This name is a synonym of Begonia handelii var. prostrata (Irmsch.) Tebbitt.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 362735) with original publication details: Mitt. Inst. Allg. Bot. Hamburg 10: 517 1939.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:20011629-1.
This name was in version 1 of The Plant List, record kew-362735, and has not been changed.