This name is a synonym of Calystegia spithamaea var. pubescens (A. Gray) C.F. Reed.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50086335) with original publication details: Rhodora 10(111): 55 1908.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:64659-2.
This name was in version 1 of The Plant List, record tro-50086335.