https://theses.gla.ac.uk/ Theses Digitisation: https://www.gla.ac.uk/myglasgow/research/enlighten/theses/digitisation/ This is a digitised version of the original print thesis. Copyright and moral rights for this work are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This work cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Enlighten: Theses https://theses.gla.ac.uk/ [email protected] A Phylogeny of Begoniaceae Bercht. & J.Presl. A thesis submitted to the University of Glasgow for the degree of Doctor of Philosophy Laura Lowe Forrest Division of Environmental and Evolutionary Biology December 2000 ProQuest Number: 10656230 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10656230 Published by ProQuest LLO (2017). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLO. ProQuest LLO. 789 East Eisenhower Parkway P.Q. Box 1346 Ann Arbor, Ml 48106- 1346 GLASGOW u n iver sity UBRARY 12- 1( 5" ~ Gn Declaration I hereby declare that this thesis is composed of work carried out by myself unless otherwise acknowledged and cited and that this thesis is of my own composition. The research was carried out in the period of April 1997 to December 2000. This dissertation has not in whole or in part been previously presented for any other degree. “I see a rose, that strange thing, and what’s there But a seeming coloured something on the air With the transparencies that make up me. Thickened to existence by my notice” Norman McCaig, 'Ego’ II Abstract Begonia is one of the largest angiosperm genera, with 1400 species currently recognised. These were placed into 63 sections in the most recent taxonomic treatment. However, there is considerable uncertainty in both section inter-relationships and sectional composition, and there is no formalised phylogenetic hypothesis for the genus. Using the nuclear internal transcribed spacers (ITS) and partial large subunit (268) sequences of ribosomal DMA, I have produced phylogenetic trees to form the basis of a cladistic framework for the interpretation of the evolution and sectional level systematics of Begonia. Maximum parsimony, maximum likelihood and minimum evolution cladograms were produced for 35 Begonia, one Symbegonia and two Datisca species, for partial 268, ITS and combined sequence data. The results of the analyses suggest that African taxa are basal in Begonia, but that there is not sufficient information to elucidate the precise relationships among these basal lineages. The genus Symbegonia is nested deeply within Begonia. A far larger data set was constructed by sequencing the ITS region for 153 species. Different alignment methods (automated, elision and manual) were tested on these sequences, as were different search strategies. The topology which was taken to be the best estimate of the ITS phylogeny of Begoniaceae was constructed using manual alignment, culled of ambiguous regions, and adjusted to reflect the topologies of smaller, localised, compartment analyses. In the resulting tree, the African species of Begonia resolve as paraphyletic, with both Asian species (including Socotra) and American species (sister to southern African species) monophyletic. Comparisons were made between the ITS sequence data and trees produced from the chloroplast trnC - trnD inter-genic spacer. Parsimony analyses of trnC - trnD sequences support African taxa as basal in Begonia\ however, in contrast to the ITS data, trnC - trnD suggests polyphyly / paraphyly of American taxa, albeit with little bootstrap support. A morphological data matrix (67 characters for 159 taxa) did not produce a phylogenetic hypothesis for Begonia that was congruent with any other Hi available data. Using a combined morphology - ITS analysis, the fit of individual morphological characters to a fundamental tree was examined. Some characters fitted the combined topology well, although some of the characters which have traditionally been considered important in Begonia taxonomy (e.g. the number of placental branches) proved misleading. The ITS tree was used as a framework for reviewing chromosome evolution in the genus (604 published counts from 239 species). In contrast to sequence divergence, which was greatest among African species, chromosome number diversity was greatest among American species. The correlation between phylogenetic relationships implied by the ITS tree and the geographical distributions of species was explored to obtain biogeographic hypotheses which may explain the present-day distribution of Begonia. As a general rule, related species are geographically proximal, suggesting limited dispersal of lineages. This finding contradicts