Ceratozamia chamberlainii: a Cycad of the Huasteca, Mexico

Ceratozamia chamberlainii is a cycad of the Sierra Madre Oriental in eastern Mexico, found in the karst country of the Huasteca, where southern San Luis Potosí meets Querétaro and northern Hidalgo; it grows on rocks in cloud forest and pine-oak forest, mostly between 900 and 1,200 m (about 2,950 to 3,950 ft). Described in 2017, this species of the genus Ceratozamia is recognised by its reddish-brown young leaves and by the reddish veins that its mature leaflets keep. Its populations were formerly identified as Ceratozamia fuscoviridis, and the IUCN Red List assesses it as Endangered.

Key facts about Ceratozamia chamberlainii

Accepted name: Ceratozamia chamberlainii Mart.-Domínguez, Nic.-Mor. & D.W.Stev. (2017), accepted by The World List of Cycads (version 2026.08.15) and by the World Checklist of Vascular Plants (WCVP, the database behind POWO, read via GBIF)
Former names and synonyms: no synonym; its populations were previously identified as Ceratozamia fuscoviridis
Family: Zamiaceae, order Cycadales
Common names: no English name; “chamal” and “chamalillo” in San Luis Potosí, “teocintle” in Hidalgo (Spanish names from herbarium labels)
Natural range: Mexico, karst region of the Huasteca (San Luis Potosí, Querétaro, Hidalgo), mainly between 900 and 1,200 m
IUCN status: Endangered (EN, criteria A2c; B1ab(i,ii,iii)), assessment published in 2022
CITES and other protection: CITES Appendix I (whole genus, since 1985); Annex A in the European Union
Documented hardiness: no data (see Cold hardiness)
Light and soil: in the wild, rock outcrops in cloud forest and pine-oak forest
Habit and adult size: trunk 20 to 60 cm, upright or lying on the ground; 10 to 40 leaves (sometimes only 5), 1 to 2.07 m long
In the UK, US and Australia: Montgomery Botanical Center (Florida), the Huntington and the University of California Botanical Garden at Berkeley (California); none in the UK or Australia
Toxicity: no data specific to the species; treat it as poisonous, like all cycads (see Toxicity and precautions)

How to recognise Ceratozamia chamberlainii

It is recognised by its leaves, reddish brown when they emerge, a colour that persists in the adult on the articulation and base of the leaflets, and by its oblong, leathery leaflets crossed by clearly visible reddish-brown veins. The 2022 monograph by Martínez-Domínguez and colleagues describes it as follows:

Trunk: above ground, upright or decumbent, 20 to 60 cm long and 15 to 30 cm across.
Leaves: 10 to 40 (sometimes 5), drooping, 100 to 207 cm long, reddish brown with greyish-white hairs when they emerge; petiole 30 to 69 cm, blackish brown when mature, with 9 to 30 short, stout prickles; rachis reddish brown and prickly.
Leaflets: 20 to 42 pairs, oblong, leathery, dark green; median leaflets 20 to 37 cm by 2.3 to 4 cm; veins and articulation reddish brown.
Male cones: one or two, cylindrical, upright, 20 to 31 cm by 4.5 to 6 cm, greenish brown turning greenish, with reddish-brown hairs.
Female cones: cylindrical, upright, 25.5 to 30 cm by 7.5 to 10.5 cm, greyish green turning pale greyish brown, with an acuminate tip; 49 to 180 scales.
Seeds: oval, 2.2 to 3.5 cm (sometimes 4 cm), with whitish-red to pink flesh before maturity, then light brown.

The original description (Martínez-Domínguez and colleagues, 2017) picks out as distinctive characters a petiole and rachis armed with many short prickles; leaves reddish brown at emergence, the colour remaining in the adult on the articulation, the petiole and the leaflet margins; and oblong leaflets, flat but curved downwards in the outer half of the leaf, not sickle-shaped at the base, leathery, with an asymmetric tip and reddish-brown veins. The female cone has an acuminate tip, is pale greyish brown with red hairs and has green scales. Its measurements largely overlap those of the monograph, with some differences: 5 to 40 leaves; 20 to 42 leaflets (the text does not say whether these are pairs); male cones 26 to 31 cm by 4.8 to 6 cm, greenish yellow with brown down when mature, on a reddish-brown peduncle 6 to 10.3 cm long, with microsporophylls 1.6 to 2.3 cm by 1.1 to 1.5 cm; a solitary female cone 28 to 30 cm by 9 to 10.5 cm, greyish green with reddish-brown down when it emerges, on a peduncle 4.5 to 11 cm long, carrying 72 to 190 scales; seeds 3 to 4 cm long. The trunk is described as above ground, 20 to 60 cm tall and 15 to 30 cm across, and the stipules as felted, reddish brown, 2 to 3 cm long.

