This name is a synonym of Spirodela punctata (G.Mey.) C.H.Thomps..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 194596) with original publication details: Ber. Schweiz. Bot. Ges. 42: 188 1933.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:242866-2.
This name was in version 1 of The Plant List, record kew-194596.