae, Poaceae, Brassicaceae, and Chenopodiaceae families in 1-4 places. Quantitative indicators of the species representation of the head and tail parts of the spectra of the complete flora, adventitious and natural fractions were determined. The floras of the physical-geographical regions of the Samara-Ulyanovsk Volga region have the values of a number of family spectrum parameters that can be considered characteristic of the area. Using the obtained values of the parameters, it is possible to evaluate any floristic sample belonging to a given territory in terms of its completeness.