This name is a synonym of Ranunculus canus var. ludovicianus (Greene) L.D. Benson.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 27103143) with original publication details: Bull. Calif. Acad. Sci. 2(5B): 58 1886.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:217412-2.
This name was in version 1 of The Plant List, record tro-27103143, and has not been changed.