| Summary: | <i>Kitagawia</i> Pimenov is one of the segregate genera of <i>Peucedanum</i> sensu lato within the Apiaceae. The phylogenetic position and morphological delimitation of <i>Kitagawia</i> have been controversial. In this study, we used plastid genome (plastome) and nuclear ribosomal DNA (nrDNA) sequences to reconstruct the phylogeny of <i>Kitagawia</i>, along with comparative plastome and morphological analyses between <i>Kitagawia</i> and related taxa. The phylogenetic results identified that all examined <i>Kitagawia</i> species were divided into Subclade I and Subclade II within the tribe Selineae, and they were all distant from the representative members of <i>Peucedanum</i> sensu stricto. The plastomes of <i>Kitagawia</i> 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 <i>Kitagawia</i> species within Subclade I from Subclade II and other related genera. This study supported the separation of <i>Kitagawia</i> from <i>Peucedanum</i> sensu lato, confirmed that <i>Kitagawia</i> belongs to Selineae, and two species (<i>K. praeruptora</i> and <i>K. formosana</i>) within Subclade II should be placed in a new genus. We believe that the “core” <i>Kitagawia</i> 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 <i>Kitagawia</i>.
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