Abstract
Imbralyx R. Geesink (Fabaceae: Millettieae) was long recognized as part of the genus Fordia Hemsl. However, Imbralyx has a unique characteristic combination of characters within Millettieae and it can be readily distinguished from Fordia and other genera of the tribe, including transitional inflorescences to pseudoracemes, distinctly imbricate calyx lobes in buds, spindle-shaped flowerbuds, white flowers, distinct hypanthium, monadelphous stamens, and glabrous leaflets with raised nervation on both surfaces. Recent molecular evidence also suggested that Imbralyx should be treated as a genus distinct from Fordia, because the two genera were placed respectively in two different main subclades within the core Millettieae, i.e. Canavanine group and Non-canavanie group, which is consistent with previous chemical evidence. So far the genus Imbralyx comprises nine species and two varieties from Asia, but only one epithet has been definitely associated with the generic name. Therefore, ten new combinations in Imbralyx are proposed in this paper. Additionally, lectotypes are re-designated here for the two basionyms Millettia albiflora Prain and M. unifoliata Prain.
References
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<p>Evans, S.V., Fellows, L.E. & Bell, E.A. (1985) Distribution and systematic significance of basic non-protein amino acids and amines in the Tephrosieae.<em> Biochemical Systematics and Ecology </em>13 (3): 271–302. https://doi.org/10.1016/0305-1978(85)90038-9</p>
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<p>Hu, J.M., Lavin, M., Wojciechowski, M.F. & Sanderson, M.J. (2000) Phylogenetic systematics of the tribe Millettieae (Leguminosae) based on chloroplast <em>trnK/matK</em> sequences and its implications for evolutionary patterns in Papilionoideae. <em>American Journal of Botany</em> 87: 418–430. https://doi.org/10.2307/2656638</p>
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<p>Lock, J.M. & Ford, C.S. (2004) <em>Legumes of Malesia: a check-list</em>. Royal Botanical Gardens, Kew, 253 pp.</p>
<p>LPWG (2017) A new subfamily classification of the Leguminosae based on a taxonomically comprehensive phylogeny. <em>Taxon</em> 66: 44‒77. https://doi.org/10.12705/661.3</p>
<p>Mattapha, S. (2017) <em>The Systematics of Tribe Millettieae (Leguminosae-Papilionoideae)</em>. The University of Reading. Unpublished PhD thesis. 227 pp.</p>
<p>Mattapha, S., Veesommai, A., Patthum, S. & Chantaranothai, P. (2019a) Two new records and lectotypified taxa of the genus <em>Millettia</em> (Fabaceae: Millettieae) for Thailand. <em>Thai Forest Bulletin (Botany)</em> 47 (1): 5‒10. https://doi.org/10.20531/tfb.2019.47.1.02</p>
<p>Mattapha, S., Forest, F., Hawkins, J.A., Suddee, S., Tetsana, N. & Chantaranothai, P. (2019b) Three new species, lectotypifications and synonymisations in <em>Millettia</em> (Fabaceae: Faboideae) for Thailand. <em>Thai Forest Bulletin (Botany)</em> 47: 171‒183. https://doi.org/10.20531/tfb.2019.47.2.07</p>
<p>Miquel, F.A.W. (1855) <em>Flora van Nederlandsch Indie</em>. Vol. 1. Fleischer, Leipzig. 1116 pp.</p>
<p>Oyebanji, O., Zhang, R., Chen, S.Y. & Yi, T.S. (2020) New insights into the plastome evolution of the Millettioid/Phaseoloid Clade (Papilionoideae, Leguminosae). <em>Frontiers in Plant Science</em> 11: 151. https://doi.org/10.3389/fpls.2020.00151</p>
