Abstract
The cycad Ceratozamia latifolia was first described by Miquel in 1847 based on plant of unknown provenance cultivated in Hortus Botanicus in Amsterdam which was obtained from Belgium, and for which no type specimen was collected or preserved. The description was based on a juvenile plant, lacked a detailed explanation of the species’ characteristics, and had no accompanying illustrations. Since then, the concept of C. latifolia long time remained as a nomen dubium, often referring to a species probably from Veracruz, Mexico. However, the neotypification of C. latifolia in 1986 linked the poor description of C. latifolia to a known population from San Luis Potosí (SLP), Mexico. This neotypification brought complications to the taxonomy of the genus: 1) Because the neotype population belonged to the then recently described species C. microstrobila, C. microstrobila fell into synonymy with C. latifolia due to nomenclatural priority. 2) Because the neotypification of the name was part of a paper focused on nomenclature, no description, circumscription, or formal synonymizations were made, leaving the correct application of the name C. latifolia unclear. This ambiguity led taxonomists and horticulturists to identify plants from different populations of SLP as C. latifolia, even though the morphological differences among populations were clear. In this study, we focus in a group of populations from the Municipality of Xilitla, SLP, that were considered to be C. latifolia since 1980s. However, when comparing the morphology between wild C. latifolia plants and the plants from Xilitla, they differ in multiple vegetative and reproductive traits. Here, we present morphological and anatomical data to demonstrate that these populations from Xilitla do not correspond to the current concept of C. latifolia or to the southern neighbors C. chamberlainii or C. fuscoviridis, but rather they belong to a new species that we describe as C. reesii sp. nov.
References
<p>Avendaño, S., Vovides, A.P. & Castillo-Campos, G. (2003) A new species of <em>Ceratozamia</em> (Zamiaceae, Cycadales) from Veracruz, Mexico. <em>Botanical Journal of the Linnean Society</em> 141: 395–398. https://doi.org/10.1046/j.1095-8339.2003.00145.x</p>
<p>Brongniart, A.T. (1846) Note sur un nouveau genre de CycadeiÌes du Mexique. <em>Annales des Science Naturelles, seiÌr 3</em> 5: 5–10.</p>
<p>Brummitt, N.A., Bachman, S.P., Griffiths-Lee, J., Lutz, M., Moat, J.F., Farjon, A., Donaldson, J.S., Hilton-Taylor, C., Meagher, T.R., Albuquerque, S., Aletrari, E., Andrews, A.K., Atchison, G., Baloch, E., Barlozzini, B., Brunazzi, A., Carretero, J., Celesti, M., Chadburn, H., Cianfoni, E., Cockel, C., Coldwell, V., Concetti, B., Contu, S., Crook, V., Dyson, P., Gardiner, L., Ghanim, N., Greene, H., Groom, A., Harker, R., Hopkins, D., Khela, S., Lakeman-Fraser, P., Lindon, H., Lockwood, H., Loftus, C., Lombrici, D., Lopez-Poveda, L., Lyon, J., Malcolm-Tompkins, P., McGregor, K., Moreno, L., Murray, L., Nazar, K., Power, E., Quiton Tuijtelaars, M., Salter, R., Segrott, R., Thacker, H., Thomas, L.J., Tingvoll, S., Watkinson, G., Wojtaszekova, K. & Nic Lughadha, E.M. (2015) Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants. <em>PLoS One</em> 10 (8): e0135152.</p>
<p>Bull, W. (1879) <em>A retail list of new beautiful & rare plants offered by William Bull</em>, vol. 154. London: printed for W. Bull.</p>
<p>Calonje, M., Stevenson, D.W. & Osborne, R. (2022) The World List of Cycads, online edition [Internet]. 2013–2021. Available from: http://www.cycadlist.org (accessed 6 June 2022)</p>
<p>Calonje, M. & Sennikov, A.N. (2017) In the process in saving plant names from oblivion: the revised nomenclature of <em>Ceratozamia fuscoviridis</em> (Zamiaceae). <em>Taxon</em> 66: 158–164. https://doi.org/10.12705/661.9</p>
<p>Chamberlain, C.J. (1932) <em>Methods in Plant Histology</em>. University of Chicago Press, Chicago, 177 pp.</p>
<p>Chemnick, J., Gregory, T., Haynes, J., Pérez-Farrera, M.A. & Whitelock, L. (2009) Key to the species of Ceratozamia. <em>Cycad Newsletter</em> 32 (4): 6–9.</p>
<p>Dehgan, B. & Dehgan, N.B. (1988) Comparative pollen morphology and taxonomic affinities in Cycadales. <em>American Journal of Botany</em> 75 (10): 1501–1516. https://doi.org/10.1002/j.1537-2197.1988.tb11224.x</p>
