Zamia grijalvensis

Zamia grijalvensis is a cycad endemic to Chiapas, in southern Mexico, where a single population is known, in tropical dry forest on limestone slopes of the middle basin of the Río Grijalva. Described in 2012, this species of the genus Zamia resembles Zamia lacandona in its foliage but differs in its habit and, above all, in the colour and bearing of its cones. Its authors suspect it to be of hybrid origin, and its chromosome number varies. With no more than about 300 plants counted when it was described, it is rated Critically Endangered by the IUCN, and it is practically absent from cultivation.

Key facts about Zamia grijalvensis

  • Accepted name: Zamia grijalvensis Pérez-Farr., Vovides & Mart.-Camilo (2012), accepted by The World List of Cycads (version 2026.08.15) and by GBIF; POWO could not be consulted directly
  • Former names and synonyms: none
  • Family: Zamiaceae, order Cycadales
  • Common names: no name attested, in English or in any other language
  • Natural range: Mexico, Chiapas, middle basin of the Río Grijalva, between the Central Depression and the northern mountains; a single population known in 2012
  • IUCN status: Critically Endangered (CR B1ab(iii,v)), assessment by M. Pérez-Farrera and A.P. Vovides published in 2022
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union
  • Documented hardiness: no data (see Cold hardiness)
  • Light and soil: in the wild, deciduous tropical forest at 650 to 700 m, on slopes of up to 45° and limestone cliffs, with a shallow calcareous soil (rendzina); no cultivation data specific to the species
  • Habit and adult size: underground stem 24 to 42 cm long and 6.3 to 8 cm across; usually a single leaf 122.5 to 171.5 cm long, with 14 to 29 pairs of leaflets
  • In the UK, US and Australia: no record in BGCI or in the online catalogue of Montgomery Botanical Center
  • Toxicity: no analysis specific to the species; treat it as poisonous, like other Zamia (see Toxicity and precautions)

How to recognise Zamia grijalvensis

It is a Zamia with an underground stem that usually carries just one large leaf, erect and then arching, with leathery, toothed, slightly sickle-shaped leaflets. Its foliage is so like that of Zamia lacandona that a reliable identification requires the cones and the stem.

The original description (Pérez-Farrera and colleagues, 2012) gives the following measurements:

  • Stem: underground, 24 to 42 cm long and 6.3 to 8 cm in diameter, always narrowed or constricted in the middle.
  • Leaves: usually one, sometimes two depending on the condition and age of the plant, erect then arching, 122.5 to 171.5 cm long and 48 to 86 cm wide; petiole cylindrical, orange at the base, dark green to brown, covered in brown down and armed with short, stout prickles over about three quarters of its length from the base.
  • Leaflets: 14 to 29 pairs, linear to slightly sickle-shaped in the middle of the leaf, more lanceolate towards the tip, 24.5 to 43 cm long and 2.2 to 3.2 cm wide, with a slightly rolled margin, toothed in the upper half of the leaf (teeth 0.76 to 3.14 mm long); reddish brown when they emerge, dark green when mature; where they join the rachis they form a pale brown ring. Seedling leaves carry four leaflets.
  • Male cones: one or two per plant, erect, cylindrical, ochre to brown, finely downy, 11.3 to 23.7 cm long and 1 to 1.4 cm wide, on a downy stalk 7.6 to 19.1 cm long; each scale usually bears 12 pollen sacs (sometimes 8).
  • Female cone: erect, cylindrical and barrel-shaped, ending in a short point, dark reddish brown to orange-brown, 14.2 to 22.5 cm long and 5 to 6.6 cm wide, on a stalk 5.4 to 11.6 cm long; two ovules per scale.
  • Seeds: ovoid to angular, 1.65 to 1.98 cm long and 0.94 to 1.24 cm wide, with a bright orange fleshy coat (sarcotesta) when ripe.

The authors counted 2n = 19 chromosomes in one plant and 2n = 20 in another, with up to six telocentric chromosomes. These preliminary counts concern only two individuals from the type locality, grown at the Xalapa botanical garden.

Hybrids

No named hybrid involves Zamia grijalvensis, and no horticultural hybrid is documented. The species itself may be of hybrid origin: this is the hypothesis put forward in its description, based on its variable karyotype and on the cases of natural hybridisation already reported among Mesoamerican Zamia. According to the authors, one parent could be Zamia loddigesii or a species of the Zamia katzeriana complex, to which Zamia lacandona belongs. The hypothesis has not been demonstrated.

