Boni Song ¹ Changkun Liu ² Jiao-Jiao Deng ¹ Wei-Yan Tan ¹ Song-Dong Zhou ^1* Xing-Jin He ¹

• ¹ Key Laboratory of Biological Resources and Ecological Environment of the Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
• ² School of Resources, Environment and Chemistry, Chuxiong Normal University, Chuxiong, China

The Peucedanum s.l. genus, the backbone member of subfamily Apioideae, was not a monophyletic group. Previous studies confirmed that only P. morisonii belonged to Peucedanum s.s. in China, and the classifications of other Peucedanum s.l. members need to be re-explored, especially for those endemic to China, such as P. dissolutum, P. guangxiense, P. mashanense, P. medicum, P. ampliatum, P. formosanum, P. harry-smithii, P. harry-smithii var. grande, P. harry-smithii var. subglabrum, P. huangshanense, P. japonicum, P. praeruptorum, P. turgeniifolium and P. wawrae. Here, we obtained 103 high-quality plastomes and 43 nrDNA sequences by genome skimming and performed phylogenetic analyses respectively based on concatenated plastid protein-coding genes and nrDNA sequences. Both analyses failed to recover Peucedanum s.l. as a monophyletic group and robustly supported that P. morisonii, the representative of Peucedanum s.s., was distantly related to other Peucedanum s.l. members, which implied that these Peucedanum s.l. taxa were not the "truly Peucedanum plant". Among these Peucedanum s.l. members, plastid-based phylogenies recognized two monophyletic clades, clade A (four species) and clade B (ten taxa). Meanwhile, obvious recognized features from morphology, plastome, and chromosome number for each clade were detected: dorsally compressed and glabrous mericarps with filiform dorsal ribs, winged lateral ribs, and numerous vittae in commissure and each furrow, IRa/LSC border fell into rpl23 gene, overall plastome size of 152,288-154,686 bp, and chromosome numbers of 2n=20 were found in clade A, whereas dorsally compressed and pubescent mericarps with filiform dorsal ribs, winged lateral ribs, and numerous vittae in commissure and each furrow, IRa/LSC border fell into ycf2 gene, overall plastome size of 146,718-147,592 bp, and chromosome numbers of 2n=22 were discovered in clade B.. Therefore, we established two new genera (Shanopeucedanum gen. nov. and Sinopeucedanum gen. nov.) to respectively accommodate taxa of clades A and B. Furthermore, molecular dating analysis showed that the diversification of clades A and B respectively occurred at early Pleistocene and late Pliocene, which may be drove by the complex geological and climate shifts of these periods. In summary, our study impelled the revisions of Peucedanum s.l. members and improved the taxonomic system of Apiaceae family.