This name is a synonym of Spirodela polyrrhiza (L.) Schleid..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 109319) with original publication details: Oestr. Fl. ed. 2, 1: 64 1814.
This name was in version 1 of The Plant List, record kew-109319.