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 and as an invalid name (record 109336) with original publication details: Enum. Pl. Transsilv. 635 1866.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:526220-1.
This name was in version 1 of The Plant List, record kew-109336.