An evidence-chain framework for classification under reticulate evolution: Formalizing subtribal and generic delimitation in Campanuleae (Campanulaceae)

Phylogenomic studies have greatly improved our understanding of relationships in reticulate plant groups, but they have also made classificatory decisions more difficult, especially where cytonuclear discordance, introgression, hybridization, and allopolyploidization obscure lineage boundaries. Tribe Campanuleae provides a strong model for addressing this problem because its long-recognized taxonomic difficulties can now be reassessed in light of accumulated nuclear, plastid, and conflict-aware phylogenomic evidence. Here, we present an evidence-chain framework for translating such evidence into formal taxonomic decisions and apply it at two levels in Campanuleae: subtribal classification across the tribe and generic delimitation within subtribe Phyteumatinae. Based on the combined evaluation of phylogenomic structure, conflict patterns, process inference, morphology, geography, cytology, and nomenclatural considerations, we recognize four subtribes in Campanuleae: Phyteumatinae, Campanulinae, Musschiinae, and Jasioninae. Within Phyteumatinae, we recognize 19 genera and propose an updated generic classification supported by concordant evidence rather than topology alone. Because evidentiary completeness differs among generic groups, we distinguish strongly corroborated circumscription decisions from medium-confidence implementations that remain open to further testing as additional comparative evidence becomes available. This treatment includes the description of three new genera, Graecodon , Adriacodon , and Anatocodon , together with 118 new combinations and 12 new synonyms. By making the link between evidence, confidence level, and taxonomic action explicit, this study provides a more transparent basis for classification in a clade shaped by reticulate evolution and offers a practical model for taxonomic decision-making in other phylogenetically complex groups.