European invasion in progress: Myriophyllum heterophyllum Michx. (Haloragaceae) in Croatia.
In Europe, Myriophyllum heterophyllum Michx. (Haloragaceae) has had the status of invasive species in freshwater ecosystems since 2012. During phytosociological research in the Neretva River Delta in July 2016, we noted a high coverage of species Myriophyllum heterophyllum within vegetation of rooted leaf-floating macrophytes of the Nymphaeion albae Oberd. 1957 alliance (the order Potamogetonetalia Koch 1926). In this paper, alongside the finding of the new locality with M. heterophyllum in Croatia, its phytosociology is reported.