The article provides an annotated list of new floristic finds in the flora of the Middle Dnieper (on territory of Cherkasy region, as well as adjacent districts of Kyiv and Poltava regions), both aboriginal rare and alien species, including “runaways from culture”. In some cases, notes are given on the taxonomic status, features of the natural range, ancient indications of the localities of certain species in the region. For the first time, 31 new taxa were introduced for the regional flora of Cherkasy region, including 8 native and 23 alien. The most valuable is the information about rare aboriginal plants, in particular Asparagus tenuifolius, Euphorbia salicifolia, Polygonum patulum, Rosa andegavensis, etc. In the Uman district of Cherkasy region, the location of three species of flora that were considered disappeared in the region: Pentanema oculus-christi, Salvia dumetorum and Staphylea pinnata. For once, 3 new alien species have been introduced for the flora of Poltava region: Anthriscus caucalis, Lonicera × notha and L. ruprechtiana. The research revealed new locations of invasively active foreign plants, including ergasiophygophytes: Phytolacca acinosa, Silphium perfoliatum, Vitis riparia, Zizania latifolia etc., and quarantine xenophytes: Cenchrus longispinus and Eriochloa villosa. Progressive distribution of xenophytes with primary sub-Mediterranean and Central Asian habitats has been noted. Population growing of foreign plants emphasizes the existing negative trend of adventitia of the flora.The issues of naturalization of ergasiophytes are discussed, in particular the presence of mass selfseeding in the centers of their primary introduction, which is the impetus for their further spread. Provided information on spontaneous seed reproduction of species such as: Castanea sativa, Catalpa ovata, C. speciosa, Pilosella aurantiaca, Verbesina encelioides, Viola sororia and other cultivated plants. The above and similar information is an considerable element of comprehensive floral research.