UNIVERSITY OF KWAZULU-NATAL SYSTEMATIC STUDIES IN GNIDIA L. (THYMELAEACEAE) ANGELA JANE BEAUMONT SYSTEMATIC STUDIES IN GNIDIA L. (THYMELAEACEAE) by ANGELA JANE BEAUMONT Submitted in fulfilment of the academic requirements for the degree of DOCTOR OF PHILOSOPHY in the School of Biological and Conservation Sciences, Faculty of Science and Agriculture, University of KwaZulu-Natal, Pietermaritzburg January 2010 STUDENT DECLARATION sa ~T.~ .~. ~!I.~ ... ~l".v.-P.I ..~.~ .. .\. N.. ~ N! );):, .~ .. k... (THJ1m~.4A~.I3.~E A.€) (Thesis Title) I A. N. 6"~. ~ f:\ o.-.A.~~ e.~ .A.~ M.C? NT '" . (full name) ....... ~.S..~.~~?"J'.~~ '" '" .. , (Student Number) declare that: (i) The research reported in this dissertation, except where otherwise indicated, is the result of my own endeavours in the School of Biological and ConseNation Sciences, University of KwaZulu-Natal, Pietermaritzburg; (ii) This dissertation has not been submitted for any degrees or examination at any other University; (iii) This thesis does not contain data, figures or writing, unless specifically acknowledged, copied from other researchers; and (iv) Where I have reproduced a publication of which I am an author or co-author, I have indicated which part of the publication was contributed by me. Signed at ... .e1.~T~.~.M.~~!!:?~.~.f?~ .... on the .3.9........ day of ................. J>.~.~~.~.~~.~., 2009. DECLARATION BY SUPERVISORS We hereby declare that we acted as Supervisors for this PhD student: Student's Full Name: ANGELA JANE BEAUMONT Student Number: 882225798 Thesis Title: SYSTEMATIC STUDIES IN GNIDIA L. (THYMELAEACEAE). Regular consultation took place between the student and ourselves throughout the investigation. We advised the student to the best of our ability and approved the final document for submission to the Faculty of Science and Agriculture Higher Degrees Office for examination by the University appointed Examiners. SUPERVISOR: PROFESSOR TJ EDWARDS CO-SUPERVISOR: PROFESSO J VAN STADEN 11 DECLARATION BY SiPERVISOR We hereby declare that we acted as suprrviSOrs for this PD student: Studenfs Full Name: . .41~' .J!:>.IJ& &.'IM~d. .. Student Number: ~.S.. ~.~.~ ..~.:r.5~ ,. Thesis Title:.5.~~:T.~.M.f:l.T.~~... ~I~.~!.~.$ .I.~ ~.N..I J::nA '-:-:.~. ('TH ~ (Y\ e L-A€ PI C€- ~€.). Regular consultation took place between the student an ourselves throughout the investigation. We advised the student to the best of our ability and approved the final document for submis ion to the Faculty of Science and Agriculture Higher Degrees Office for examination by the University appointed Examiners. ' SUPERVISOR: CO-SUPERVISOR: PROFESSOR J AN STADEN 11 FACULTY OF SCIENCE AND AGRICULTURE DECLARATION 1 - PLAGIARISM I, ....A:~..~.~.I:-:.A .... ;rA.N~ ... G.~.~.~.M.C?~T. ...., declare that I. The research reported in this thesis, except where otherwise indicated, is my original research. 2. This thesis has not been submitted for any degree or examination at any other university. 3. This thesis does not contain other persons' data, pictures, graphs or other information, unless specifically acknowledged as being sourced from other persons. 4. This thesis does not contain other persons' writing, unless specifically acknowledged as being sourced from other researchers. Where other written sources have been quoted, then: a. Their words have been re-written but the general infonnation attributed to them has been referenced b. Where their exact words have been used, then their writing has been placed in italics and inside quotation marks, and referenced. 5. This thesis does not contain text, graphics or tables copied and pasted from the Internet, unless specifically acknowledged, and the source being detailed in the thesis and in the References sections. Signed .....•.....~ . Declaration Plagiarism 22105108 FHDR Approved 111 FACULTY OF SCIENCE AND AGRICULTURE DECLARATION 2 - PUBLICATIONS DETAILS OF CONTRIBUTION TO PUBLICATIONS that form part and/or include research presented in this thesis (include publications in preparation, submitted, in press and published and give details of the contributions of each author to the experimental work and writing ofeach publication) Publication I BEAUMONT, AJ. 2000. Gnidia. In: GOLDBLATI, P. & MANNING, J. (eds.). Cape Plants. A conspectus of the Cape Flora of South Africa. Strelitzia 9: 676-680. National Botanical Institute, Pretoria. Publication 2 BEAUMONT, AJ., EDWARDS, T.J. & SMITH, F.R. 2001. Leaf and bract diversity in Gnidia (Thymelaeaceae): patterns and taxonomic value. Systematics and Geography ofPlants 71: 399-418. Publication 3 BEAUMONT, AJ., EDWARDS, T.J. &SMITH, F.R. 2001. Patterns of diversity among involucral bracts, inflorescences and flowers in Gnidia (Thymelaeaceae). Systematics and Geography ofPlants 71: 419-431. Publication 