This name is a synonym of Allium howellii var. sanbenitense (Traub) Ownbey & Aase.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 295729) with original publication details: Pl. Life 28: 66 1972.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:8788-2.
This name was in version 1 of The Plant List, record kew-295729, and has not been changed.