This name is a synonym of Rhododendron leptocarpum Nutt..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 12305008) with original publication details: Notes Roy. Bot. Gard. Edinburgh 16(79): 211–214 1931.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:332883-1.
This name was in version 1 of The Plant List, record tro-12305008, and has not been changed.