Abstract
This study provides an updated list of Begonia occurring in Laos, and a new species is added to the checklist. The new taxon, Begonia xenos C.W.Lin, Phonep. & Rahm is similar to B. sinofloribunda Dorr in habit and leaf shape, but the new species differs in its staminate flowers having 4 tepals (vs. 2) with slightly crenulate (vs. entire) margins, pistillate flowers with 5 tepals (vs. 2 or 3) and a 2-locular (vs. 3-locular) ovary.
References
<p>Averyanov, L.V., Nuraliev, M.S., Konstantinov, E.L., Maisak, T.V., Kopylov-Guskov, Y.O., Lyskov, D.F., Quang, B.H., Kuznetsov, A.N., Kuznetsov, S.P., Nguyen, K.S. & Shui, Y.M. (2021) New and noteworthy species of <em>Begonia</em> (Begoniaceae) from Vietnam and Laos. <em>Phytotaxa</em> 522 (2): 75–93. https://doi.org/10.11646/phytotaxa.522.2.1</p>
<p>De Candolle, A. (1859) Mémoire sur la famille des Bégoniacées. <em>Annales des sciences naturelles. Botanique, Ser. 4.</em> 11: 93–149.</p>
<p>Ding, H.B., Maw, M.B., Yang, B., Bouamanivong, S. & Tan, Y.H. (2020) An updated checklist of <em>Begonia</em> (Begoniaceae) in Laos, with two new species and five new records.<em> PhytoKeys</em> 138: 187–201. https://doi.org/10.3897/phytokeys.138.46718</p>
<p>Dorr, L.J. (1999) A new name in <em>Begonia</em> (Begoniaceae) from China. <em>Harvard Papers in Botany</em> 4 (1): 265.</p>
<p>Hughes, M., Moonlight, P.W., Jara, A. &. Pullan, M. (2015) <em>Begonia</em> Resource Centre. Available from: http://padme.rbge.org.uk/begonia (accessed 25 March 2022)</p>
<p>IUCN (2019) Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Downloadable from https://www.iucnredlist.org/resources/redlistguidelines (accessed 21 March 2022)</p>
<p>Lanorsavanh, S., Souvannakhoummane, K., Lamxay, V. & Chanthavongsa, K. (2021) Two new species and a new record of <em>Begonia</em> (Begoniaceae) from Vangvieng karst limestone in central Laos. <em>Thai Forest Bulletin (Botany) </em>49 (2): 191–200. https://doi.org/10.20531/tfb.2021.49.2.06</p>
<p>Lanorsavanh, S., Hughes, M., Souvannakhoummane, K. & Lamxay, V. (2020) <em>Begonia phouchomvoyensis</em> (Begoniaceae), a new species from Laos. <em>Taiwania </em>65 (1): 37–40. https://doi.org/10.6165/tai.2020.65.37</p>
<p>Linnaeus, C. (1753) <em>Species plantarum, exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibustrivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas</em>, vol .1. Salvius, Stockholm, 1200 pp. https://doi.org/10.5962/bhl.title.59734</p>
<p>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., Marasinghe, L.D.K., O’Connor, M., Peng, C.-I, Pérez, Á.J., Phuttai, T., Pullan, M., Rajbhandary, S., Reynel, C., Rubite, R.R., Julia, S., 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 <em>Begonia</em> (Begoniaceae). <em>Taxon</em> 67: 267–323. https://doi.org/10.12705/672.3</p>
<p>Peng, C.-I, Wang, H., Kono, Y. & Yang, H.A. (2014) <em>Begonia wui-senioris</em> (sect. <em>Platycentrum</em>, Begoniaceae), a new species from Myanmar. <em>Botanical Studies </em>55:e13. https://doi.org/10.1186/1999-3110-55-13</p>
<p>Phonepaseuth, P., Souladeth, P., Lanorsavanh, S., Tagane, S., Vongthavone, T. & Souvannakhoummane, K. (2021) New distribution records of <em>Begonia</em> L., <em>B. murina</em> Craib and <em>B. poilanei</em> Kiew (Begoniaceae: Cucurbitales) for Laos. <em>Journal of Threatened Taxa </em>13 (12): 19849–19854. https://doi.org/10.11609/jott.6856.13.12.19849-19854</p>
<p>Shui, Y.M., Chen, W.H., Peng, H., Huang, S.H. & Liu, Z.W. (2019) Taxonomy of Begonias. Yunnan Science and Technology Press, Kunming. 468 pp.</p>
<p>Souvannakhoummane, K., Lanorsavanh, S., Averyanov, L.V. & Lamxay, V. (2021) Seven new species and seven new records of <em>Begonia</em> L. (Begoniaceae) in the flora of Laos. <em>Turczaninowia </em>24 (2): 99–119. https://doi.org/10.14258/turczaninowia.24.2.12</p>
