This name is a synonym of Muhlenbergia tenuissima (J.Presl) Kunth.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 437770) with original publication details: Reliq. Haenk. 1: 230 1830.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:418438-1.
This name was in version 1 of The Plant List, record kew-437770, and has not been changed.