Hybrids

No natural or garden hybrid has been documented.

Possible confusion

Ceratozamia chamberlainii is close, in both geography and appearance, to two species of the Sierra Madre Oriental:

Ceratozamia fuscoviridis, from central Hidalgo and Veracruz, under whose name its populations used to be filed; it differs in leaflet shape, in the colour of the young leaves and of the female cone, and in the shape of the cone scales;
Ceratozamia latifolia, from San Luis Potosí, has an unarmed petiole or one with three prickles at most, papery leaflets and yellowish to greenish articulations.

The description of Ceratozamia aurantiaca (2021) points out that the northern species of the genus, Ceratozamia chamberlainii among them, always produce brownish to reddish young leaves.

Taxonomy

Ceratozamia chamberlainii was split from Ceratozamia fuscoviridis in 2017. It is accepted by The World List of Cycads and by the WCVP, which records its publication in Phytotaxa 317, page 22.

Several populations in the karst region of the Huasteca had a disputed identity and were referred to Ceratozamia fuscoviridis. Lilí Martínez-Domínguez, Fernando Nicolalde-Morejón and Dennis Stevenson reviewed the history of that name, examined herbarium specimens and studied the populations in the field. Their analysis of qualitative and quantitative morphological variation led them to recognise two species: Ceratozamia fuscoviridis, from central Hidalgo towards Veracruz, and a new species, Ceratozamia chamberlainii, from southern San Luis Potosí to northern Hidalgo. The same authors’ 2018 taxonomic review of the Ceratozamia of the Sierra Madre Oriental, and then the 2022 monograph of the genus, kept this treatment.

For readers, this means that old plants or specimens labelled Ceratozamia fuscoviridis may belong to this species. No published genetic study yet places it within the genus: it was not among the species sampled in the phylogenomic study by Habib and colleagues (2023).

Etymology and history

The epithet honours Charles Joseph Chamberlain (1863–1943), of the University of Chicago, regarded by some as the father of the modern study of cycads, for his work on their biology and his fieldwork in Mexico (Haynes, 2022, as quoted by The World List of Cycads).

The type specimen, a female plant, was collected on 20 March 2016 at La Ceiba, in the municipality of Xilitla (San Luis Potosí), by Lilí Martínez-Domínguez, Fernando Nicolalde-Morejón and Q. Santiago-Jiménez (number 933). The holotype is kept in the CIB herbarium, with isotypes at MEXU and NY. The altitude of the collection differs between sources: 850 m in the original description, as in The World List of Cycads, but 1,044 m in the 2022 monograph. The other specimens examined for the description, the oldest dating from 1991 (E. Carranza 3119, MEXU), come from Landa de Matamoros (Querétaro), Chapulhuacán and La Misión (Hidalgo) and Xilitla (San Luis Potosí). The name was published in 2017 in volume 317 of Phytotaxa.

Common names

There is no English name. From herbarium labels, the 2022 monograph records the Spanish names “chamal” and “chamalillo” in San Luis Potosí and “teocintle” in Hidalgo. These names are shared: “chamalillo” is also given for Ceratozamia hildae, and similar names apply to other cycads of the region.

In the wild

Ceratozamia chamberlainii lives in the northern part of the karst region of the Huasteca, in the states of San Luis Potosí (Xilitla, Aquismón, Tamazunchale), Querétaro (Landa de Matamoros) and Hidalgo (Chapulhuacán, La Misión). It grows in cloud forest and pine-oak forest, on rock outcrops, mainly between 900 and 1,200 m; the specimens cited in the monograph range from 600 to 1,500 m, with one recorded at 1,948 m. The WCVP gives its range as north-eastern Mexico.

The original description mentions only pine-oak forest, where the plant grows on rock outcrops with exposed faces, between 900 and 1,200 m; cloud forest is added by the 2022 monograph. The type specimen itself, collected at 850 m according to the description, lies slightly below that range.

The monograph counts nine populations, with adults, juveniles and seedlings, some of them inside the Sierra Gorda Biosphere Reserve (Querétaro).

Conservation status and regulation

Ceratozamia chamberlainii is assessed as Endangered (EN, criteria A2c; B1ab(i,ii,iii)) on the IUCN Red List, in the assessment by J.D. Bösenberg, F. Nicolalde-Morejón and L. Martínez-Domínguez published in 2022. The category is given by The World List of Cycads and confirmed by the Red List data relayed by GBIF (checked on 30 October 2026).