Possible confusion

With Zamia lacandona

The most likely confusion is with Zamia lacandona, which also carries a single leaf, rarely two, erect then arching. According to the original description, Zamia grijalvensis differs in:

  • its 14 to 29 pairs of leaflets, against 7 to 12;
  • its erect male cone, which hangs down in Zamia lacandona;
  • its reddish brown to orange-brown female cone, whereas that of Zamia lacandona is dark brown with paler, beige scale faces;
  • its stem constricted in the middle (conical in Zamia lacandona) and the pale brown ring where the leaflets join the rachis (dark brown);
  • its longer leaflet teeth (0.76 to 3.14 mm, against 1 to 1.25 mm).

The habitat differs too: Zamia lacandona lives in the evergreen rainforest of the Lacandon forest, Zamia grijalvensis in deciduous tropical dry forest in the Central Depression of Chiapas. The original description contradicts itself on the colour of the young leaves: the Latin diagnosis calls them reddish brown in Zamia grijalvensis and red to purple in Zamia lacandona, whereas the comparative paragraph calls them red to purple in both species.

With the other Zamia of Chiapas

The key in the original description separates the Zamia of Chiapas as follows: Zamia soconuscensis has untoothed leaflets; Zamia herrerae paper-thin leaflets; Zamia katzeriana elliptic leaflets; Zamia variegata yellow-spotted leaflets; Zamia loddigesii linear leaflets in the middle of the leaf. That leaves the two species with sickle-shaped leaflets, Zamia lacandona and Zamia grijalvensis, separated by the number of leaflet pairs and the bearing of the male cone.

Taxonomy

Zamia grijalvensis is an accepted name according to The World List of Cycads and GBIF; POWO could not be consulted directly. It was described in 2012 in the Nordic Journal of Botany (volume 30, pages 565 to 570), in a paper by Miguel Ángel Pérez-Farrera, Andrew P. Vovides, Rubén Martínez-Camilo, Nayely Martínez-Meléndez, Héctor Gómez-Domínguez and Sonia Galicia-Castellanos; the name is attributed to the first three. It has never changed and has no synonym (The World List of Cycads).

The holotype was collected in July 2010 in the Montañas del Norte of Chiapas and deposited at the Eizi Matuda herbarium (HEM) in Tuxtla Gutiérrez, with isotypes in Mexico City (MEXU), St Louis (MO) and Xalapa (XAL). The original description gives it the collection number Pérez-Farrera 2620a, but that number belongs to the type of Ceratozamia vovidesii. The monograph of the genus Ceratozamia published in 2022 treated this as a typographical error: the holotype of Zamia grijalvensis is the specimen Pérez-Farrera 3026, which matches the description (Martínez-Domínguez and colleagues, 2022), and The World List of Cycads gives the same number. The exact site was deliberately withheld in the publication, to protect the population from collectors.

The authors placed the species in the Zamia splendens group defined by Schutzman and Vovides (1998), which they call the Zamia katzeriana group, Zamia splendens then being treated as a synonym of Zamia katzeriana. This group brings together species with stiff, leathery, toothed leaflets: Zamia cremnophila, Zamia standleyi, Zamia lacandona and Zamia purpurea. The known chromosome numbers of the group are all 2n = 16, except in Zamia lacandona (2n = 16, 17, 18) and Zamia grijalvensis (2n = 19, 20).

The authors point out that Zamia show the greatest variation in chromosome number and shape among living cycads. In Zamia paucijuga and Zamia prasina, numerous telocentric chromosomes, produced by breaks at the centromere, go with high numbers, in widespread species of seasonally dry habitats; the idea that environmental stress plays a part in these breaks remains under discussion. With only two plants counted, the authors themselves considered it too early to draw conclusions.

Etymology and history

The epithet grijalvensis honours the Río Grijalva, which crosses half of Chiapas through the Central Depression and the northern mountains, and whose dams produce, according to the authors, more than half of Mexico’s hydroelectric power (Pérez-Farrera and colleagues, 2012; Haynes, 2022, as given by The World List of Cycads).

The species was found during botanical surveys and environmental impact studies for a hydroelectric project, funded by Mexico’s Federal Electricity Commission. Living plants were placed in the National Cycad Collection of the Francisco Javier Clavijero botanical garden in Xalapa and at the University of Sciences and Arts of Chiapas. After more than three years in cultivation at Xalapa without any change of form, the authors ruled out a simple effect of the environment and described the species as new.

Common names

No common name is attested for Zamia grijalvensis, in English or in Spanish: the original description, The World List of Cycads and Species+ give none.

In the wild

Zamia grijalvensis is known only from Chiapas. In 2012 the authors knew a single population, over a small area between the Central Depression and the northern mountains of the state, at 650 to 700 m above sea level.

It grows in a three-layered deciduous tropical forest. The upper layer is dominated by Pseudobombax ellipticum and Cochlospermum vitifolium; the lower layer includes Agave grijalvensis, Selenicereus grandiflorus and species of Euphorbia. The terrain has slopes of up to 45° and cliffs, on karst limestone covered by a shallow soil of the rendzina type.

