This name is a synonym of Apocynum androsaemifolium subsp. pumilum (A.Gray) B.Boivin.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 12936) with original publication details: Man. Bot. San Francisco 240 1894.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:16640-2.
This name was in version 1 of The Plant List, record kew-12936, and has not been changed.