Like the whole genus, it has been listed in CITES Appendix I since 1 August 1985, and in Annex A of Regulation (EC) No 338/97 in the European Union (annexes now set by Regulation (EU) 2026/1383, applicable since 29 June 2026). Species+ does not list this recent name separately, but the listing covers the whole genus, seeds included (checked on 30 October 2026). International trade is therefore limited to artificially propagated plants with the required permits.

This general information does not replace the official texts: check the regulations in force before buying or exchanging plants, ask the seller for proof of origin, and prefer plants raised from cultivated seed.

Growing Ceratozamia chamberlainii

No growing guide and no grower’s report have been published for Ceratozamia chamberlainii. Its habitat, mountain forest on rock in a region that is also home to Ceratozamia hildae and Ceratozamia latifolia, points to a plant for partial shade in free-draining, stony soil. The relative hardiness reported for those two species should not be assumed for it: no data support it.

Outdoor and in-ground cultivation

No outdoor planting has been documented. In frost-free or nearly frost-free gardens, a lightly shaded, sheltered spot in very free-draining, stony ground would match its habitat; this is inferred from the wild, not tested.

Container cultivation

No container-growing report has been published. A coarse, free-draining compost, bright shade and a frost-free winter shelter would follow its habitat; plants in collections are usually grown this way, but no result has been described for this species.

In cultivation in the UK, US and Australia

In the United States, Montgomery Botanical Center (Coral Gables, Florida) lists six accessions in its online catalogue, and declares the species to BGCI PlantSearch, as do the Huntington (San Marino, California) and the University of California Botanical Garden at Berkeley. The only other holder declared to BGCI is the Clavijero botanic garden in Xalapa, Mexico. No garden in the UK or Australia declares it (BGCI and Montgomery checked on 30 October 2026). A BGCI listing shows that a garden has declared the species at some point, not that a living plant is there today.

Propagation

No data specific to the species. Like all Ceratozamia, it has separate male and female plants and is propagated from fertilised seed. The seedlings recorded in wild populations show that it regenerates naturally.

Pests and diseases

No pest or disease has been documented for this species.

Cold hardiness

There are no data on the cold tolerance of Ceratozamia chamberlainii. Its habitat, mountain forest of the Sierra Madre Oriental at 900 to 1,200 m, is cooler than that of the lowland species, but no minimum temperature has been published for its sites.

Mediterranean and European experience

No cultivation has been reported in France or Italy, in the ground or in a pot. At the Jardin zoologique tropical in La Londe-les-Maures (Var, on the French Riviera), no observation of it has been published. A grower in Ravenna (Emilia-Romagna, Italy) mentioned on the Tropicamente forum in June 2012 a Ceratozamia labelled “fuscoviridis”, kept frost-free in winter; since that name covered both species until 2017, the report cannot be attributed to Ceratozamia chamberlainii.

United Kingdom, United States and Australia

No cold record and no commercial hardiness rating have been published. The gardens that hold it in Florida and California do not state its growing conditions; in the UK it would need a frost-free glasshouse.

Toxicity and precautions

No toxicity study concerns this species or the genus, but the risk is documented in other cycads: their seeds and leaves contain toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived, a compound harmful to the liver and nervous system. Treat the plant as poisonous to people, dogs, cats and livestock; if any part is swallowed, call a poison centre, a doctor or a vet straight away.

Traditional uses

No use has been documented; the 2022 monograph records none.

Frequently asked questions

Where does Ceratozamia chamberlainii grow?

In the karst region of the Huasteca, in eastern Mexico (San Luis Potosí, Querétaro and Hidalgo), in cloud forest and pine-oak forest, mostly between 900 and 1,200 m.

How does it differ from Ceratozamia fuscoviridis?

By its oblong, leathery leaflets with reddish-brown veins, its reddish-brown young leaves and its petioles armed with many short prickles. Ceratozamia fuscoviridis has yellowish to greenish leaflet articulations.

Who was Chamberlain?

Charles Joseph Chamberlain (1863–1943), a botanist at the University of Chicago and a pioneer in the study of cycads, who did fieldwork on Mexican cycads.

Is it endangered?

Yes. It has been assessed as Endangered by the IUCN since 2022. Nine populations are known, some of them in the Sierra Gorda Biosphere Reserve.

Is it frost-hardy?

Nobody knows. No trial or cultivation report has been published. Its region is home to species reputed to be slightly hardy, but that proves nothing for this one.

Can it be grown?

Yes, in principle, but no cultivation result has been published. Any plant offered should come from artificial propagation, with CITES documents; growing it in a pot, sheltered from frost, remains the prudent approach.