observations made on morphology, where the close affinities of morphologically disparate (but geographically proximal) taxa were previously unsuspected. Mechanisms responsible for the evolution of large genera were discussed, and Willis’ ‘age and area’ hypothesis compared to the ‘relict’ hypothesis of Cronk. In Begonia, the morphological diversity of the genus, and most of the species, are encompassed among the putatively derived lineages, favouring the ‘relict’ hypothesis. IV Acknowledgements As must be the case with any work of this kind, I owe thanks to a large number of people. Firstly, there are all the people who helped me organise my field work in south west China, 1997, and who assisted when I got there. Particular thanks are due to Mark Tebbitt, Zoe Badcock, Mark Watson, David Chamberlain, Pete Hollingsworth, Jim Dickson, Nick Turland and Rod Taylor. From Kunming, Yunnan, I would like to thank Guan Kaiun, and most specially Tian Dai’ke and Li Di-Xi (who both accompanied me down to the Vietnamese border and across to Nanning, Guangxi; I am particularly grateful to them for taking such care to find me vegetarian things to eat, to Tian for interpretation, to Driver Li for keeping the jeep on the goat-tracks which appear to pass for roads, and to both of them for spotting many Begonia that I would have trotted blithely past). Wei Yi Gang looked after me very well in Guilin, Guangxi and showed me a golden Camilia (which otherwise I would probably still not know existed). In Beijing, Fu De-Zhe, Qin Hai-Nin, Ban Qin, Song Shu-Yin, Sun Qi-Gao (who sorted out my paperwork, and made sure I left the country), Jin Xiao-Bai (who kindly provided me with living material of B. morsei, which survived just long enough for me to get some DNA out of it), Liu Zhao-Hua (who very kindly acted as interpreter, personal shopper and general dogsbody) and Jason Hilton (who gamely assisted in some spectacular hangovers) all deserve acknowledgement. I am very grateful to Malcolm Wilkins and the MacIntyre Begonia Trust Trustees for funding my collecting trip. People who have provided me with information about Begonia include Jan Doorenbos, Marc Sosef and Ferry Bouman in the Netherlands (I am particularly grateful to Ferry for taking me to visit the herbarium in Leiden, and for being good-natured when we found that the specimen we had gone to see was on loan to a 'L. Forrest’ in Glasgow....), Martin Sands in Kew, Tracy McLellan, South Africa, and Susan Swensen in Ithaca, New York. Friends and colleagues who have brought back living or silica dried material of Begonia from their travels include Peter Wilkie, Mary Mendum, George Argent, Toby Pennington, Philip Thomas, Nick Turland, Colin Pendry, Bill Baker, Mark Hughes and Michael Moller. There are several people who have been involved in keeping the living collections of Begonia going. They include John Stevensen, Euan Donaldson, David Menzies, Paul Mathews and many others at Glasgow Botanic Garden. Also Fiona Inches, Allister Reid, Fred Mobeck, Louise Galloway, Andrea Fowler, Steve Scott and Neil Watherston in Horticulture, and Becky Govier (for help with accessioning), at the Royal Botanic Garden Edinburgh. Essential Begonia advice has been provided by Zoe Badcock, Mark Tebbitt, Mark Hughes and Vanessa Plana. The Begonia group meetings in the Marina have been a very valuable source of ideas .... General advice has come from numerous sources, including Cymon Cox, Terry Hedderson, Ken Johnson, Richard Bateman, Quentin Cronk, James Richardson, Rod Page, Vince Smith, Diana Percy, Michael Moller, Kwiton Jong, Hans Sluiman, Pete Hollingsworth and Toby Pennington (for whom I summarise that chapter on species concepts which I spared everyone the ordeal of: Species are progress reports in the history of life (Eldridge, 1995). Fin.) My attempts in the laboratory have been inevitably assisted by Caroline Guihal, Jill Preston, Michelle Hollingsworth, Alex Ponge and James Richardson. I am very grateful to Jill Harrison, Andy Hudson and other folk at the University of Edinburgh for lab space, chemicals and advice on cloning. Other people who deserve a mention include the Library staff at the Royal Botanic Garden, Edinburgh. Furthermore, Steve Cafferty has raided the BM library for me on a few occasions, when I've had trouble getting hold of papers. David Ingram and Richard Bateman kindly allowed me to move my studies across to the Royal Botanic Garden Edinburgh (and Steve Blackmore and Mary Gibby haven’t objected yet). I would like to thank everyone at the Gardens (including Antonia) for providing a supportive, enthusiastic and friendly place to study.