Cycas elephantipes

Cycas elephantipes is a cycad of Thailand, known only from a few sandstone plateaus in Chaiyaphum Province, in the north-east of the country. This member of the genus Cycas was described in 2003 by Anders Lindström and Ken Hill, and owes its name to the strongly swollen base of its trunk, with thick, deeply fissured bark that recalls an elephant’s foot. It has no former scientific name. The IUCN lists it as Endangered, its wild population having been heavily reduced by the collection of plants for sale. Very little is known about it in cultivation.

Key facts about Cycas elephantipes

  • Accepted name: Cycas elephantipes A.Lindstr. & K.D.Hill (published 2003), accepted by The World List of Cycads (version 2026.08.15); the World Checklist of Vascular Plants (WCVP), on which POWO is based, also accepts it (consulted through GBIF on 31 October 2026)
  • Former names and synonyms: none
  • Family: Cycadaceae, order Cycadales; section not stated
  • Common names: no English name could be traced to a reliable source; no Thai name checked in a reference source
  • Natural range: Thailand, Chaiyaphum Province (Nong Bua Rawe district)
  • IUCN status: Endangered (EN A2d; B1ab(v)), assessment by A. Lindström published in 2022
  • CITES and other protection: CITES Appendix II; Annex B in the European Union
  • Documented hardiness: no data (see Cold hardiness)
  • Light and soil: in the wild, open to closed woodland, dry for part of the year, on top of sandstone plateaus; needs in cultivation not documented
  • Habit and adult size: trunk 1 to 3 m tall, 15 to 20 cm across, swollen at the base; 40 to 70 leaves 1 to 1.6 m long
  • In the UK, US and Australia: not recorded in the botanic garden catalogues or the BGCI PlantSearch lists consulted
  • Toxicity: not studied for the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas elephantipes

The swollen base of the trunk, covered in thick, dark, corky and deeply fissured bark, and the dense crown of grey-green leaves identify it. Instead of the original description (Lindström and Hill, Brittonia, 2003), the characters below come from Ken Hill’s description published on The Cycad Pages of the Royal Botanic Garden Sydney, a site now offline, as reproduced by the llifle encyclopedia.

  • Trunk: above ground, 1 to 3 m tall, 15 to 20 cm in diameter, rough, swollen at the base.
  • Crown: 40 to 70 grey-green, semi-glossy leaves.
  • Leaves: 100 to 160 cm long, flat in section, with 75 to 300 leaflets; white down on young leaves, shed as they open; rachis ending in a spine 6 to 22 mm long; petiole 20 to 45 cm, partly spiny.
  • Median leaflets: 15 to 25 cm long and 6 to 10 mm wide, slightly keeled, with slightly recurved margins and a sharp tip.
  • Male cones: ovoid, orange or brown, 30 to 55 cm long and 12 to 16 cm across; firm scales 4 to 4.5 cm long, ending in an upturned point 1.5 to 3 cm long.
  • Megasporophylls: about 20 cm, with grey down, bearing 2 to 4 ovules; blade about 12 by 8 cm, deeply comb-like, with some twenty soft spines.
  • Seeds: flattened-ovoid, with a yellow sarcotesta.

Hybrids

No hybrid of Cycas elephantipes is known from the published sources.

Possible confusion

Its closest relative is Cycas pachypoda, from southern Vietnam, which also has a swollen trunk base. According to Hill’s description reproduced by llifle, Cycas elephantipes is larger, with bigger leaves and leaflets and, above all, much larger male cones with longer scales and longer apical points. It can also be confused with Cycas siamensis, another Thai cycad with a swollen trunk, which The World List of Cycads also records in Chaiyaphum Province.

Plants in the trade are often doubtful. In 2010, on the French forum Fous de palmiers, growers tried to identify a Thai cycad with a swollen trunk bought in Europe as Cycas elephantipes, and concluded that it was probably another species of the group; in 2009, on the Italian forum Tropicamente, a grower described the name on nursery plants with swollen bases as “rather hypothetical”. Without documented provenance, such a label should be treated with caution.

