This name is a synonym of Rhododendron mekongense Franch..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50065016) with original publication details: Quart. Bull. Amer. Rhododendron Soc. 29: 144 1975.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:333263-1.
This name was in version 1 of The Plant List, record tro-50065016.