The genus Polygonum L. s. str. is a taxon of the Polygonaceae family that is complex in systematic terms. As a result of a critical study of the genus in the South of the Middle Volga region (within Penza, Samara, and Ulyanovsk regions), 13 species (P. arenastrum Boreau, P. aviculare L., P. calcatum Lindm., P. caspicum Kom., P. neglectum Besser, P. novoascanicum Klokov, P. patuliforme Worosch., P. patulum M. Bieb., P. pseudoarenarium Klokov, P. rectum (Chrtek) H. Scholz, P. salsugineum M. Bieb., P. samarense H. Gross, P. volchovense Tzvelev) from 5 subsections of the type section were identified.
Keywords: key for species identification, Penza region, Polygonum, Samara region, species synopsis, Ulyanovsk regionAll articles can be accessed under Creative Commons Attribution 4.0 International Public License (CC BY 4.0).