The Collaborative International Dictionary
Cabomba caroliniana
fanwort \fanwort\ n. a common aquatic plant ( Cabomba caroliniana) of eastern North America having floating and submerged leaves and white yellow-spotted flowers.
Syn: water-shield, Cabomba caroliniana.
Wikipedia
Cabomba caroliniana
Cabomba caroliniana is an aquatic perennial herbaceous plant native to North America and South America. It is a Weed of National Significance in Australia and on the list of invasive alien species of Union concern in the EU.