Unravelling Aganope (Fabaceae) in Yunnan and Southeast Asia: insights into species delimitation and generic placement from genomic and ecological evidence

We aimed to identify a sterile Aganope specimen collected in Yunnan using genomic and limited morphological evidence. Although A. thyrsiflora is the only Aganope species currently recorded from Yunnan, our specimen did not match this taxon. To clarify its identity, we sequenced and assembled chloroplast genomes (plastomes) from five Asian Aganope species and reconstructed phylogenies using whole plastome data, nuclear ITS, and chloroplast trnK sequences. Notably, we recovered complete plastomes from 19th-century herbarium material of A. polystachya . Phylogenomic analyses placed A. polystachya within Derris , suggesting that its current placement in Aganope may be inappropriate and consistent with its original description as D. polystachya . For the Yunnan specimen, two hypotheses were assessed: (1) A. balansae extends beyond Southeast Asia into Yunnan and includes both our unidentified specimen and A. dinghuensis , rendering the latter a synonym of A. balansae ; or (2) A. balansae , A. dinghuensis , and the Yunnan specimen represents distinct species. Phylogenomic results, climatic niche similarities, and published morphological descriptions support the first hypothesis, indicating that A. balansae could be more widely distributed than currently recognized, while A. dinghuensis likely represents a local variant. With chloroplast genomes data now available for five out of the six Asian Aganope species, this study lays the groundwork for future taxonomic clarification. Given the limited sampling, reliance on partly sterile material, and lack of comprehensive morphological comparisons, future research integrating expanded field surveys, fertile morphological material assessments, and broader molecular sampling will be essential to resolve the taxonomy of Aganope , particularly the status of A. dinghuensis and its relationship to A. balansae .