Local, Regional and Monographic Approaches to Cyrtandra (Gesneriaceae)
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Local, regional and monographic approaches to Cyrtandra (Gesneriaceae) Gemma L.C. Bramley Doctor of Philosophy The University of Edinburgh Royal Botanic Garden, Edinburgh 2003 ell DECLARATION I hereby declare that the work contained within this thesis is my own, unless otherwise acknowledged and cited, and that this thesis is my own composition. This thesis has not in whole or in part been previously presented for any other degree. ABSTRACT A local revision reviewed collections of Cyrtandra from Mount Kerinci, Sumatra, recognising thirteen species, three of which are newly described: C. aureotincta, C. patentiserrata, and C. stenoptera. In a regional approach covering species from Peninsular Malaysia, nine species of Cyrtandra (Gesneriaceae) were recognised. Three [C. cupulata, C. pendula, C. wallichii] are common and occur more or less throughout the area; four [C. dispar, C. gimlettei, C. patula, C. suffruticosa]have more restricted distributions, and two [C. lanceolata, C. stonei] are local endemics. Three species and one variety are reduced to synonymy: C. barbata (= C. cupulata), C. falcata (= C. suffruticosa), C. rotundfolia (= C. pendula), and C. cupulata var. minor (= C. cupulata). A phylogenetic approach involved a monographic revision of Cyrtandra section Dissimiles. Eleven species were reviewed, one of which is newly described (C. fulvisericea); one species, C. producta (= C. Irisepala) is reduced to synonymy. Phylogenetic analyses of sequences of the internal transcribed spacer (ITS) region of 18-26S nuclear ribosomal DNA of Cyrtandra species from one community on Mount Kerinci, Sumatra, suggest that this community is an assembly of three distinct phyletic lineages, resulting from a gradual accumulation of diversity through time, although one lineage shows evidence of more recent, continuing speciation than the other two. Phylogenetic analyses of a second, larger sample of Cyrtandra ITS sequences suggest that Peninsular Malaysian Cyrtandra species have affinities with Sumatran and Bomean species, following previously recognised floristic patterns. These affinities can be explained historically, as periods of lower sea levels in the Pleistocene exposed land bridges between the Malay Peninsula, Sumatra and Borneo. A smaller sample of Cyrtandra species was sequenced for the trnL-F region of the chloroplast genome, and phylogenetic analyses recognised major groups represented in the ITS phylogeny, suggesting congruence between the ITS and trnL-F data, and that the ITS phylogeny is an approximation of true evolutionary history. Large genera such as Cyrtandra have the potential to provide answers to critical biological questions concerned with ecology, conservation, evolution and biogeography. A taxonomic framework is a critical first step: to achieve monographs of large genera demands their division into groups of species treatable in short periods. Genera can be divided geographically or phylogenetically, and the resulting taxonomic revisions have different merits. A local approach to Cyrtandra monography, such as the Kerinci revision, is not entirely suitable because the genus is species-rich with a large distribution, making local revisions too repetitive and time consuming to cover the whole genus. However, local revisions are useful as indicators of the species richness of areas and provide an introduction to the genus for those who are new to it. A monographic approach is hampered by the lack of an infrageneric classification for Cyrtandra. It requires a well-sampled molecular and morphological phylogeny, so that molecular data can corroborate morphologically defined groups as shown for section Dissimiles. Such a phylogeny could be produced using ITS and trnL-F sequences, with the addition of key morphological characters. A regional approach is most suitable for Cyrtandra because of its distribution across the islands of SE Asia and its high degree of local endemism. Larger islands, with high species richness, could be further divided or worked on by a team of taxonomists. Regional approaches are the most efficient way to achieve the much- needed increase in collections of Cyrtandra, vital for the completion of accurate revisionary work and a molecular phylogeny of the genus. Regional approaches may not be as suitable for other large genera as for Cyrtandra, as they are distributed in different areas and have different patterns of endemism. Local and regional approaches are most suitable for considering which areas, species or habitats should be prioritised for conservation, when assessing the species diversity of areas, and also for local botanists and ecologists. 