This name is a synonym of Begonia grandis subsp. sinensis (A.DC.) Irmsch..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 361542) with original publication details: Mitt. Inst. Allg. Bot. Hamburg 10: 494 1939.
This name was in version 1 of The Plant List, record kew-361542, and has not been changed.