<p>Polhill, R.M. (1971) Some observations on generic limits in Dalbergieae-Lonchocarpineae Benth. (Leguminosae). <em>Kew Bulletin </em>25 (2): 259–273. https://doi.org/10.2307/4103221</p>
<p>Qian, Y.Y. (2001) <em>Millettia pendula</em> Benth. (Papilionaceae), a new record to China. <em>Acta Phytotaxonomica Sinica </em>39 (5): 464–465.</p>
<p>Schot, A.M. (1991) Phylogenetic relations and historical biogeography of <em>Fordia</em> and <em>Imbralyx</em> (Papilionoideae: Millettieae). <em>Blumea</em> 36: 205–234.</p>
<p>Schrire, B.D. (2005) Tribe Millettieae. <em>In:</em> Lewis, G., Schrire, B., Mackinder, B. & Lock, M. (Eds.) <em>Legumes of the World</em>. Royal Botanical Gardens, Kew, pp. 367–387.</p>
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<p>Turland, N.J., Wiersema, J.H., Barrie, F.R., Greuter, W., Hawksworth, D.L., Herendeen, P.S., Knapp, S., Kusber, W.-H., Li, D.-Z., Marhold, K., May, T.W., McNeill, J., Monro, A.M., Prado, J., Price, M.J. & Smith, G.F. (2018) <em>International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017</em>. Regnum Vegetabile 159. Koeltz Botanical Books, Glashütten, 254 pp. https://doi.org/10.12705/Code.2018</p>
<p>WCVP (2021) <em>World Checklist of Vascular Plants</em>, version 2.0. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet: http://wcvp.science.kew.org (accessed 1 July 2021)</p>
<p>Wei, Z. & Pedley, L. (2010) <em>Millettia </em>Wight & Arnott. <em>In: </em>Wu, Z.Y., Raven, P.H. & Hong, D.Y. (Eds.) <em>Flora of China</em> 10. Science Press, Beijing and Missouri Botanical Garden Press, St. Louis, pp. 176–181.</p>
<p>Whitmore, T.C. (1969) Notes on the systematy of Malayan Phanerogams III. Legumionsae. <em>Gardens’ Bulletin Singapore</em> 24: 4–6.</p>
<p>Whitmore, T.C. (1971) Notes on the systematy of Malayan phanerogams: IX. Leguminosae (b). <em>Federation Museums Journal </em>13: 136–137.</p>
<p>Wight, R. & Arnott, G.A.W. (1834) <em>Prodromus Florae Peninsulae Indiae Orientalis</em> 1. Parbury, Allen & Co., London, 480 pp. https://doi.org/10.5962/bhl.title.252</p>
<p>Wojciechowski, M.F., Lavin, M. & Sanderson, M.J. (2004) A phylogeny of legumes (Leguminosae) based on analysis of the plastid <em>matK</em> gene resolves many well-supported subclades within the family. <em>American Journal of Botany</em> 91 (11): 1845–1861. http://dx.doi.org/10.3732/ajb.91.11.1846</p>
<p>Buijsen, J.R.M. (1989) Revision of the genus <em>Fordia</em> (Papilionaceae: Millettieae). <em>Blumea</em> 33: 239–261.</p>
<p>Craib, W.G. (1928) <em>Florae Siamensis Enumeratio.</em> Vol. 1 part 3. Siam Society, Bangkok, pp. 377–383.</p>
<p>Dasuki, U.A. & Schot, A.M. (1991) Taxonomy of <em>Fordia</em> Hemsley (Papilionaceae: Millettieae). <em>Blumea</em> 36: 191–204.</p>
<p>de Queiroz, L.P., Pastore, J.F.B., Cardoso, D., Snak, C., Lima, A.L.D.C., Gagnon, E., Vatanparast, M., Holland, A.E. & Egan, A.N. (2015) A multilocus phylogenetic analysis reveals the monophyly of a recircumscribed papilionoid legume tribe Diocleae with well-supported generic relationships. <em>Molecular Phylogenetics Evolution</em> 90: 1–19. http://dx.doi.org/10.1016/j.ympev.2015.04.016</p>
<p>Dunn, S.T. (1911) Some additions to the Leguminous genus <em>Fordia</em>. <em>Bulletin of Miscellaneous Information (Royal Botanic Gardens, Kew)</em> 1911: 62–64. https://doi.org/10.2307/4119552</p>