4 EDWARDS, T.J., BE-AUMONT, AJ. &STYLES, D. 2001. New records and distributional disjunctions from South Africa, Zimbabwe and Mozambique. Bothalia 31: 199-201. Publication 5 BEAUMONT, AJ., EDWARDS, T.J. & SMITH, FR. 2006. The first record of gynodioecy in a species of Gnidia (Thymelaeaceae) from South Africa. Botanical Journal of the Linnean Society 152: 219-233. iv Publication 6 BEAUMONT, A.J., EDWARDS, T.J., MANNING, J., MAURIN, 0., RAUTENBACH, M., MOTSI, M.C., FAY, M.F., CHASE, M.W. & VAN DER BANK, M. 2009. Gnidia (Thymelaeaceae) is not monophyletic: taxonomic implications for Thymelaeoideae and a partial new generic taxonomy for Gnidia. Botanical Journal of the Linnean Society 160: 402-417. I am the senior author ofall the publications except for publication 4, in which I am a co-author. In publication 6, the molecular work was done by M. VAN DER BANK and M. RAUTENBACH (Molecular Systematics Laboratory, Department of Botany and Plant Biotechnology, University ofJohannesburg, South Africa). Signed: A. J. Beaumont Declaration Publications FHDR 22105108 Approved v ABSTRACT SYSTEMATIC STUDIES IN GNIDIA L. (THYMELAEACEAE) BEAUMONT, A.J., Ph.D. thesis, University of KwaZulu-Natal, 2010 Gnidia L., variously estimated to contain 100–160 species, is the largest genus in the sub-cosmopolitan family Thymelaeaceae. Most species are shrubby, and occur in tropical and southern Africa, with one species reaching southern India and Sri Lanka, and 14 species endemic to Madagascar. Assorted segregate genera have been established using characters considered by some as too few, too trivial or unreliable. Generic limits have been contentious with authors following either a narrower concept of Gnidia or a broader circumscription within which segregate genera are placed in synonymy under Gnidia. Regional treatments for African and Madagascan floras have been published over the last century until very recently, but the genus was last revised in its entirety 153 years ago. Today, a broad-based concept of Gnidia is generally recognised, but there is no modern infrageneric classification, and species relationships are poorly understood. Homogenous groups of species are identified by their similarities of leaf length and width or bract length and width ratios. Species comprising the homogenous groups for leaf ratios differ to those comprising the homogenous groups based on bract ratios, and there is no correlation between leaf and bract length and width ratios. This suggests that the factors influencing leaf diversity differ from those influencing vi bract diversity. Bracts differ most from leaves in species with capitate inflorescences, and involucres of several layers of bracts likely protect reproductive organs (flowers) in heads. Previously overlooked morphological and micromorphological details, and morphometric analyses of leaf, bract and floral dimension data help define individual species, and clades of species derived from phylogenetic analyses of molecular data. Evidence from a phylogenetic analysis of nuclear ribosomal and plastid DNA sequence data confirms the polyphyly of Gnidia. Three lineages contain Gnidia species and species of genera from southern Africa, southern South America or Australia, while another lineage corresponds largely to the previously recognized genus Lasiosiphon. The genus Lasiosiphon is reinstated characterised by flowers mostly in heads, bracts different from the leaves, and the presence of smooth hairs; it now includes species with tetramerous flowers as well as ones with pentamerous flowers. Gynodioecy is recorded for the first time in a single species and represents the first documented example of sexual polymorphism involving unisexual flowers in Gnidia and sub- Saharan Thymelaeaceae. The findings of this thesis are discussed in terms of their phylogenetic value and contribution to our better understanding of the generic limits of Gnidia and its relationships with other southern hemisphere Thymelaeoideae. The circumscription and generic affinities of Gnidia as suggested by results presented in this thesis are compared to previous classification systems for congruence and dissimilarity. vii ACKNOWLEDGEMENTS I thank Professor T.J. Edwards for his supervision of this thesis, for his critical input, constructive comments, and support. I am grateful to Professor J. van Staden of the Centre for Plant Growth and Development for chairing my research committee meetings and for facilitating the completion of this thesis. I thank Dr. W. Cress for his participation and input in my research committee meetings. A special thank you goes to Professor R.P. Beckett for his assistance in the field, constructive advice, and use of computer facilities and for his unwavering support, hospitality and friendship.