Cycas fugax

Cycas fugax is a cycad from northern Vietnam, known only from Phu Tho province, north-west of Hanoi, where it had almost vanished from the wild before botanists recognised it as a species. Described in 2004 by Ken Hill, Nguyen Tien Hiep and Phan Ke Loc, this member of the genus Cycas now survives mainly in private gardens in Vietnam and in a few collections. Adult plants carry enormous leaves, up to about 4 m long according to a collector who saw them in Phu Tho. The IUCN lists it as Critically Endangered, and several sources regard it as possibly, or even actually, extinct in the wild.

Key facts about Cycas fugax

  • Accepted name: Cycas fugax 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 established name in English or Vietnamese (see Common names)
  • Natural range: northern Vietnam, Phu Tho province (Phong Chau district)
  • IUCN status: Critically Endangered (CR), confirmed in the assessment published in 2023 according to the Red List data relayed by GBIF; “possibly extinct in the wild” in the 2010 assessment
  • 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: not documented in the sources consulted
  • Habit and adult size: leaves up to 3.5 to 4 m long, according to a collector; the measurements of the original description could not be consulted
  • In the UK, US and Australia: no garden record found
  • Toxicity: no data for the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas fugax

The honest answer is that its botanical measurements are not available here. The species is described in the revision of the Cycas of Vietnam by Hill, Nguyen and Phan (2004, pages 145 to 146, figures 2 and 3), a paper behind a paywall that could not be consulted, so no trunk, leaflet or cone measurement is given on this page. What collectors have published offers a few pointers:

  • Very long leaves: a French collector who saw the species in private gardens of Phu Tho in 2010 describes leaves “up to 4 metres and more”, and an old female plant carrying a single leaf about 3.5 m long.
  • Young plants: in cultivation, seedlings had already formed a well-developed caudex (the swollen stem base) in their first year, and the most advanced carried four or five leaves (same source, 2011).
  • Growth: the same collector compares its rapid growth with that of Cycas debaoensis and Cycas micholitzii.

An online identification key, seen only as a search-engine extract, places the species in section Stangerioides, the group of Cycas with soft male cones, comb-like megasporophylls (the fertile leaves of female plants) and yellow seeds whose flesh has no fibrous layer (Hill 2008). This placement could not be checked against the original description and should be treated as unconfirmed.

Hybrids

No hybrid, natural or in cultivation, is documented.

Possible confusion

Without the original description, no comparison based on measurements can be offered. Northern Vietnam is home to other cycads that Hill (2008) places in section Stangerioides, such as Cycas dolichophylla and Cycas balansae, which also have comb-like megasporophylls. The collector who visited Phu Tho in 2010 saw Cycas dolichophylla planted in the same gardens as Cycas fugax. Only a plant of known origin, or an examination of its cones, allows a reliable identification.

Taxonomy

Cycas fugax is a name accepted by The World List of Cycads; POWO could not be consulted directly, and a search-engine extract of its record cites the authors as “K.D.Hill, N.H.Tuan & P.K.Lôc”, whereas The World List of Cycads gives the second author as “T.H.Nguyên”, the Vietnamese botanist Nguyen Tien Hiep. The name was published in 2004 in The Botanical Review (volume 70, pages 145 to 146), in the revision of the genus in Vietnam that described several new species. The type was collected on 13 January 2000 in Phong Chau district, Phu Tho province, between 400 and 900 m (Nguyen & Hill 4112; holotype in the Hanoi herbarium, HN, isotype in Sydney, NSW).

The name has not changed since publication, and no synonym is recorded.

Etymology and history

The epithet comes from the Latin fugax, “fleeting, transient”: according to The World List of Cycads, it recalls that the species had almost disappeared before it was recognised as distinct.

