Phylogenetic analysis of nrDNA ITS sequences reveals relationships within five groups of Iranian Apiaceae subfamily Apioideae

Abstract

The flora of Iran is rich in endemic species of Apiaceae, many of which have been poorly investigated and whose phylogenetic relationships are unknown. We investigate the relationships within five genus groups of Apiaceae subfamily Apioideae native to the Flora Iranica region using nuclear ribosomal DNA ITS sequences. Supplementary comparative data come from morphology and, for one of these groups, petiole anatomy and palynology. These groups of Apioideae are circumscribed initially on the basis of morphological similarities and/or the results of previous molecular systematic investigations, then redefined and confirmed as monophyletic based on the results of maximum parsimony, maximum likelihood, and Bayesian analyses of ITS sequences from a broader sampling of species. These five redefined groups and their constituent genera include the Cachrys group (Alococarpum, Azilia, Bilacunaria, Cachrys, Diplotaenia, Eriocycla, Ferulago, Prangos), Cymbocarpum group (Cymbocarpum, Ducrosia, Kalakia), Ferula group (Dorema, Ferula, Leutea), Johrenia group (Holandrea, Johrenia, Johreniopsis), and Opopanax group (Opopanax, Smyrniopsis). Azilia eryngioides is a sister group to all other members of the Cachrys group, coincident with its highly unusual morphology. The monotypic Alococarpum may be transferred into Prangos pending further study. The Cymbocarpum group is contained within tribe Tordylieae, the latter now expanded to include Cymbocarpum, and the monotypic Kalakia is submerged within Cymbocarpum. Dorema and Leutea arise from within a paraphyletic Ferula in tribe Scandiceae; nomenclatural changes are suggested, but must await supporting evidence from chloroplast DNA. Neither Johrenia nor Johreniopsis of the Johrenia group (tribe Selineae) is monophyletic, with all examined species except Johrenia golestanica arising from within a paraphyletic Holandrea. Holandrea may be transferred into Johrenia and J. golestanica may constitute a new, monotypic genus pending confirmation from further investigations. Opopanax and Smyrniopsis, traditionally treated in two tribes, are confirmed as monophyletic sister groups in the Apioid superclade. They share similar morphological attributes and are closely allied to Petroedmondia, Magydaris, and Crenosciadium.