Ceratozamia kuesteriana

Ceratozamia kuesteriana is a small cycad of southern Tamaulipas, in north-eastern Mexico, where it grows on limestone rocks in pine-oak forest and cloud forest between 1,100 and 1,500 m (about 3,610 to 4,920 ft). This species of the genus Ceratozamia is recognised by its narrow, almost linear, channelled leaflets and its reddish-brown young leaves. Described as early as 1857 from a plant grown in St Petersburg, it is assessed as Critically Endangered by the IUCN. Growers rank it among the more cold-tolerant Ceratozamia, but no reliable outdoor measurement has yet been published.

Key facts about Ceratozamia kuesteriana

  • Accepted name: Ceratozamia kuesteriana Regel (1857), accepted by The World List of Cycads (version 2026.08.15), by Species+ and by the World Checklist of Vascular Plants (WCVP, the database behind POWO, read via GBIF)
  • Former names and synonyms: none according to The World List of Cycads; the WCVP places Ceratozamia angustifolia Lindl. (1881) under this name
  • Family: Zamiaceae, order Cycadales
  • Common names: none recorded, in English or in Mexico
  • Natural range: Mexico, southern Tamaulipas (municipalities of Gómez Farías, Ocampo and Tula), 1,100 to 1,500 m
  • IUCN status: Critically Endangered (CR A2cd), assessment published in 2022
  • CITES and other protection: CITES Appendix I (whole genus, since 1985); Annex A in the European Union, seeds included
  • Documented hardiness: young plants unharmed at −4 °C (24.8 °F) in a greenhouse in southern France in February 2012; no outdoor measurement published (see Cold hardiness)
  • Light and soil: in the wild, limestone rocks in forest; in cultivation, light to partial shade and a very free-draining substrate
  • Habit and adult size: trunk 10 to 30 cm, partly underground; 1 to 11 leaves, 0.8 to 1.3 m long
  • In the UK, US and Australia: declared by 4 British, 22 American and 4 Australian gardens to BGCI PlantSearch (see In cultivation)
  • Toxicity: no data specific to the species; treat it as poisonous, like all cycads (see Toxicity and precautions)

How to recognise Ceratozamia kuesteriana

Look for many narrow leaflets, less than 1 cm wide, curved upwards and channelled, on rising leaves, and for reddish-brown new growth. The 2022 monograph of the genus, by Lilí Martínez-Domínguez and colleagues, describes it as follows:

  • Trunk: short, 10 to 30 cm long and 10 to 25 cm in diameter, half underground, upright; persistent, triangular, reddish-brown cataphylls, woolly when they emerge and partly remaining so.
  • Leaves: 1 to 11, rising, 80 to 133 cm long; reddish brown with greyish-white hairs when they emerge, then hairless. The greenish-brown petiole, 30 to 72 cm long, bears 1 to 10 tiny prickles; the axis is sometimes unarmed.
  • Leaflets: 22 to 50 pairs, linear, curved upwards, sickle-shaped at the base, papery and channelled; median leaflets 17 to 32 cm long and 0.6 to 1 cm wide, with a brown articulation on the axis.
  • Male cones: solitary, cylindrical, upright, small, 11 to 15 cm long and 1.6 to 2.5 cm across, greenish yellow, then yellowish brown with reddish-brown hairs; stalk 8 to 14 cm long.
  • Female cones: solitary, upright, 13 to 21 cm long and 7 to 9 cm across, green with brown hairs, then greyish green with black hairs; scales with two straight horns 3 to 5 mm long, set at an obtuse angle.
  • Seeds: egg-shaped, 1.5 to 2.3 cm long, with a reddish-white fleshy coat before ripening, light brown when ripe.

In cultivation, the colour of the new leaves is what growers notice first; French growers describe a deep red flush that turns green as the leaves mature.

Hybrids

No natural hybrid is documented. A garden hybrid, Ceratozamia hildae × Ceratozamia kuesteriana, is declared to BGCI PlantSearch by the Gardens of Golden Gate Park in San Francisco; it has not been described in a publication.

Possible confusion

According to the 2022 monograph, the most similar species is Ceratozamia sabatoi, of Querétaro and Hidalgo; Ceratozamia kuesteriana is easily told apart by its channelled leaflets and rising leaves. In the same region:

  • Ceratozamia hildae has leaflets grouped in clusters;
  • Ceratozamia latifolia has broad, oblong leaflets several centimetres wide.

In collections, a young plant can be mistaken for Ceratozamia mirandae, of Chiapas: in 2019 a grower in the Gard (southern France) hesitated between the two on the Fous de palmiers forum and asked for close-ups of the leaf bases and leaflets to decide. Only a plant of documented origin can be named with confidence.

