Stefan Dressler

Traditional plant use in Burkina Faso (West Africa): a national-scale analysis with focus on traditional medicine

BackgroundThe West African country of Burkina Faso (BFA) is an example for the enduring importance of traditional plant use today. A large proportion of its 17 million inhabitants lives in rural communities and strongly depends on local plant products for their livelihood. However, literature on traditional plant use is still scarce and a comprehensive analysis for the country is still missing.MethodsIn this study we combine the information of a recently published plant checklist with information from ethnobotanical literature for a comprehensive, national scale analysis of plant use in Burkina Faso. We quantify the application of plant species in 10 different use categories, evaluate plant use on a plant family level and use the relative importance index to rank all species in the country according to their usefulness. We focus on traditional medicine and quantify the use of plants as remedy against 22 classes of health disorders, evaluate plant use in traditional medicine on the level of plant families and rank all species used in traditional medicine according to their respective usefulness.ResultsA total of 1033 species (50%) in Burkina Faso had a documented use. Traditional medicine, human nutrition and animal fodder were the most important use categories. The 12 most common plant families in BFA differed considerably in their usefulness and application. Fabaceae, Poaceae and Malvaceae were the plant families with the most used species. In this study Khaya senegalensis, Adansonia digitata and Diospyros mespiliformis were ranked the top useful plants in BFA. Infections/Infestations, digestive system disorders and genitourinary disorders are the health problems most commonly addressed with medicinal plants. Fabaceae, Poaceae, Asteraceae, Apocynaceae, Malvaceae and Rubiaceae were the most important plant families in traditional medicine. Tamarindus indica, Vitellaria paradoxa and Adansonia digitata were ranked the most important medicinal plants.ConclusionsThe national-scale analysis revealed systematic patterns of traditional plant use throughout BFA. These results are of interest for applied research, as a detailed knowledge of traditional plant use can a) help to communicate conservation needs and b) facilitate future research on drug screening.

Chromosome numbers of the flora of Germany—a new online database of georeferenced chromosome counts and flow cytometric ploidy estimates

Abstract Chromosomal speciation processes gain increasing attention in plant systematics and evolution, and new approaches revealed a high diversity in chromosome numbers even within recognized taxa. Reliable counts linked to known accessions are thus needed yet often hardly available. We present a new online database for chromosome counts and ploidy estimates of the flora of Germany with a detailed documentation of the examined material, and its sampling locality. The chromosome database builds upon a relational database and includes standardized taxon identification, study date, georeferenced locality and additional collection as well as publication details from which the karyological information was extracted. In order to reach the best compatibility with other botanical publications of the study region, taxonomic concepts and nomenclature follow the “Rothmaler”, a widely accepted field flora of vascular plants in Germany. Our online database is available at http://chromosomes.senckenberg.de. The site consists of the main page with project information, a search tool, an interactive map display, a contact and a data submission form. The zoomable map shows the localities of the search result, allows to refine the geographic search as well as to select individual data points.

The Vascular Plant Diversity of Burkina Faso (West Africa) — A Quantitative Analysis and Implications for Conservation

Abstract Zizka, A., A. Thiombiano, S. Dressler, B. M. I. Nacoulma, A. Ouédraogo, I. Ouédraogo, O. ouédraogo, G. Zizka, K. Hahn & M. Schmidt (2015). The vascular plant diversity of Burkina Faso (West Africa) — a quantitative analysis and implications for conservation. Candollea 70: 9–20 In English, English and French abstracts. Based on a species inventory and the related distribution dataset, the authors present a quantitative analysis of the vascular plant diversity of Burkina Faso (BFA) and its four phytogeographic zones. We analyzed species richness, higher taxon diversity, life forms, chorological types, introduced species, habitat preferences and the number of rare species. The flora of BFA comprises 1972 non-cultivated vascular plant species in 752 genera and 145 families. Species richness and plant family richness are highest in the South Sudanian zone in the South of the country. Fabaceae, Poaceae and Cyperaceae are the most species rich plant families. Only one species (Isoetes jaegeri Pitot) is endemic to the country, whereas the vast majority occurs throughout Africa. The flora is dominated by therophytes and phanerophytes. Our results show a good representation of the West African flora in BFA. The flora and vegetation of the four phytogeographic zones within BFA is determined by the latitudinal climatic gradient of the region. The relative number of phanerophytes and forest species decrease along the gradient, while the relative number of therophytes increase. Based on the specimen record we classified 38% of the plant species as “rare” to BFA. The analyses show that the south-west of BFA is a center of national biodiversity and a potential “hotspot” for conservation. In addition to its high species richness this area harbors the highest number of rare species (409 species, 29%) including the endemic species.

