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 109334) with original publication details: Gen. N. Amer. Pl. 1: 19 1818.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:526218-1.
This name was in version 1 of The Plant List, record kew-109334.