This name is a synonym of Prestonia didyma (Vell.) Woodson.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 177979) with original publication details: Apocyn. S. Amer. 152 1878.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:81707-1.
This name was in version 1 of The Plant List, record kew-177979, and has not been changed.