A new hybrid between two alien Helichrysum species (Compositae, Gnaphalieae) from NW Spain

© 2019, Springer Nature Switzerland AG. Hybridisation events between Invasive Alien Species can contribute to the acquisition of novel traits or a higher fitness through gene exchange and, in consequence, facilitate the adaptation to new environments and the colonization of new territories. Using morphological data and DNA sequences, we have identified and described a new hybrid between Helichrysum petiolare and H. foetidum. Both species are original to South Africa, but have become invasive in the coast of Galicia, NW Spain. The hybrids were raised in the laboratory from achenes collected from H. petiolare in isolated populations far from the core invaded area, but have so far not been found in the wild. Up to now, there is no evidence that the hybrids are themselves fertile. We consider that the risk assessment for these invasive species must take into account the potential crosses in natural areas, a phenomenon with implications in the species capacity to affect the invaded habitats.