This name is a synonym of Vigna megatyla (Piper) A. Delgado.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 13012262) with original publication details: Contr. U.S. Natl. Herb. 22(9): 675 1926.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:307623-2.
This name was in version 1 of The Plant List, record tro-13012262, and has not been changed.