This name is a synonym of Watsonia marginata (L.f.) Ker Gawl..
The record derives from iPlants
(data supplied on 2012-03-23)
which reports it as a synonym (record 322916) with original publication details: J. Linn. Soc., Bot. 16: 158 1877.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:439580-1.
This name was in version 1 of The Plant List, record kew-322916.