New generic classification for Korean Peucedanum L. (Apiaceae) species based on deep phylogenomic study

BACKGROUND: Peucedanum L. (Apiaceae) is a species-rich genus with taxonomically complex relationships and longstanding uncertainties in its circumscription. In particular, the phylogenetic relationships and taxonomic positions of Korean Peucedanum taxa remain unresolved due to morphological convergence and limited molecular evidence. RESULTS: To clarify these relationships, we generated complete plastome sequences for 13 accessions representing 12 taxa in Korea, including Sillaphyton podagraria (formerly P. insolens). Comparative plastome analyses revealed differences in plastome size, inverted repeat boundaries, and repeat content between Peucedanum and S. podagraria. Phylogenomic reconstruction confirmed the polyphyly of Peucedanum s.l., resolving three distinct clades (A, B, and C). Ten Korean taxa formed a monophyletic group corresponding to Kitagawia, whereas P. japonicum clustered with Sinopeucedanum. Mericarp anatomical characteristics further supported these phylogenetic relationships, showing distinct combinations of vittae, oil ducts, and crystal types among the clades. Molecular dating analyses suggested that rapid diversification within Apioideae occurred from the Late Miocene (ca. 8.1-8.2 million years ago, MYA) to the Quaternary, likely driven by climatic and topographic changes. The three clades subsequently diverged at approximately 3.50, 3.27, and 2.29 MYA, respectively. CONCLUSIONS: Overall, an integrative approach combining plastome structural variation, mericarp morphology, phylogenetic relationships, and divergence time estimates supports the transfer of Korean Peucedanum taxa to Kitagawia (except for P. formosanum due to a discrepancy with previous findings). Furthermore, it supported the reassignment of P. japonicum to Sinopeucedanum. These results highlight the importance of combining molecular and morphological evidence to resolve taxonomic ambiguities and to elucidate patterns of lineage diversification within Apiaceae.