Lena Struwe

Gentianaceae : systematics and natural history

1. Gentianaceae in context V. A. Albert and L. Struwe 2. Systematics, character evolution and biogeography of Gentianaceae, including a new tribal and subtribal classification L. Struwe, J. Kadereit, J. Klackenberg, S. Nilsson, M. Thiv, B. von Hagen and V. A. Albert 3. Cladistics of Gentianaceae: a morphological approach S. Meszaros, J. De Laet, V. Goethals, E. Smets and S. Nilsson 4. Gentianaceae - a review of palynology S. Nilsson 5. The seeds of Gentianaceae F. Bouman, L. Cobb, N. Devente, V. Goethals, P. J. M. Maas and E. Smets 6. Chemotaxonomy and pharmacology of Gentianaceae S. R. Jensen and J. Schripsema Index.

PHYLOGENY OF THE RUBIACEAE AND THE LOGANIACEAE: CONGRUENCE OR CONFLICT BETWEEN MORPHOLOGICAL AND MOLECULAR DATA?

Phylogenetic analyses of 33 genera of Rubiaceae were performed using morphological and a few chemical characters. Parsimony analysis based on 29 characters resulted in eight equally parsimonious trees, with a consistency index of 0.40 and a retention index of 0.69. These results were compared to a phylogenetic analysis of the same genera based on chloroplast DNA restriction site data. There are discrepancies between the two analyses, but if we consider groupings reflected in the present classification there is much congruency. With the exception of four genera, all the genera are positioned in the same group of taxa in the two analyses. Clades of taxa representing three of the four subfamilies (~the Antirheoideae, ~the Rubioideae, and the ~Ixoroideae) are monophyletic, while the fourth subfamily Cinchonoideae is shown to be paraphyletic. Both analyses support a widened tribe Chiococceae, including the former subtribe Portlandiinae (Condamineeae). Furthermore, in both analyses the tribe Hamelieae is placed outside the subfamily Rubioideae where it is now housed. In search for the most plausible sister group to the Rubiaceae, the genus Cinchona (Rubiaceae) was analyzed together with 13 genera of the Loganiaceae, Nerium (Apocynaceae), and Exacum (Gentianaceae). Cornus (Comaceae), Olea (Oleaceae), and these two genera together were used as outgroups. The analysis, including 25 characters, 16 taxa, and with Cornus and Olea together as an outgroup, resulted in four equally parsimonious trees, with a consistency index of 0.53 and a retention index of 0.62. The non-Loganiaceae taxa Cinchona (Rubiaceae), Nerium (Apocynaceae), and Exacum (Gentianaceae) were all found to have their closest relatives within the Loganiaceae indicating that the Loganiaceae are paraphyletic and ought to be reclassified. As a result of the morphological data the most plausible sister group to the Rubiaceae is the tribe Gelsemieae of the Loganiaceae.

rbcL sequences support exclusion ofRetzia, Desfontainia, andNicodemia from theGentianales

The taxonomic positions ofRetzia, Desfontainia, andNicodemia have been much discussed, and all three genera have been included inLoganiaceae (Gentianales). We have made a cladistic analysis ofrbcL gene sequences to determine the relationships of these taxa toGentianales. Four newrbcL sequences are presented; i.e., ofRetzia, Desfontainia, Diervilla (Caprifoliaceae), andEuthystachys (Stilbaceae). Our results show thatRetzia, Desfontainia, andNicodemia are not closely related toLoganiaceae or theGentianales. Retzia is most closely related toEuthystachys and is better included inStilbaceae. The positions ofDesfontainia andNicodemia are not settled, butDesfontainia shows affinity for theDipsacales s.l. andNicodemia for theLamiales s.l.

Andean Speciation and Vicariance in Neotropical Macrocarpaea (Gentianaceae-Helieae)

Abstract The genus Macrocarpaea (Griseb.) Gilg (Gentianaceae, Helieae) is among the largest woody genera of tropical gentians, with most of its species occurring in the wet mountainous forests of the Andes. Phylogenetic and dispersal-vicariance analyses (DIVA) of 57 of the 105 currently recognized species in the genus, using two data sets from nuclear DNA (ITS and 5S-NTS sequences) and morphology, show a single origin of the Andean species from an ancestral distribution that includes southeastern Brazil. Within the Andes, species divide into two major clades: (1) northern species from the cordilleras of northern Ecuador, Colombia, and Venezuela; and (2) southern species of the Andean Amotape–Huancabamba Zone in Ecuador and Peru, as well as the Andes of central and southern Peru and Bolivia. The Amotape–Huancabamba Zone is supported as the ancestral area for Macrocarpaea within the Andes. There are repeated speciation patterns within the Andes, and three Mesoamerican species derive from the northern clade, as is the single sampled species from the Guayana Shield. The position of the subclade of the three Caribbean species is less certain, but it currently nests among Andean species. An Atlantic coastal Brazilian clade is placed as sister group to all other Macrocarpaea, providing further support for an ancestral refuge in southeastern Brazil for the Helieae. The biogeographic analysis showed that local speciation is more common than long-distance dispersal, and allopatric speciation is more common than sympatric speciation. Using detailed, georeferenced herbarium collection data, patterns in environmental characteristics between clades and sister species were analyzed with Spatial Evolutionary and Ecological Vicariance Analysis (SEEVA), utilizing geographic information system (GIS) and statistical methods. Sister clades and taxa were evaluated for statistical significance in variables such as annual rainfall and temperature, elevation, temperature and rainfall seasonality, geological bedrock age, and soil type to evaluate ecological vicariance between sister groups. The results indicate that there are no general patterns for each variable, but that there are many significant divergences in ecological niches between both larger sister groups and sister species, and ecological niche conservation was also observed when subsequent nodes in the phylogeny were compared.

