This name is a synonym of Rhododendron tubiforme (Cowan & Davidian) Davidian.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50064981) with original publication details: Rhododendron Year Book 3: 86 1948.
This name was in version 1 of The Plant List, record tro-50064981, and has not been changed.