Cladistic analysis of morphological characters in Hypericum (Hypericaceae)

Abstract

Hypericum is a worldwide‐distributed genus with almost 500 species, including the medically used, facultative apomictic species H. perforatum. It is one of the few large plant genera for which alpha taxonomy has been completed and most species have been described. To conduct a formal cladistic analysis of the genus, we coded 89 morphological characters for all described taxa and analyzed the data for the species using parsimony and Bayesian methods. The obtained trees indicate that Hypericum is monophyletic if the monotypic genus Santomasia is included, and that Lianthus is its sister. The arrangement of the remaining genera of Hypericaceae included in the analysis is in congruence with molecular phylogenies. Within Hypericum the cladistic analysis revealed a basal grade containing Mediterranean species and three big clades containing most of the diversity of the genus. In contrast to earlier assumptions, we found no indication for an African origin of Hypericum, but assume that the genus evolved in what today is the Mediterranean area. Our phylogenies indicate a shrubby habit to be the ancestral state within Hypericum from which species with tree‐like and herbaceous habit evolved, and that apomixis originated at least three times independently within the genus.

Phylogeny of the clusioid clade (Malpighiales): Evidence from the plastid and mitochondrial genomes

“…However, in our analyses, Santomasia, Thornea , and Triadenum are well supported as members of a subclade of Hypericum (83 BP). This result does not agree with a recent morphological analysis of Hypericaceae where only Santomasia was found to be embedded within Hypericum (Nürk and Blattner 2010). The distribution of staminodes in the androecium of Hypericeae species offers additional support for our result.…”

“…In particular, molecular results surprisingly suggest that the pantropical Symphonieae (Clusiaceae s.s.), with their unique stigmas, are not monophyletic (Gustafsson et al, 2002; Sweeney, 2008). Additionally, intergeneric relationships in most clusioid subclades are unknown, and it is thought that some genera are likely not monophyletic (e.g., Hypericum , Garcinia , Ledermanniella s.s.; Stevens, 2007a, b; Sweeney, 2008; Thiv et al, 2009; Nürk and Blattner, 2010). The major goal of our study is to assemble the first well‐supported multigene phylogeny of the clusioid clade with dense taxonomic sampling.…”

Explosive radiation in high Andean Hypericum—rates of diversification among New World lineages

“…Nevertheless, it partially rejects the traditional infrageneric classification (Robson, 1977 onwards), revealing sect. Trigynobrathys (Robson, 1990) to be non-monophyletic 2 , a result reported also in other studies (Nürk and Blattner, 2010; Meseguer et al, 2013; Nürk et al, 2013). The extensive sampling in this study highlights the number of species, which group in a polyphyletic position.…”

“…Trigynobrathys groups within a clade containing mainly species belonging to sect. Brathys , a result also revealed in phylogenetic studies analyzing morphological (Nürk and Blattner, 2010) and rDNA ITS data (Nürk et al, 2013). …”

“…Around 65 of the ~100 species described in Hypericum in South America are páramo endemics. Overall, Hypericum is of temperate origin and has its main center of species richness in the Old World (Nürk and Blattner, 2010; Meseguer et al, 2013; Nürk et al, 2013). Molecular phylogenetic studies using sequences of the nuclear rDNA internal transcribed spacers (ITS) (Meseguer et al, 2013; Nürk et al, 2013) and chloroplast data (Meseguer et al, 2013) revealed the three large Hypericum sections Myriandra, Brathys and Trigynobrathys sensu Robson (1977, 1987, 1990, 2012) as a monophyletic group, which includes ca.…”