This name is a synonym of Rhododendron calostrotum var. calciphilum (Hutch. & Kingdon-Ward) Davidian.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50156490) with original publication details: Notes Roy. Bot. Gard. Edinburgh 16(79): 179 1931.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:332080-1.
This name was in version 1 of The Plant List, record tro-50156490, and has not been changed.