Molecular phylogeny of Philippine Amorphophallus (Araceae): evidence of polyphyly and multiple colonization events

Background and aims – The Philippines harbours 22 recognized species of Amorphophallus , with 20 endemic taxa; however, their phylogenetic relationships remain poorly understood owing to limited molecular data. This study explored the monophyly and phylogenetic placement of Philippine Amorphophallus using molecular markers. Material and methods – Two plastid markers ( rbcL and matK ) and nuclear ribosomal DNA (ITS1) were sequenced for 26 Philippine Amorphophallus specimens. Maximum Likelihood and Bayesian inference analyses were performed on individual and combined datasets comprising 471 GenBank sequences representing 158 Amorphophallus species and three outgroups, and 63 Philippine Amorphophallus sequences generated in this study. Key results – Philippine Amorphophallus is polyphyletic, with species distributed across different clades. A strongly supported Paeoniifolius-Manta clade was recovered, including several Philippine taxa ( A. paeoniifolius , A. rostratus , A. samarensis , and A. urceolatus ) characterized by sessile spadices and verruculate petioles. Two Palawan accessions ( A. natolii and A. cf. natolii ) grouped within A. subgenus Metandrium , distinctly separated from other Philippine species. Conclusion – Results imply two independent colonization events from northern and southern biogeographical routes of Southeast Asia and Borneo. Unresolved polytomies indicate the need for phylogenomic studies. This first comprehensive molecular phylogeny of Philippine Amorphophallus provides a foundation for systematic revisions, biogeography, and recognition of latent diversity in this megadiverse archipelago.