According to the authors, the cones appear, as in most Zamia, at the start of the rainy season, from mid to late spring, and the female cones ripen from August to October. The pollinators are unknown; by comparison with related species they would most probably be weevils (families Curculionidae or Belidae), which remains an inference.

Conservation status and regulation

Zamia grijalvensis is rated Critically Endangered (CR) on the IUCN Red List, in the assessment by Miguel Pérez-Farrera and Andrew Vovides published in 2022, under criteria B1ab(iii,v): a very small range, with a decline in habitat quality and in the number of mature individuals. The category is confirmed by GBIF and The World List of Cycads; the Red List itself could not be consulted.

In the original description, the authors counted no more than about 300 plants, which were regenerating poorly, threatened by the conversion of their habitat to subsistence farming and grazing and by uncontrolled annual forest fires. They already recommended the category Critically Endangered pending the possible discovery of other populations. A popular-science article from the Institute of Biological Sciences of the University of Sciences and Arts of Chiapas lists it, with Ceratozamia zoquorum and Ceratozamia becerrae, among the cycads of the state whose conservation is a high priority, threatened by habitat conversion, deforestation, fire, collecting and illegal trade (Cruz Campuzano and Pérez Farrera, 2021).

Like all Zamia except Zamia restrepoi, Zamia grijalvensis falls under CITES Appendix II, where the genus has been listed since 4 February 1977. The listing carries annotation #4 (as revised at CoP20, in force since 5 March 2026): seeds, pollen, and seedlings or tissue cultures obtained in vitro and transported in sterile containers are not covered by CITES. International trade in the plants themselves requires an export permit. In the European Union the species falls under Annex B of Regulation (EC) No 338/97, whose current annexes are set by Regulation (EU) 2026/1383, applicable since 29 June 2026.

Species+ has a separate entry for the species (Appendix II, Annex B, Mexico). Databases checked on 19 October 2026 (Species+, GBIF, The World List of Cycads). This general information does not replace the official texts: check the regulations in force before buying or exchanging plants or seeds, and ask the seller for proof of origin.

Growing Zamia grijalvensis

Zamia grijalvensis is practically not grown outside conservation collections. The only documented cultivated plants are those at the Xalapa botanical garden and the University of Chiapas, brought into cultivation for the description. No growing advice specific to the species has been published.

Simon Lavaud, of the French specialist nursery Cycadales.eu, places the species among the Zamia of Mexico and northern Central America, which he rates of medium difficulty outside the tropics (Lavaud, 2023). For this group he recommends:

  • a free-draining compost, neutral or slightly calcareous;
  • winters at 5 to 10 °C (41 to 50 °F), with daytime rises towards 20 to 25 °C (68 to 77 °F), and a compost kept fairly dry but never parched;
  • summers at 15 to 20 °C (59 to 68 °F) at night and 25 to 30 °C (77 to 86 °F) by day;
  • at least four to six months of summer temperatures a year.

This is advice for a group of species, not measurements made on Zamia grijalvensis. Its natural habitat, on limestone with a marked dry season, points the same way.

Outdoor and in-ground cultivation

No outdoor planting is documented anywhere outside Mexico. The species comes from a frost-free tropical dry forest at low elevation, and nothing is known of its tolerance of cold.

Container cultivation

No container cultivation is documented outside the two Mexican institutions. Should plants of legal, artificially propagated origin become available, the advice above for the Mexican Zamia would be the starting point: a mineral, free-draining, slightly calcareous compost, warmth in summer and a drier winter under glass.

In cultivation in the UK, US and Australia

In short: no record in any of the three countries.

  • United States: no accession in the online catalogue of Montgomery Botanical Center (Coral Gables, Florida), and no American garden declares it to BGCI (both queried on 25 October 2026).
  • United Kingdom: no record in BGCI.
  • Australia: no record in BGCI.

The only garden that declares the species to BGCI is the Francisco Javier Clavijero botanical garden in Xalapa, Mexico, where the plants used for the description were grown. A BGCI declaration shows that a garden held the plant at some point, not that it is alive there today.

Propagation

Seed is the only practicable method. The species has separate male and female plants, so both sexes are needed and, in cultivation, hand pollination. No germination data specific to the species have been published.

Pests and diseases

No pest or disease specific to the species has been documented. The general risks of the genus in cultivation are scale insects and rot of the stem and roots in a compost that is too wet and cold; Lavaud (2023) notes that keeping the compost drier in winter limits such rot in Zamia from seasonally dry climates.

Cold hardiness

No data exist on the cold tolerance of Zamia grijalvensis, and no temperature threshold can be given. The species comes from a tropical dry forest at low elevation.

Mediterranean and European experience

No cultivation has been reported in France or elsewhere in Europe, and no dated frost episode concerns the species.

