A taxonomic revision of the genus Henckelia Spreng. (Gesneriaceae) in Thailand and surrounding countries Thesis submitted for the Degree of Doctor of Philosophy August 2020 Sukontip Sirimongkol Department of Botany School of Natural Sciences Trinity College Dublin, The University of Dublin Declaration I declare that this thesis has not been submitted as an exercise for a degree at this or any other university and it is entirely my own work except where duly indicated and clearly acknowledged in the text. I agree to deposit this thesis in the University's open access institutional repository or allow the Library to do so on my behalf, subject to Irish Copyright Legislation and Trinity College Library conditions of use and acknowledgement. Sukontip Sirimongkol i ii Acknowledgements I wish to thank the Royal Thai Government for a scholarship and also would like to acknowledge the support from the Forest Herbarium, the Department of National Parks Wildlife and Plant Conservation that enabled me to study for a PhD in Trinity College Dublin, Ireland. This funding would not have been granted without the help of Dr Somran Suddee, who requested this grant to support the Forest Herbarium (BKF) staff in their study abroad. Thank you. He also supported me in obtaining taxonomic knowledge and in fieldwork in Thailand. I am grateful to The Office of the Civil Service Commission and the Office of Educational Affairs in London for all their help. I would like to express my sincere thanks to my supervisor Prof Dr John Parnell for super support and guidance of my work and life in Trinity College Dublin. From the beginning of my plan to study abroad, he was kind, supportive and helpful with all facilities and even contacted third parties. I got a warm welcome from the first day in Ireland. He drove me from the airport to the accommodation. My life in Ireland was not easy and there are many things and conditions that made my life rough and difficult. I can stand strong again and again due to his kind support and non-stop solution to my problems. He was patient in correcting my work and never gave up trying to help me improve when I was studying here. My co-supervisor, Prof Dr Trevor Hodkinson assisted me with DNA extraction and molecular analyses. He also kindly proof-read my work and always welcomed me when I needed help. I would like to thank Dr Chalermpol Suwanphakdee, Dr Phinyarat Kongprakhon, Mrs Chantana Khensiri, Ms Jet Beekwilder, Ms Wanniga Moonsuk and Ms Erika Soldi for helping with molecular work, Prof Dr Fraser Mitchell and Ms Jacqueline Stone for kindly helping with pollen grainswork, Dr Somran Suddee, Dr Joeri Sergej Strijk and Ms Anne Dubéarnès while I am writing the thesis. I would like to thank Dr Sutee Duangjai, Ms Rumrada Meeboonya, Dr Witsanu Saisorn for kindly helping with my molecular data analysis, and also Dr Ponlawat Pattarakulpisutti, Mr Jarupund Pakawat and Dr Alina Premrov for helping with data analysis. My research has progressed because I got more great support from my colleagues, including the BKF staff, Dr Kongkanda Chayamarit, Dr Rachun Pooma, Dr Voradol Chamchumroon, Ms Nannapat Pattarahirantricin, Mr. Manop Poopath, Mr Piyachart Trisarasri, Mr Preecha Karraket, Mr Thanongsak Jonganurak, Ms Sawita Yooprasert, Mr Sukid Rueangruea, Mrs Orathai Kerdkaew, Mr. Saran Jirakan and Dr Kanchana Pruesapan from the Bangkok Herbarium (BK) for preparation of specimens to loan to Ireland and Mr Phattaravee Prommanut for kindly checking some specimens from Thailand. I also thank Dr Pimwadee Pornpongrungrueng from Khon Kaen University and iii Dr Komsan Rueangritsarakul from the Royal Forest Department for guidance about life in Dublin, and Dr Bhanubong Bongcheewin for guidance before travelling. My field survey in Thailand, would not have been so smooth and successful without help from Mr. Piros Boonchum, Mr Akkanitphong Sawatna, Ms Chanchanok Phongsasat, Mr. Phromwarong Khuenwang, Mr. Wattana Saengkam, Mr. Wuttipong Dongkhamfuu, Mr. Krissayam Kongsatree, Mr Chatchai Yotawut, Ms Nipaporn Paisarn, Mr. Ta Sapniyomphong, Mrs Sopa Boonchum, and Ms Wipaphon Baiya. A special thanks to Dr Voradol Chamchumroon, Mr Manop Poopath, Mr Saran Jirankan, Ms Sawita Yooprasert, Dr Rachun Pooma and Ms Nannaphat Pattarahirantricin who accompanied and helped during the field trips. I would like to thank Dr David J. Middleton from Singapore Botanic Gardens for helpful advice on the Gesneriaceae, Prof Anton Weber from University of Vienna for kind delivery of the Gesneriaceae references, Prof Michael Möller from Royal Botanic Gardens Edinburgh and Dr Carmen Puglisi from Royal Botanic Gardens Kew for great support and advice about the Gesneriaceae work and Dr Avishek Bhattacharjee from Central National Herbarium, Botanical Survey of India for kindly sending images of type specimens. I thank Dr Pramote Triboun for giving guidance and suggestions, Mr Pakkapol Thaowetsuwan from Royal Botanic Garden Edinburgh for kind help with many references from the Edinburgh Herbarium, Mr Jaresak Saewai from