Original paper

Major clades within Apiaceae subfamily Apioideae as inferred by phylogenetic analysis of nrDNA ITS sequences

Downie, Stephen R.; Spalik, Krzysztof; Katz-Downie, Deborah S.; Reduron, Jean-Pierre


The results of phylogenetic analyses of 1240 nrDNA ITS sequences of Apiaceae subfamily Apioideae, representing 292 genera and 959 species from all major clades of the subfamily except those most basally branching, were compared to a preexisting phylogenetic classification for the group based on several molecular markers and a smaller sampling of taxa. This was done to confirm previously defined tribal and generic limits and to identify additional major clades and genera whose monophyly and relationships can be tested in future studies. All species for which ITS data are available in Gen-Bank plus newly obtained sequences for 53 additional taxa were considered for inclusion in this study and their simultaneous analysis permitted misidentifications and other problematic sequences to be revealed. Analyses of these ITS data, in conjunction with results of recently published molecular studies, identified 41 major clades in Apioideae, of which 21 have already been recognized at the tribal or subtribal rank. No major changes to the preexisting phylogenetic classification of Apioideae are proposed, other than the recognition of additional major clades and the expansion of others to accommodate increased sampling. As noted in previous studies, many genera are not monophyletic; indeed, 18 genera are highly polyphyletic, with their members occurring in 2 to 7 major clades. Each of the 1240 accessions examined can be unambiguously assigned to a particular major clade. Resolution of relationships, as well as the formal recognition of several major clades, must await supporting data, such as that from the cpDNA trnQ(UUG)−5' trnK(UUU) intergenic spacer region. An ITS-based classification of the subfamily is proposed that enables direct and precise references to specific groups and facilitates sampling and hypothesis testing in future systematic studies.


apiaceae subfamily apioideaeclassificationnrdna itsphylogeny