Taxonomy

Ceratozamia kuesteriana is accepted by The World List of Cycads, by Species+ and by the WCVP, which records its publication in the Bulletin de la Société Impériale des Naturalistes de Moscou 30(1), page 187 (1857), and places it in north-eastern Mexico. It was described by the botanist Eduard Regel (pages 187–188, plates 3 and 4).

The sources differ on synonymy. The World List of Cycads gives it no synonym, whereas the WCVP places under it Ceratozamia angustifolia Lindl., published in 1881 (Illustration Horticole 28: 32). The name Ceratozamia angustifolia is therefore treated as a synonym of this species by Kew’s checklist, but not by the reference list of cycad specialists.

It is one of the oldest species of the genus, described eleven years after Ceratozamia mexicana. As with that species, the type is a plant cultivated in Europe rather than a specimen collected in the wild, which long left its exact origin unclear. In the phylogeny of the genus published in 2023 by Habib and colleagues, the genus divides into three main clades.

Etymology and history

The epithet honours Baron K. von Kuester (1820–1893), a nineteenth-century Russian plant collector and patron of the Imperial Botanic Garden in St Petersburg (The World List of Cycads, after the etymological compendium of Haynes, 2022).

The type is a plant grown at the botanic garden of St Petersburg (“Ex Horto Petropolitano”), prepared by Regel in 1856; according to The World List of Cycads, it came from material collected in Mexico by the collector Karwinsky in 1843. The holotype is kept at the Komarov Botanical Institute in St Petersburg (LE), with an isotype at Utrecht (U). The oldest wild specimen cited by the 2022 monograph was collected in 1961 in the municipality of Gómez Farías, Tamaulipas.

Common names

No common name is recorded. The 2022 monograph lists none in Mexico, Species+ gives none, and no English name specific to the species is in use.

In the wild

Ceratozamia kuesteriana is endemic to Tamaulipas. According to the 2022 monograph, it grows on karst rocks in pine-oak forest and cloud forest, between 1,100 and 1,500 m; the specimens studied come from the municipalities of Gómez Farías, Ocampo and Tula. Going by the ranges given by The World List of Cycads, Tamaulipas is the northernmost state where the genus grows. No study of its populations, pollination or phenology has been published.

Conservation status and regulation

Ceratozamia kuesteriana is assessed as Critically Endangered (CR, criterion A2cd) on the IUCN Red List, in an assessment by J.D. Bösenberg published in 2022: criterion A2 reflects a marked observed decline of the populations, linked to habitat loss and collecting. The category is given by The World List of Cycads and by the Red List data distributed through GBIF (checked on 30 October 2026); the 2022 monograph gives the same category, adding criterion B2ab(ii,iii,iv).

Like the whole genus, it has been covered by CITES Appendix I since 1 August 1985, and by 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), seeds included (Species+, checked on 30 October 2026). Plants offered for sale should come from cultivated seed, with the documents to prove it.

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 kuesteriana

No botanic garden or institution has published growing advice for this species; what follows comes from amateur growers, mostly in France, who grow it in pots and find it fairly easy and robust. They recommend light or partial shade (a plant kept in deep shade in a greenhouse produced drawn, pale leaves), a free-draining compost such as good potting compost mixed with coarse sand, regular watering during growth and little in winter. Its leaves are brittle and should be kept out of the wind and away from paths. A bare-root plant that had spent more than ten days in transit lost its old leaves after potting, then produced a healthy new flush a few months later.

Outdoor and in-ground cultivation

No outdoor planting with a documented result has been published. Its mountain habitat in pine-oak and cloud forest suggests a sheltered, lightly shaded spot in very free-draining soil in mild climates, such as coastal California or the Mediterranean, with protection ready for frosty nights; this is inferred from the habitat, not tested.

Container cultivation

Its small size makes it an easy container plant to move under cover or protect, as several growers point out. Use a gritty mix and a deep pot; an offset received without roots took a year to root for one French grower.

In cultivation in the UK, US and Australia

Forty gardens worldwide declare Ceratozamia kuesteriana to BGCI PlantSearch (queried on 30 October 2026). In the United Kingdom, these are the Royal Botanic Gardens, Kew, the Royal Botanic Garden Edinburgh, Oxford Botanic Garden and Glasgow Botanic Gardens; Edinburgh’s online Garden Explorer lists an accession dating from 1933. In the United States, 22 gardens declare it, including Montgomery Botanical Center (Coral Gables, Florida; 22 accessions in its online catalogue), Fairchild Tropical Botanic Garden, Naples Botanical Garden, the Huntington, Lotusland, San Diego Botanic Garden, the New York Botanical Garden and the Gardens of Golden Gate Park in San Francisco. In Australia, the Royal Botanic Garden Sydney, Royal Botanic Gardens Victoria (Melbourne), the Botanic Garden of Adelaide and the Cairns Botanic Gardens declare it. A BGCI listing does not say whether the plants are under glass or outdoors.