United Kingdom, United States and Australia

No cold record exists, since the species is not known in cultivation in these countries. In the UK it could only be grown under heated glass.

Toxicity and precautions

No toxicity study specific to Zamia grijalvensis has been published. The risk is, however, documented in the genus: pharmacological studies cited by The Gymnosperm Database found in Zamia toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived. The ASPCA lists Zamia furfuracea as toxic to dogs, cats and horses (cycasin and BMAA, a neurotoxic amino acid; vomiting, bloody diarrhoea, liver damage), the seeds being the most dangerous part. In the absence of evidence to the contrary, treat the plant as poisonous: keep seeds and leaves out of reach of children and animals, and wear gloves to clean seeds. If any part is swallowed, contact a poison centre, a doctor or a vet straight away.

Traditional uses

No traditional use is documented for this recently described and very localised species.

Frequently asked questions

Is it a palm?

No. Despite its foliage, Zamia grijalvensis is a cycad of the family Zamiaceae, a seed plant with naked seeds that reproduces by cones, with no close relationship to palms.

Where does it grow?

Only in Chiapas, in southern Mexico: a single population is known, in dry forest on limestone in the Río Grijalva basin, at about 650 to 700 m.

How can it be told from Zamia lacandona?

Mainly by the cones: in Zamia grijalvensis the male cone is erect and the female cone reddish brown to orange-brown. It also has more pairs of leaflets (14 to 29, against 7 to 12) and lives in dry forest, not rainforest.

Is it of hybrid origin?

Possibly, but this has not been demonstrated. Its authors suggested it because of its variable chromosome number (2n = 19 and 20), naming Zamia loddigesii or a species of the Zamia katzeriana group as possible parents.

Is it endangered?

Yes, seriously. The IUCN rates it Critically Endangered (2022): in 2012 only about 300 plants were known, threatened by farming, grazing and fire.

Can it be grown?

It is practically unobtainable outside conservation collections, and no specific growing advice exists. For Mexican Zamia in general, Lavaud (2023) recommends a free-draining, slightly calcareous compost, frost-free glass and long, warm summers.

Is it poisonous?

It should be assumed so. No analysis concerns it, but the Zamia studied contain serious toxins, mainly in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Pérez-Farrera, M.Á., Vovides, A.P., Martínez-Camilo, R., Martínez-Meléndez, N., Gómez-Domínguez, H. & Galicia-Castellanos, S. (2012). Zamia grijalvensis sp. nov. (Zamiaceae, Cycadales) from Chiapas, Mexico with notes on hybridization and karyology. Nordic Journal of Botany 30(5): 565–570. https://doi.org/10.1111/j.1756-1051.2012.01453.x [Protologue; full text read: description, type, etymology, habitat, numbers, comparison with Zamia lacandona, key to the Zamia of Chiapas, hybrid hypothesis, karyology.]
  • Martínez-Domínguez, L., Nicolalde-Morejón, F., Vergara-Silva, F. & Stevenson, D.W. (2022). Monograph of Ceratozamia (Zamiaceae, Cycadales): an endangered genus. PhytoKeys 208: 1–102. https://doi.org/10.3897/phytokeys.208.80382 [Correction of the holotype number of Zamia grijalvensis (3026, not 2620a); passage on Ceratozamia vovidesii read.]
  • Schutzman, B. & Vovides, A.P. (1998). A new Zamia (Zamiaceae, Cycadales) from eastern Chiapas, Mexico. Novon 8: 441–446. [Definition of the Zamia splendens group; cited by the protologue, not consulted.]
  • Pérez-Farrera, M. & Vovides, A.P. (2022). Zamia grijalvensis. The IUCN Red List of Threatened Species 2022: e.T66910233A66910238. https://doi.org/10.2305/IUCN.UK.2022-1.RLTS.T66910233A66910238.en [Critically Endangered assessment; reference checked on Crossref, Red List page not consulted.]
  • Cruz Campuzano, E.A. & Pérez Farrera, M.Á. (2021). Las cícadas: estandartes de la flora chiapaneca en peligro de extinción. Gaceta de divulgación científica del Instituto de Ciencias Biológicas de la Unicach 2(1): 7 ff. [Popular-science article; priority species and threats in Chiapas; read.]
  • Lavaud, S. (2023). Comment cultiver les Zamia en climat tempéré. Cycadales.eu. [Growing advice for groups of species; read directly.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. https://doi.org/10.11646/phytotaxa.550.1.1 [Source of the etymology given by The World List of Cycads; not consulted directly.]
  • Calonje, M., Stevenson, D.W. & Osborne, R. (2026). The World List of Cycads, version 2026.08.15. Montgomery Botanical Center, Coral Gables. https://doi.org/10.5281/zenodo.21958524 [Reference checklist; consulted directly.]