This name is a synonym of Pappobolus nigrescens (Heiser) Panero.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 22ED0962-8E1A-4849-99C0-B9CEDF117238) with original publication details: Brittonia 8: 287 287 1957.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:309329-2.
This name was in version 1 of The Plant List, record gcc-114420, and has not been changed.