Phylogenetic relationships in the Hamamelidaceae: Evidence from the nucleotide sequences of the plastid gene matK

Abstract

The Hamamelidaceae is a family that bridges the basal elements of the Rosidae and the 'lower' Hamamelidae, thus a better understanding of the phylogeny of the family is important for clarifying evolutionary patterns in the diversification of eudicots. However, subfamilial as well as tribal relationships in the Hamamelidaceae have been controversial. Nucleotide sequences of the chloroplast gene mark were used to study the intergeneric relationships of the family. In the phylogenetic trees, constructed using parsimony analysis, the clade containing Altingia and Liquidambar (Altingioideae) is sister to a clade that includes all other Hamamelidaceae. Exbucklandia and Rhodoleia form a clade, suggesting a close relationship between the two genera. Dixanthus is sister to the monophyletic Hamamelidoideae. The paraphyletic arrangement of Disanthus, Mytilaria and Exbucklandia with respect to the Hamamelidoideae does not support the combination of these genera in one subfamily. In the Hamamelidoideae, the matK phylogeny supports the monophyly of several previously recognized groups with modifications, including the tribes Eustigmateae (incl. Molinadendron), Fothergilleae (excl. Molinadendron and Matudaea), and the subtribe Dicoryphinae. However, the Hamamelideae as traditionally circumscribed is polyphyletic. Apetaly has evolved three times independently in the Hamamelidoideae.