<p>Fragnière, Y., Bétrisey, S., Cardinaux, L., Stoffel, M., Kozlowski, G. & Linder, P. (2015) Fighting their last stand? A global analysis of the distribution and conservation status of gymnosperms. <em>Journal of Biogeography</em> 42 (5): 809–820.</p>
<p>García, E. (2004) <em>Modificaciones al sistema de clasificación climática de Köppen</em>. CONABIO, Mexico City, 96 pp.</p>
<p>Gutiérrez-Ortega, J.S., Yamamoto, T., Vovides, A.P., Pérez-Farrera, M.A., Martínez, J.F., Molina-Freaner, F., Watano, Y. & Kajita, T. (2018a) 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. https://doi.org/10.1093/aob/mcx123</p>
<p>Gutiérrez-Ortega, J.S., Jiménez-Cedillo, K., Pérez-Farrera, M.A., Vovides, A.P., Martínez, J.F., Molina-Freaner, F., Imai, R., Tsuda, Y., Matsuki, Y., Suyama, Y., Watano, Y. & Kajita, T. (2018b) Considering evolutionary processes in cycad conservation: identification of evolutionarily significant units within <em>Dioon sonorense</em> (Zamiaceae) in northwestern Mexico. <em>Conservation Genetics</em> 19 (5): 1069–1081. https://doi.org/10.1007/s10592-018-1079-2</p>
<p>Gutiérrez-Ortega, J.S., Jiménez-Cedillo, K., Pérez-Farrera, M.A., Martínez, J.F., Molina-Freaner, F., Watano, Y. & Kajita, T. (2018c) Species definition of <em>Dioon sonorense</em> (Zamiaceae, Cycadales), and description of <em>D. vovidesii</em>, a new cycad species from northwestern Mexico. <em>Phytotaxa</em> 369 (2): 107–114. https://doi.org/10.11646/phytotaxa.369.2.4</p>
<p>Gutiérrez-Ortega, J.S., Salinas-Rodríguez, M.M., Ito, T., Pérez-Farrera, M.A., Vovides, A.P., Martínez, J.F., Molina-Freaner, F., Hernández-López, A., Kawaguchi, L., Nagano, A.J., Kajita, T., Watano, Y., Tsuchimatsu, T., Takahashi, Y. & Murakami, M. (2020) Niche conservatism promotes speciation in cycads: the case of <em>Dioon merolae</em> (Zamiaceae) in Mexico. <em>New Phytologist</em> 227 (6): 1872–1884. https://doi.org/10.1111/nph.16647</p>
<p>Gutiérrez-Ortega, J.S., Pérez-Farrera, M.A., Vovides, A.P., Chávez-Cortázar, A., López, S., Santos-Hernández, N.G. & Ruíz-Roblero, S. K. (2021) <em>Ceratozamia sanchezae</em> (Zamiaceae): a new cycad species from Chiapas Highlands (Mexico). <em>Phytotaxa</em> 500 (3): 201–216. https://doi.org/10.11646/phytotaxa.500.3.4</p>
<p>Hammer, Ø., Harper, D.A.T. & Ryan, P.D. (2020) <em>PAST-palaeontological statistics</em>, 4, ver. 1.89. Palaeontol. Electron, pp. 1–9.</p>
<p>Hill, K.D., Stevenson, D.W. & Osborne, R. (2004) The world list of cycads. <em>In</em>: Walters, T. & Osborne, R. (Eds.) <em>Cycad Classification: Concepts and Recommendations</em>. CABI Publishing, Cambridge, MA, pp. 219–235.</p>
<p>Hill, K.D., Stevenson, D.W. & Osborne, R. (2007) The world list of cycads. Proceedings of the 7th International Conference on Cycad Biology (CYCAD 2005), Xalapa, Mexico, January 2005. <em>Memoirs of the New York Botanical Garden</em> 97: 454–483.</p>
<p>IUCN (2010) <em>The IUCN Red List of Threatened Species</em>. October 2010 update. Cycad facts.</p>
<p>Kvaček, Z. (2014) New fossil records of <em>Ceratozamia</em> (Zamiaceae, Cycadales) from the European Oligocene and lower Miocene.<em> Acta Palaeobotanica</em> 54 (2): 231–247. https://doi.org/10.2478/acpa-2014-0012</p>
<p>Landry, G.P. & Wilson, M.C. (1979) A new species of <em>Ceratozamia</em> (Cycadaceae) from San Luis Potosí. <em>Brittonia</em> 31: 422–424. https://doi.org/10.2307/2806139</p>
<p>Martínez-Dominguez, L., Nicolalde-Morejón, F. & Stevenson, D.W. (2017) Qualitative and quantitative morphological evidence for recognition of a new species within <em>Ceratozamia</em> (Zamiaceae) from Mexico. <em>Phytotaxa</em> 317 (1): 17–28. https://doi.org/10.11646/phytotaxa.317.1.2</p>
<p>Martínez-Domínguez, L., Nicolalde-Morejón, F., Vergara-Silva, F. & Stevenson, D.W. (2018a) Taxonomic review of <em>Ceratozamia</em> (Zamiaceae) in the Sierra Madre Oriental, Mexico. <em>PhytoKeys</em> 100: 91–124. https://doi.org/10.3897/phytokeys.100.23152</p>
<p>Medellín-Leal, F. (1963) A new species of <em>Ceratozamia</em> from San Luis Potosí. <em>Brittonia</em> 15: 175–176. https://doi.org/10.2307/2805404</p>
