The morphologically variable genusArchidendronis the second largest mimosoid legume genus from the Indomalayan-Australasian region, yet it has not been well represented in phylogenetic studies. Phylogenies that have included multiple representatives ofArchidendronsuggest it may not be monophyletic, and the same applies toArchidendropsis, another understudied genus of the Archidendron clade. The most comprehensive phylogeny ofArchidendronandArchidendropsisto date is presented, based on four nuclear markers (ITS, ETS, SHMT and RBPCO). Exemplars from all genera of the wider Archidendron clade are sampled, including representatives of all series withinArchidendronand the two subgenera ofArchidendropsis. Our results confirm thatArchidendronandArchidendropsisare not monophyletic. WithinArchidendron, only one series (ser. Ptenopae) is resolved as monophyletic and species ofArchidendronare divided into two primarily geographic lineages. One clade is distributed in western Malesia and mainland Asia and includes most representatives of seriesClypeariae, while the other is mostly restricted to eastern Malesia and Australia and includes representatives of the seven other series plus two samples of seriesClypeariae. No taxonomic changes are made forArchidendrondue to the high level of topological uncertainty and the lack of discrete macromorphological characters separating these two lineages. Each of the two subgenera ofArchidendropsisis monophyletic but they are not closely related. A new genus endemic to Queensland (Australia),HeliodendronGill.K. Br. & Bayly,gen. nov., is described for the former Archidendropsis subg. Basaltica, and combinations for its three species are proposed:Heliodendron basalticum(F. Muell.) Gill.K. Br. & Bayly,comb. nov.,Heliodendron thozetianum(F. Muell.) Gill.K. Br. & Bayly,comb. nov., andHeliodendron xanthoxylon(C.T. White & W.D. Francis) Gill.K. Br. & Bayly,comb. nov.
