This name is a synonym of Carex × anticostensis (Fernald) Lepage.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 230468) with original publication details: Rhodora 48: 146 1946.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:47019-2.
This name was in version 1 of The Plant List, record kew-230468, and has not been changed.