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Citation for Study 13339

About Citation title: "Molecular phylogenetics and morphological evolution of St. John's wort (Hypericum; Hypericaceae).".
About Study name: "Molecular phylogenetics and morphological evolution of St. John's wort (Hypericum; Hypericaceae).".
About This study is part of submission 13339 (Status: Published).

Citation

N?rk N.M., Madri??n S., Carine M., Chase M., & Blattner F. 2012. Molecular phylogenetics and morphological evolution of St. John's wort (Hypericum; Hypericaceae). Molecular Phylogenetics and Evolution, .

Authors

  • N?rk N.M. (submitter) Phone 01772357156
  • Madri??n S. Phone +57 (1) 339-4949 x2729
  • Carine M.
  • Chase M.
  • Blattner F.

Abstract

Phylogenetic hypotheses for the large cosmopolitan genus Hypericum (St. John's wort) have previously been based on morphology, and molecular studies have thus far included only a few species. In this study, we used 360 sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) for 206 species representing Hypericum (incl. Triadenum and Thornea) and three other genera of Hypericaceae to generate an explicit phylogenetic hypothesis for the genus using parsimony and model-based methods. The results indicate that the small genus Triadenum is nested in a clade within Hypericum containing most of the New World species. Sister to Hypericum is Thornea from Central America. Within Hypericum, three large clades and two smaller grades were found; these are based on their general morphology, especially characters used previously in taxonomy of the genus. Relative to the most recent classification, around 60% of the sections of Hypericum were monophyletic. We used a Bayesian approach to reconstruct ancestral states of selected morphological characters, which resulted in recognition of characters that support major clades within the genus and a revised interpretation of morphological evolution in Hypericum. The shrubby habit represents the plesiomorphic state from which herbs evolved several times. Sclerophyllous treelets have radiated convergently in high-elevation habitats in tropical Africa and South America.

Keywords

character evolution; Hypericaceae; internal transcribed spacer (ITS); phylogeny; Thornea; Triadenum

External links

About this resource

  • Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S13339
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