This name is a synonym of Begonia arborescens Raddi.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 360983) with original publication details: Webbia 12: 499 1957.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:30387-2.
This name was in version 1 of The Plant List, record kew-360983.