Cycas brachycantha

Cycas brachycantha is a small cycad endemic to northern Vietnam, known only from Bắc Kạn province, around Ba Bể National Park, where it grows in cracks in limestone ridges in the shade of evergreen forest. Described in 2004 by Ken Hill, Nguyễn Tiến Hiệp and Phan Kế Lộc, this species of the genus Cycas takes its name from the short spines on its leaf stalks. The IUCN lists it as Vulnerable (VU). It is one of the least known species of the genus, and the original description could not be consulted for this page.

Key facts about Cycas brachycantha

  • Accepted name: Cycas brachycantha K.D.Hill, T.H.Nguyên & P.K.Lôc (2004), accepted by The World List of Cycads (version 2026.08.15); POWO could not be consulted directly
  • Former names and synonyms: none
  • Family: Cycadaceae, order Cycadales
  • Common names: no name attested, in English, Vietnamese or any other language
  • Natural range: northern Vietnam, Bắc Kạn province (type locality: Hin Dan mountain, Ba Bể)
  • IUCN status: Vulnerable (VU); assessed by K. D. Hill (2010, criterion D2), reassessed by J. D. Bösenberg in Red List version 2023-1, VU maintained according to GBIF
  • 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: cracks in limestone ridges, often without soil, under evergreen forest, according to secondary sources (see In the wild)
  • Habit and adult size: stem often underground, 9 to 10 cm across, or up to about 1 m tall; 5 to 10 leaves, 1.4 to 2.5 m long, according to secondary sources
  • In the UK, US and Australia: only San Diego Botanic Garden (California) declares it, in BGCI PlantSearch
  • Toxicity: no data specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas brachycantha

The feature behind its name is a leaf stalk armed with short spines (Haynes 2022, taken up by The World List of Cycads). The original description, published in 2004 in The Botanical Review (pages 155 to 157, figure 6), is behind a paywall and could not be consulted. The details below come only from the English Wikipedia article, which draws on Ken Hill’s Cycad Pages for the Royal Botanic Garden Sydney (now offline); they could not be checked against the original text:

  • Stem: 9 to 10 cm across, often underground, or upright to about 1 m above ground; 5 to 10 leaves in the crown.
  • Leaves: pinnate, 1.4 to 2.5 m long, slightly keeled to flat, a very glossy dark green, with 100 to 210 leaflets; the leaf ends in a pair of leaflets, not a spine; young leaves white and woolly, soon hairless; petiole spiny and hairless.
  • Leaflets: 20 to 25 cm by 10 to 14 mm, angled forward at 70 to 85°.
  • Male cones: single, spindle-shaped, yellow, 12 to 14 cm by 3 to 4 cm.
  • Megasporophylls (the fertile leaves of female plants): 8 to 12 cm long, densely brown-felted, carrying 2 to 4 hairless ovules; soft lateral spines on the blade and no terminal spine.
  • Seeds: ovoid, with a yellow fleshy coat and a rough inner shell.

Hairless ovules, megasporophylls with soft lateral spines and no terminal spine, and a yellow seed coat match the characters by which Ken Hill defines section Stangerioides, the large group of Cycas of northern Vietnam, Laos and southern China (Hill 2008). Wikipedia also mentions a “closed” female cone; Cycas megasporophylls do not form a closed cone, and this statement is not taken up here.

Hybrids

No natural or garden hybrid is documented, and no published genetic study covers the species.

Possible confusion

Several other Cycas grow on limestone in northern Vietnam, and the distinguishing characters given in the original description could not be consulted. The available sources allow only a few comparisons:

  • Cycas ferruginea, from the limestone cliffs of Lạng Sơn and Thái Nguyên provinces and western Guangxi: recognised by the thick dark red down on its young growth (Hill 2008), whereas the young leaves of Cycas brachycantha are described as white and woolly. Cycas ferruginea also has short petiole spines (1 to 3 mm according to Hill), so this character alone does not separate them.
  • Cycas sexseminifera and Cycas tropophylla, which also grow on bare limestone walls (Hill 2008); their comparison with Cycas brachycantha is not documented.
  • The species with divided leaflets, such as Cycas micholitzii or Cycas multipinnata, are ruled out at once: the leaflets of Cycas brachycantha are simple.

