Berberis jiuzhaigouensis (Berberidaceae), a new riparian shrub from northern Sichuan, China

<i>Berberisjiuzhaigouensis</i> is herein described as a new deciduous species endemic to riparian habitats in Jiuzhaigou, northern Sichuan, China. Phylogenetic analyses based on complete plastome sequences and 322 nuclear loci consistently recover <i>B.jiuzhaigouensis</i> as a distinct and divergent lineage, genetically separated from all morphologically similar species and most closely related to <i>B.gilgiana</i>. Species delimitation analyses employing both topology-based (SODA) and substitution-based (bPTP, mPTP) frameworks further corroborate its taxonomic distinctiveness. This discovery highlights previously overlooked species diversity within <i>Berberis</i> in the Hengduan Mountains region.