This name is a synonym of Rosa × odorata var. gigantea (Collett ex Cr‚p.) Rehder & E.H.Wilson.
The record derives from RJP
(data supplied on 2011-10-18)
which reports it as a synonym (record 11884) with original publication details: Plantae wilsonianae Plantae wilsonianae; 1911 339 1915.
This name record (from RJP) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Rosa duclouxii in version 1 of The Plant List.