Abstract
Colocasia spongifolia sp. nov. (Araceae) is a large herb in forest edges on mountain slopes in southern China and central Vietnam. The plant is remarkable for its distinct vegetative morphology, while floral morphology places it as a close wild relative of C. esculenta (taro), among other closely-related species. The name given here reflects a thick, rubbery, spongy leaf blade unlike the blades in other Colocasia species known to us. The blade has exceptionally large spongy mesophyll cavities that are visible to the naked eye. Vegetative reproduction appears to be limited to direct (though shy) sprouting of lateral buds to form new erect stems, without production of side-tubers or stolons. In contrast to other Colocasia species, dense spreading colonies (clumps or patches) were not seen.
References
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<p>Nguyen, V.D. (2005a) Araceae. <em>In:</em> Ban, N.T. (Ed.) <em>Checklist of Plant Species in Vietnam</em>. Agricultural Publishing House, Hanoi, pp. 871–897.</p>
<p>Nguyen, V.D. (2005b) A new species of <em>Colocasia</em> (Araceae) contributed to the flora of Vietnam. <em>VNU Journal of Science, Natural Sciences and Technology </em>21: 54–56.</p>
<p>Nguyen, V.D. (2017) <em>Ho Ray </em>- Araceae Juss<em>. Flora of Vietnam</em> 16. Publishing House for Science and Technology, Hanoi, 458 pp.</p>
<p>Nguyen, V.D., Matthews, P.J., Ahmed, I. & Nguyen, C.S. (2016) <em>Colocasia yunnanensis </em>(Araceae), a new record for the flora of Vietnam. <em>The Journal of Japanese Botany</em> 91: 223–229.</p>
<p>Orchard, A.E. (2006) Infra-specific variation in <em>Colocasia esculenta</em> (L.) Schott (Araceae). <em>Australian Systematic Botany Society Newsletter</em> 129: 2–5.</p>
<p>Schott, H. (1832) Aroidearum synopsis. <em>In:</em> Schott, H. & Endlicher, S. (Eds.) <em>Meletemata Botanica</em>. Gerold, Vienna, pp. 15–32.</p>
<p>Yin, J.-T., Li, H. & Xu, Z.-F. (2004) <em>Colocasia menglaensis</em> (Araceae). a new species from southern Yunnan, China. <em>Annales Botanici Fennici</em> 41: 223–226.</p>
<p>Zhou, S.-S., Quan, R-C., Li, R., Liu, Q. & Yin, J.-T. (2020) <em>Colocasia kachinensis</em>, a new species of Araceae from Myanmar. <em>Phytokeys</em> 138: 41–47. https://doi.org/10.3897/phytokeys.138.36769</p>
<p>Zhu, D., Eyzaguirre, P.B., Zhou, M., Sears, L. & Liu, G. (Eds.) (2000) <em>Ethnobotany and genetic diversity of Asian taro: focus on China</em>. IPGRI Office for East Asia, Beijing, 99 pp.</p>
<p>Beck, H.E., Zimmermann, N.E., McVicar, T.R., Vergopolan, N., Berg, A. & Wood, E.F. (2018) Present and future Köppen-Geiger climate classification maps at 1-km resolution. <em>Nature Scientific Data </em>5: 180214. https://doi.org/10.1038/sdata.2018.214</p>
<p>Boyce, P.C. & Croat, T.B. (2011 onwards) <em>The Überlist of Araceae, Totals for Published and Estimated Number of Species in Aroid Genera. </em>Available from: http://www.aroid.org/genera/20201008Uberlist.pdf (accessed 10 November 2021)</p>
<p>Boyce, P.C., Sookchaloem, D., Hetterscheid, W.L.A., Gusman, G., Jacobsen, N., Idei, T. & Nguyen, V.D. (2012) Araceae. <em>Flora of Thailand</em> 11: 101–321.</p>
<p>Cai, X.-Z., Long, C.-L. & Liu, K.-M. (2006) <em>Colocasia yunnanensis</em> (Araceae), a new species from Yunnan, China. <em>Annales Botanici Fennici</em> 43: 139–142.</p>
<p>Chaïr, H., Traore, R.E., Duval, M.F., Rivallan, R., Mukherjee, A., Aboagye, L.M., Van Rensburg, W.J., Andrianavalona, V., Pinheiro de Carvalho, M.A.A., Saborio, F., Sri Prana, M., Komolong, B., Lawac, F. & Lebot, V. (2016) Genetic diversification and dispersal of taro (<em>Colocasia esculenta </em>(L.) Schott). <em>PLoS One</em> 11: e0157712. https://doi.org/10.1371/journal.pone.0157712</p>
<p>Climate-Data.org (2021) <em>Hue, Vietnam & Mengla, China.</em> Available from: https://en.climate-data.org/asia (accessed 1 March 2021)</p>
<p>Gogoi, R. & Borah, S. (2013) Two new species and a new record for <em>Colocasia </em>(Araceae: Colocasieae) from Arunachal Pradesh, Northeast India. <em>Gardens’ Bulletin Singapore </em>65: 27–37.</p>
