This name is a synonym of Muhlenbergia wrightii Vasey ex J.M.Coult..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 425013) with original publication details: Repert. Spec. Nov. Regni Veg. 17: 213 1921.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:164735-2.
This name was in version 1 of The Plant List, record kew-425013, and has not been changed.