<p>Medina-Villarreal, A., González-Astorga, J. & de Los Monteros, A.E. (2019) Evolution of <em>Ceratozamia</em> cycads: A proximate-ultimate approach. <em>Molecular Phylogenetics and Evolution</em> 139: 106530. https://doi.org/10.1016/j.ympev.2019.106530</p>
<p>Miquel, F.A.W. (1847a) Over eenige nieuwe of zeldame Cycadeën in den Hortus Botanicus Amsterdam. Derde gedeelte. <em>Tijdschrift voor de wisen natuurkundige wetenschappen, uitgegeven door de eerste klasse van het Kon. Ned. Instituut van Wetenschappen, Letteren en Schoone Kunsten</em> 1: 197–208.</p>
<p>Miquel, F.A.W. (1847b) Over eenige nieuwe of zeldame Cycadeën in den Hortus Botanicus Amsterdam. Eerste gedeelte. <em>Tijdschrift voor de wisen natuurkundige wetenschappen, uitgegeven door de eerste klasse van het Kon. Ned. Instituut van Wetenschappen, Letteren en Schoone Kunsten</em> 1: 33–43.</p>
<p>Miquel, F.A.W. (1861) Prodromus systematis cycadearum: in honorem festi diei XV kal. m. julii MDCCCLXI, quo Academia rheno-trajectina exacta XLV lustra celebrat. C. Van der Post Jr.</p>
<p>Miquel, F.A.W. (1868) Noveaux matériaux pour servir á la connaissance des Cycadées. Cinquiéme partie, Cycadées de L’Amérique. <em>Archives Néerlandaises des Sciences Exactes et Naturelles</em> 3 (5): 417–427.</p>
<p>Moretti, A. (1990) Karyotypic data on North and Central American Zamiaceae (Cycadales) and their phylogenetic implications. <em>American Journal of Botany</em> 77 (8): 1016–1029. https://doi.org/10.1002/j.1537-2197.1990.tb13597.x</p>
<p>Nicolalde-Morejón, F., Vergara-Silva, F., González-Astorga, J., Stevenson, D.W., Vovides, A.P. & Sosa, V. (2011) A character-based approach in the Mexican cycads supports diverse multigene combinations for DNA barcoding. <em>Cladistics</em> 27 (2): 150–164. https://doi.org/10.1111/j.1096-0031.2010.00321.x</p>
<p>Osborne, R., Stevenson, D.W. & Hill, K.D. (1999) The world list of cycads. <em>In</em>: Chen, C.J. (Ed.) <em>Proceedings of the Fourth International Conference on Cycad Biology (CYCAD 96)</em>. International Academic Publishers, Beijing, China, pp. 224–239.</p>
<p>Osborne, R., Calonje, M., Hill, K.D., Stanberg, L. & Stevenson, D.W. (2012) The world list of cycads. Proceedings of the 8th International Conference on Cycad Biology (CYCAD 2008). Panama City, Panama, January 2008. <em>Memoirs of the New York Botanical Garden</em> 106: 480–510.</p>
<p>Osborne, R. & Hendricks, J. (1985) A world list of cycads. <em>Encephalartos</em> 3: 13–17.</p>
<p>Ossenbach, C. (2007) Horti Selbyani: History of Orchids in Central America Part II: The New Republics—1821-1870. <em>Selbyana</em> 28 (2): 169–209.</p>
<p>Pérez-Farrera, M.A., Vovides, A.P., Martínez-Camilo, R., Martínez Melendez, N. & Iglesias, C. (2009) A reassessment of the <em>Ceratozamia miqueliana</em> species complex (Zamiaceae) of southeastern Mexico, with comments on species relationships. <em>Systematics and Biodiverstiy</em> 7: 433–443. https://doi.org/10.1017/S1477200009990211</p>
<p>Pérez-Farrera, M.A., Vovides, A.P., González, D., López, S., Hernández-Sandoval, L. & Martínez, M. (2017) Estimation of genetic variation in closely related cycad species in <em>Ceratozamia</em> (Zamiaceae: Cycadales) using RAPDs markers. <em>Revista de Biología Tropical</em> 65 (1): 305–319.</p>
<p>Pérez-Farrera, M.A., Gutiérrez-Ortega, J.S., Haynes, J.L., Chemnick, J., Salas-Morales, S.H., Calonje, M. & Vovides, A.P. (2021a) <em>Ceratozamia aurantiaca</em> (Zamiaceae): A New Cycad Species from the Northern Rainforests of Oaxaca, Mexico. <em>Taxonomy</em> 1: 243–255. https://doi.org/10.3390/taxonomy1030018</p>
<p>Pérez-Farrera, M.A., Gutiérrez-Ortega, J.S., Vovides, A.P., Calonje, M. & Díaz-Jiménez, P. (2021b) <em>Ceratozamia dominguezii</em> (Zamiaceae): A New Cycad Species from Southeastern Mexico. <em>Taxonomy</em> 1 (4): 345–359. https://doi.org/10.3390/taxonomy1040026</p>
<p>Pulido, M.T., Vargas-Zenteno, M., Vite, A. & Vovides, A.P. (2015) Range Extension of the Endangered Mexican Cycad <em>Ceratozamia fuscoviridis</em> Moore (Teosintle): Implications for Conservation. <em>Tropical Conservation Science</em> 8: 778–795.</p>
<p>Purvis, M.J., Collier, D.C. & Walls, D. (1966) <em>Laboratory Techniques in Botany</em>. Butterworths, London, 439 pp.</p>