The epithet is shared with an unrelated plant, the yam Dioscorea elephantipes, and with a widely sold yucca, Yucca elephantipes, which often dominate search results.

Taxonomy

Cycas elephantipes is accepted by The World List of Cycads; the World Checklist of Vascular Plants (WCVP), on which POWO is based, also accepts it (consulted through GBIF on 31 October 2026). Anders Lindström and Ken Hill described it in “New species and a new record of Cycas (Cycadaceae) from Thailand”, in Brittonia 54(4) (page 301, figure 3), dated 2002 but published in 2003. The same paper describes Cycas petraea, from Loei Province (Thailand) and Vientiane (Laos). The type was collected by Ken Hill in 2000 (number 5089) at Nong Bua Raheo and is held at the Forest Herbarium in Bangkok (BKF).

No published source states the section to which the species belongs. According to The Cycad Pages, it is very close to Cycas pachypoda, described from Vietnam in 2004; in 2010 a member of the Fous de palmiers forum wondered whether the two might be a single species, a question that no publication consulted answers.

Etymology and history

The epithet combines the Greek elephas, “elephant”, and the Latin suffix -pes, “foot”, after the large swollen base of the trunk, which recalls an elephant’s foot (Haynes 2022, cited by The World List of Cycads). The species was collected for its description in 2000, during Ken Hill’s surveys in Thailand. A French grower reported on the Fous de palmiers forum that seed of the species germinated in December 2010, without saying where it came from. No other information on its introduction into cultivation is documented.

Common names

No English common name could be traced to a reliable source. The name “elephant-foot cycad” and the Thai names that circulate online are confirmed neither by Species+ nor by The World List of Cycads.

In the wild

Cycas elephantipes is known only from Chaiyaphum Province, in north-eastern Thailand (The World List of Cycads; Species+; the Thai Biodiversity Information Facility). According to Hill’s description reproduced by llifle, it grows on a few high sandstone plateaus around Nong Bua Raheo, in open to closed woodland that is dry and deciduous for part of the year, with a mostly grassy understorey, around the tops of the massifs and mainly near the upper edges of steep slopes and cliffs. It is locally abundant there. The altitude of these sites is not documented.

Conservation status and regulation

Cycas elephantipes is listed as Endangered (EN A2d; B1ab(v)) by the IUCN, in the assessment by A. Lindström published in 2022, cited by The World List of Cycads; it replaced an assessment by K. D. Hill (2010). The EN category is confirmed by the IUCN data relayed by GBIF (consulted on 21 October 2026). Criterion A2d refers to a past population decline caused by exploitation, and B1ab(v) to a very small extent of occurrence with a continuing decline in the number of mature plants. According to The Cycad Pages, the population has been heavily reduced by the collection of wild plants for sale, and continued collection would threaten the survival of the species. The Thai Biodiversity Information Facility confirms its listing in CITES Appendix II in Thailand.

Like the whole family Cycadaceae, it is listed in CITES Appendix II, with annotation #4 (CoP20 version, in force since 5 March 2026), which exempts seeds, pollen and seedlings or tissue cultures obtained in vitro in sterile containers; live plants still need permits. The United Kingdom, the United States and Australia 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+ confirms this status and gives Thailand as the only range state (consulted on 21 October 2026). This general information does not replace the official texts: check the rules in force before buying or exchanging plants, and buy only plants raised from seed in cultivation.

Growing Cycas elephantipes

In short: no published growing data specific to the species exist. Its habitat suggests a frost-free, sunny or lightly shaded position, a very free-draining mix and a drier rest season, but none of this has been tested.

Outdoor and in-ground cultivation

The growing advice on llifle (tropical climate with a dry winter, free-draining soil, bright light) is repeated word for word on pages for several different Cycas and cannot be taken as specific to this one. From its habitat on sandstone plateaus that dry out for part of the year, a very free-draining soil and a drier period seem logical, but this is a deduction, not a result. No outdoor planting has been documented anywhere; in climates where frost never occurs, such as southern Florida or tropical Queensland, an in-ground trial would be possible but untested.

