This name is a synonym of Hilaria belangeri var. longifolia (Vasey ex Beal) Hitchc..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 418951) with original publication details: Grass. N. Amer. 2: 69 1896.
This name was in version 1 of The Plant List, record kew-418951, and has not been changed.