<p>Regel, E. (1857) Zwei neue cycadeen, die im Botanischen Garten zu Petersburg kultivirt warden, nebst Beiträgen zur Kenntniss dieser Familie. <em>Bulletin de la Société des naturalistes de Moscou</em> 30: 163–191.</p>
<p>Regel, E.A. (1876) Cycadearum generum specierumque revisio. <em>Trudy Imperatorskago S.-Peterburgskago Botanicheskago Sada</em> 4 (4): 275–320.</p>
<p>Schuster, J. (1932) Cycadaceae. <em>Das Pflanzenreich</em> 99: 1–168.</p>
<p>Smith, G.F., Figueiredo, E. & Moore, G. (2016) Increasing nomenclatural stability by preventing the introduction of long-forgotten names that will compete with ones in use: A solution must be found, and soon. <em>Taxon</em> 65 (6): 1385–1390. https://doi.org/10.12705/656.11</p>
<p>Standley, P.C. (1920) Trees and Shrubs of Mexico. <em>Contributions from the United States National Herbarium</em> 23(1). US Government Printing Office. https://doi.org/10.5962/bhl.title.15726</p>
<p>Stevenson, D.W., Osborne, R. & Hendricks, J. (1990) A world list of cycads. Proceedings of the First International Conference on Cycad Biology (CYCAD 87). <em>Memoirs of the New York Botanical Garden</em> 57: 200–206.</p>
<p>Stevenson, D.W. & Osborne, R. (1993) The world list of cycads. <em>In</em>: Stevenson, D.W. & Norstog, K.J. (Eds.) <em>Proceedings of the Second International Conference on Cycad Biology (CYCAD 90)</em>. Palm & Cycad Societies of Australia Ltd., Milton, Queensland, Australia, pp. 354–364.</p>
<p>Stevenson, D.W., Osborne, R. & Hill, K.D. (1995) The world list of cycads. <em>In</em>: Vorster, P. (Ed.) <em>Proceedings of the Third International Conference on Cycad Biology (CYCAD 93)</em>. The Cycad Society of South Africa, Stellenbosch, South Africa, pp. 55–64.</p>
<p>Stevenson, D.W. & Sabato, S. (1986) Typification of names in <em>Ceratozamia</em> Brongn., <em>Dion</em> Lindl., and <em>Microcycas</em> A. DC. (Zamiaceae). <em>Taxon</em> 35 (3): 578–584. https://doi.org/10.2307/1221921</p>
<p>Stevenson, D.W., Sabato, S. & Vázquez Torres, M. (1986) A new species of <em>Ceratozamia</em> (Zamiaceae) from Veracruz, Mexico with comments on species relationships, habitats, and vegetative morphology in <em>Ceratozamia</em>. <em>Brittonia</em> 38: 17–26. https://doi.org/10.2307/2807413</p>
<p>Thiers, B. (2022) Index Herbariorum: A Global Directory of Public Herbaria and Associated Staff. New York Botanical Garden’s Virtual Herbarium. Available from: http://sweetgum.nybg.org/science/ih/ (accessed 22 November 2021)</p>
<p>Thiselton-Dyer, W.T. (1884) Cycadaceae. <em>Biologia Centrali-Americana Botany</em> 3: 190–195.</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. (Eds.) (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>. <em>Regnum Vegetabile</em> 159. Glashütten: Koeltz Botanical Books. https://doi.org/10.12705/Code.2018</p>
<p>Vázquez Torres, M. & Vovides, A.P. (1998) A new species of <em>Ceratozamia </em>(Zamiaceae) from Veracruz, Mexico. <em>Novon </em>8: 87–90.</p>
<p>Vovides, A.P. (1981) Lista preliminar de plantas mexicanas raras o en peligro de extinción. <em>Biótica</em> 6 (2): 219–231.</p>
<p>Vovides, A.P. & Rees, J.D. (1983) <em>Ceratozamia microstrobila </em>(Zamiaceae) a new species from San Luis Potosí, Mexico. <em>Madroño</em> 30: 39–42.</p>
<p>Vovides, A.P., Avendaño, S., Pérez-Farrera, M. & Stevenson, D.W. (2012) What is <em>Ceratozamia brevifrons</em> (Zamiaceae)? <em>Brittonia</em> 64 (1): 35–42.</p>
<p>Vovides, A.P., Rees, J.D. & Vázquez Torres, M. (1983) Zamiaceae. <em>In</em>: Gómez-Pompa, A. & Sosa, V. (Eds.) <em>Flora de Veracruz, </em>26. Xalapa, INIREB Fasc, pp. 1–31.</p>
<p>Vovides, A.P., Avendaño, S., Pérez-Farrera, M.A. & González-Astorga, J. (2008) A new species of <em>Ceratozamia</em> (Cycadales, Zamiaceae) from Veracruz, Mexico. <em>Novon: A Journal for Botanical Nomenclature</em> 18 (1): 109–114. https://doi.org/10.3417/2006063</p>
<p>Vovides, A.P., Pérez-Farrera, M.A., Gutiérrez-Ortega, J.S., Avendaño, S., Medina-Villarreal, A., González-Astorga, J. & Galicia, S. (2020) A revision of the <em>Ceratozamia miqueliana </em>(Zamiaceae) species complex based on analyses of leaflet anatomical characters, <em>Flora</em> 270: 151649. https://doi.org/10.1016/j.flora.2020.151649</p>
