Estimation of phylogenetic relationships among some Hypericum (Hypericaceae) species using internal transcribed spacer sequences

Thirty-four taxa representing 12 sections of the genus Hypericum were analyzed along with two representatives of Thornea using nuclear internal transcribed spacer (ITS) sequences in order to assess the scope of phylogenetic relationships in this species-rich genus. The resulting parsimony analysis corroborates the actual classification and interspecific affinities. The molecular data provide support for the monophyletic assemblage of the sections Androsaemum, Hypericum, Olympia, and Drosocarpium and for the polyphyletic origin of Ascyreia, Taeniocarpium, Myriandra, and Adenosepalum. The earlier evolutionary hypotheses concerning the origin of Hypericum balearicum and Hypericum calycinum, and the relatedness of Adenosepalum representatives, are not supported by our data analysis as well as hybrid origin of Hypericum perforatum. The obtained results encourage the use of ITS sequence analysis in resolving the phylogenetic relationships within the member-rich genus Hypericum.