This name is a synonym of Rhododendron concinnum Hemsl..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 12303891) with original publication details: Bot. Mag. 135: , pl. 8280 1909.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:332235-1.
This name was in version 1 of The Plant List, record tro-12303891, and has not been changed.