11 ACKNOWLEDGEMENTS I would like to thank my supervisors, Quentin Cronk, Toby Pennington, Mary Mendum and Philip Smith, for their expert advice, support, time and understanding throughout my PhD. They have never failed to inspire me. The RBGE has been a fantastic place to work, and it is difficult to think of anyone who has not helped me in some way during my three years here. I am especially grateful to Michelle Hollingsworth and Alex Ponge for all their assistance in the lab, Frieda Christie and Ruth Hollands for help with sciereid work, and for general advice I thank Michael Möller, Hannah Atkins, Peter Wilkie, George Argent, Mark Newman, B.L. Burn, O.M. Hilliard, Pete Hollingsworth, Vanessa Plana, David Harris, Robert Mill, Mark Hughes and Christina Oliver. Thank you also Helen Hoy and Adele Smith in the Herbarium office, Len Scott and Duncan Reddish for help with computers, and all the staff in the Library. I would like to thank the curators of the following herbaria for loans of material or for permission to work in their herbaria: A, BlOT, BO, BM, CANB, K, KEP, L, SING. Dr Sri Tjitrosoedirdjo and Nurainas were very helpful during my visit to Bogor. I owe particular thanks to Professor Toni Weber who kindly gave me his photographs and notes on Peninsular Malaysian Cyrtandra. My fieldwork in Peninsular Malaysia would not have been possible without permission from the Economic Planning Unit of the Government of Malaysia, I am most grateful to them for this. The success of the trip was largely due to the staff of the Forest Research Institute Malaysia, in particular Yen-Yen Sam, Dr Leng Guan Saw and Markandan Moorthy, and Dr Ruth Kiew made us very welcome in Singapore. Thanks also to Sophie Neale for being a great travelling companion. I am grateful to the University of Edinburgh Davis Expedition Fund, and the Oleg Polunin Memorial Fund for financial support for fieldwork, and the BBSRC for supporting my PhD through a studentship. 111 On a more personal note, I can't say how much I have appreciated being surrounded by so many good friends. For making every day more enjoyable and encouraging me when I was (occasionally!) struggling to be enthusiastic, thank you Michelle, Alex, Hannah, Sophie, Mary, Daniela, Christy, Emily, Peter, Susana, Nazre, Alan, Graham, Jane, Mark H and Jeremy. Outside of the RBGE, thank you Ian, Paula, Rich, Debs, James, Loma, Caroline and Charmaine. Despite being thousands of miles away for most of my thesis, Simon has been a tower of strength. His understanding and belief in me have helped me immensely. My family, especially my parents and my sister, have provided unfailing support through some difficult times. I would not have been able to do this without them. Thank you Uncle Neil for help with scanning, and Grandad G and Melissa for checking references. This thesis is dedicated to Nanny, Barbara M. Gilchrist, who sadly passed away before its completion. iv OBJECTIVES Cyrtandra J.R. & G.Forst. is the largest genus in the Gesneriaceae, containing over 600 species. It occurs throughout the primary rain forests of SE Asia, and is also present on the islands of the Pacific and Hawaii. It is poorly known and many species are undescribed. There is no modem monograph of Cyrtandra, due to its huge size: all recent revisions have been regional. The lack of monographs of large genera such as Cyrtandra is a problem in angiosperm taxonomy: genera with more than 400 species account for 23% of angiosperm species (R. Scotland, pers. comm.). Without monographs, the potential of large genera such as Cyrtandra to provide answers to critical biological questions concerned with ecology, conservation, evolution and biogeography is diminished. A taxonomic framework is a critical first step: to achieve monographs of large genera demands their division into groups of species treatable in short periods. Genera can be divided geographically or phylogenetically, and the resulting taxonomic revisions are likely to have different merits. This thesis has the following objectives: a) to discuss the problem of large genera: their reality, their use, and strategies that have been taken towards dividing them for taxonomic treatment; b) to investigate the relative merits of different taxonomic approaches to large genera by taking three taxonomic approaches to Cyrtandra: a local approach, revising the Cyrtandra species of Mount Kerinci, Sumatra; a regional approach, revising the Cyrtandra species of Peninsular Malaysia; a phylogenetic/monographic approach, revising Cyrtandra Section Dissimiles C.B.Clarke; c) to evaluate the suitability of the taxonomic approaches to Cyrtandra and suggest a future strategy for Cyrtandra taxonomy. v to assess the suitability of the taxonomic approaches to other large genera to demonstrate the utility of molecular phylogenies in evolutionary biology and biogeography by carrying out molecular phylogenetic analyses of nuclear