This name is a synonym of Rhododendron augustinii subsp. chasmanthum (Diels) Cullen.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50067355) with original publication details: Acta Botanica Yunnanica 4(3): 255 1982.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:921398-1.
This name was in version 1 of The Plant List, record tro-50067355, and has not been changed.