Dioon vovidesii

Dioon vovidesii is a cycad of central Sonora, in north-western Mexico, and the northernmost species of the genus Dioon: in the Sierra de Mazatán it reaches the area of the 29th parallel. It grows between 850 and 1,800 m in xerophytic scrub, oak woodland and dry tropical forest, under a more seasonal climate than that of the other Dioon. Its populations were included in Dioon sonorense until 2018, when they were described as a separate species and named after the botanist Andrew P. Vovides. A plant 0.6 to 1.5 m tall with narrow leaflets, it has not yet been assessed by the IUCN, and no growing report on it has been published.

Key facts about Dioon vovidesii

  • Accepted name: Dioon vovidesii Gut.Ortega & Pérez-Farr. (2018), according to The World List of Cycads and IPNI; also accepted by Kew’s World Checklist of Vascular Plants, the database behind POWO (June 2026 version, published on GBIF)
  • Former names and synonyms: no synonym; its populations were formerly included in Dioon sonorense and, before 1998, in Dioon tomasellii var. sonorense
  • Family: Zamiaceae, order Cycadales
  • Common names: no English name attested, and no local name specific to the species (see Common names)
  • Natural range: Mexico, central Sonora (Sierra de Mazatán, Bacanora, Soyopa, Nuri), between 850 and 1,800 m
  • IUCN status: Not Evaluated (NE)
  • CITES and other protection: CITES Appendix II through the listing of all cycads (annotation #4: seeds exempt), without a Species+ record of its own; Annex B in the European Union; not named in the Mexican standard NOM-059-SEMARNAT, which lists Dioon sonorense as “in danger of extinction” (P)
  • Documented hardiness: not documented; its habitat has colder winters than that of Dioon sonorense, but no measured value has been published (see Cold hardiness)
  • Light and soil: not documented in cultivation; in the wild, xerophytic scrub, oak woodland and tropical deciduous forest
  • Habit and adult size: plant 0.6 to 1.5 m tall; trunk 20 to 36 cm across; 13 to 39 leaves, 61 to 133 cm long
  • In the UK, US and Australia: Montgomery Botanical Center (two accessions), Fairchild Tropical Botanic Garden, Naples Botanical Garden and UC Berkeley (BGCI); no garden documented in the UK or Australia
  • Toxicity: no analysis specific to the species; toxins documented in other cycads (see Toxicity and precautions)

How to recognise Dioon vovidesii

Dioon vovidesii is recognised by its numerous leaves carrying 59 to 100 pairs of narrow leaflets, by the triangular scales of its female cones and by its ovoid seeds; in the field, an origin in central Sonora is the simplest clue. The revision of the genus published in 2020 by Hernández-Tapia, Jiménez-Ramírez and Vovides gives the following description:

  • Habit: a plant 0.6 to 1.5 m tall; trunk 19.7 to 36 cm in diameter; cataphylls triangular and woolly;
  • Leaves: 13 to 39 in the crown, 61 to 133 cm long and 11 to 30 cm wide, felted at first and later almost hairless, with brown hairs; petiole 2.5 to 11 cm long, woolly at the base;
  • Leaflets: 59 to 100 pairs, linear to lance-shaped with a drawn-out tip, spreading to drooping, not overlapping; the middle ones 7.9 to 14.7 cm long and 0.3 to 0.66 cm wide; margin entire, sometimes with one or two small teeth;
  • Male cones: globose, about 15 cm by 8 to 9 cm, on a 5 cm stalk;
  • Female cones: ovoid, 27 to 30 cm by 17 to 21 cm, stalked; megasporophylls triangular, flat to curved, 8.5 to 9 cm long;
  • Seeds: ovoid, with an orange-brown sarcotesta.

Hybrids

No hybrid of Dioon vovidesii has been reported.

Possible confusion

The most likely confusion is with Dioon sonorense, its sister species, which grows further south, in southern Sonora and northern Sinaloa. According to the 2020 revision, Dioon sonorense is smaller (up to 60 cm tall), with longer, finer leaflets, oblong, trowel-shaped megasporophylls and spherical seeds; Dioon vovidesii is taller (up to 1.5 m), with shorter, broader leaflets, triangular megasporophylls and ovoid seeds. The two species also differ in the anatomy of the leaflet epidermis and in their genetics (Gutiérrez-Ortega and co-authors, 2018a).