<p>Vovides, A.P., Pérez-Farrera, M.A., González, D. & Avendaño, S. (2004) Relationships and Phytogeography in <em>Ceratozamia</em> (Zamiaceae). <em>In</em>: Walters, T. & Osborne, R. (Eds.) <em>Cycad Classification: Concepts and Recommendations</em>. CABI Publishing, Wallingford, UK, pp. 109–125.</p>
<p>Vovides, A.P., Stevenson, D.W., Pérez-Farrera, M.A., López-Mendoza, S. & Avendaño, S. (2016) What is <em>Ceratozamia mexicana</em> (Zamiaceae)? <em>Botanical Sciences</em> 94 (2): 419–429.</p>
<p>Walters, T., Osborne, R. & Decker, D. (2004) ‘<em>We Hold these Truths...</em>’. <em>In</em>: Walters, T. & Osborne, R. (Eds.) <em>Cycad classification: concepts and recommendations</em>. CABI Publishing, Wallingford, UK, pp. 1–11.</p>
<p>Wendland, H. (1854) Descriptio speciei novae e genere<em> Ceratozamiae</em>. <em>Index palmarum, cyclanthearum, pandanearum, cycadearum, quae in hortis europaeis coluntur, synonymis gravioribus interpositis</em>. Hannoverae, 68 pp.</p>
<p>Whitelock, L.M. (2002) <em>The cycads</em>. Timber Press. Portland, OR. 532 pp.</p>
<p>Whitelock, L.M. (2004) Range and variation in the genus <em>Ceratozamia</em> (Zamiaceae). <em>The Botanical Review</em> 70 (2): 235–239. https://doi.org/10.1663/0006-8101(2004)070[0235:RAVITG]2.0.CO;2</p>
<p>Brongniart, A.T. (1846) Note sur un nouveau genre de CycadeiÌes du Mexique. <em>Annales des Science Naturelles, seiÌr 3</em> 5: 5–10.</p>
<p>Brummitt, N.A., Bachman, S.P., Griffiths-Lee, J., Lutz, M., Moat, J.F., Farjon, A., Donaldson, J.S., Hilton-Taylor, C., Meagher, T.R., Albuquerque, S., Aletrari, E., Andrews, A.K., Atchison, G., Baloch, E., Barlozzini, B., Brunazzi, A., Carretero, J., Celesti, M., Chadburn, H., Cianfoni, E., Cockel, C., Coldwell, V., Concetti, B., Contu, S., Crook, V., Dyson, P., Gardiner, L., Ghanim, N., Greene, H., Groom, A., Harker, R., Hopkins, D., Khela, S., Lakeman-Fraser, P., Lindon, H., Lockwood, H., Loftus, C., Lombrici, D., Lopez-Poveda, L., Lyon, J., Malcolm-Tompkins, P., McGregor, K., Moreno, L., Murray, L., Nazar, K., Power, E., Quiton Tuijtelaars, M., Salter, R., Segrott, R., Thacker, H., Thomas, L.J., Tingvoll, S., Watkinson, G., Wojtaszekova, K. & Nic Lughadha, E.M. (2015) Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants. <em>PLoS One</em> 10 (8): e0135152.</p>
<p>Bull, W. (1879) <em>A retail list of new beautiful & rare plants offered by William Bull</em>, vol. 154. London: printed for W. Bull.</p>
<p>Calonje, M., Stevenson, D.W. & Osborne, R. (2022) The World List of Cycads, online edition [Internet]. 2013–2021. Available from: http://www.cycadlist.org (accessed 6 June 2022)</p>
<p>Calonje, M. & Sennikov, A.N. (2017) In the process in saving plant names from oblivion: the revised nomenclature of <em>Ceratozamia fuscoviridis</em> (Zamiaceae). <em>Taxon</em> 66: 158–164. https://doi.org/10.12705/661.9</p>
<p>Chamberlain, C.J. (1932) <em>Methods in Plant Histology</em>. University of Chicago Press, Chicago, 177 pp.</p>
<p>Chemnick, J., Gregory, T., Haynes, J., Pérez-Farrera, M.A. & Whitelock, L. (2009) Key to the species of Ceratozamia. <em>Cycad Newsletter</em> 32 (4): 6–9.</p>
<p>Dehgan, B. & Dehgan, N.B. (1988) Comparative pollen morphology and taxonomic affinities in Cycadales. <em>American Journal of Botany</em> 75 (10): 1501–1516. https://doi.org/10.1002/j.1537-2197.1988.tb11224.x</p>
<p>Fragnière, Y., Bétrisey, S., Cardinaux, L., Stoffel, M., Kozlowski, G. & Linder, P. (2015) Fighting their last stand? A global analysis of the distribution and conservation status of gymnosperms. <em>Journal of Biogeography</em> 42 (5): 809–820.</p>
<p>García, E. (2004) <em>Modificaciones al sistema de clasificación climática de Köppen</em>. CONABIO, Mexico City, 96 pp.</p>
<p>Gutiérrez-Ortega, J.S., Yamamoto, T., Vovides, A.P., Pérez-Farrera, M.A., Martínez, J.F., Molina-Freaner, F., Watano, Y. & Kajita, T. (2018a) 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. https://doi.org/10.1093/aob/mcx123</p>
<p>Gutiérrez-Ortega, J.S., Jiménez-Cedillo, K., Pérez-Farrera, M.A., Vovides, A.P., Martínez, J.F., Molina-Freaner, F., Imai, R., Tsuda, Y., Matsuki, Y., Suyama, Y., Watano, Y. & Kajita, T. (2018b) Considering evolutionary processes in cycad conservation: identification of evolutionarily significant units within <em>Dioon sonorense</em> (Zamiaceae) in northwestern Mexico. <em>Conservation Genetics</em> 19 (5): 1069–1081. https://doi.org/10.1007/s10592-018-1079-2</p>