<p>Souvannakhoummane, K., Lanorsavanh, S., Park, J.H., Kang, H.S., Ahn, T.H., Xayalath, S. & Phongoudom, C. (2020) <em>Begonia colliculata</em> (Begoniaceae), a new species from Nam Kading National Protected Area, Bolikhamxai province, Laos.<em> Thai Forest Bulletin (Botany)</em> 48 (2): 108–113. https://doi.org/10.20531/tfb.2020.48.2.04</p>
<p>De Candolle, A. (1859) Mémoire sur la famille des Bégoniacées. <em>Annales des sciences naturelles. Botanique, Ser. 4.</em> 11: 93–149.</p>
<p>Ding, H.B., Maw, M.B., Yang, B., Bouamanivong, S. & Tan, Y.H. (2020) An updated checklist of <em>Begonia</em> (Begoniaceae) in Laos, with two new species and five new records.<em> PhytoKeys</em> 138: 187–201. https://doi.org/10.3897/phytokeys.138.46718</p>
<p>Dorr, L.J. (1999) A new name in <em>Begonia</em> (Begoniaceae) from China. <em>Harvard Papers in Botany</em> 4 (1): 265.</p>
<p>Hughes, M., Moonlight, P.W., Jara, A. &. Pullan, M. (2015) <em>Begonia</em> Resource Centre. Available from: http://padme.rbge.org.uk/begonia (accessed 25 March 2022)</p>
<p>IUCN (2019) Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Downloadable from https://www.iucnredlist.org/resources/redlistguidelines (accessed 21 March 2022)</p>
<p>Lanorsavanh, S., Souvannakhoummane, K., Lamxay, V. & Chanthavongsa, K. (2021) Two new species and a new record of <em>Begonia</em> (Begoniaceae) from Vangvieng karst limestone in central Laos. <em>Thai Forest Bulletin (Botany) </em>49 (2): 191–200. https://doi.org/10.20531/tfb.2021.49.2.06</p>
<p>Lanorsavanh, S., Hughes, M., Souvannakhoummane, K. & Lamxay, V. (2020) <em>Begonia phouchomvoyensis</em> (Begoniaceae), a new species from Laos. <em>Taiwania </em>65 (1): 37–40. https://doi.org/10.6165/tai.2020.65.37</p>
<p>Linnaeus, C. (1753) <em>Species plantarum, exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibustrivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas</em>, vol .1. Salvius, Stockholm, 1200 pp. https://doi.org/10.5962/bhl.title.59734</p>
<p>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., Marasinghe, L.D.K., O’Connor, M., Peng, C.-I, Pérez, Á.J., Phuttai, T., Pullan, M., Rajbhandary, S., Reynel, C., Rubite, R.R., Julia, S., 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 <em>Begonia</em> (Begoniaceae). <em>Taxon</em> 67: 267–323. https://doi.org/10.12705/672.3</p>
<p>Peng, C.-I, Wang, H., Kono, Y. & Yang, H.A. (2014) <em>Begonia wui-senioris</em> (sect. <em>Platycentrum</em>, Begoniaceae), a new species from Myanmar. <em>Botanical Studies </em>55:e13. https://doi.org/10.1186/1999-3110-55-13</p>
<p>Phonepaseuth, P., Souladeth, P., Lanorsavanh, S., Tagane, S., Vongthavone, T. & Souvannakhoummane, K. (2021) New distribution records of <em>Begonia</em> L., <em>B. murina</em> Craib and <em>B. poilanei</em> Kiew (Begoniaceae: Cucurbitales) for Laos. <em>Journal of Threatened Taxa </em>13 (12): 19849–19854. https://doi.org/10.11609/jott.6856.13.12.19849-19854</p>
<p>Shui, Y.M., Chen, W.H., Peng, H., Huang, S.H. & Liu, Z.W. (2019) Taxonomy of Begonias. Yunnan Science and Technology Press, Kunming. 468 pp.</p>
<p>Souvannakhoummane, K., Lanorsavanh, S., Averyanov, L.V. & Lamxay, V. (2021) Seven new species and seven new records of <em>Begonia</em> L. (Begoniaceae) in the flora of Laos. <em>Turczaninowia </em>24 (2): 99–119. https://doi.org/10.14258/turczaninowia.24.2.12</p>
<p>Souvannakhoummane, K., Lanorsavanh, S., Park, J.H., Kang, H.S., Ahn, T.H., Xayalath, S. & Phongoudom, C. (2020) <em>Begonia colliculata</em> (Begoniaceae), a new species from Nam Kading National Protected Area, Bolikhamxai province, Laos.<em> Thai Forest Bulletin (Botany)</em> 48 (2): 108–113. https://doi.org/10.20531/tfb.2020.48.2.04</p>