Dioon vovidesii can also be confused with Dioon tomasellii, further south-east, whose megasporophylls are triangular but elongated and whose leaflets are much broader and sickle-shaped. Online comparisons with Dioon angustifolium, from north-eastern Mexico, rest only on a shared dry habitat: according to the 2020 revision, that species belongs to another clade of the genus (Edule).

Taxonomy

Dioon vovidesii is accepted by The World List of Cycads, IPNI and Kew’s World Checklist of Vascular Plants (June 2026 version, published on GBIF). It was described by José Said Gutiérrez-Ortega and Miguel Ángel Pérez-Farrera in an article co-signed by Karen Jiménez-Cedillo, José F. Martínez, Francisco Molina-Freaner, Yasuyuki Watano and Tadashi Kajita, published online on 13 September 2018 in Phytotaxa (volume 369, issue 2, pages 107 to 114; name published on page 109). The type was collected on 17 August 2016 in the Sierra de Mazatán (Sonora) by Pérez-Farrera (number 3453); the holotype is held at the HEM herbarium, with duplicates at XAL and MEXU.

Its populations were first included in 1984 in Dioon tomasellii var. sonorense, then in Dioon sonorense, raised to species rank in 1998. The 2018 article showed, from the morphology of the leaves and leaflets, the anatomy of the cuticle and epidermis and population genetics, that Dioon sonorense as then understood combined two biological units: the populations of southern Sonora and northern Sinaloa, which keep the name Dioon sonorense, and the northernmost populations, described as Dioon vovidesii. A genetic study published the same year had identified these units as distinct evolutionarily significant units to be taken into account in conservation (Gutiérrez-Ortega and co-authors, 2018b).

In 2021, a study based on thousands of markers spread across the genome confirmed the separation of the two species, placed their boundary near the 28th parallel, where there is no marked geographical barrier, and dated their divergence to about 829,000 years ago (Gutiérrez-Ortega and co-authors, 2021). A second split, about 693,000 years ago, produced two lineages within Dioon vovidesii. These dates assume a generation time of 100 years. In the 2020 revision, which follows the phylogeny of Dorsey and colleagues (2018), the species belongs to the western clade, with Dioon sonorense, Dioon tomasellii and Dioon stevensonii.

Etymology and history

The epithet honours Andrew P. Vovides, of the Instituto de Ecología in Xalapa (Veracruz), for his work on the systematics, ecology and conservation of Mexican cycads (The World List of Cycads, after Haynes 2022; IPNI). Vovides himself described or co-described several Dioon, including Dioon stevensonii (2009). Aldo Moretti, of the Naples botanic garden, recalls meeting him in Xalapa during the Neapolitan expedition of 1979 and describes him as the most assiduous and prolific author of scientific papers on cycads (Moretti, published in 2022). The genus name comes from the Greek dis, “two”, and ōon, “egg”, for the two seeds borne on each scale of the female cone.

Its populations were known to botanists long before the species was described: the 2020 revision cites collections made in the Rosario area (Sonora) in 1959 and 1960, and at Mazatán in 1979 and 1980. In his account of the 1979 expedition, Moretti relates that, after studying a population in the sierra south of Álamos, the Naples team moved on to Mazatán, where they visited a site with plants then attributed to Dioon tomasellii var. sonorense; a photograph in the account shows one of these plants growing on rock with very little humus, in a very hot, dry habitat. Mazatán lies in the area now attributed to Dioon vovidesii, whose type locality is the nearby Sierra de Mazatán, while the Álamos population falls within Dioon sonorense. No information is documented on its introduction into cultivation.

Common names

No English name is attested for Dioon vovidesii, and “Vovides’ cycad” does not appear in any reference source. No Spanish name specific to the species is attested either. In 2010, the Mexican standard NOM-059-SEMARNAT-2010 gave Dioon sonorense, which then included these populations, the names palma de la virgen (Sonora, Sinaloa) and peyote (Sonora); it is not known which of them are used for the populations of central Sonora.

In the wild

Dioon vovidesii is endemic to central Sonora. The 2021 study sampled its populations at Nuri, Bacanora, El Novillo and three sites in the Sierra de Mazatán; the 2020 revision also cites specimens from Soyopa and Rosario. The Sierra de Mazatán, near the 29th parallel, holds the northernmost populations of the genus: it is an isolated mountain surrounded by the vegetation of the Sonoran Desert (Gutiérrez-Ortega and co-authors, 2021). The coordinates of the populations are not published, to discourage illegal collecting.

