Symphyotrichum ciliatum in Romania: trends of spread and invaded plant communities.
Symphyotrichum ciliatum was reported as invasive in Romania in the early 1970s. In this study we have analysed its invasion history, current distribution in Romania, habitat preferences and the associated plant communities. Data recorded during our recent field work, as well as from herbaria and previously published papers, were used in the analysis. This data confirms its invasive character. Given the abrupt increase in the slope of the invasion curve during the last decade, we can assume that S. ciliatum is still far from reaching the saturation phase of its invasion in Romania. Habitats invaded by this species are mostly anthropogenic herb stands associated with rail and road transport networks, and the continental inland salt steppes. The classical methodology of the Zürich-Montpellier school was used for the field phytosociological research and the classification of the investigated communities was done using the deductive method. The phytocoenoses dominated by S. ciliatum were classified as derivate communities. The description of these communities included data about plant composition, synecology and distribution in the study area.