Epilobium ciliatum Raf., a new plant invader in Slovenia and Croatia

Abstract

The North American invasive species Epilobium ciliatum Raf. was recently recorded for the first time in Slovenia and Croatia. The most reliable character with which to distinguish E. ciliatum from all native European Epilobium species is the presence of conspicuous longitudinal white stripes on the seed testa. If seeds are not available, E. ciliatum may easily be misidentified as E. roseum. With fieldwork and revision of herbarium material we ascertained that the invasion towards the territory discussed came from the north, which is in agreement with the north west to south east direction of the spread in Europe. At least in Eastern Slovenia E. ciliatum has already become an important member of ruderal plant communities. Rapid spreading and naturalization as in the case of E. ciliatum can give rise to concern that it will replace some indigenous species with a similar ecology or hybridise and so by introgression cause »genetic« pollution of native relatives’ populations. Further spread to the south and east is expected