Taxonomy

Cycas brachycantha is accepted by The World List of Cycads; POWO could not be consulted directly. The species was described in 2004 by Ken Hill, Nguyễn Tiến Hiệp and Phan Kế Lộc in their revision of the genus in Vietnam, published in The Botanical Review (70(2): 134–193), on pages 155 to 157, with figure 6. Its IPNI identifier is 60436309-2. It has no synonym and has never been placed under another species.

Its reproductive characters place it in section Stangerioides, which Hill defines by soft male cones, comb-like megasporophylls, hairless ovules and yellow seeds whose fleshy coat comes away easily (Hill 2008). No phylogenetic study consulted gives its position within the section.

Etymology and history

The name comes from the Greek brachys (“short”) and acanthos (“spine”), referring to the characteristically short petiole spines (Haynes 2022, taken up by The World List of Cycads).

The type is collection no. 4119 by Nguyễn Tiến Hiệp and Ken Hill, made on 17 January 2000 on Hin Dan mountain, at Ba Bể in Bắc Kạn province; the holotype is in Hanoi (HN), with an isotype in Sydney (NSW). It is one of the new species described in the 2004 Vietnamese revision. A later collection, made in Ba Bể National Park in March 2001 by Phan Kế Lộc and colleagues, records an altitude of 700 m on its label, as published through GBIF.

Common names

No common name is attested for this species, in English or in Vietnamese; Species+ records none.

In the wild

According to The World List of Cycads, Cycas brachycantha is known only from Bắc Kạn province, in northern Vietnam; the type locality, Hin Dan mountain, lies at Ba Bể, and the English Wikipedia article places the species in Ba Bể National Park. According to the same source, it grows in cracks and crevices, often without soil, on limestone ridges under evergreen forest. As the original description could not be read, these habitat details have not been checked at the source; the 2001 herbarium collection from the national park, at 700 m, is consistent with them.

No information has been published on pollination, seed dispersal or population size.

Conservation status and regulation

Cycas brachycantha was listed as Vulnerable (VU, criterion D2) in the IUCN assessment by Ken Hill published in 2010, according to The World List of Cycads. Criterion D2 covers species with a very small range or very few locations, exposed to threats that could quickly push them to Critically Endangered. A reassessment by John Donald Bösenberg was published in Red List version 2023-1 (reference checked on Crossref), and the category now distributed by the IUCN, as relayed by GBIF, remains Vulnerable (consulted on 21 October 2026). The Red List itself could not be consulted directly, and the 2023 criteria are not known. A “Near Threatened” category that circulates online appears only in the categories of the English Wikipedia article, without a reference.

Like every species in the genus except Cycas beddomei, Cycas brachycantha is listed in CITES Appendix II, where the family Cycadaceae has been included since 4 February 1977. The listing carries annotation #4 (CoP20 version, in force since 5 March 2026), which exempts seeds in particular; international trade in the plants themselves requires an export permit. Australia, the United Kingdom and the United States apply CITES through their own national legislation; in the European Union the species is in Annex B of Regulation (EC) No 338/97, whose annexes in force are set by Commission Regulation (EU) 2026/1383, applicable since 29 June 2026. Species+, the official CITES database, confirms this status. This general information does not replace the official texts: check the rules in force before buying or exchanging plants, and prefer plants raised from seed in cultivation.

Growing Cycas brachycantha

In short: no institution has published growing advice and no grower’s report has been published; the species appears to be extremely rare in collections. What follows is deduced from its habitat, not from published results.

Outdoor and in-ground cultivation

The habitat described, cracks in limestone rock in the shade of humid evergreen forest, suggests a very free-draining, possibly limy substrate, filtered light and a warm, humid climate. No outdoor planting has been documented anywhere, not even in tropical or subtropical gardens.

Container cultivation

Its often underground stem and modest size would suit it to pot culture, in a mineral mix under bright, filtered light. In the United Kingdom and other temperate regions, it would be a plant for a heated glasshouse. No account of pot culture has been published, and the Jardin zoologique tropical at La Londe-les-Maures, in the south of France, has published nothing on this species.

In cultivation in the UK, US and Australia

In short: a single, undated record.

  • United States: San Diego Botanic Garden (Encinitas, California) declares the species in BGCI PlantSearch (consulted in October 2026); the garden’s own pages do not name it, and whether the plant is grown outdoors or under cover is not stated.
  • United Kingdom and Australia: no garden declares it, and it is absent from the online catalogues consulted (Montgomery Botanical Center, Fairchild Tropical Botanic Garden, the Royal Botanic Garden Sydney, Mount Annan, the Royal Botanic Gardens Victoria, Cambridge, Edinburgh, Chelsea Physic Garden).

