This name is a synonym of Ranunculus alismifolius var. lemmonii (A. Gray) L.D. Benson.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 27103166) with original publication details: Proc. Amer. Acad. Arts 10: 68 1874.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:713078-1.
This name was in version 1 of The Plant List, record tro-27103166, and has not been changed.