Sources

Reference sites

The World List of Cycads (version 2026.08.15), Ceratozamia chamberlainii: https://cycadlist.org/scientific_name/818 — authors, publication, type, range, IUCN status (EN, 2022), etymology. Checklist of the IUCN Cycad Specialist Group, reliable; reread on 30 October 2026.
World Checklist of Vascular Plants (WCVP, Royal Botanic Gardens, Kew), via GBIF, Ceratozamia chamberlainii: https://api.gbif.org/v1/species/207874431 — accepted name, Phytotaxa 317: 22 (2017), north-eastern Mexico. Kew data, the basis of POWO, distributed by GBIF; consulted on 30 October 2026.
GBIF, IUCN Red List data for Ceratozamia chamberlainii: https://api.gbif.org/v1/species/10140349/iucnRedListCategory — Endangered (EN). IUCN Red List data distributed by GBIF; consulted on 30 October 2026.
Species+ (UNEP-WCMC), Ceratozamia: https://speciesplus.net/species#/taxon_concepts/13147/legal — CITES Appendix I since 1 August 1985, Annex A in the European Union; the species is not listed under its own name. Official CITES and EU database; queried on 30 October 2026.
PubMed Central, monograph of Ceratozamia (PhytoKeys 208): https://pmc.ncbi.nlm.nih.gov/articles/PMC9849018/ — description, range, altitudes, common names, populations. Peer-reviewed article, open access.
PubMed Central, Martínez-Domínguez et al. (2018), Taxonomic review of Ceratozamia in the Sierra Madre Oriental: https://pmc.ncbi.nlm.nih.gov/articles/PMC6023955/ — description and habitat. Peer-reviewed article, open access.
Plazi TreatmentBank, treatment of Ceratozamia chamberlainii (Martínez-Domínguez et al. 2017, Phytotaxa 317(1), pp. 22–23): https://treatment.plazi.org/id/FF35878CEE10FFD45FB129802C89FC59 — taxonomic part of the original description (type, specimens, measurements, habitat, etymology). Faithful extraction of the primary source.
Tropicamente forum, topic “Ceratozamia mexicana”: https://www.tropicamente.it/forums/topic/ceratozamia-mexicana/page/2/ — a Ceratozamia labelled “fuscoviridis” grown in Ravenna, June 2012 (post 38965), a label that may cover either species. Italian growers’ forum, anecdotal.
BGCI PlantSearch: https://plantsearch.bgci.org/ — four gardens declaring the species (Montgomery Botanical Center, the Huntington, University of California Botanical Garden at Berkeley, Jardín Botánico Francisco Javier Clavijero). Global database of garden lists; queried on 30 October 2026.
Montgomery Botanical Center, living collection (BG-BASE catalogue): https://www.montgomerybotanical.org/research/living-collection/ — six accessions (20010170 to 20010174, 20220167). Botanic garden catalogue; consulted on 30 October 2026.

Bibliography

Martínez-Domínguez, L., Nicolalde-Morejón, F. & Stevenson, D.W. (2017). Qualitative and quantitative morphological evidence for recognition of a new species within Ceratozamia (Zamiaceae) from Mexico. Phytotaxa 317(1): 17–28. https://doi.org/10.11646/phytotaxa.317.1.2 [Original description: diagnosis, type, specimens examined, description, etymology, range and habitat (taxonomic part, via Plazi); the morphometric analyses are known from the abstract. Primary source.]
Martínez-Domínguez, L., Nicolalde-Morejón, F., Vergara-Silva, F. & Stevenson, D.W. (2018). Taxonomic review of Ceratozamia (Zamiaceae) in the Sierra Madre Oriental, Mexico. PhytoKeys 100: 91–124. https://doi.org/10.3897/phytokeys.100.23152 [Description and habitat; open access.]
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 [Description, range, altitudes, common names, populations; open access.]
Pérez-Farrera, M.A., Gutiérrez-Ortega, J.S., Haynes, J.L., Chemnick, J., Salas-Morales, S.H., Calonje, M. & Vovides, A.P. (2021). Ceratozamia aurantiaca (Zamiaceae): a new cycad species from the northern rainforests of Oaxaca, Mexico. Taxonomy 1(3): 243–255. https://doi.org/10.3390/taxonomy1030018 [Colour of the young leaves in the northern species; open access.]
Bösenberg, J.D., Nicolalde-Morejón, F. & Martínez-Domínguez, L. (2022). Ceratozamia chamberlainii. The IUCN Red List of Threatened Species 2022: e.T126333682A126334155. https://doi.org/10.2305/IUCN.UK.2022-1.RLTS.T126333682A126334155.en [Current assessment, Endangered; category given by The World List of Cycads and GBIF, reference found on Crossref.]
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.]
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.]