Thornea

Abstract: Completion of a detailed monograph of Hypericum using traditional methods has stimulated the publication of phylogenetic treatments of the genus using molecular methods. The relationships thereby revealed differ from those of the traditional account in several ways that are discussed here. A key point of conflict concerns taxa that share a specific set of morphological characters, i.e. the ‘ Elodes ’ syndrome (pseudotubular corolla, sterile stamen fascicles, stamen filaments ± united in the fascicle and sometimes petal appendages), which was found to be paraphyletic in each molecular study. The various groups with this syndrome were shown to have arisen from various parts of Hypericum , apparently suddenly, probably as the result of a genetic switch, the action of which can also be reversed. The formerly segregated genera with this floral syndrome should therefore all be re-incorporated in Hypericum. This necessitates the re-establishment of one section, namely Hypericum sect. Elodea , and recognition of two new sections within Hypericum , namely Hypericum sect. Lianthus and Hypericum sect. Thornea , which are proposed here. The remaining species have resolved in various places in recent molecular phylogenetic trees that differ from each other and from the classification adopted in the monograph. In particular, in molecular results the herbaceous species with ‘3’ (i.e. 2+2+1) stamen fascicles all form a single clade; whereas, in the traditional treatment adopted in the monograph, they form three distinct, distantly related groups. In light of recent molecular studies, Hypericum is now interpreted to comprise two distinct groups (respectively mainly Old World and mainly New World) that differ in the presence or absence of dark (hypericin-containing) glands and in the arrangement of the stamen fascicles. These two clades are described as subgenera, with the New World clade named Hypericum subgenus Brathys. By drawing attention to this grouping, the molecular work has improved on the monograph.

Abstract: 1 Introduction 1.1 The genus Hypericum 1.1.1 Origin of the name, phytochemistry & economic importance 1.1.2 Biology of Hypericum 1.1.3 Distribution and biogeography 1.2 Objectives of this study 1.2.1 Phylogeny 1.2.2 Character evolution and ecology 1.2.3 Historical biogeography 1.2.4 Diversification 1.3 Methods 1.3.1 Phylogenetic inference 1.3.2 Character evolution 1.3.4 The molecular clock 1.3.5 Biogeography 1.3.6 Diversification rates 2 Cladistic analysis of morphological characters in Hypericum (Hypericaceae) 2.1 Introduction 2.2 Materials & methods 2.2.1 Character coding 2.2.2 Phylogenetic inference 2.3 Results 2.4 Discussion 2.4.1 Character coding 2.4.2 Phylogeny of Hypericaceae 2.4.3 Phylogenetic inference within Hypericum 2.4.4 Character evolution 2.4.5 Biogeography 2.5 Conclusions 3 Molecular phylogeny and character evolution in St. John’s wort (Hypericum) 3.1 Introduction 3.2 Materials & methods 3.2.1 Taxon sampling 3.2.2 Molecular methods 3.2.3 Phylogenetic inference 3.2.4 Character reconstruction 3.3 Results 3.4 Discussion 3.4.1 Phylogeny of Hypericaceae 3.4.2 Character evolution 3.4.3 Phylogeny and classification 3.5 Conclusions 4 Out of the tropics? Historical biogeography of the temperate genus Hypericum 4.1 Introduction 4.2 Methods 4.2.1 Divergence time estimations 4.2.2 Diversification rates 4.2.3 Biogeographic analyses 4.3 Results & discussion 4.3.1 Age estimations 4.3.2 Ancestral area reconstructions: model comparison 4.3.3 Historical biogeography 4.3.4 Diversification rate shifts 4.4 Conclusions 5 Synthesis 5.1 Phylogeny and biogeography 5.2 Character evolution 5.3 Nuclear rDNA internal transcribed spacer, hybridization and concerted evolution 5.4 Evolutionary scenario of Hypericum s. l. Abstract References Acknowledgements Abbreviations Figures & Tables Appendix S1 Active compounds S1.1 Description of Hypericum S1.2 Species taxonomy S2 orphological phylogeny S2.2 Morphological character coding S3.1 Voucher: ITS sequences, direct and cloned S3.2 Character coding for ancestral character reconstructions by Bayesian MCMC optimization on the ITS phylogeny S4 Historical biogeography and diversification rate shift analyses CV & Publications

Abstract: Summary The wood anatomy of the new genus Thor nea (Hypericaceae) is described and compared with that of other presumed relatives in the family. Woods of Thornea are very similar to those of Hypericum and Triadenum but quite dissimilar to those of Cratoxylum, with which Thornea presumably shares common ancestry.