This name is a synonym of Polyalthia cauliflora Hook.f. & Thomson.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 61(2): 68 1892.
This name record (from WCSP (in review)) 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 Polyalthia pycnantha in version 1 of The Plant List.