Molecular systematics of Old World Apioideae (Apiaceae): relationships among some members of tribe Peucedaneae sensu lato, the placement of several island-endemic species, and resolution within the apioid superclade

Comparative sequencing of the two internal transcribed spacer regions of nu clear ribosomal DNA was carried out to examine evolutionary relationships a mong representatives of Old World Apiaceae (Umbelliferae) subfamily Apioide ae. Emphasis was placed on delimiting groups within the previously designat ed apioid superclade and clarifying relationships within and among the peuc edanoid genera Angelica, Ferula, Heracleum, and Peucedanum. These spacer da ta, and those obtained from the chloroplast rps16 intron for a subset of th e taxa, also enabled hypotheses on the phylogenetic placement of several na rrowly distributed endemic species. The monophyly of Drude's tribe Echinoph oreae is confirmed and it is sister to the Socotran endemic genera Nirarath amnos and Rughidia; the Balearic Islands endemic genus Naufraga allies with Apium graveolens; tribes Careae and Pyramidoptereae are recognized formall y to be the previously designated clades "Aegopodium" and "Crithmum"; and t ribes Oenantheae and Scandiceae are each expanded to include two species of Apium, previously attributable to Helosciadium, and four species of Ferula , respectively. Within the apioid superclade, dye major lineages are recogn ized that are consistent with all available molecular evidence: tribe Echin ophoreae, the clades "Pimpinella" and "Heracleum," and the more narrowly ci rcumscribed clades "Angelica" and "Apium." Angelica and Ferula each compris e at least two lineages; Heracleum is polyphyletic if Heracleum candicans i s retained in the genus; and Peucedanum is distributed in three well-separa ted clades with some species allied with those species of Angelica referred to Xanthogalum.