This name is a synonym of Zamia floridana var. umbrosa (Small) D.B.Ward.
The record derives from WCSP
(data supplied on 2012-03-26)
which reports it as a synonym (record 378754) with original publication details: J. New York Bot. Gard. 22: 136 1921.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:270578-2.
This name was in version 1 of The Plant List, record kew-2469597, and has not been changed.