This name is a synonym of Sphaerostigma gauriflorum (Torr. & A. Gray) Walp..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50082577) with original publication details: Fl. N. Amer. 1(3): 510 1840.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:613723-1.
This name was in version 1 of The Plant List, record tro-50082577, and has not been changed.