No first-hand report from a private grower could be read.

Propagation

Like all Cycas, Cycas brachycantha is dioecious: a male and a female plant are needed for fertile seed, and in cultivation pollination is often done by hand. No germination data specific to the species have been published. Seeds are exempt from CITES under annotation #4; given the rarity of the species, look only for seeds or plants of cultivated and legal origin.

Pests and diseases

No pest or disease specific to the species is documented. Scale insects, including Aulacaspis yasumatsui, threaten all cultivated Cycas, and stem and root rots affect cycads kept in a substrate that is too wet, but no attack has been reported on this species in particular.

Cold hardiness

No cold-tolerance data exist for Cycas brachycantha. No published source gives a minimum temperature, in the wild or in cultivation.

European experience

No cultivation result has been published in Europe, in the open ground or in a pot, and no dated frost episode concerns the species. In the absence of data, keep it in a pot, frost-free.

United Kingdom, United States and Australia

No cold reading and no dated growing report are documented in any country. No USDA zone can be given without a documented trial.

Toxicity and precautions

No toxicity analysis specific to Cycas brachycantha has been published, but the risk is well documented in the genus: Cycas tissues, and the seeds above all, contain cycasin, which is converted during digestion into methylazoxymethanol, toxic to the liver and nervous system, along with a neurotoxic amino acid, BMAA. The ASPCA lists the sago palm (Cycas revoluta) as poisonous to dogs, cats and horses. Until proven otherwise, treat the plant as poisonous: keep seeds and leaves out of reach of children and pets, and wear gloves to clean the seeds. If any part is swallowed, contact a poison centre, a doctor or a vet straight away.

Traditional uses

No use of this species is documented. Its rarity and CITES listing rule out any collection from the wild in any case.

Frequently asked questions

What does brachycantha mean?

“Short-spined”. The name combines the Greek brachys (“short”) and acanthos (“spine”) and refers to the spines on the leaf stalk.

Where does it grow in the wild?

Only in Bắc Kạn province, in northern Vietnam, around Ba Bể, in cracks in limestone rock under forest.

How can it be recognised?

By its often underground stem, leaves no more than 2.5 m long without a terminal spine, and the short spines of its petiole; these characters, however, come from secondary sources, and the comparison with related species still needs checking against the original description.

Which group does it belong to?

Section Stangerioides, the group of Cycas of northern Vietnam, Laos and southern China with soft male cones, hairless ovules and yellow seeds.

Is it endangered?

Yes. The IUCN has listed it as Vulnerable since 2010 because of its tiny range, a category kept in the reassessment published in 2023.

Can it be grown outdoors in the UK?

Almost certainly not. No cold data or growing experience exist, and its habitat is tropical; grow it in a pot under heated glass.

Is it poisonous?

It must be assumed so. No analysis exists for the species, but the Cycas studied contain dangerous toxins, especially in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Hill, K.D., Nguyễn, T.H. & Lôc, P.K. (2004). The genus Cycas (Cycadaceae) in Vietnam. The Botanical Review 70(2): 134–193. doi:10.1663/0006-8101(2004)070[0134:TGCCIV]2.0.CO;2 [Original description (pages 155–157, figure 6); reference checked on Crossref, text not consulted (paywalled).]
  • Hill, K.D. (2008). The genus Cycas (Cycadaceae) in China. Telopea 12(1): 71–118. doi:10.7751/telopea20085804 [Definition of section Stangerioides; habitat and characters of Cycas ferruginea, Cycas sexseminifera and Cycas tropophylla; full text consulted.]
  • Hill, K.D. (2010). Cycas brachycantha. The IUCN Red List of Threatened Species 2010: e.T42071A10643586. doi:10.2305/IUCN.UK.2010-3.RLTS.T42071A10643586.en [First assessment (VU D2); reference checked on Crossref, category taken from The World List of Cycads, page not consulted (access blocked).]
  • Bösenberg, J.D. (2023). Cycas brachycantha. The IUCN Red List of Threatened Species 2023: e.T42071A67337542. doi:10.2305/IUCN.UK.2023-1.RLTS.T42071A67337542.en [Current assessment; reference checked on Crossref, VU category relayed by GBIF, text not consulted (access blocked).]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology; taken up through 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; consulted directly.]