This name is a synonym of Washingtonia robusta H.Wendl..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 339832) with original publication details: Amer. J. Bot. 30: 233 1943.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:267789-2.
This name was in version 1 of The Plant List, record kew-339832, and has not been changed.