Systematics/Phytogeography / Taxonomie/ Section
Boatwright, James S. , Le Roux, Marianne M. , Wink, Michael , Tilney, Patricia M. , Van Wyk, Ben-Erik .
Systematics of the tribe Crotalarieae and a new generic classification for Lebeckia (Fabaceae).
A systematic study of generic relationships within the tribe Crotalarieae was undertaken using sequences from the internal transcribed spacer (nrITS), rbcL and morphological data. The Crotalarieae are strongly supported to be monophyletic and sister to the tribe Genisteae. Four major lineages are identified based on sequence data: the “Cape” group consisting of Aspalathus, Lebeckia, Rafnia, Spartidium and Wiborgia; the Lotononis group consisting of Lotononis section Lotononis and allies, Pearsonia, Robynsiophyton and Rothia; a group consisting of Lotononis section Leptis, L. section Listia and allies; and the Crotalaria group consisting of Bolusia, Crotalaria and Lotononis hirsuta (Lotononis section Euchlora). Lebeckia, Lotononis and Wiborgia are paraphyletic in the molecular analyses. Molecular, morphological and anatomical data support a new generic classification. It is proposed that Lebeckia be divided into three genera, viz. Lebeckia (L. sect. Lebeckia), Calobota (L. sect. Calobota, L. sect. Stiza and the monotypic genus Spartidium) and a new genus ‘Wiborgiella’ (L. sect. Viborgioides, L. inflata, L. mucronata and surprisingly, including Wiborgia humilis). Characters supporting these groups are a combination of habit, bark formation on twigs, leaf type and anatomy, and anther configuration. When the molecular and morphological data sets were combined, the same major clades are retrieved, with the notable exception that Lotononis (excluding L. hirsuta) and Lebeckia senso stricto are supported to be monophyletic. The results from this study are an important step towards a natural and phylogenetic generic classification system for the tribe Crotalarieae.
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1 - University of Johannesburg, Department of Botany and Plant Biotechnology, P.O. Box 524, Auckland Park, Johannesburg, Gauteng, 2006, South Africa
2 - University of Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg, 69120, Germany
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 10:45 AM