02248nas a2200157 4500008004100000020001600041245010900057210006900166300000800235490000600243520163400249100002301883700002401906700002501930856013501955 2013 eng d a- 1664-802100aExplosive radiation in high Andean Hypericum– Rates of diversification among New World lineages0 aExplosive radiation in high Andean iHypericumi Rates of diversif a1750 v43 a

The páramos, high-elevation Andean grasslands ranging from ca. 2800m to the snow line, harbor one of the fastest evolving biomes worldwide since their appearance in the northern Andes 3–5 million years (Ma) ago. Hypericum (St. John’s wort), with over 65% of its Neotropical species, has a center of diversity in these high Mountain ecosystems. Using nuclear rDNA internal transcribed spacer (ITS) sequences of a broad sample of New World Hypericum species we investigate phylogenetic patterns, estimate divergence times, and provide the first insights into diversification rates within the genus in the Neotropics. Two lineages appear to have independently dispersed into South America around 3.5 Ma ago, one of which has radiated in the páramos (Brathys). We find strong support for the polyphyly of section Trigynobrathys, several species of which group within Brathys, while others are found in temperate lowland South America (Trigynobrathys s.str.). All páramo species of Hypericum group in one clade. Within these páramo Hypericum species enormous phenotypic evolution has taken place (life forms from arborescent to prostrate shrubs) evidently in a short time frame. We hypothesize multiple mechanisms to be responsible for the low differentiation in the ITS region contrary to the high morphological diversity found in Hypericum in the páramos. Amongst these may be ongoing hybridization and incomplete lineage sorting, as well as the putative adaptive radiation, which can explain the contrast between phenotypic diversity and the close phylogenetic relationships.

1 aNürk, Nicolai, M.1 aScheriau, Charlotte1 aMadriñán, Santiago uhttp://www.frontiersin.org/Journal/Abstract.aspx?s=1254&name=evolutionary_and_population_genetics&ART_DOI=10.3389/fgene.2013.0017502320nas a2200265 4500008004100000020001400041245010800055210006900163250001500232300001000247490000700257520148200264653002401746653001701770653003801787653001401825653001201839653001401851100002301865700002501888700002101913700002001934700002401954856007601978 2013 eng d a1055-790300aMolecular phylogenetics and morphological evolution of St. John's wort (Hypericum; Hypericaceae)0 aMolecular phylogenetics and morphological evolution of St Johns  a08.09.2012 a1--160 v663 a

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. Arborescent species have radiated convergently in high-elevation habitats in tropical Africa and South America.

10aCharacter evolution10aHypericaceae10aInternal transcribed spacer (ITS)10aPhylogeny10aThornea10aTriadenum1 aNürk, Nicolai, M.1 aMadriñán, Santiago1 aCarine, Mark, A.1 aChase, Mark, W.1 aBlattner, Frank, R. uhttp://www.sciencedirect.com/science/article/pii/S1055790312003314?v=s5