This name is a synonym of Rhododendron grande Wight.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50060102) with original publication details: Rhododendron Sikkim Himalaya pl. 9 1849.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:331950-1.
This name was in version 1 of The Plant List, record tro-50060102, and has not been changed.