In 2010 a French collector travelled to the area where the species was first described. With the help of a local resident he found it only in private gardens; he was told that wild plants remained, but could not check that they belonged to the same species. He brought back seeds, which germinated at the end of 2010, and in 2013 he reported that plants offered by a seller had been raised from those seeds (Fous de palmiers forum). The World List of Cycads now also shows photographs of Cycas fugax taken in Phu Tho province.

Common names

No established common name is recorded for this species, in English, French or Vietnamese, in the sources consulted. The REPAD database of recently extinct species lists “Fugax cycad” as a proposed name, not as a name in use. The generic Vietnamese word for cycads, thiên tuế, is not attributed specifically to this species by any verified source.

In the wild

Cycas fugax has been recorded in the wild only in Phu Tho province, in northern Vietnam; the type label gives an altitude of 400 to 900 m. Its natural habitat, pollinator and phenology are not described in the sources that could be consulted. According to the compilations that draw on the IUCN assessments, the last record in the wild dates from 2004. GBIF holds a single record under this name, a preserved specimen without locality data (consulted on 21 October 2026).

Conservation status and regulation

Cycas fugax is listed as Critically Endangered (CR) by the IUCN. The 2010 assessment, by Osborne, Hill, Nguyen and Phan, used criteria A2cd (a past decline of more than 80%) and B1ab(i,ii,iii,v) (a tiny and shrinking range) and described the species as “possibly extinct in the wild”. A reassessment by T. H. Nguyen was published in version 2023-1 of the Red List (reference checked on Crossref), and the Red List data relayed by GBIF give the current category as CR (consulted on 21 October 2026); the criteria of the new assessment could not be read, since the Red List itself could not be consulted. According to an online compilation, Recently Extinct Species, POWO and Christenhusz and Govaerts (2024) go further and list the species as extinct in the wild; these two sources were not consulted directly.

The survival of the species therefore depends almost entirely on cultivated plants, in Vietnam and in collections. The causes of its decline are not described in the sources consulted.

Like every species in the genus except Cycas beddomei, Cycas fugax is listed in CITES Appendix II, through the listing of the family Cycadaceae, included since 4 February 1977. The listing carries annotation #4 (CoP20 version, in force since 5 March 2026): seeds, pollen, seedlings or tissue cultures obtained in vitro and transported in sterile containers, and cut flowers of artificially propagated plants, are exempt, whereas 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, lists the species with this status and a range in Vietnam (search of 12 October 2026). This general information does not replace the official texts: check the rules in force before buying or exchanging plants, ask the seller for proof of origin and prefer plants raised from cultivated seed.

Growing Cycas fugax

In short: no institution has published growing advice for this species, and the only growing reports come from a few French collectors, all with plants in pots.

Outdoor and in-ground cultivation

No planting in the open ground has been documented outside Vietnam, where the plants seen in 2010 were growing in village gardens. Its native region, northern Vietnam, has cool winters, but no source links the species to a particular soil or exposure, and nothing allows its tolerance of frost to be assessed.

Container cultivation

All the reports concern pot-grown plants. A grower in Belley (Ain) and Montpellier (Hérault), France, reports on the Fous de palmiers forum that he raised about twenty plants from seed brought back from Vietnam in 2010. In 2013 he described them as “fairly robust despite many scale attacks” and fast-growing for a cycad, and warned that adults become “monsters” with 4 m leaves: room is needed. He started the seedlings indoors before moving them outside for the warm season. A grower in Nîmes (Gard) posted photographs of his plants on the same forum in 2011, and another collector mentioned a young plant in 2013. The Jardin zoologique tropical at La Londe-les-Maures, in the south of France, has published no observation on this species.

In cultivation in the UK, US and Australia

No record of Cycas fugax was found in BGCI PlantSearch, in the online catalogue of Montgomery Botanical Center (Florida), or in the online catalogues of British, American and Australian gardens (searches of 19 and 21 October 2026). No report from an English-speaking grower could be read. The plants known in Europe all trace back to seed collected from cultivated plants in Vietnam.

