XVI International Botanical Congess

ITS sequences of nrDNA were determined for 15 species of the Illiciaceae to reconstruct phylogenetic relationships. The ITS trees show a major dichotomy between the two North American species and the remaining eastern Asian species. This suggests that the existing division between the two sections of Illicium (Illicium and Cymbostemon) based on tepal characters is poorly defined. The ITS phylogeny is congruent with palynology: the three species with trizonocolpate pollen from sect. Illicium consistently form a clade, although nesting within the species of sect. Cymbostemon, which generally have trisyncolpate pollen. The low ITS sequence divergence and a close relationships among eastern Asian species suggest a recent diversification of this group of species or an unusual slowdown of sequence mutations.