This name is a synonym of Apocynum androsaemifolium var. incanum A.DC..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 329926) with original publication details: Atti Reale Accad. Lincei, Mem. Cl. Sci. Fis. Va, 9: 98 1913.
This name was in version 1 of The Plant List, record kew-329926.