This name is a synonym of Plantago australis subsp. supina (Pilg.) Rahn.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 25200510) with original publication details: Bot. Jahrb. Syst. 50: 282 1913.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:201343-2.
This name was in version 1 of The Plant List, record tro-25200510.