The article describes a study of plant communities of the south-western part of the Central Russian Upland that form in batches of various crops. Field studies employed the methods of reconnaissance floristic survey. Species diversity of the plant complexes and plant communities were studied with the morphological-ecological-geographical method. The results attest significant differences in their taxonomic and typological structures. In most familial spectra of studied floras, representatives of Asteraceae and Poaceae families prevail, while the counts of species of families Brassicaceae, Caryophillaceae, Fabaceae and Lamiaceae are also high, In the alien fraction of the studied flora, the importance of the following families increases: Amaranthaceae, Apiaceae, Asteraceae, Brassicaceae, Euphorbiaceae, Lamiaceae, Malvaceae, Portulacaceae. Most weeds pertain to annual xeromesophilic species. The work is aimed at formation and development of sustainable agro-environmental systems with rational use of biological resources.