<p>Dunn, S.T. (1912) A revision of the genus <em>Millettia</em> Wight et Arn. <em>Journal of the Linnean Society of London, Botany</em> 41: 123–243. https://doi.org/10.1111/j.1095-8339.1912.tb02482.x</p>
<p>Dunn, S.T. (1914) Decades Kewenses: LXXX. <em>Bulletin of Miscellaneous Information, Royal Gardens, Kew</em> 1914 (6): 205–209. https://doi.org/10.2307/4119502</p>
<p>Evans, S.V., Fellows, L.E. & Bell, E.A. (1985) Distribution and systematic significance of basic non-protein amino acids and amines in the Tephrosieae.<em> Biochemical Systematics and Ecology </em>13 (3): 271–302. https://doi.org/10.1016/0305-1978(85)90038-9</p>
<p>Forbes, F.B. & Hemsley, W.B. (1886) An enumeration of all the plants known from China Proper, Formosa, Hainan, Corea, the Luchu Archipelago, and the island of Hongkong, together with their distribution and synonymy. Part II.<em> Journal of the Linnean Society of London, Botany</em> 23: 81–162. https://doi.org/10.1111/j.1095-8339.1886.tb00531.x</p>
<p>Gagnepain, F. (1913) Especes nouvelles de Millettia. <em>Notulae Systematicae</em> 2: 350–367.</p>
<p>Geesink, R. (1984) <em>Scala Millettiearum. A survey of the genera of the tribe Millettieae (Legum.-Pap.) with methodological considerations</em>. Leiden Botanical Series 8. E. J. Brill & Leiden University Press, Leiden, 131 pp. https://doi.org/10.2307/2806098</p>
<p>Hu, J.M., Lavin, M., Wojciechowski, M.F. & Sanderson, M.J. (2000) Phylogenetic systematics of the tribe Millettieae (Leguminosae) based on chloroplast <em>trnK/matK</em> sequences and its implications for evolutionary patterns in Papilionoideae. <em>American Journal of Botany</em> 87: 418–430. https://doi.org/10.2307/2656638</p>
<p>Hu, J.M., Lavin, M., Wojciechowski, M.F. & Sanderson, M.J. (2002) Phylogenetic analysis of nuclear ribosomal ITS/5.8S sequences in the tribe Millettieae (Fabaceae): <em>Poecilanthe-Cyclolobium</em>, the core Millettieae, and the <em>Callerya</em> group. <em>Systematic Botany</em> 27: 722–733</p>
<p>Kajita, T., Ohashi, H., Tateishi, Y., Bailey, C.D. & Doyle, J.J. (2001) rbcL and legume phylogeny, with particular reference to Phaseoleae, Millettieae and allies. <em>Systematic Botany</em> 26: 515–536.</p>
<p>King, G. (1897: 93) Material for a Flora of the Malayan Peninsula. <em>Journal of the Asiatic Society of Bengal</em> 66: 1–346.</p>
<p>Kurz, S. (1873) New Burmese Plants. Part II. <em>Journal of the Asiatic Society of Bengal. Part 2. Natural History</em> 42: 59–110.</p>
<p>Lôc, P.K. & Vidal, J.E. (2001) Legumineuses-Papilionoideae-Millettieae.<em> In: </em>Morat, P. (Ed.) <em>Flore du Cambodge, du Laos et du Vietnam 30</em>. Museum National D’histoire Naturelle, Paris, 191 pp. https://doi.org/10.1111/j.1756-1051.2001.tb01334.x</p>
<p>Lock, J.M. & Ford, C.S. (2004) <em>Legumes of Malesia: a check-list</em>. Royal Botanical Gardens, Kew, 253 pp.</p>
<p>LPWG (2017) A new subfamily classification of the Leguminosae based on a taxonomically comprehensive phylogeny. <em>Taxon</em> 66: 44‒77. https://doi.org/10.12705/661.3</p>
<p>Mattapha, S. (2017) <em>The Systematics of Tribe Millettieae (Leguminosae-Papilionoideae)</em>. The University of Reading. Unpublished PhD thesis. 227 pp.</p>
