This name is a synonym of Rhododendron trichostomum var. radinum (Balf. f. & W.W. Sm.) Cowan & Davidian.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 12304881) with original publication details: Notes Roy. Bot. Gard. Edinburgh 9(44–45): 268–269 1916.
This name was in version 1 of The Plant List, record tro-12304881, and has not been changed.