This name is a synonym of Polyscias samoensis (A.Gray) Harms.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50006611) with original publication details: U.S. Expl. Exped., Phan. 1: 717 1854.
This name record (from Tropicos) 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 Panax samoense in version 1 of The Plant List.