<p>Mattapha, S., Veesommai, A., Patthum, S. & Chantaranothai, P. (2019a) Two new records and lectotypified taxa of the genus <em>Millettia</em> (Fabaceae: Millettieae) for Thailand. <em>Thai Forest Bulletin (Botany)</em> 47 (1): 5‒10. https://doi.org/10.20531/tfb.2019.47.1.02</p>
<p>Mattapha, S., Forest, F., Hawkins, J.A., Suddee, S., Tetsana, N. & Chantaranothai, P. (2019b) Three new species, lectotypifications and synonymisations in <em>Millettia</em> (Fabaceae: Faboideae) for Thailand. <em>Thai Forest Bulletin (Botany)</em> 47: 171‒183. https://doi.org/10.20531/tfb.2019.47.2.07</p>
<p>Miquel, F.A.W. (1855) <em>Flora van Nederlandsch Indie</em>. Vol. 1. Fleischer, Leipzig. 1116 pp.</p>
<p>Oyebanji, O., Zhang, R., Chen, S.Y. & Yi, T.S. (2020) New insights into the plastome evolution of the Millettioid/Phaseoloid Clade (Papilionoideae, Leguminosae). <em>Frontiers in Plant Science</em> 11: 151. https://doi.org/10.3389/fpls.2020.00151</p>
<p>Polhill, R.M. (1971) Some observations on generic limits in Dalbergieae-Lonchocarpineae Benth. (Leguminosae). <em>Kew Bulletin </em>25 (2): 259–273. https://doi.org/10.2307/4103221</p>
<p>Qian, Y.Y. (2001) <em>Millettia pendula</em> Benth. (Papilionaceae), a new record to China. <em>Acta Phytotaxonomica Sinica </em>39 (5): 464–465.</p>
<p>Schot, A.M. (1991) Phylogenetic relations and historical biogeography of <em>Fordia</em> and <em>Imbralyx</em> (Papilionoideae: Millettieae). <em>Blumea</em> 36: 205–234.</p>
<p>Schrire, B.D. (2005) Tribe Millettieae. <em>In:</em> Lewis, G., Schrire, B., Mackinder, B. & Lock, M. (Eds.) <em>Legumes of the World</em>. Royal Botanical Gardens, Kew, pp. 367–387.</p>
<p>Sun, H. (2006) Trib. Tephrosieae (Benth.) Hutch. <em>In: </em>Peng, H. (Ed.) <em>Flora Yunnanica</em>. Tomus 10. Science Press, Beijing, pp. 391–434.</p>
<p>Turland, N.J., Wiersema, J.H., Barrie, F.R., Greuter, W., Hawksworth, D.L., Herendeen, P.S., Knapp, S., Kusber, W.-H., Li, D.-Z., Marhold, K., May, T.W., McNeill, J., Monro, A.M., Prado, J., Price, M.J. & Smith, G.F. (2018) <em>International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017</em>. Regnum Vegetabile 159. Koeltz Botanical Books, Glashütten, 254 pp. https://doi.org/10.12705/Code.2018</p>
<p>WCVP (2021) <em>World Checklist of Vascular Plants</em>, version 2.0. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet: http://wcvp.science.kew.org (accessed 1 July 2021)</p>
<p>Wei, Z. & Pedley, L. (2010) <em>Millettia </em>Wight & Arnott. <em>In: </em>Wu, Z.Y., Raven, P.H. & Hong, D.Y. (Eds.) <em>Flora of China</em> 10. Science Press, Beijing and Missouri Botanical Garden Press, St. Louis, pp. 176–181.</p>
<p>Whitmore, T.C. (1969) Notes on the systematy of Malayan Phanerogams III. Legumionsae. <em>Gardens’ Bulletin Singapore</em> 24: 4–6.</p>
<p>Whitmore, T.C. (1971) Notes on the systematy of Malayan phanerogams: IX. Leguminosae (b). <em>Federation Museums Journal </em>13: 136–137.</p>
<p>Wight, R. & Arnott, G.A.W. (1834) <em>Prodromus Florae Peninsulae Indiae Orientalis</em> 1. Parbury, Allen & Co., London, 480 pp. https://doi.org/10.5962/bhl.title.252</p>
<p>Wojciechowski, M.F., Lavin, M. & Sanderson, M.J. (2004) A phylogeny of legumes (Leguminosae) based on analysis of the plastid <em>matK</em> gene resolves many well-supported subclades within the family. <em>American Journal of Botany</em> 91 (11): 1845–1861. http://dx.doi.org/10.3732/ajb.91.11.1846</p>