Molecular phylogenetic and biogeographic evidence of Willd. (Acanthaceae, Barlerieae) focusing on Indian endemics.

Willd., a genus belonging to the Acanthaceae family, is primarily distributed in tropical and subtropical regions worldwide, encompassing approximately 153 species. While considerable morphological research has been conducted on , it has not completely dispelled taxonomic ambiguities and conflicting interpretations. Molecular analysis emerges as a valuable tool for resolving these taxonomic uncertainties, but the availability of nucleotide sequence data for has been limited thus far. This study delivers a phylogenetic analysis of species, utilizing both chloroplast and nuclear regions. The results of Bayesian Inference and Maximum Likelihood phylogenetic analyses consistently segregate the studied species into two principal clades, denoted as Clade A and Clade B. Notably, this analysis firmly positions the Indian endemic within Clade A, supported by robust statistical evidence. Furthermore, our biogeographical analysis strongly suggests that the origin of might be traced back to Eurasia. This research establishes a foundational molecular phylogeny of , offering valuable insights for future taxonomic investigations. Additionally, it sheds light on the evolutionary history and biogeographical origins of the genus.