Systematics of Hermannia L. (Malvaceae): A Taxonomic Revision of the Genus. by David Gwynne-Evans Thesis presented for the degree of DOCTOR OF PHILOSOPHY In the DEPARTMENT OF BOTANY UNIVERSITY OF CAPE TOWN 31 Oct 2015 University of Cape Town Supervised by Prof. Terry Hedderson The copyright of this thesis vests in the author. No quotation from it or information derived from it is to be published without full acknowledgement of the source. The thesis is to be used for private study or non- commercial research purposes only. Published by the University of Cape Town (UCT) in terms of the non-exclusive license granted to UCT by the author. University of Cape Town CONTENTS Systematics of Hermannia L. (Malvaceae): ....................................................................... i A Taxonomic Revision of the Genus. ................................................................................. i Contents ......................................................................................................................... ii List of Figures ............................................................................................................. xiii List of Tables .............................................................................................................. xxii Acknowledgements ................................................................................................... xxiii Abstract ....................................................................................................................... xxv Acronyms .................................................................................................................. xxvii Acronyms of herbaria ............................................................................................ xxviii 1. Introduction and background ..................................................................................... 31 1.1 Hermannia: A poorly-known genus rich in diversity and morphological variation .......................................................................................................................... 31 1.1.1 Prior estimates of species numbers and representation of Hermannia species. .............................................................................................................. 31 1.1.2 Morphological diversity. ...................................................................... 32 1.1.3 Existing knowledge of useful and medicinal properties ...................... 36 1.2 Taxonomy ......................................................................................................... 37 1.2.1 Taxonomic position of Hermannia ...................................................... 37 1.2.1.1 Linnaeus and the placement of Hermannia in the 18th century38 1.2.1.2 19th and 20th century taxonomy of the genus ......................... 38 1.2.1.3 Contemporary taxonomy ........................................................ 39 1.2.1.4 Developmental hypotheses for Hermannia ............................ 41 1.2.1.5 Placement of the Australian taxon Gilesia biniflora .............. 42 1.2.2 The Pre-Linnaean history of Hermannia ............................................. 42 1.2.3 Noteworthy conceptual and taxonomic contributions within Hermannia44 1.3 Biogeography ................................................................................................... 53 1.3.1.1 Diversity of the CFR and Linder‘s ‗Cape floral clades‘ ........ 54 1.3.1.2 Known ages of Cape floral clades .......................................... 54 ii 1.4 Ecology ............................................................................................................. 55 1.5 Need for the study, aims and thesis prospectus. ............................................... 58 2. An overview of morphology in Hermannia............................................................... 61 2.1 Introduction ...................................................................................................... 61 2.2 Methods ............................................................................................................ 61 2.3 The characters .................................................................................................. 62 2.3.1 Habit ..................................................................................................... 62 2.3.2 Rootstock .............................................................................................. 64 2.3.3 Stems .................................................................................................... 65 2.3.4 Indumentum ......................................................................................... 68 2.3.4.1 Texture ................................................................................... 68 2.3.4.2 Trichome colour ..................................................................... 69 2.3.4.3 Glandular hairs ....................................................................... 70 2.3.4.4 Stellate hairs ........................................................................... 71 2.3.4.5 Simple hairs ............................................................................ 73 2.3.4.6 Multicellular hairs .................................................................. 74 2.3.5 Stipules ................................................................................................. 74 2.3.6 Leaves ................................................................................................... 74 2.3.6.1 Petioles ................................................................................... 74 2.3.6.2 Leaf shape .............................................................................. 75 2.3.6.3 Leaf margin ............................................................................ 76 2.3.6.4 Leaf indumentum ................................................................... 77 2.3.6.5 Leaf Venation ......................................................................... 77 2.3.7 Inflorescence ........................................................................................ 78 2.3.7.1 Bracts and bracteoles .............................................................. 78 2.3.7.2 Calyx ...................................................................................... 79 2.3.7.3 Petals ...................................................................................... 81 iii 2.3.7.4 Stamens .................................................................................. 82 2.3.7.5 Anthers ................................................................................... 83 2.3.7.6 Ovary ...................................................................................... 85 2.3.7.7 Style........................................................................................ 85 2.3.7.8 Capsule ................................................................................... 86 2.3.7.9 Seed ........................................................................................ 87 2.3.7.10 Pollen...................................................................................... 89 2.3.8 Positioning of anatomical elements ...................................................... 89 2.4 Concluding comments ...................................................................................... 90 3. Phylogeny reconstruction........................................................................................... 91 3.1 Introduction ...................................................................................................... 91 3.1.1 The broader picture: subfamilial relationships ..................................... 91 3.1.2 Previous groups within Hermannia ...................................................... 92 3.1.2.1 The subsect. Cristatae ............................................................ 93 3.1.2.2 ―Marehnia‖ ............................................................................. 94 3.1.3 Linking the American, tropical and southern African species. ............ 94 3.1.4 Molecular approaches .......................................................................... 95 3.1.4.1 Gene trees, species trees and systematics: a cladistic perspective 96 3.1.5 The advantages and disadvantages of the ITS gene region. ................. 96 3.1.6 Why use molecular dating? .................................................................. 97 3.1.7 Dating – tying up key divergence events with associated factors ........ 98 3.1.8 Timing of radiations and dispersal events ............................................ 98 3.1.9 Calibrating the phylogenetic tree ......................................................... 99 3.1.9.1 Calibration Dates – the suitability of using the split up of Gondwanaland ........................................................................ 99 3.1.9.2 Dates nodes at higher taxonomic levels – orders and families100 3.1.9.3 A fossil date for the Bombacaceae ....................................... 100 iv 3.1.9.4 Dating using the Cape coastal limestones ............................ 101 3.1.9.5 Dating using inland limestones ............................................ 102 3.1.10 Objectives ........................................................................................... 102 3.2 Materials and methods ................................................................................... 103 3.2.1 Collection of material ........................................................................