Hypericum anagalloides (Penninghertshooi), een nieuwe exoot in Nederland

Hypericum anagalloides, a species from North America, was discovered in a water storage facility in Groot Hoenlo (municipality of Olst, Province of Overijssel). This is the first time the species is found in the Netherlands. Up to now its origin is unclear. We describe the locality and the vegetation where the species was found. As it shows signs of invasive behaviour we suggest to be alert for new localities and to extend the identification key in Heukels’ Flora to enable fast recognition and action.