This volume contains data on morphology, ecology, and chorology of feral species and subspecies of 31 families of flowering plants. The families have been arranged essentially according to the Engler system. Conforming to the latest views (Takhtadzhyn, Sistema magnoliofitov [System of Magnoliophyta] 1987), some families have, however, been subdivided into some smaller families. Thus, family Biebersteiniaceae has been separated from family Geraniaceae; family Zygophyllaceae s.l. is represented in Siberia by 4 smaller (in volume) families: Zygophyllaceae s. str., Rutaceae, Nitrariaceae, and Peganaceae. This critical study has provided the specific characteristics of taxonomy and chorology of 299 species and subspecies belonging to 101 genera including 6 taxa that are new for science and their diagnosis in Latin.