This name is a synonym of Rhododendron longesquamatum C.K. Schneid..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50000673) with original publication details: Bull. Misc. Inform. Kew 1910(4): 106 1910.
This name was in version 1 of The Plant List, record tro-50000673, and has not been changed.