Evidence from Phylogenomics and Morphology Provide Insights into the Phylogeny, Plastome Evolution, and Taxonomy of Kitagawia

Pimenov is one of the segregate genera of sensu lato within the Apiaceae. The phylogenetic position and morphological delimitation of have been controversial. In this study, we used plastid genome (plastome) and nuclear ribosomal DNA (nrDNA) sequences to reconstruct the phylogeny of , along with comparative plastome and morphological analyses between and related taxa. The phylogenetic results identified that all examined species were divided into Subclade I and Subclade II within the tribe Selineae, and they were all distant from the representative members of sensu stricto. The plastomes of and related taxa showed visible differences in the LSC/IRa junction (JLA) and several hypervariable regions, which separated Subclade I and Subclade II from other taxa. Fruit anatomical and micromorphological characteristics, as well as general morphological characteristics, distinguished the four species within Subclade I from Subclade II and other related genera. This study supported the separation of from sensu lato, confirmed that belongs to Selineae, and two species ( and ) within Subclade II should be placed in a new genus. We believe that the "core" should be limited to Subclade I, and this genus can be distinguished by the association of a series of morphological characteristics. Overall, our study provides new insights into the phylogeny, plastome evolution, and taxonomy of .