Left: Water lettuce, water hyacinth and salvinia cultivated for sale in Europe. Water lettuce has been eradicated from New Zealand, while the other species are subjected to an eradication programme. Credit: Rohan Wells. Middle: Water hyacinth establish in a taro plantation in Yap, Micronesia. Credit: Paul Champion. Right: Water lettuce, naturalised on the River Erft, Germany. Credit: Paul Champion