This name is a synonym of Carex nigra subsp. juncea (Fr.) Soó.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 342724) with original publication details: Fl. Zap. Sibiri 3: 468 1929.
This name was in version 1 of The Plant List, record kew-342724.