This name is a synonym of Rhododendron temenium var. dealbatum (Cowan) D.F. Chamb..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50060600) with original publication details: Sp. Rhodod. 549 1930.
This name was in version 1 of The Plant List, record tro-50060600, and has not been changed.