Genetic insights: integrating DNA barcoding with taxonomy in the study of <i>Baccaurea</i> (Phyllanthaceae)

Traditional taxonomic revisions based on macromorphological and leaf anatomical traits may have limitations in accurately distinguishing certain species within the genus. To improve taxonomic clarity, this study applied DNA barcoding to enhance the understanding of the taxonomy and phylogeny of <i>Baccaurea</i> Lour., a plant genus widely utilized for food, medicine, and building materials. DNA barcode regions, including <i>rbc</i>L, ITS2, and <i>trn</i>H-<i>psb</i>A, were used to analyze 64 samples representing 19 <i>Baccaurea</i> species. Using similarity Basic Local Alignment Search Tool and phylogenetic tree inference, we determined the discriminatory efficiencies of <i>rbc</i>L, ITS2, <i>trn</i>H<i>-ps</i>bA, and their combinations <i>rbc</i>L + ITS2 and <i>rbc</i>L + ITS2 + <i>trn</i>H-<i>psb</i>A as 21.1%, 89.5%, 87.5%, 89.5%, and 89.5%, respectively. The Neighbor-Joining tree revealed well-defined, monophyletic species clusters that largely align with phylogenetic positions based on macromorphological features. Notably, our results indicate that <i>Baccaurea parviflora</i> and the synonymized <i>Baccaurea scortechinii</i> are distinct species, recommending the re-establishment of <i>B. scortechinii</i> as a separate species. DNA barcoding is useful in delineating species boundaries, facilitating routine specimen identification, and flagging atypical samples for detailed examination.