<p>Gutiérrez-Ortega, J.S., Jiménez-Cedillo, K., Pérez-Farrera, M.A., Martínez, J.F., Molina-Freaner, F., Watano, Y. & Kajita, T. (2018c) Species definition of <em>Dioon sonorense</em> (Zamiaceae, Cycadales), and description of <em>D. vovidesii</em>, a new cycad species from northwestern Mexico. <em>Phytotaxa</em> 369 (2): 107–114. https://doi.org/10.11646/phytotaxa.369.2.4</p>
<p>Gutiérrez-Ortega, J.S., Salinas-Rodríguez, M.M., Ito, T., Pérez-Farrera, M.A., Vovides, A.P., Martínez, J.F., Molina-Freaner, F., Hernández-López, A., Kawaguchi, L., Nagano, A.J., Kajita, T., Watano, Y., Tsuchimatsu, T., Takahashi, Y. & Murakami, M. (2020) Niche conservatism promotes speciation in cycads: the case of <em>Dioon merolae</em> (Zamiaceae) in Mexico. <em>New Phytologist</em> 227 (6): 1872–1884. https://doi.org/10.1111/nph.16647</p>
<p>Gutiérrez-Ortega, J.S., Pérez-Farrera, M.A., Vovides, A.P., Chávez-Cortázar, A., López, S., Santos-Hernández, N.G. & Ruíz-Roblero, S. K. (2021) <em>Ceratozamia sanchezae</em> (Zamiaceae): a new cycad species from Chiapas Highlands (Mexico). <em>Phytotaxa</em> 500 (3): 201–216. https://doi.org/10.11646/phytotaxa.500.3.4</p>
<p>Hammer, Ø., Harper, D.A.T. & Ryan, P.D. (2020) <em>PAST-palaeontological statistics</em>, 4, ver. 1.89. Palaeontol. Electron, pp. 1–9.</p>
<p>Hill, K.D., Stevenson, D.W. & Osborne, R. (2004) The world list of cycads. <em>In</em>: Walters, T. & Osborne, R. (Eds.) <em>Cycad Classification: Concepts and Recommendations</em>. CABI Publishing, Cambridge, MA, pp. 219–235.</p>
<p>Hill, K.D., Stevenson, D.W. & Osborne, R. (2007) The world list of cycads. Proceedings of the 7th International Conference on Cycad Biology (CYCAD 2005), Xalapa, Mexico, January 2005. <em>Memoirs of the New York Botanical Garden</em> 97: 454–483.</p>
<p>IUCN (2010) <em>The IUCN Red List of Threatened Species</em>. October 2010 update. Cycad facts.</p>
<p>Kvaček, Z. (2014) New fossil records of <em>Ceratozamia</em> (Zamiaceae, Cycadales) from the European Oligocene and lower Miocene.<em> Acta Palaeobotanica</em> 54 (2): 231–247. https://doi.org/10.2478/acpa-2014-0012</p>
<p>Landry, G.P. & Wilson, M.C. (1979) A new species of <em>Ceratozamia</em> (Cycadaceae) from San Luis Potosí. <em>Brittonia</em> 31: 422–424. https://doi.org/10.2307/2806139</p>
<p>Martínez-Dominguez, L., Nicolalde-Morejón, F. & Stevenson, D.W. (2017) Qualitative and quantitative morphological evidence for recognition of a new species within <em>Ceratozamia</em> (Zamiaceae) from Mexico. <em>Phytotaxa</em> 317 (1): 17–28. https://doi.org/10.11646/phytotaxa.317.1.2</p>
<p>Martínez-Domínguez, L., Nicolalde-Morejón, F., Vergara-Silva, F. & Stevenson, D.W. (2018a) Taxonomic review of <em>Ceratozamia</em> (Zamiaceae) in the Sierra Madre Oriental, Mexico. <em>PhytoKeys</em> 100: 91–124. https://doi.org/10.3897/phytokeys.100.23152</p>
<p>Medellín-Leal, F. (1963) A new species of <em>Ceratozamia</em> from San Luis Potosí. <em>Brittonia</em> 15: 175–176. https://doi.org/10.2307/2805404</p>
<p>Medina-Villarreal, A., González-Astorga, J. & de Los Monteros, A.E. (2019) Evolution of <em>Ceratozamia</em> cycads: A proximate-ultimate approach. <em>Molecular Phylogenetics and Evolution</em> 139: 106530. https://doi.org/10.1016/j.ympev.2019.106530</p>
<p>Miquel, F.A.W. (1847a) Over eenige nieuwe of zeldame Cycadeën in den Hortus Botanicus Amsterdam. Derde gedeelte. <em>Tijdschrift voor de wisen natuurkundige wetenschappen, uitgegeven door de eerste klasse van het Kon. Ned. Instituut van Wetenschappen, Letteren en Schoone Kunsten</em> 1: 197–208.</p>
<p>Miquel, F.A.W. (1847b) Over eenige nieuwe of zeldame Cycadeën in den Hortus Botanicus Amsterdam. Eerste gedeelte. <em>Tijdschrift voor de wisen natuurkundige wetenschappen, uitgegeven door de eerste klasse van het Kon. Ned. Instituut van Wetenschappen, Letteren en Schoone Kunsten</em> 1: 33–43.</p>
<p>Miquel, F.A.W. (1861) Prodromus systematis cycadearum: in honorem festi diei XV kal. m. julii MDCCCLXI, quo Academia rheno-trajectina exacta XLV lustra celebrat. C. Van der Post Jr.</p>
<p>Miquel, F.A.W. (1868) Noveaux matériaux pour servir á la connaissance des Cycadées. Cinquiéme partie, Cycadées de L’Amérique. <em>Archives Néerlandaises des Sciences Exactes et Naturelles</em> 3 (5): 417–427.</p>
