This name is a synonym of Calystegia pubescens Lindl..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 8502151) with original publication details: Bot. Mag. (Tokyo) 39(468): 304 1925.
This name was in version 1 of The Plant List, record tro-8502151.