The evolution of afro-montane Delphinium (Ranunculaceae): Morphospecies, phylogenetics and biogeography

The genus Delphinium (Ranunculaceae) consists of ca. 300 species and has a mainly holarctic distribution. Few species hove been described from high-altitude areas in West and East Tropical Africa, where the environmental conditions are mostly temperate-like. We aim to clarify the taxonomy of these afro-montane Delphinium species and to understand their evolutionary history in terms of their floral morphology and their phylogenetic and biogeographic relationships. Based on herbarium specimens, we analyze flower shape variation, map the geographic distribution of the morphologically defined taxa and reconstruct the molecular phylogeny of the group. Our quantitative analyses of flower shapes indicate that three species can be defined based on floral morphological traits, hence confirming the latest taxonomic treatment of the group where D. dasycaulon, D. leroyi and D. macrocentrum were described. The examination of herbarium specimens indicates that these three species are almost parapatric. However, their respective monophyly is not supported by molecular data. Considering their relatively young age, the non-monophyly of each of the three morphospecies could be due to incomplete lineage sorting and/or hybridization events. Alternatively, the transition to the D. leroyi floral morph could be the result of evolutionary convergence in the two main groups of afro-montane Delphinium driven by similar pollinators in different sky islands of the East African Rift System. We hypothesize that the main branches of the East African Rift System, as physical barriers to dispersal, may have prevented genetic exchange among geographic clusters.

Taxon and trait recognition from digitized herbarium specimens using deep convolutional neural networks

Abstract Herbaria worldwide are housing a treasure of hundreds of millions of herbarium specimens, which are increasingly being digitized and thereby more accessible to the scientific community. At the same time, deep-learning algorithms are rapidly improving pattern recognition from images and these techniques are more and more being applied to biological objects. In this study, we are using digital images of herbarium specimens in order to identify taxa and traits of these collection objects by applying convolutional neural networks (CNN). Images of the 1000 species most frequently documented by herbarium specimens on GBIF have been downloaded and combined with morphological trait data, preprocessed and divided into training and test datasets for species and trait recognition. Good performance in both domains suggests substantial potential of this approach for supporting taxonomy and natural history collection management. Trait recognition is also promising for applications in functional ecology.

Comprehensive and reliable: a new online portal of critical plant taxa in Germany

Morphological identification of apomictic micro-species is difficult and requires detailed comparisons with referenced herbarium material. Access to such is limited because herbaria are scattered, and even in public collections misidentifications are not uncommon in these critical taxa. In close collaboration with taxonomic experts of the apomictic polyploid genera Hieracium, Pilosella, Taraxacum sect. Palustria (Asteraceae) and Alchemilla, Crataegus, Rosa, Rubus (Rosaceae), we established an online portal (http://webapp.senckenberg.de/bestikri/) displaying georeferenced and validated herbarium specimens for each respective micro-species of the German Flora. Our focus was on taxonomic reliability rather than on sheer data quantity and thus identifications were validated. We additionally offer macro-photographs as well as descriptions of taxonomically important morphological characters of the respective genera. Comprising currently >400 taxa, we trust the online portal will greatly facilitate research into difficult polyploid, apomictic taxa of the Central European flora.

Two New Species in Marcgravia (Marcgraviaceae) from Central and Adjacent South America

Two species are described as new: Marcgravia panamensis (subg. Orthothalamium- Paucflorae), a new species from Panama, is the only species of the genus having leaves with dotted abaxial surfaces but only a few erect flowers per inflorescence. Marcgravia roonii (subg. Orthothal- amium-Multiflorae), a new species from Costa Rica, Colombia, and Ecuador, has the typical leaves of M. nervosa but a completely different in- florescence structure. Marcgravia membranacea is considered to be a synonym of M. nervosa.