This name is a synonym of Ranunculus hydrocharoides var. natans (Nees ex G. Don) L.D. Benson ex Standl. & Steyerm..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50227290) with original publication details: Gen. Hist. 1: 31 1831.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:713302-1.
This name was in version 1 of The Plant List, record tro-50227290, and has not been changed.