This name is a synonym of Rhododendron concinnum Hemsl..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50002313) with original publication details: J. Arnold Arbor. 20(4): 424–425 1939.
This name was in version 1 of The Plant List, record tro-50002313, and has not been changed.