A taxonomic study of the type section of the genus Lebeckia Thunb. (sect. Lebeckia; syn. Eu-Lebeckia Benth., Phyllodiastrum Walp.) is presented. The genus Lebeckia (Fabaceae, Crotalarieae) is endemic to the western parts of southern Africa and the type section is endemic to the Cape Floristic Region. Species delimitations and relationships within the sections of the genus are not clear and are in urgent need of a revision since the genus has not been studied in its entirety for nearly 150 years. Lebeckia section Lebeckia, now consists of 14 species, all with acicular (needle-shaped) leaves. Based on fruit morphology, four informal species groups have here been distinguished within the section. An analysis of morphological characters revealed the existence of four undescribed species, namely “L. brevicarpa” M.M.le Roux and B-E.van Wyk sp. nov. ined., [previously confused with L. sepiaria (L.) Thunb.], “L. brevipes” M.M.le Roux and B-E.van Wyk sp. nov. ined., (hitherto confused with L. longipes Bolus and L. pauciflora Eckl. and Zeyh.), “L. uniflora” B-E.van Wyk and M.M.le Roux [previously confused with L. wrightii Bolus] and “L. zeyheri” M.M.le Roux and B-E.van Wyk [previously considered to be a variety of L. plukenetiana E.Mey.] A key to the 14 species of section Lebeckia is presented. Diagnostic characters, nomenclature, typification and distribution maps of all the species are presented, discussed and illustrated. Morphological data was used in a cladistic analysis and resulted in a partially resolved cladogram, confirming the presence of four (presumably monophyletic) groups within the section. In a molecular systematic study, four DNA sequences were used to explore relationships, but the resolution was low and unsatisfactory and the result only partially supported the hypothesis based on morphological characters. However, the molecular phylogeny agreed with the morphological analysis in providing convincing support for the monophyly of the section. / Prof. B.E. van Wyk
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:2812 |
| Date | 13 June 2008 |
| Creators | Le Roux, Margaretha Marianne |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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