Abstract
Begonia xuansonensis, a new species from northern Vietnam, is described and illustrated. The new species is characterized by reddish-orange to orange tepals, which is a rare type of flower coloration in Asian species of the genus. Begonia xuansonensis is most similar to B. lowiana, but differs from the latter by stipules 4–6 × 1.5–2 mm, orange tepals and ovary, and abaxially densely red setose inner tepals of staminate and pistillate flowers. The new species also shows similarity with B. cathayana, differing in stipules 4–6 mm long, uniformly dark green adaxial side of leaf blade, abaxially densely red setose inner tepals of a staminate flower and three styles in a pistillate flower. Begonia xuansonensis is tentatively assigned to B. sect. Platycentrum on the basis of actinomorphic androecium, apically rounded anthers and fruit with three unequal wings. Morphological description and detailed photographs of the new species are provided, accompanied by information on its ecology, provisional conservation status, and a taxonomic comparison with similar species.
References
<p>Averyanov, L.V. & Nguyen, H.Q. (2012) Eleven new species of Begonia L. (Begoniaceae) from Laos and Vietnam. Turczaninowia 15 (2): 5–32.<br>Cheek, M., Lughadha, E.N., Kirk, P., Lindon, H., Carretero, J., Looney, B., Douglas, B., Haelewaters, D., Gaya, E., Llewellyn, T., Aisnworth, A.M., Gafforov, Y., Hyde, K., Crous, P., Hughes, M., Walker, B.E., Forzza, R.C., Wong, K.M. & Niskanen, T. (2020) New scientific discoveries: plants and fungi. Plants, People, Planet 2 (5): 371–388. https://doi.org/10.1002/ppp3.10148<br>Chen, W.H., Radbouchoom, S., Nguyen, H.Q., Nguyen, H.T., Nguyen, K.S. & Shui, Y.M. (2018) Seven new species of Begonia (Begoniaceae) in Northern Vietnam and Southern China. PhytoKeys 94: 65–85. https://doi.org/10.3897/phytokeys.94.23248<br>Chen, W.H., Nguyen, H.Q., Radbouchoom, S., Xi, H.H., Nguyen, H.T. & Shui, Y.M. (2020) Two new baccate species of Begonia sect. Platycentrum (Begoniaceae) from Vietnam. Phytotaxa 433 (1): 92–100. https://doi.org/10.11646/phytotaxa.443.1.8<br>de Wilde, J.J.F.E. (2011) Begoniaceae. In: Kubitzki, K. (Ed.) The Families and Genera of Vascular Plants. Vol. 10. Springer, Berlin, pp. 56–71. https://doi.org/10.11646/phytotaxa.411.1.5<br>de Candolle, A.L.P.P. (1859) Mémoire sur la famille des Bégoniacées. Annales des Sciences Naturelles; Botanique Sér 4, 11: 93–149.<br>Do, T.V., Luu, A.N.D. & Dong, W.K. (2020) Begonia tadungensis (Begonia sect. Platycentrum), a new species from southern Vietnam. Phytotaxa 449 (1): 65–74. https://doi.org/10.11646/phytotaxa.449.1.6<br>Doorenbos, J., Sosef, M.S.M. & de Wilde, J.J.F.E. (1998) The sections of Begonia including descriptions, keys, and species lists (Studies in Begoniaceae VI). Wageningen Agricultural University Papers 98 (2): 99–266.<br>Gagnepain, M.F. (1919) Nouveaux Begonia d’Asie. Quelques synonymes. Bulletin du Muséum National d’Histoire Naturelle 25: 194–201.<br>Girmansyah, D. (2009) A taxonomic study of Bali and Lombok Begonia (Begoniaceae). Reinwardtia 12: 419–434. https://doi.org/10.14203/reinwardtia.v12i5.81<br>Girmansyah, D., Susila, S. & Hughes, M. (2019) A revision of Begonia sect. Petermannia on Sumatra, Indonesia. Phytotaxa 407 (1): 79–100. https://doi.org/10.11646/phytotaxa.407.1.11<br>Hemsley, W.B. (1908) Begonia cathayana. Curtis’s Botanical Magazine 134: tab. 8202.<br>Hughes, M., Moonlight, P.W., Jara-Muñoz, A., Tebbitt, M.C., Wilson, H.P. & Pullan, M. (2021) Begonia Resource Centre. Online database. Available from: http://padme.rbge.org.uk/begonia/ (accessed 16 January 2021)<br>Hughes, M., Peng, C.-I, Liu, Y., Thomas, D.C., Phutthai, T., Rubite, P.R., Girmansyah, D., Ardi, W.H., Tanaka, N., Mui, C.Y. & Tan, J. (2018) Species portraits. In: Hughes, M. & Peng, C.