Container cultivation

In the United Kingdom and other temperate regions it is a plant for a frost-free glasshouse or conservatory. No container growing report has been published.

In cultivation in the UK, US and Australia

In short: no record. Cycas elephantipes does not appear in the online catalogues of Montgomery Botanical Center, Fairchild Tropical Botanic Garden or the Royal Botanic Garden Sydney, nor in the lists of British, American and Australian gardens in BGCI PlantSearch, as compiled in October 2026. No report from a private grower in these countries has been published. Its rarity in collections is consistent with its small wild population and the strict controls on trade.

Propagation

Like all Cycas, Cycas elephantipes is dioecious: a male and a female plant are needed for fertile seed. It is propagated from seed, as for other Cycas; no data specific to the species have been published. Buy only seed-raised plants from cultivation: wild-collected plants have contributed to the decline of the species.

Pests and diseases

No data specific to Cycas elephantipes are documented. Like all Cycas, it can be attacked by the Asian cycad scale, Aulacaspis yasumatsui, a pest native to Thailand, and can rot in waterlogged compost.

Cold hardiness

No cold-tolerance value has been published. No growing report is documented from France or Italy. Its native range is tropical: until data appear, keep it frost-free.

Toxicity and precautions

No toxicity analysis specific to Cycas elephantipes is documented, 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. In dogs, cats and horses the ASPCA reports vomiting, sometimes bloody diarrhoea, jaundice, liver damage and fatal cases, and Pet Poison Helpline adds neurological signs. Wear gloves to handle the seeds and their fleshy coat, pick up fallen seeds and keep plants out of reach of children and pets; if any part is swallowed, contact a poison centre, a doctor or a vet straight away.

Traditional uses

No traditional use specific to Cycas elephantipes is documented. Its only documented use is ornamental, and it is precisely this demand that drives collection from the wild.

Frequently asked questions

Where does the name elephantipes come from?

From Greek and Latin: “elephant’s foot”. It refers to the strongly swollen base of the trunk and its fissured bark.

Where does Cycas elephantipes grow?

Only in Thailand, on a few sandstone plateaus in Chaiyaphum Province. It has one of the smallest ranges in the genus.

How does it differ from Cycas pachypoda?

Cycas elephantipes is larger. Its leaves and leaflets are bigger and its male cones much larger; Cycas pachypoda also grows far away, in southern Vietnam.

Is it the same as Cycas siamensis?

No. Both are Thai cycads with a swollen trunk and both occur in Chaiyaphum Province, but they are separate species; plants sold under either name without provenance may be misidentified.

Is it cold-hardy?

Nobody knows. No cold-tolerance data exist; grow it frost-free.

Is it endangered?

Yes. The IUCN lists it as Endangered (2022), because of its tiny range and the collection of plants for the trade.

Is it poisonous?

It must be assumed so. It has not been studied, but all parts of Cycas are poisonous, especially the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Lindström, A.J. & Hill, K.D. (2003). New species and a new record of Cycas (Cycadaceae) from Thailand. Brittonia 54(4): 298–304 (dated 2002). doi:10.1663/0007-196X(2003)54[298:NSAANR]2.0.CO;2 [Protologue (page 301, figure 3); reference checked on Crossref.]
  • Lindstrom, A. (2022). Cycas elephantipes. The IUCN Red List of Threatened Species 2022: e.T178862A68900505. doi:10.2305/IUCN.UK.2022-1.RLTS.T178862A68900505.en [Current assessment, EN A2d; B1ab(v) according to The World List of Cycads; reference checked on Crossref (a second version, e.T178862A243416415, also exists), category confirmed by GBIF.]
  • Hill, K.D. (2010). Cycas elephantipes. The IUCN Red List of Threatened Species 2010: e.T178862A7630157. doi:10.2305/IUCN.UK.2010-3.RLTS.T178862A7630157.en [Previous assessment; reference checked on Crossref.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology; cited 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. doi:10.5281/zenodo.21958524 [Reference checklist.]