Polyalthia angustifolia A.C.Sm., Bull. Torrey Bot. Club 70: 538. 1943. Type: FIJI: Viti Levu, J.W. Gillespie 2198 (holotype: A!; isotypes: BISH, GH!).

The historical delimitation of the genus Polyalthia has been shown to be highly polyphyletic, and large-scale taxonomic realignment and recognition of new genera has been undertaken to ensure strict monophyly of genera (Mols et al. 2008; Saunders et al. 2011; Xue et al. 2011, 2012, in press; Chaowasku et al. 2012). As part of this series of taxonomic revisions, chloroplast DNA regions were sequenced from eight species from the Melanesian island of Fiji (Xue, 2013) that had previously been assigned to Polyalthia. Phylogenetic analysis of this data revealed that most of these species align with either Hubera (Chaowasku et al. 2012; Xue 2013) or Meiogyne (Xue 2013; Xue et al. in press), although one species, Polyalthia angustifolia A.C.Sm., which was sequenced from the type material, is nested within the Goniothalamus clade (Xue 2013). Polyalthia angustifolia was originally described from fruiting material (Smith 1943), and it is likely that its incorrect generic affiliation was due to the absence of flowers, which are very different in Polyalthia and Goniothalamus. Subsequent phylogenetic analyses with a larger taxon sampling (C.C. Tang et al., unpubl.) have revealed Polyalthia angustifolia as sister to the Fijian species Goniothalamus monospermus (Baill.) R.M.K.Saunders with strong support (posterior clade probability = 1; bootstrap support = 96%); these two species are morphologically distinct, as Polyalthia angustifolia seeds lack the broad lateral testa wings that are diagnostic of Goniothalamus monospermus (Van Setten and Koek-Noorman 1992: pl. 39i). The transfer of the name Polyalthia angustifolia to Goniothalamus is accordingly validated here.