Propagation

From fresh seed, after pollination between a male and a female plant, almost always by hand in cultivation. The species sometimes produces offsets, which root slowly. Clean the seeds wearing gloves and sow them warm in a free-draining mix.

Pests and diseases

No pest or disease specific to the species has been documented. As with other cycads, the main danger in cultivation is root and trunk rot in cold, wet soil; watch for scale insects as well.

Cold hardiness

Ceratozamia kuesteriana has a reputation as one of the hardier Ceratozamia, because it lives in the mountains of north-eastern Mexico. The published data are thin, however: no outdoor result has been documented, and the only precise value comes from a greenhouse.

Mediterranean and European experience

  • A grower in Roussillon (Pyrénées-Orientales, southern France) reports on the Fous de palmiers forum that his young Ceratozamia kuesteriana, grown in a greenhouse, were unharmed in February 2012 when the temperature in the greenhouse fell to −4 °C (24.8 °F); whether the greenhouse was heated is not stated.
  • A grower in Ravenna (Emilia-Romagna, Italy) wrote on the Tropicamente forum in September 2012 that he had read that the species should be among the hardiest of the genus, but had not tested it in hard frost; in February 2012, with −8 °C (17.6 °F) outside, his cold greenhouse fell to −2 °C (28.4 °F).
  • In 2009, a contributor to the same forum relayed a ranking by growers in northern California, who placed Ceratozamia kuesteriana, Ceratozamia latifolia and Ceratozamia hildae among the cycads that take minima of −7 to −9 °C (19 to 16 °F) with light to moderate leaf damage; this is second-hand, with no place or date.

The Jardin zoologique tropical in La Londe-les-Maures (Var, on the French Riviera) has published no observation of this species.

United Kingdom, United States and Australia

No dated cold record and no commercial hardiness rating have been published. In the UK it is a glasshouse plant, as at Kew, Edinburgh and Oxford. In mild Mediterranean-type climates, such as coastal California or southern Australia, an outdoor trial only makes sense in a sheltered spot, in very free-draining soil, with protection ready for cold nights.

Toxicity and precautions

No toxicity study specific to Ceratozamia kuesteriana has been published. 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. Dogs, livestock and people can be seriously poisoned. Treat the plant as poisonous, keep seeds and leaves out of reach of children and animals, wear gloves to clean seeds, and if any part is swallowed, call a poison centre, a doctor or a vet straight away.

Traditional uses

The 2022 monograph records no use for this species. Its only documented use is ornamental, in collections.

Frequently asked questions

Is Ceratozamia kuesteriana cold-hardy?

Not proven. It is reputed to be one of the hardier Ceratozamia, but no outdoor result has been published; young plants took −4 °C (24.8 °F) in a greenhouse in southern France. Winter protection remains essential outside mild climates.

Why are its young leaves red?

It is a feature of the species: its leaves emerge reddish brown, then turn green as they mature.

How do I recognise Ceratozamia kuesteriana?

By its very narrow leaflets, less than a centimetre wide, curved upwards and channelled, on upright leaves about a metre long, together with its reddish-brown new growth.

Sun or shade?

Light or partial shade. Too much shade gives drawn leaves, and its brittle leaves dislike wind; no result in full sun has been published.

Why was it described in Russia?

Because the type is a plant grown at the botanic garden of St Petersburg, from material sent from Mexico in the 1840s. Eduard Regel described it in 1857 and named it after Baron von Kuester, a patron of the garden.

Is it endangered?

Yes. It is assessed as Critically Endangered by the IUCN (2022) and lives only in a few mountains of southern Tamaulipas.

Can it be bought freely?

Not without documents. Like the whole genus, it is listed in CITES Appendix I and Annex A of the EU regulation, seeds included; only plants raised in cultivation, with paperwork, can be traded.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Regel, E. (1857). [Description of Ceratozamia kuesteriana.] Bulletin de la Société Impériale des Naturalistes de Moscou 30(1): 187–188, pl. 3, fig. 6; pl. 4, fig. 22. [Original description; reference given by The World List of Cycads.]
  • 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, status; open access.]
  • Habib, S., Gong, Y., Dong, S., Lindstrom, A., Stevenson, D.W., Wu, H. & Zhang, S. (2023). Phylotranscriptomics shed light on intrageneric relationships and historical biogeography of Ceratozamia (Cycadales). Plants 12(3): 478. https://doi.org/10.3390/plants12030478 [Phylogeny of the genus; abstract.]
  • Bösenberg, J.D. (2022). Ceratozamia kuesteriana. The IUCN Red List of Threatened Species 2022: e.T42101A69868021. https://doi.org/10.2305/IUCN.UK.2022-1.RLTS.T42101A69868021.en [Red List assessment; category confirmed by GBIF.]
  • 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 quoted 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.]