<p>Moretti, A. (1990) Karyotypic data on North and Central American Zamiaceae (Cycadales) and their phylogenetic implications. <em>American Journal of Botany</em> 77 (8): 1016–1029. https://doi.org/10.1002/j.1537-2197.1990.tb13597.x</p>
<p>Nicolalde-Morejón, F., Vergara-Silva, F., González-Astorga, J., Stevenson, D.W., Vovides, A.P. & Sosa, V. (2011) A character-based approach in the Mexican cycads supports diverse multigene combinations for DNA barcoding. <em>Cladistics</em> 27 (2): 150–164. https://doi.org/10.1111/j.1096-0031.2010.00321.x</p>
<p>Osborne, R., Stevenson, D.W. & Hill, K.D. (1999) The world list of cycads. <em>In</em>: Chen, C.J. (Ed.) <em>Proceedings of the Fourth International Conference on Cycad Biology (CYCAD 96)</em>. International Academic Publishers, Beijing, China, pp. 224–239.</p>
<p>Osborne, R., Calonje, M., Hill, K.D., Stanberg, L. & Stevenson, D.W. (2012) The world list of cycads. Proceedings of the 8th International Conference on Cycad Biology (CYCAD 2008). Panama City, Panama, January 2008. <em>Memoirs of the New York Botanical Garden</em> 106: 480–510.</p>
<p>Osborne, R. & Hendricks, J. (1985) A world list of cycads. <em>Encephalartos</em> 3: 13–17.</p>
<p>Ossenbach, C. (2007) Horti Selbyani: History of Orchids in Central America Part II: The New Republics—1821-1870. <em>Selbyana</em> 28 (2): 169–209.</p>
<p>Pérez-Farrera, M.A., Vovides, A.P., Martínez-Camilo, R., Martínez Melendez, N. & Iglesias, C. (2009) A reassessment of the <em>Ceratozamia miqueliana</em> species complex (Zamiaceae) of southeastern Mexico, with comments on species relationships. <em>Systematics and Biodiverstiy</em> 7: 433–443. https://doi.org/10.1017/S1477200009990211</p>
<p>Pérez-Farrera, M.A., Vovides, A.P., González, D., López, S., Hernández-Sandoval, L. & Martínez, M. (2017) Estimation of genetic variation in closely related cycad species in <em>Ceratozamia</em> (Zamiaceae: Cycadales) using RAPDs markers. <em>Revista de Biología Tropical</em> 65 (1): 305–319.</p>
<p>Pérez-Farrera, M.A., Gutiérrez-Ortega, J.S., Haynes, J.L., Chemnick, J., Salas-Morales, S.H., Calonje, M. & Vovides, A.P. (2021a) <em>Ceratozamia aurantiaca</em> (Zamiaceae): A New Cycad Species from the Northern Rainforests of Oaxaca, Mexico. <em>Taxonomy</em> 1: 243–255. https://doi.org/10.3390/taxonomy1030018</p>
<p>Pérez-Farrera, M.A., Gutiérrez-Ortega, J.S., Vovides, A.P., Calonje, M. & Díaz-Jiménez, P. (2021b) <em>Ceratozamia dominguezii</em> (Zamiaceae): A New Cycad Species from Southeastern Mexico. <em>Taxonomy</em> 1 (4): 345–359. https://doi.org/10.3390/taxonomy1040026</p>
<p>Pulido, M.T., Vargas-Zenteno, M., Vite, A. & Vovides, A.P. (2015) Range Extension of the Endangered Mexican Cycad <em>Ceratozamia fuscoviridis</em> Moore (Teosintle): Implications for Conservation. <em>Tropical Conservation Science</em> 8: 778–795.</p>
<p>Purvis, M.J., Collier, D.C. & Walls, D. (1966) <em>Laboratory Techniques in Botany</em>. Butterworths, London, 439 pp.</p>
<p>Regel, E. (1857) Zwei neue cycadeen, die im Botanischen Garten zu Petersburg kultivirt warden, nebst Beiträgen zur Kenntniss dieser Familie. <em>Bulletin de la Société des naturalistes de Moscou</em> 30: 163–191.</p>
<p>Regel, E.A. (1876) Cycadearum generum specierumque revisio. <em>Trudy Imperatorskago S.-Peterburgskago Botanicheskago Sada</em> 4 (4): 275–320.</p>
<p>Schuster, J. (1932) Cycadaceae. <em>Das Pflanzenreich</em> 99: 1–168.</p>
<p>Smith, G.F., Figueiredo, E. & Moore, G. (2016) Increasing nomenclatural stability by preventing the introduction of long-forgotten names that will compete with ones in use: A solution must be found, and soon. <em>Taxon</em> 65 (6): 1385–1390. https://doi.org/10.12705/656.11</p>
<p>Standley, P.C. (1920) Trees and Shrubs of Mexico. <em>Contributions from the United States National Herbarium</em> 23(1). US Government Printing Office. https://doi.org/10.5962/bhl.title.15726</p>
<p>Stevenson, D.W., Osborne, R. & Hendricks, J. (1990) A world list of cycads. Proceedings of the First International Conference on Cycad Biology (CYCAD 87). <em>Memoirs of the New York Botanical Garden</em> 57: 200–206.</p>