Propagation

The plant is dioecious: a male and a female plant are needed to obtain seed. The seeds brought back from Vietnam in 2010 germinated indoors after a few months, around Christmas, according to the Fous de palmiers forum. Seeds are exempt from CITES under annotation #4; given the rarity of the species, choose seed harvested from cultivated plants.

Pests and diseases

Scale insects are the only problem reported in cultivation, without the species being named (Fous de palmiers forum, 2013). The Asian cycad scale, Aulacaspis yasumatsui, can attack every cultivated Cycas.

Cold hardiness

No cold-tolerance data exist for Cycas fugax. Northern Vietnam has cool winters, but nothing allows us to say that the plant tolerates frost.

Mediterranean experience

No result has been published in Europe for plants in the open ground, and no dated frost event concerns the species. In the south of France, whose climate is comparable to that of coastal California or southern Australia, the plants mentioned on the Fous de palmiers forum (Montpellier, Nîmes) are grown in pots, and none has been tried in the ground.

United Kingdom, United States and Australia

No cold reading or dated growing report was found, either on forums or from botanic gardens. No USDA zone can be given. In the UK and in most of the United States and Australia outside the tropics, keep it frost-free under glass until data become available.

Toxicity and precautions

No toxicity analysis specific to Cycas fugax has been found. The risk is, however, 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 in the sources consulted. The plants seen in private gardens around Phu Tho are grown as ornamentals, and no other use is reported.

Frequently asked questions

Why is it called fugax?

Because the species was almost extinct when it was recognised: fugax means “fleeting” in Latin.

Does it still exist in the wild?

It is doubtful. The IUCN described it in 2010 as “possibly extinct in the wild”, the last wild record dates from 2004, and some compilations now treat it as extinct in the wild.

Where can it be found today?

Mainly in private gardens in northern Vietnam and in a few collections, including some in Europe raised from seed collected on those cultivated plants.

How big does it get?

Its leaves can exceed 3.5 to 4 m on adult plants, according to a collector who saw it in Vietnam. The measurements of the original description could not be consulted.

Is it easy to grow?

Fairly, according to collectors: it grows quickly for a cycad and the plants are robust, but they are prone to scale insects and become very large.

Can it be grown outdoors in the UK?

Almost certainly not. There are no cold data at all, and the few plants known in Europe are kept in pots; in the UK it would need a heated glasshouse.

Is it poisonous?

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

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Hill, K.D., Nguyen, T.H. & Phan, K.L. (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 (pp. 145–146, figs 2–3); not consulted (paywall), cited after The World List of Cycads.]
  • Hill, K.D. (2008). The genus Cycas (Cycadaceae) in China. Telopea 12(1): 71–118. doi:10.7751/telopea20085804 [Definition of section Stangerioides; full text consulted.]
  • Nguyen, T.H. (2023). Cycas fugax. The IUCN Red List of Threatened Species 2023-1: e.T42039A68901336. doi:10.2305/IUCN.UK.2023-1.RLTS.T42039A68901336.en [Current assessment (CR); reference checked on Crossref, category relayed by GBIF; Red List page not consulted (access blocked).]
  • Osborne, R., Hill, K.D., Nguyen, T.H. & Phan, K.L. (2010). Cycas fugax. The IUCN Red List of Threatened Species 2010-3: e.T42039A165418490. doi:10.2305/IUCN.UK.2010-3.RLTS.T42039A165418490.en [Previous assessment (CR, “possibly extinct in the wild”), criteria as given by The World List of Cycads; reference checked on Crossref, Red List page not consulted.]
  • Christenhusz, M.J.M. & Govaerts, R. (2024). Plant extinction in the Anthropocene. Botanical Journal of the Linnean Society 207: 183–196. doi:10.1093/botlinnean/boae045 [Status “extinct in the wild”, cited after Recently Extinct Species; not consulted.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Source of the etymologies 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. doi:10.5281/zenodo.21958524 [Reference checklist; consulted directly.]