-I. (Eds.) Asian Begonia: 300 Species Portraits. KBC Press, Taipei & RBGE, Edinburgh.<br>Irmscher, E. (1953) Neue Begoniaceen, von O. Beccari in Malesien gesammelt. Webbia 9 (2): 469–509. https://doi.org/10.1080/00837792.1954.10669621 <br>IUCN Standards and Petitions Subcommittee (2019) Guidelines for Using the IUCN Red List Categories and Criteria, Version 14. Prepared by the Standards and Petitions Subcommittee. [https://www.iucnredlist.org/resources/redlistguidelines]<br>Kiew, R. (2004) Begonia sizemoreae Kiew (Begoniaceae), a handsome new Begonia from Vietnam. Gardens’ Bulletin Singapore 56 (4): 95–100.<br>Kiew, R. (2005) Begonias of Peninsular Malaysia. Natural History Publications (Borneo) Sdn. Bhd., Kota Kinabalu, 308 pp.<br>Kiew, R. (2007) Notes on Vietnamese Begonia (Begoniaceae), including three new species. Adansonia 29 (2): 229–238.<br>King, G. (1902) Materials for a flora of the Malayan Peninsula. No. 13. Journal of the Asiatic Society of Bengal. Part 2. Natural History 71 (1): 46–80.<br>Klotzsch, J.F. (1854) Begoniaceen-Gattungen und Arten. Monatsberichte der Königlich preussischen Akademie der Wissenschaften zu Berlin 1854: 119–128.<br>Klotzsch, J.F. (1855) Begoniaceen-Gattungen und Arten. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin 1855: 121–255.<br>Ku, T.C., Peng, C.I & Turland, N.J. (2007) Begoniaceae. In: Wu, Z.Y. & Raven, P.H. (Eds.) Flora of China, Vol. 13. Science Press, Beijing; Missouri Botanical Garden Press, St. Louis, pp. 153–207.<br>Lin, C.W., Chung S.W. & Peng, C.I. (2014) Three new species of Begonia (sect. Petermannia, Begoniaceae) from Sarawak, Borneo. Phytotaxa 191 (1): 129–140. https://doi.org/10.11646/phytotaxa.191.1.8<br>Lin, C.W. & Peng, C.I. (2019) Five new species of Begonia (sect. Petermannia, Begoniaceae) from western Sarawak, Borneo. Taiwania 64 (2): 124–138. https://doi.org/10.6165/tai.2019.64.124<br>Lin, C.W., Hsu, T.C., Luu, H.T., Nguyen, I.L.P.T., Yang, T.Y.A. & Li, C.W. (2021) Revision of Begonia (Begoniaceae) in Bidoup-Nui Ba National Park, Southern Vietnam, including two new species. Phytotaxa 496 (1): 77–89. https://doi.org/10.11646/phytotaxa.496.1.4<br>Linneaus, C. (1753) Species plantarum, exhibentes plantas rite cognitas ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. Imprensis Laurentii Salvii, Homiae, 1056 pp. https://doi.org/10.5962/bhl.title.669<br>Low, Y.W., Joffre, A.A. & Muhammad Ariffin, A.K. (2015) Novitates Bruneienses, 2. A remarkable new species of Begonia sect. Petermannia (Begoniaceae) from Brunei Darussalam. Gardens’ Bulletin Singapore 67 (1): 61–68. https://doi.org/10.3850/s2382581215000071<br>Lý, N.S., Peng, C.I. & Hughes, M. (2018) Begonia lecongkietii (sect. Petermannia), a new species from Mount Dầu, South Central Coast Region, Vietnam. Edinburgh Journal of Botany 75 (2): 167–172. https://doi.org/10.1017/S0960428618000033<br>Moonlight, P.W., Ardi, W.H., Padilla, L.A., Chung, K.F., Fuller, D., Girmansyah, D., Hollands, R., Jara-Muñoz, A., Kiew, R., Leong, W.C., Liu, Y., Mahardika, A.S., Marasinghe, L.D.K., O’Connor, M., Peng, C.I, Pérez, Á.J., Phutthai, T., Pullan, M.R., Rajbhandary, S., Reynel, C., Rubite, R.R., Sang, J., Scherberich, D., Shui, Y.M., Tebbitt, M.C., Thomas, D.C., Wilson, H.P., Zaini, N.H. & Hughes, M. (2018) Dividing and conquering the fastest-growing genus: Towards a natural sectional classification of the mega-diverse genus Begonia (Begoniaceae). Taxon 67 (2): 267–323. https://doi.org/10.12705/672.3<br>Nguyen, H.Q. (2004) A new species of a peltate-leaved Begonia (Begoniaceae) from Vietnam. Novon 14 (1): 105–107.<br>Nguyen, H.Q. & Tebbitt, M.C. (2005) An unusual new species of Begonia (Begoniaceae) from Vietnam. Gardens’ Bulletin Singapore 57: 247–251.