Central European botanic gardens as centres of dispersal of alien plants

The aim of the work was to estimate the specific role that Central European botanic gardens play in the dispersal of alien plants, which results from the wide variety of plants cultivated in the gardens and regular international exchange of plant material between these institutions. We compared the results of recent field studies (in eight Polish botanic gardens) and a review of older literature data and herbarium collections (from Central European botanic gardens). We found that in Poland the proportion of botanic garden escapes was lower (3%) than would be expected from the "tens rule". Botanic gardens have played a considerable role in the development of the synanthropic flora of Central Europe in the last 200 years. We determined a group of species introduced through a network of botanic gardens and propose 5 theoretical patterns to describe the mode and pathways of the early stages of introduction of these species.