In vitro and in vivo antimalarial activity and cytotoxicity of extracts, fractions and a substance isolated from the Amazonian plant Tachia grandiflora (Gentianaceae).

Tachia sp. are used as antimalarials in the Amazon Region and in vivo antimalarial activity of a Tachia sp. has been previously reported. Tachia grandiflora Maguire and Weaver is an Amazonian antimalarial plant and herein its cytotoxicity and antimalarial activity were investigated. Spectral analysis of the tetraoxygenated xanthone decussatin and the iridoid aglyone amplexine isolated, respectively, from the chloroform fractions of root methanol and leaf ethanol extracts was performed. In vitro inhibition of the growth of Plasmodium falciparum Welch was evaluated using optical microscopy on blood smears. Crude extracts of leaves and roots were inactive in vitro. However, chloroform fractions of the root and leaf extracts [half-maximal inhibitory concentration (IC50) = 10.5 and 35.8 µg/mL, respectively] and amplexine (IC50= 7.1 µg/mL) were active in vitro. Extracts and fractions were not toxic to type MRC-5 human fibroblasts (IC50> 50 µg/mL). Water extracts of the roots of T. grandiflora administered by mouth were the most active extracts in the Peters 4-day suppression test in Plasmodium berghei-infected mice. At 500 mg/kg/day, these extracts exhibited 45-59% inhibition five to seven days after infection. T. grandiflora infusions, fractions and isolated substance have potential as antimalarials.

Morphology-based phylogeny and revision of Prepusa and Senaea (Gentianaceae: Helieae) — rare endemics from eastern Brazil

SummaryA morphology-based phylogeny and taxonomic revision of Prepusa Mart. and Senaea Taub. are presented. Based on studies of herbarium collections, five species of Prepusa and two species of Senaea are recognised. All are endemic to montane habitats in the Brazilian states of Bahia, Espírito Santo, Minas Gerais and Rio de Janeiro. Morphological descriptions, identification keys, illustrations and distribution maps for each species are provided. Prepusa and Senaea are morphologically, geographically, and phylogenetically isolated within Helieae, and their close relationship is supported by 6-merous flowers. Phylogenetic analyses of 33 morphological characters using both parsimony and Bayesian methods provide a consistent picture of the relationships of Prepusa and Senaea. The two genera are monophyletic and sister to one another. There is some support for the relationships within Prepusa.ResumoSão apresentadas a filogenia morfológica e as revisões taxonômicas de Prepusa Mart. e Senaea Taub. Baseado no estudo de coleções de herbários, cinco espécies de Prepusa e duas de Senaea são reconhecidas. Todas são endêmicas a habitats montanos dos estados brasileiros da Bahia, Espírito Santo, Minas Gerais e Rio de Janeiro. São apresentados descrições morfológicas, chaves de identificação, ilustrações e mapas da distribuição de cada espécie. Prepusa e Senaea são morfológica, geográfica e filogeneticamente isolados entre as Helieae e a presença de flores 6-meras sustenta sua proximidade filogenética. Análises filogenéticas de 33 caracteres morfológicos usando parcimônia e métodos Bayesianos apresentam um quadro consistente das relações de Prepusa e Senaea. Os gêneros são monofiléticos e irmãos entre si. Há sustentação para as relações entre as espécies de Prepusa.

