This name is a synonym of Cracca elegans (Schumach.) Kuntze.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 13033417) with original publication details: Beskr. Guin. Pl. 376 1827.
This name record (from Tropicos) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Tephrosia elegans in version 1 of The Plant List.