The Collaborative International Dictionary
Hottonia inflata
Water feather \Wa"ter feath"er\ Water feather-foil \Wa"ter feath"er-foil`\ (Bot.) The water violet ( Hottonia palustris); also, the less showy American plant Hottonia inflata.
Wikipedia
Hottonia inflata
Hottonia inflata (American featherfoil or featherfoil) of the family Primulaceae is an aquatic plant.