According to the 2020 revision, the species grows between 850 and 1,800 m in xerophytic scrub, in tropical deciduous forest and in the transition between the two. The 2021 study describes it in xerophytic scrub or oak woodland of North American affinity, whereas Dioon sonorense lives in dry forests of tropical origin. The climate of its sites is more seasonal, hotter and drier, with colder winters than that of Dioon sonorense; the two species nevertheless occupy the same ecological niche. The authors suggest that the common ancestor of the two species spread northwards through continuous tropical forest before the Sonoran Desert expanded over the last million years, isolating the populations.

Conservation status and regulation

Dioon vovidesii has not yet been assessed by the IUCN (Not Evaluated, NE, according to The World List of Cycads; no assessment is registered with Crossref). Its populations formerly fell under Dioon sonorense, whose assessment by J.D. Bösenberg, dated June 2019 and published in 2022, rates it Endangered (EN). The 2021 study reports that the Nuri population, at the southern edge of the range, has been decimated by illegal collecting and that the remaining plants are in poor condition; it alone makes up the southern lineage of the species, with a small effective population size.

The species has no record of its own in Species+, but it is covered by the listing of all cycads in CITES Appendix II, in force since 1977. Annotation #4, in the version in force since 5 March 2026, exempts seeds, pollen, in vitro cultures in sterile containers and cut flowers. In the European Union these plants are in Annex B (Regulation (EU) 2026/1383, applicable since 29 June 2026).

In Mexico, the 2010 list of the standard NOM-059-SEMARNAT-2010, which predates the description, classes Dioon sonorense “in danger of extinction” (P). The update of 14 November 2019 keeps Dioon sonorense in category P without naming Dioon vovidesii. Databases checked on 30 October 2026 (Species+, GBIF, The World List of Cycads, Crossref); check the regulations in force before any purchase or import.

Growing Dioon vovidesii

No grower’s report on Dioon vovidesii has been published, and no nursery offer is documented by a verifiable source. Plants sold as Dioon sonorense without a stated origin could belong to it, but this cannot be checked. The growing advice and cold-hardiness figures found online for this species are extrapolations from its habitat. Moretti’s observation of 1979, plants on almost bare rock in a very hot, dry setting, points to a mineral, very free-draining substrate, but says nothing about frost tolerance. For general principles, see the genus page and the page on Dioon sonorense.

Outdoor and in-ground cultivation

No outdoor planting is documented. Its habitat, with a hot, dry season, summer rain and cold winters by Mexican standards, suggests a plant for climates with dry winters and full sun, such as the south-western United States, but this has not been tested in any published trial. No observation on this species has been published by the Jardin zoologique tropical at La Londe-les-Maures, in the south of France.

Container cultivation

In cooler or wetter climates, including the United Kingdom, the cautious choice is a pot in a very free-draining mineral mix, moved into a bright, frost-free place for the winter. No growing result in a container has been reported.

In cultivation in the UK, US and Australia

  • United States: the Montgomery Botanical Center, at Coral Gables in Florida, lists two accessions in its online catalogue, both numbered in 2004, well before the species was described. Fairchild Tropical Botanic Garden (Miami), Naples Botanical Garden (Florida) and the University of California Botanical Garden at Berkeley also declare it to BGCI PlantSearch.
  • United Kingdom and Australia: no garden declares it to BGCI and no other source mentions it.

Propagation

No propagation data specific to Dioon vovidesii are documented. Sowing fresh seed is the normal method for cycads, and seeds are exempt from CITES permits.

Pests and diseases

No disease or pest is documented for Dioon vovidesii.

Cold hardiness

The cold hardiness of Dioon vovidesii is unknown. All that is known is that its sites have colder winters and wider temperature ranges than those of Dioon sonorense (Gutiérrez-Ortega and co-authors, 2021), but no minimum temperature has been published and no cultivated plant has been followed through cold weather.

Mediterranean and European experience

No growing report exists in Europe: the species is not mentioned on the French forum Fous de palmiers or on the Italian forum Tropicamente, and the Jardin zoologique tropical at La Londe-les-Maures has published no observation on it.

United Kingdom, United States and Australia

No cold reading has been published from these countries. The figures of −4 to −7 °C (25 to 19 °F) or USDA zone 9a that circulate for this species do not rest on any published observation and should not be taken as data; no USDA zone can be given.

