Taxonomic revision of the genus Pseudocodon (Campanulaceae) based on character analysis and molecular phylogeny

All taxa of the newly established genus Pseudocodon (= Codonopsis subg. Pseudocodonopsis), except for Pseudocodon rosulatus, form a complicated group extremely controversial on species delimitation. In the present study, numerous field trips were made, 29 populations were observed, and over 800 specimens of the genus preserved in 18 herbaria were critically examined. Statistical analysis of the characters was carried out based on 148 samples from specimens and 16 field populations. Four fragments of chloroplast DNA (atpB, matK, rbcL, petD with petB-petD spacer) and ITS of nuclear DNA were used in the molecular phylogenetic analysis of 40 samples from specimens and 22 field populations. A taxonomic revision of the genus Pseudocodon is presented on the basis of these studies. We recognize eight species: Pseudocodon convolvulaceus, Pse. graminifolius, Pse. grey-wilsonii, Pse. hirsutus, Pse. petiolatus, Pse. retroserratus, Pse. rosulatus, and Pse. vinciflorus. In the present study, one new species and one new subspecies are described, and one new combination is made. In addition, nine taxa are treated as synonyms, and six lectotypes are designated.