<br>Nguyen, H.Q. & Tebbitt, M.C. (2006) Begonia hahiepiana, a new species of Begonia section Sphenanthera (Begoniaceae) from Vietnam. Novon 16 (3): 374–377. https://doi.org/10.3417/1055-3177(2006)16[374:BHANSO]2.0.CO;2<br>Nguyen, Q.H., Peng, C.I & Ku, S.M. (2010) Begonia vietnamensis, an attractive new species with peltate leaves from Vietnam. Begonian 77: 18–21.<br>Peng, C.I, Hsieh, T.Y. & Nguyen, Q.H. (2007) Begonia kui (sect. Coelocentrum, Begoniaceae), a new species from Vietnam. Botanical Studies 48: 127–132.<br>Peng, C.I, Ku, S.M., Yang, H.A., Leong, W.C., Liu, Y., Nguyen, T.H., Yoshiko, K. & Chung, K.F. (2014) Two new species of Begonia sect. Coelocentrum, B. guixiensis and B. longa, from Sino-Vietnamese limestone karsts. Botanical Studies 55: e52. https://doi.org/10.1186/s40529-015-0089-3<br>Peng, C.I, Lin, C.W., Yang, H.A., Kono, Y. & Nguyen, H.Q. (2015a) Six new species of Begonia (Begoniaceae) from limestone areas in Northern Vietnam. Botanical Studies 56: e9. http://dx.doi.org/10.1186/s40529-015-0089-3<br>Peng, C.I, Yang, H.A., Kono, Y., Jung, M.J. & Nguyen, T.H. (2015b) Four new species of Begonia (Begoniaceae) from Vietnam: B. abbreviata, B. calciphila, B. sphenantheroides and B. tamdaoensis. Phytotaxa 222 (2): 83–99. https://doi.org/10.11646/phytotaxa.222.2.1<br>Peng, C.I, Truong, N.D., Nguyen, D.D. & Lin, C.W. (2018) Begonia austrovietnamica (sect. Alicida, Begoniaceae), a handsome new species from South Vietnam. Phytotaxa 381 (1): 95–99. https://doi.org/10.11646/phytotaxa.381.1.12<br>Pham, V.T., Trinh, N.B., Phan, K.L. & Lin, C.W. (2019) Two new species, Begonia dinhdui and B. bacmeensis (Begoniaceae), from Vietnam. Phytotaxa 427 (1): 22–30. http://dx.doi.org/10.11646/phytotaxa.427.1.3<br>Pham, V.T., Dinh, Q.D., Nguyen, V.C., Trinh, N.B., Nguyen, D.D., Nguyen, T.H. & Lin, C.W. (2021) Begonia of Vietnam: an updated checklist, including a new species and a new record. Phytotaxa 507 (2): 144–154. https://doi.org/10.11646/phytotaxa.507.2.2<br>Radbouchoom, S., Chen, W.H., Guo, S.W., Nguyen, H.Q., Nguyen, S.K., Nguyen, H.T. & Shui, Y.M. (2019) Two new peltate-leaved species of Begonia L. (Begoniaceae) from northern Vietnam. Phytotaxa 407 (1): 71–78. https://doi.org/10.11646/phytotaxa.407.1.10<br>Ridley, H.N. (1911) An account of a botanical expedition to lower Siam. Journal of the Straits Branch of the Royal Asiatic Society 59: 15–237.<br>Ridley, H.N. (1922) The flora of the Malay Peninsula, 1. Reeve and Co, London, 912 pp. https://doi.org/10.5962/bhl.title.10921<br>Sang, J., Kiew, R. & Ling, C.Y. (2016) Six new species of Begonia (Begoniaceae) from Central Sarawak, Borneo. Phytotaxa 277 (2): 171–181. https://doi.org/10.11646/phytotaxa.277.2.4<br>Shui, Y.M. (2006) A new species of Begonia section Platycentrum (Begoniaceae) from Vietnam. Novon 16 (2): 269–271. https://doi.org/10.3417/1055-3177(2006)16[269:ANSOBS]2.0.CO;2<br>Shui, Y.M. & Chen, W.H. (2017) Begonia of China. Yunnan Science & Technology Press, Kunming, 285 pp.<br>Shui, Y.M., Peng, C.I & Wu, C.Y. (2002) Synopsis of the Chinese species of Begonia (Begoniaceae), with a reappraisal of sectional delimitation. Botanical Bulletin of Academia Sinica 43: 313–327.<br>Shui, Y.M., Vu, C.T., Le, T.A., Pham, T.T.D., Nguyen, V.D., Duong, T.M.H. & Lei, L.G. (2019a) Two new cane-like species of Begonia L. (Begoniaceae) from central Vietnam. Phytotaxa 411 (1): 57–64. https://doi.org/10.11646/phytotaxa.411.1.5<br>Shui, Y.M., Chen, W.H., Peng, H., Huang, S.H. & Liu, Z.W. (2019b) Taxonomy of Begonias. Yunnan Science & Technology Press, Kunming, 468 pp.<br>Truong, Q.T., Kiew, R. & Vermeulen, J.J. (2005) Begonia bataiensis Kiew, a new species in section Leprosae (Begoniaceae) from Vietnam. Gardens’ Bulletin Singapore 57: 19–23.</p>