This name is a synonym of Ranunculus aquatilis var. diffusus With..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 27101502) with original publication details: Amer. Midl. Naturalist 58(1): 32 1957.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:217152-2.
This name was in version 1 of The Plant List, record tro-27101502.