The problem of assessing the completeness of the identification of flora is a very significant element of study. The approach proposed in this work is based on an assessment of the complex of parameters of the taxonomic spectra of flora (generic and family). As a model object, the authors considered the flora of the Soksky physical-geographical region, located in the Trans-Volga sector of the Samara region. To solve this problem, the authors used 124 source floristic lists and their combinations (over 400). Depending on the increase in the number of species according to the parameters of taxonomic spectra, the authors determined the main levels of floristic sampling. Such levels determine the reliable characteristics of the flora, corresponding to the ecological and geographical conditions. The authors found that, in the spectrum of families, the first triad of leading families (Asteraceae – Poaceae – Fabaceae) was established after 700 species were in the sample. The fourth place in the spectrum is occupied by the Rosaceae family, and the fifth, designated by us as the leading Brassicaceae, effectively takes its place with only 1000 species in the sample. The content of species in the top ten families tends to a value of 61–60% with 800 species or more. As part of the flora of the Soksky district, among families containing one species, there are 80% of families, which for this territory we can consider really repetitive? The formation of the spectrum of genera is somewhat slower than that of the spectrum of families. Leading genera (Carex, Galium, Potentilla, Artemisia, Astragalus, Salix) appear in the spectrum when the number of samples is already 300 species or more and is stably present in its composition. However, they all move to the head of the spectrum only after reaching a sample size of 1100 species.