This name is a synonym of Aira flexuosa var. umbrosa (Wimm. & Grab.) Litv..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 25559566) with original publication details: Fl. Siles. 1: 65 1827.
This name was in version 1 of The Plant List, record tro-25559566.