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Type: Correspondence
Published: 2020-11-10
Page range: 69–89
Abstract views: 19
PDF downloaded: 1

Review of “Taxonomic revision of the genus Dioon (Zamiaceae)” published in Phytotaxa 442(4): 267–290

Research Associate, Fairchild Tropical Botanic Garden, 10900 Old Cutler Road, Coral Gables, Florida, U.S.A.
Gymnosperms Dioon cycad Mexico


Dioon Lindley (1843: 59–60) is the best understood of the three cycad genera in Mesoamerica. As such, the appearance of an article published earlier this year in Phytotaxa, claiming to be a revision of the genus, was somewhat surprising. While the article provides a fairly thorough summary of previous work, there is no taxonomic revision. There are also numerous issues/errors (some quite serious) that need to be clarified and/or corrected (see separate Appendix for full list). This correspondence will critique the aforementioned article section by section, beginning with the title and stated goals.


<p class="Reference">Calonje, M., Stevenson, D.W. &amp; Osborne, R. (2020) The World List of Cycads, online edition [Internet]. 2013–2020. [<a href=""></a>]</p><p class="Reference">De Luca, P., Sabato, S. &amp; Vázquez Torres, M. (1981) <em>Dioon merolae</em> (Zamiaceae), a new species from Mexico. <em>Brittonia</em> 33 (2): 179–185.</p><p class="Reference">         <a href=""></a></p><p class="Reference">Dorsey, B.L., Gregory, T.J., Sass, C. &amp; Specht, C.D. (2018) Pleistocene diversification in an ancient lineage: a role for glacial cycles in the evolutionary history of <em>Dioon</em> Lindl. (Zamiaceae). <em>American Journal of Botany </em>105: 1512–1530.</p><p class="Reference">         <a href=""></a></p><p class="Reference">Gregory, T.J. &amp; Chemnick, J. (2004) Hypotheses on the relationship between biogeography and speciation in <em>Dioon</em> (Zamiaceae). <em>In</em>: Walters, T. &amp; Osborne, R. (Eds.) <em>Cycad Classification: Concepts and Recommendations</em>. CABI, Wallingford, UK, pp. 137–148.</p><p class="Reference">Gregory, T.J., Chemnick, J., Salas-Morales, S. &amp; Vovides, A.P. (2003) A new species in the genus <em>Dioon </em>(Zamiaceae) from north-central Oaxaca, Mexico.<strong> </strong><em>Botanical Journal of the Linnean Society</em> 141: 471–476.</p><p class="Reference">         <a href=""></a></p><p class="Reference">Gregory, T., Haynes, J. &amp; Chemnick, J. (2005) <em>Key to the species of </em>Dioon. The Cycad Society. Available from: <a href=""></a> (accessed 25 May 2020)</p><p class="Reference">Gutiérrez-Ortega, J.S., Yamamoto, T., Vovides, A.P., Peréz-Farrera, M.A., Martínez, J.F., Molina-Freaner, F., Watano, Y. &amp; Kajita, T. (2018) Aridification as a driver of biodiversity: a case study for the cycad genus <em>Dioon</em> (Zamiaceae). <em>Annals of Botany</em> 121: 47–60.</p><p class="Reference">         <a href=""></a></p><p class="Reference">Haynes, J.L. &amp; Bonta, M.A. (2007) An emended description of <em>Dioon mejiae</em> Standl. &amp; L.O. Williams (Zamiaceae). Proceedings of the 7<sup>th</sup> International Conference on Cycad Biology, Xalapa, Mexico, January 2005. <em>Memoirs of the New York Botanical Garden</em> 97: 418–443.</p><p class="Reference">Lindley, J. (1843) Ornamental flower-garden and shrubbery. <em>Edwards’s Botanical Register</em> 29: misc. 59–60.</p><p class="Reference">Moretti, A., Caputo, P., Cozzolino, S., De Luca, P., Gaudio, L., Siniscalco, G. &amp; Stevenson, D.W. (1993) A phylogenetic analysis of <em>Dioon </em>(Zamiaceae). <em>American Journal of Botany </em>80 (2): 204–214.</p><p class="Reference">         <a href=""></a></p><p class="Reference">Nicolalde-Morejón, F., Vergara-Silva, F., González-Astorga, J., Vovides, A.P. &amp; Espinosa de los Monteros, A. (2009) Reciprocal illumination of morphological characters upon a molecular hypothesis supports the proposal of a new species of cycad from Mexico. <em>Systematics &amp; Biodiversity</em> 7: 73–79.</p><p class="Reference">         <a href=""></a></p><p class="Reference">Salas-Morales, S.H., Chemnick, J. &amp; Gregory, T.J. (2016) A new cycad species in the genus <em>Dioon</em> (Zamiaceae) from the Mixteca region of Oaxaca, Mexico.<em> Cactus &amp; Succulent Journal</em> 88: 35–42.</p><p class="Reference">         <a href=""></a></p><p class="Reference">Standley, P.C. &amp; Williams, L.O. (1950) <em>Dioon mejiae</em>, a new cycad from Honduras. <em>Ceiba </em>1: 36–38.</p><p class="Reference">Walters, T. &amp; Osborne, R. (2004) <em>Cycad Classification: Concepts and Recommendations</em>. CABI, Wallingford, UK.</p><p>Yáñez, L. (2006) <em>Las Cycadas: biología y conservación en México</em>. Ed. Universidad Autónoma de Chapingo, División de Ciencias Forestales. Mexico. ISBN: 968-02-0277-1</p>