Utility of Secondary Structure in Phylogenetic Reconstructions Using nrDNA ITS Sequences - An Example from Potalieae (Gentianaceae: Asteridae)

Abstract The gentians (Gentianaceae, Asteridae) form a morphologically and ecologically diverse group of plants with interesting phytochemical and medicinal properties. The family contains six tribes, but phylogenetic relationships among the three more derived tribes (Gentianeae, Helieae, and Potalieae) are considered ambiguous. In an attempt to resolve alignment ambiguity and provide better scientific support for relationships, the internal transcribed spacer (ITS) of the nuclear ribosomal DNA was aligned for several gentian sequences with reference to the ITS secondary structure proposed for Anvillen radiata (Asteraceae) using Dynalign. We present here the first secondary structure of ITS for Gentianaceae, which may guide alignment of ITS data in other asterids taxa. The study included 42 species, with representatives from tribes Chironieae, Gentianeae, Helieae, and Potalieae, and with the majority of species from Potalieae. Phylogenetic analyses based on secondary structure alignment using parsimony and Bayesian methods provided additional support for Gentianeae plus Helieae as the sister group to Potalieae. Prepusa (Helieae) showed ambivalent associations. Within tribe Potalieae, the subtribes Potaliinae and Lisianthiinae were supported as monophyletic. Bisgoeppertia (Chironieae) was placed unambiguously inside Lisianthius (Potalieae-Lisianthiinae) in all analyses. Neurotheca (Potalieae-Faroinae) was positioned as sister to Lisianthiinae, making subtribe Faroinae paraphyletic.

The global distribution of wild tarragon (Artemisia dracunculus L.; Asteraceae) cytotypes with twenty-seven new records from North America

Artemisia dracunculus (wild or Russian tarragon), is a polymorphic, herbaceous perennial with a widespread distribution that spans western North America, Eastern Europe and most temperate of Asia. This wild relative of the culinary herb French tarragon has recently been the focus of a number of studies which have investigated its medicinal activity in type 2 diabetes bioassays. The species is documented as having from diploid to decaploid cytotypes and chemical variation has previously been shown to occur between cytotypes. To help focus germplasm collecting efforts for ongoing studies on variation of medicinal compounds within the species, a literature review of the geographical occurrences of cytotypes was conducted. This review revealed a lack of records from North America. In order to fill in this gap in the cytogeographic distribution, meiotic chromosome counts and flow cytometry were used to determine the ploidy level of 27 individuals from 16 different populations throughout the western United States. The results revealed distinct patterns of cytotype distribution. Both diploids and polyploid cytotypes were found in Eurasia, and the distributional range of each cytotype was found to be increasingly restricted as ploidy increased. For North America, even with the inclusion of many new records, only diploid populations were documented, with the exception of one hexaploid record from Arizona which was found in the literature.

A Monograph of Neotropical Potalia Aublet (Gentianaceae: Potalieae)

Abstract The first revision of the neotropical genus Potalia (Gentianaceae: Potalieae, formerly Loganiaceae) is presented. This genus was formerly considered monotypic, with Potalia amara being the only recognized species. New morphological and anatomical studies show that Potalia resinifera should be resurrected and that nine newly discovered species should be recognized; one endemic to Central America (P. turbinata), two endemic to Chocó, Colombia (P. chocoensis and P. crassa), two endemic to white-sand areas along Rio Negro and its tributaries (P. elegans and P. maguireorum; Brazil, Colombia, and Venezuela), and the last two endemic to white-sand areas in the western Amazon basin (P. coronata and P. yanamonoensis; Peru, Brazil and Colombia). Potalia amara sensu stricto is restricted to the Guianas and northeast Brazil, whereas P. resinifera is widespread in lowland Amazonia and the Andean foothills. Morphological differences between the species are primarily in fruit and inflorescence morphology, but there are also differences in plant size, leaf shape, and corolla color. Potalia resinifera shows the greatest infraspecific variation. Phylogenetic relationships between Potalia and its close relatives Anthocleista from Africa and Fagraea from tropical Asia-Australia-Pacifics are discussed. The widespread pharmacological uses of Potalia species by indigenous peoples of the Neotropics are reviewed and vernacular names are listed.

Voucher Specimens are Essential for Documenting Source Material Used in Medicinal Plant Investigations

Plant-based natural products research is conducted using a wide variety of source material. The plant material is often obtained directly from the wild, from cultivated plants originally obtained from the wild, or purchased in raw or processed forms. In plant science a voucher specimen usually consists of a pressed, dried herbarium specimen with detailed collection data and serves as a record of an individual plant in time and space. This review article describes why vouchering is necessary and documents actual examples of how improper vouchering can result in serious problems. The primary reason for vouchering is to have a permanent record documenting the material that was used in a particular study. If a specimen is not saved or is not made available to others, the true identity of the plant materials used in a research project may be questioned. Due to the morphological and chemical complexities of interspecific hybrids, within-species variation, and the difficulty associated with identifying species in certain plant genera, the preservation of vouchers is essential for the documentation of the identity and source of such plant material. The use of best practices in specimen preparation is critical for successful documentation. The lack of proper voucher specimens for some research projects has led to serious problems, such as the inability to reproduce critical results, the association of chemical data with the wrong genus and species, and even the complete rejection of the published research results. In cases where plant material was initially misidentified and properly prepared voucher specimens were available, the identities of the research material were eventually corrected and the data was subsequently associated with the correct species, retaining the inherent scientific value of the research.