This name is a synonym of Desmodium procumbens var. exiguum (A.Gray) B.G.Schub..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 13015097) with original publication details: Revis. Gen. Pl. 1: 198 1891.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:155948-2.
This name was in version 1 of The Plant List, record tro-13015097, and has not been changed.