Phylogeny of Apiaceae subtribe Daucinae and the taxonomic delineation of its genera

Scandiceae subtribe Daucinae encompasses umbellifers that have fruits with prominent secondary ridges projecting into wings (former tribe Laserpitieae) or spines (former tribe Caucalideae pro parte). It comprises several economically or medicinally important genera including Cuminum, Daucus, Laser, Laserpitium and Thapsia among others. Recent molecular studies, based mostly on nrDNA ITS sequences, revealed that neither Daucus nor Laserpitium are monophyletic. To address issues of relationships and apply respective nomenclatural changes, we obtained additional ITS sequences as well as independent data from three plastid markers-rps16 intron, rpoC1 intron and rpoB-trnC intergenic spacer-for a comprehensive sample of the subtribe. We examined data for 260 accessions representing all genera of Daucinae and 81 of its ca. 93 species. Phylogenetic trees were estimated using maximum likelihood and Bayesian inference methods. The results indicate that former Laserpitieae constitute a paraphyletic grade at the base of the spiny-fruited members of Daucinae while traditionally delimited Daucus and Laserpitium are polyphyletic. To maintain a monophyletic Daucus, we suggest including the following genera and species into its synonymy: Agrocharis, Melanoselinum, Monizia, Pachyctenium, Pseudorlaya, Rouya, Tornabenea, Athamanta dellacellae and Cryptotaenia elegans. The species of Las erpitium occur in seven clades and only six species of the Laserpitium s.str. Glade retain the generic name. Several species are transferred to Ekimia, Laser and Thapsia; additionally, a monospecific genus Siler is restored and a new genus, Silphiodaucus, is established. The inclusion of Ammodaucus into Thapsia suggested in an earlier study is not supported. The position of Laserpitium pseudomeum requires further study.