This name is a synonym of Trisetum longiglume Hack..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 447974) with original publication details: in Fl. Patagonica 3: 245 1978.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:883192-1.
This name was in version 1 of The Plant List, record kew-447974.