This name is a synonym of Carex × boenninghausiana Weihe.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 225003) with original publication details: Consp. Fl. Gallic. Crit. 3: 233 1911.
This name was in version 1 of The Plant List, record kew-225003, and has not been changed.