This name is a synonym of Lemna obscura (Austin) Daubs.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 109309) with original publication details: Manual ed. 5: 479 1867.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:137287-2.
This name was in version 1 of The Plant List, record kew-109309.