This name is a synonym of Xanthocephalum megalocephalum Fernald.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 45B60DF7-C327-4CFB-A9CF-4ECF91388D53) with original publication details: Sida 8 313 1980.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:114987-2.
This name was in version 1 of The Plant List, record gcc-42554, and has not been changed.