Polhillia on the brink: Taxonomy, ecophysiology and conservation assessment of a highly threatened Cape legume genus by Brian du Preez Thesis presented in partial fulfilment of the requirements for the degree of Master of Science (Botany) in the Faculty of Science at Stellenbosch University Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa. Supervisors: Prof. L.L. Dreyer, Prof. A.J. Valentine, Prof. M. Muasya April 2019 Stellenbosch University https://scholar.sun.ac.za DECLARATION By submitting this thesis electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the sole author thereof (save to the extent explicitly otherwise stated), that reproduction and publication thereof by Stellenbosch University will not infringe any third-party rights and that I have not previously in its entirety or in part submitted it for obtaining any qualification. Date: ……15 February 2019……… Copyright ©2019 Stellenbosch University All rights reserved. i Stellenbosch University https://scholar.sun.ac.za TABLE OF CONTENTS DECLARATION....................................................................................................................... i LIST OF FIGURES ................................................................................................................ vi LIST OF TABLES ................................................................................................................... x ABSTRACT .......................................................................................................................... xiii OPSOMMING....................................................................................................................... xiv ACKNOWLEDGEMENTS ................................................................................................. xvi DEDICATIONS ................................................................................................................... xvii CHAPTER 1 ............................................................................................................................. 1 GENERAL INTRODUCTION ............................................................................................... 1 1. Greater Cape Floristic Region ............................................................................................ 1 2. Legume systematics ............................................................................................................. 2 3. Conservation ......................................................................................................................... 9 4. Soil nitrogen fixation.......................................................................................................... 11 5. Soil nutrients....................................................................................................................... 12 6. Aims and objectives of study ............................................................................................. 14 7. Breakdown of chapters ...................................................................................................... 14 REFERENCES ....................................................................................................................... 16 CHAPTER 2 ........................................................................................................................... 30 THE GENERIC CONCEPT OF POLHILLIA C.H.STIRT. (GENISTEAE: FABACEAE): CONFIRMATION OF THE MONOPHYLY OF THE GENUS AND DESCRIPTION OF A NEW MONOTYPIC SUBGENUS ROSEOPOLHILLIA ............ 30 ABSTRACT ............................................................................................................................ 30 1. INTRODUCTION.............................................................................................................. 31 2. MATERIALS AND METHODS ...................................................................................... 34 2.1. Morphology .................................................................................................................. 34 2.2. Molecular phylogenetic reconstruction ..................................................................... 34 3. RESULTS ........................................................................................................................... 37 3.1. Morphology .................................................................................................................. 37 3.2. Molecular phylogenetic reconstruction ..................................................................... 37 4. DISCUSSION ..................................................................................................................... 42 5. TAXONOMIC TREATMENT ......................................................................................... 44 5.1. Key to the genera of SA Genisteae ............................................................................. 44 ii Stellenbosch University https://scholar.sun.ac.za 5.2. Polhillia subgen. Polhillia C.H.Stirt. .......................................................................... 45 5.2.1. Taxonomy .............................................................................................................. 45 5.2.2. Species included: ................................................................................................... 45 5.2.3. Etymology .............................................................................................................. 47 5.2.4. Diagnostic characters ........................................................................................... 47 5.2.5. Distribution ........................................................................................................... 47 5.3. Polhillia subgen. Roseopolhillia B.du Preez, subgen. nov. ....................................... 49 5.3.1. Taxonomy .............................................................................................................. 49 5.3.2. Species included: ................................................................................................... 49 5.3.3. Etymology .............................................................................................................. 49 5.3.4. Diagnostic characters ........................................................................................... 49 5.3.5. Distribution ........................................................................................................... 50 6. CONCLUSION .................................................................................................................. 50 7. ACKNOWLEDGEMENTS .............................................................................................. 50 REFERENCES ....................................................................................................................... 51 CHAPTER 3 ........................................................................................................................... 56 THE GENUS POLHILLIA C.H.STIRT. (GENISTEAE: FABACEAE): A MONOGRAPH ...................................................................................................................... 56 ABSTRACT ............................................................................................................................ 56 1. INTRODUCTION.............................................................................................................. 57 2. HISTORICAL REVIEW .................................................................................................. 61 3. MATERIALS & METHODS............................................................................................ 64 3.1. Morphology .................................................................................................................. 64 3.1.1. Material collection ................................................................................................ 64 3.1.2. Morphological examination ................................................................................. 64 3.1.3. Palynology ............................................................................................................. 64 3.1.4. Leaf Anatomy ........................................................................................................ 65 3.2. Molecular phylogenetic analysis ................................................................................ 65 3.3. Phytogeography ........................................................................................................... 66 4. RESULTS ........................................................................................................................... 66 4.1. Taxonomic significance of different disciplines ........................................................ 66 4.1.1. Morphology ........................................................................................................... 66 4.1.2. Palynology ............................................................................................................. 71 4.1.3. Leaf anatomy......................................................................................................... 72 iii Stellenbosch University https://scholar.sun.ac.za 4.2. Molecular phylogenetic analysis ................................................................................ 76 4.3. Phytogeography ..........................................................................................................