Prince of Songkla University, Hatyai Campus for accompanying me while visiting the Muséum National d'Histoire Naturelle and Kew Herbarium, Prof Dr Peter Bruyns for accompanying me while visiting the Kew Herbarium and The Natural History Museum Herbarium and Peter Phillipson from Muséum National d'Histoire Naturelle for kind helping while visiting the Herbarium. I am very grateful to the Aarhus University Herbarium (AAU), University of Aberdeen (ABD), The Natural History Museum (BM), The Forest Herbarium (BKF), Bangkok Herbarium (BK), Royal Botanic Gardens Edinburgh (E), Royal Botanic Gardens Kew (K), Kunming Institute of Botany (KUN), Naturalis (L), Queen Sirikit Botanic Gardens Herbarium (QBG) and Singapore Botanic Gardens (SING) for the loan of materials. Also, I would like to thank the staff of the Muséum National d'Histoire Naturelle (P), Royal Botanic Gardens Kew (K), The Natural History Museum (BM), Vietnam Academy of Science and Technology (VAST) (HN), VNU University of Science Herbarium (HNU) and Vietnam National Museum of Nature (VNMN). A special thanks to Dr Prachaya Srisanga from QBG for helping during my visit, and Dr Do Von Truong from VNMN for kindly driving and helping me while visiting herbaria in Hanoi, and Peter B. Phillipson (P), Lesley Walsingham (Kew), Elizabeth M. Woodgyner (Kew), Ranee Prakash (BM), Dr Jovita C. Yesilyurt (BM), Dr Tanawat Chaowasku (CMUB). Thanks to my colleaques Dr Zhao Dongwei, Dr Ponlawat Pattarakulpisutti, iv Mr Conor Owens, Dr Anindita Lahiri, Ms Anne Dubéarnès, Dr Anna Kaja Hᴓyer, Dr Eileen Power, Dr Alwynn McGeever, Dr Aoife Delaney, Dr Hannah Hamilton, Ms Jean Williams, Ms Marine Valmier, Mrs Ruchita Ingle and Dr Ana Lopez for their great support. Special thanks to Ms Anne Dubéarnès and Mr Pisut Wisessing for correcting my work and Ms Jean Williams for kindly helping submitted my thesis. I thank the staffs of the Botany Department, TCD, including Prof Dr Fraser Mitchell, Dr Daniel Kelly, Prof Dr Jennifer McElwain, Prof Dr Michael Williams, Dr Stephen Waldren, Prof Dr Nick Gray, Prof Dr Jane Stout, Dr Paul Dowding, Prof Dr Michael Jones, Dr Matthew Saunders, Ms Francess Leogue, Ms Siobhán McNamee, Ms Diane Touzel, Ms Sophia Ni Sheoin, Ms Aisling O'Mahony, Dr Jesko Zimmerman, Ms Jacqueline Stone, Ms Patricia Coughlan, Dr Michelle Murray, Dr Brian Murphy and Ms Mandy Lockhart. Special thanks to Mrs Marcella Campbell for the first warm home in Ireland and nice food in every meal when I stayed with her. She also helped me with the loan of herbarium specimens and life in Dublin. She gave me the strong advice "look forward to summer!" that made me able to fight through homesickness and cold. Thanks to Assistant Prof Dr Nattapong Kitsuwan from The University of Electro- Communications, Tokyo, Japan for advice and helping me a lot in the first six months in Dublin, Mr Pisut Wisessing, Dr Borwornsak Rotjanapittayakul, Mr Thantap Pankhao and Dr Wipawee Paulsson for giving moral support when I lived in Ireland. Ms Aroonsri Sarikhan, Mr Padraic Morgan, Mr Brian Conry, Ms Sarah Maloudi and family, Mr John Jameson, Kai and Lee Jameson, Dr Bhanumas Chantarasuwan, Mrs Watchartinnawee Pestel and family, Mrs Warin Harrison for the great support and good hospitality while I live in Ireland. I very much appreciate it. Special thanks to my friends from Thailand for a great support. Finally, I most gratefully acknowledge my parents, my sisters and my brother for all their support throughout the period of this study. v vi Summary The Gesneriaceae is a flowering plant family in the order Lamiales. Its members consist of herbs, shrubs, epiphytes, lianes (e.g. Asteranthera), and rarely trees (e.g. Sanango, Solenophora). This family is distributed in the tropics and subtropics of the Old and New World with approximately 146 genera and ca. 3,400 species. Henckelia was resurrected from Didymocarpus whilst Didymocarpus was remodelled (Weber and Burtt,1997). Their classification is based on cytological data and the phytogeography of Old World Gesneriaceae. The delimitation of Henckelia has subsequently been changed on the basis of molecular data (Wang et al., 2011; Weber et al., 2011). Results showed that only Henckelia Sect. Henckelia remained in Henckelia (Weber et al., 2011), while the remainder should be assigned to other genera (Middleton et al. 2013). The total number of species in Henckelia is 68. This thesis focused on a taxonomic revision of Henckelia in Thailand and surrounding countries (Myanmar, Laos, Cambodia and Vietnam). Twenty-four species are recognized. Identification keys and full descriptions are provided (including illustrations and distribution maps). Five new species were discovered i.e. Henckelia amplexifolia Sirim., H. campanuliflora Sirim., H. candida Sirim., H. dasycalyx Sirim. & D.J. Middleton, and H. nakianensis Sirim., J. Parn. & Hodk. The morphological investigation was extended to a numerical taxonomy study. Morphological data were analysed using non-metric multidimensional scaling (NMDS) with Jaccard as the distance measure.