This name is a synonym of Plectranthus esculentus N.E.Br..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 454094) with original publication details: Bull. Misc. Inform. Kew 1894: 13 1894.
This name record (from WCSP) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Plectranthus floribundus in version 1 of The Plant List.