This name is a synonym of Juncus alpinoarticulatus subsp. rariflorus (Hartm.) Holub.
The record derives from IOPI
(data supplied on 2012-03-23)
which reports it as a synonym (record 314331) with original publication details: Ann. Bot. Fenn. 17: 342 1980.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:883665-1.
This name was in version 1 of The Plant List, record kew-314331.