Toxicity and precautions

No toxicity analysis has been published for Dioon vovidesii, but it should be treated as poisonous. Cycads contain toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived, a toxin affecting the liver and the nervous system. The risk is documented mainly in other cycads, for dogs that chew the seeds and for livestock. Wear gloves when handling the seeds and keep them out of reach of children and pets. If any part has been eaten, contact a poison centre, a doctor or a vet without delay.

Traditional uses

No traditional use of Dioon vovidesii is documented.

Frequently asked questions

What is the difference between Dioon vovidesii and Dioon sonorense?

Size, leaflets, cones and origin. Dioon vovidesii reaches 1.5 m (5 ft), with shorter, broader leaflets, triangular megasporophylls and ovoid seeds; Dioon sonorense barely exceeds 60 cm (2 ft), with longer, finer leaflets, trowel-shaped megasporophylls and spherical seeds. The first grows in central Sonora, the second further south.

Is it the northernmost Dioon?

Yes. The 2020 revision and the 2021 study present it as the northernmost species of the genus, with populations in the Sierra de Mazatán, near the 29th parallel.

Is Dioon vovidesii hardy?

Nobody knows. Its habitat has colder winters than that of the other Dioon of western Mexico, but no temperature has been published and no growing trial is known.

Is it the most recently described Dioon?

No. Described in 2018, it was followed by Dioon salas-moralesiae in 2021 and Dioon nuusaviorum in 2026.

Can it be bought?

Rarely, and without certainty. No nursery offer is documented by a verifiable source. A plant sold as Dioon sonorense without a stated origin could be Dioon vovidesii, but this cannot be checked; buying a live plant across borders requires CITES permits.

Is it protected?

Yes. It is covered by CITES Appendix II and by Annex B in the European Union, like all cycads not listed in Appendix I. It does not yet have an IUCN category of its own.

Is it poisonous?

Yes, as a precaution. No analysis exists for the species, but the cycads studied contain dangerous toxins, especially in the seeds. If any part is eaten, call a poison centre or a vet.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Gutiérrez-Ortega, J.S., Jiménez-Cedillo, K., Pérez-Farrera, M.A., Martínez, J.F., Molina-Freaner, F., Watano, Y. & Kajita, T. (2018a). Species definition of Dioon sonorense (Zamiaceae, Cycadales), and description of D. vovidesii, a new cycad species from northwestern Mexico. Phytotaxa 369(2): 107–114. doi:10.11646/phytotaxa.369.2.4 [Protologue; abstract.]
  • Gutiérrez-Ortega, J.S., Jiménez-Cedillo, K., Pérez-Farrera, M.A., Vovides, A.P., Martínez, J.F., Molina-Freaner, F. et al. (2018b). Considering evolutionary processes in cycad conservation: identification of evolutionarily significant units within Dioon sonorense (Zamiaceae) in northwestern Mexico. Conservation Genetics 19(5): 1069–1081. doi:10.1007/s10592-018-1079-2 [Evolutionarily significant units; reference checked on Crossref.]
  • Gutiérrez-Ortega, J.S., Molina-Freaner, F., Martínez, J.F. et al. (2021). Speciation along a latitudinal gradient: the origin of the Neotropical cycad sister pair Dioon sonorense–D. vovidesii (Zamiaceae). Ecology and Evolution 11(11): 6962–6976. doi:10.1002/ece3.7545 [Delimitation, populations, climate, divergence dates; open-access article, full text.]
  • Hernández-Tapia, J.E., Jiménez-Ramírez, J. & Vovides, A.P. (2020). Taxonomic revision of the genus Dioon (Zamiaceae). Phytotaxa 442(4): 267–290. doi:10.11646/phytotaxa.442.4.2 [Description, altitudes, habitats, specimens, clades; treatment (Plazi).]
  • Dorsey, B.L., Gregory, T.J., Sass, C. & Specht, C.D. (2018). Pleistocene diversification in an ancient lineage: a role for glacial cycles in the evolutionary history of Dioon Lindl. (Zamiaceae). American Journal of Botany 105(9): 1512–1530. doi:10.1002/ajb2.1149 [Four clades; abstract.]
  • Moretti, A. (2020 [2022]). Spedizioni scientifiche dell’Orto Botanico di Napoli – Messico 1979. Delpinoa 62: 7–48. [Visit to the Mazatán plants; in Italian.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology, as given by The World List of Cycads.]
  • Calonje, M., Stevenson, D.W. & Osborne, R. (2026). The World List of Cycads, version 2026.08.15. Montgomery Botanical Center, Coral Gables. doi:10.5281/zenodo.21958524 [Reference checklist.]