<p>Stevenson, D.W. & Osborne, R. (1993) The world list of cycads. <em>In</em>: Stevenson, D.W. & Norstog, K.J. (Eds.) <em>Proceedings of the Second International Conference on Cycad Biology (CYCAD 90)</em>. Palm & Cycad Societies of Australia Ltd., Milton, Queensland, Australia, pp. 354–364.</p>
<p>Stevenson, D.W., Osborne, R. & Hill, K.D. (1995) The world list of cycads. <em>In</em>: Vorster, P. (Ed.) <em>Proceedings of the Third International Conference on Cycad Biology (CYCAD 93)</em>. The Cycad Society of South Africa, Stellenbosch, South Africa, pp. 55–64.</p>
<p>Stevenson, D.W. & Sabato, S. (1986) Typification of names in <em>Ceratozamia</em> Brongn., <em>Dion</em> Lindl., and <em>Microcycas</em> A. DC. (Zamiaceae). <em>Taxon</em> 35 (3): 578–584. https://doi.org/10.2307/1221921</p>
<p>Stevenson, D.W., Sabato, S. & Vázquez Torres, M. (1986) A new species of <em>Ceratozamia</em> (Zamiaceae) from Veracruz, Mexico with comments on species relationships, habitats, and vegetative morphology in <em>Ceratozamia</em>. <em>Brittonia</em> 38: 17–26. https://doi.org/10.2307/2807413</p>
<p>Thiers, B. (2022) Index Herbariorum: A Global Directory of Public Herbaria and Associated Staff. New York Botanical Garden’s Virtual Herbarium. Available from: http://sweetgum.nybg.org/science/ih/ (accessed 22 November 2021)</p>
<p>Thiselton-Dyer, W.T. (1884) Cycadaceae. <em>Biologia Centrali-Americana Botany</em> 3: 190–195.</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. (Eds.) (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>. <em>Regnum Vegetabile</em> 159. Glashütten: Koeltz Botanical Books. https://doi.org/10.12705/Code.2018</p>
<p>Vázquez Torres, M. & Vovides, A.P. (1998) A new species of <em>Ceratozamia </em>(Zamiaceae) from Veracruz, Mexico. <em>Novon </em>8: 87–90.</p>
<p>Vovides, A.P. (1981) Lista preliminar de plantas mexicanas raras o en peligro de extinción. <em>Biótica</em> 6 (2): 219–231.</p>
<p>Vovides, A.P. & Rees, J.D. (1983) <em>Ceratozamia microstrobila </em>(Zamiaceae) a new species from San Luis Potosí, Mexico. <em>Madroño</em> 30: 39–42.</p>
<p>Vovides, A.P., Avendaño, S., Pérez-Farrera, M. & Stevenson, D.W. (2012) What is <em>Ceratozamia brevifrons</em> (Zamiaceae)? <em>Brittonia</em> 64 (1): 35–42.</p>
<p>Vovides, A.P., Rees, J.D. & Vázquez Torres, M. (1983) Zamiaceae. <em>In</em>: Gómez-Pompa, A. & Sosa, V. (Eds.) <em>Flora de Veracruz, </em>26. Xalapa, INIREB Fasc, pp. 1–31.</p>
<p>Vovides, A.P., Avendaño, S., Pérez-Farrera, M.A. & González-Astorga, J. (2008) A new species of <em>Ceratozamia</em> (Cycadales, Zamiaceae) from Veracruz, Mexico. <em>Novon: A Journal for Botanical Nomenclature</em> 18 (1): 109–114. https://doi.org/10.3417/2006063</p>
<p>Vovides, A.P., Pérez-Farrera, M.A., Gutiérrez-Ortega, J.S., Avendaño, S., Medina-Villarreal, A., González-Astorga, J. & Galicia, S. (2020) A revision of the <em>Ceratozamia miqueliana </em>(Zamiaceae) species complex based on analyses of leaflet anatomical characters, <em>Flora</em> 270: 151649. https://doi.org/10.1016/j.flora.2020.151649</p>
<p>Vovides, A.P., Pérez-Farrera, M.A., González, D. & Avendaño, S. (2004) Relationships and Phytogeography in <em>Ceratozamia</em> (Zamiaceae). <em>In</em>: Walters, T. & Osborne, R. (Eds.) <em>Cycad Classification: Concepts and Recommendations</em>. CABI Publishing, Wallingford, UK, pp. 109–125.</p>
<p>Vovides, A.P., Stevenson, D.W., Pérez-Farrera, M.A., López-Mendoza, S. & Avendaño, S. (2016) What is <em>Ceratozamia mexicana</em> (Zamiaceae)? <em>Botanical Sciences</em> 94 (2): 419–429.</p>
<p>Walters, T., Osborne, R. & Decker, D. (2004) ‘<em>We Hold these Truths...</em>’. <em>In</em>: Walters, T. & Osborne, R. (Eds.) <em>Cycad classification: concepts and recommendations</em>. CABI Publishing, Wallingford, UK, pp. 1–11.</p>
<p>Wendland, H. (1854) Descriptio speciei novae e genere<em> Ceratozamiae</em>. <em>Index palmarum, cyclanthearum, pandanearum, cycadearum, quae in hortis europaeis coluntur, synonymis gravioribus interpositis</em>. Hannoverae, 68 pp.</p>
<p>Whitelock, L.M. (2002) <em>The cycads</em>. Timber Press. Portland, OR. 532 pp.</p>
<p>Whitelock, L.M. (2004) Range and variation in the genus <em>Ceratozamia</em> (Zamiaceae). <em>The Botanical Review</em> 70 (2): 235–239. https://doi.org/10.1663/0006-8101(2004)070[0235:RAVITG]2.0.CO;2</p>