<p>Gogoi, R., Borah, S. & Sarma, J. (2019) Taxonomic identity and lectotypification of <em>Colocasia mannii </em>(Araceae), a little known species from Northeast India. <em>Nelumbo</em> 61: 131–134. https://doi.org/10.20324/nelumbo/v61/2019/146168</p>
<p>Hay, A. (1996) A new Bornean species of <em>Colocasia</em> Schott (<em>Araceae-Colocasieae</em>), with a synopsis of the genus in Malesia and Australia. <em>Sandakania</em> 7: 31–48.</p>
<p>Hayata, B. (1919) <em>Colocasia formosana</em>. <em>Icones plantarum formosanarum nec non et contributiones ad floram formosanam</em> 8: 133–134, f. 60.</p>
<p>Hooker, J.D. (1893) Aroideae. <em>The Flora of British India, Vol. VI (Part XIX).</em> L. Reeve & Co., London, pp. 490–556.</p>
<p>Li, H. & Boyce, P.C. (2010) <em>Colocasia</em>. <em>In:</em> Wu, Z.Y., Raven, P.H. & Hong, D.Y. (Eds.) <em>Flora of China. Vol. 23 (Acoraceae through Cyperaceae)</em>. Science Press & Missouri Botanical Garden Press, Beijing & St. Louis, pp. 73–75.</p>
<p>Li, H. & Long, C.-L. (1999) A new species of <em>Colocasia</em> (Araceae) from Mts. Gaoligong, China. <em>Feddes Repertorium</em> 110: 423–424. https://doi.org/10.1002/fedr.19991100513</p>
<p>Linnaeus, C. (1753) <em>Species Plantarum, Vol. 2</em>. Stockholm.</p>
<p>Long, C.L. & Li, H. (2008) <em>Colocasia gongii </em>(Araceae), a new species from Yunnan, China. <em>Feddes Repertorium </em>111: 559–560. https://doi.org/10.1002/fedr.20001110721</p>
<p>Long, C.-L. & Liu, K.-M. (2001) <em>Colocasia lihengiae</em> (Araceae: Colocasiae), a new species from Yunnan, China. <em>Botanical Bulletin of the Academica Sinica</em> 42: 313–317.</p>
<p>Matthews, P.J. (1991) A possible tropical wildtype taro:<em> Colocasia esculenta </em>var. <em>aquatilis</em>. <em>Indo-Pacific Prehistory Association Bulletin</em> 11: 69–81. https://doi.org/10.7152/bippa.v11i0.11374</p>
<p>Matthews, P.J. (2014) <em>On the Trail of Taro: An Exploration of Natural and Cultural History. </em>National Museum of Ethnology, Osaka, 429 pp.</p>
<p>Matthews, P.J. & Ghanem, M.E. (2021) Perception gaps that may explain the status of taro (<em>Colocasia esculenta</em>) as an “orphan crop”. <em>Plants, People, Planet</em> 3: 99–112. https://doi.org/10.1002/ppp3.10155</p>
<p>Matthews, P.J., Nguyen, V.D., Tandang, D., Agoo, E.M. & Madulid, D.A. (2015) Taxonomy and ethnobotany of <em>Colocasia esculenta</em> and <em>C. formosana </em>(Araceae): implications for evolution, natural range, and domestication of taro. <em>Aroideana Supplement</em>, 38E: 153–176.</p>
<p>Mayo, S.J., Bogner, J. & Boyce, P.C. (1997) <em>The Genera of Araceae</em>. Royal Botanic Gardens, Kew, 370 pp. https://doi.org/10.1007/978-3-662-03531-3_7</p>
<p>Nguyen, V.D. (2005a) Araceae. <em>In:</em> Ban, N.T. (Ed.) <em>Checklist of Plant Species in Vietnam</em>. Agricultural Publishing House, Hanoi, pp. 871–897.</p>
<p>Nguyen, V.D. (2005b) A new species of <em>Colocasia</em> (Araceae) contributed to the flora of Vietnam. <em>VNU Journal of Science, Natural Sciences and Technology </em>21: 54–56.</p>
<p>Nguyen, V.D. (2017) <em>Ho Ray </em>- Araceae Juss<em>. Flora of Vietnam</em> 16. Publishing House for Science and Technology, Hanoi, 458 pp.</p>
<p>Nguyen, V.D., Matthews, P.J., Ahmed, I. & Nguyen, C.S. (2016) <em>Colocasia yunnanensis </em>(Araceae), a new record for the flora of Vietnam. <em>The Journal of Japanese Botany</em> 91: 223–229.</p>
<p>Orchard, A.E. (2006) Infra-specific variation in <em>Colocasia esculenta</em> (L.) Schott (Araceae). <em>Australian Systematic Botany Society Newsletter</em> 129: 2–5.</p>
<p>Schott, H. (1832) Aroidearum synopsis. <em>In:</em> Schott, H. & Endlicher, S. (Eds.) <em>Meletemata Botanica</em>. Gerold, Vienna, pp. 15–32.</p>
<p>Yin, J.-T., Li, H. & Xu, Z.-F. (2004) <em>Colocasia menglaensis</em> (Araceae). a new species from southern Yunnan, China. <em>Annales Botanici Fennici</em> 41: 223–226.</p>
<p>Zhou, S.-S., Quan, R-C., Li, R., Liu, Q. & Yin, J.-T. (2020) <em>Colocasia kachinensis</em>, a new species of Araceae from Myanmar. <em>Phytokeys</em> 138: 41–47. https://doi.org/10.3897/phytokeys.138.36769</p>
<p>Zhu, D., Eyzaguirre, P.B., Zhou, M., Sears, L. & Liu, G. (Eds.) (2000) <em>Ethnobotany and genetic diversity of Asian taro: focus on China</em>. IPGRI Office for East Asia, Beijing, 99 pp.</p>