Abstract
The results of studies. on the synanthropic flora of all Polish sea harbours are reported. The first chapters describe in outline the physiographic conditions, trade contacts and the history of research on the synanthropic flora of Polish sea harbours. The detailed part (chapter 6) gives an analysis of the synanthropic flora with reference to its, state in the particular harbours, its biological durability, the proportion of apophytes and anthropophytes, the origin of anthropophytes, the flora of the particular harbour habitats, the state of the synanthropic flora of harbours as compared with the flora of some chosen areas. In the end chapter the results are summarised and conclusions are drawn.