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 27103182) with original publication details: Proc. & Trans. Roy. Soc. Canada 2(4): 45 1884.
This name was in version 1 of The Plant List, record tro-27103182.