Cycas badensis

Cycas badensis is a cycad of the Torres Strait, north of Queensland in Australia, known only from Badu and Moa islands, where it grows in savanna woodland. Described by Ken Hill in 1996, this species of the genus Cycas can form trunks 8 m tall; it is distinguished by its orange-woolly crown, its soft cataphylls and its large dark green leaves. It is one of the least documented Australian Cycas: its male cone had not even been seen when it was described.

Key facts about Cycas badensis

  • Accepted name: Cycas badensis K.D.Hill (1996), accepted by The World List of Cycads (version 2026.08.15); POWO could not be consulted directly
  • Former names and synonyms: no synonym of its own; placed under Cycas angulata by de Laubenfels and Adema (1998)
  • Family: Cycadaceae, order Cycadales
  • Common names: no name attested, in English or any other language
  • Natural range: Australia, Queensland, Badu and Moa islands (Torres Strait)
  • IUCN status: Least Concern (LC); reassessment by J. D. Bösenberg published in Red List version 2023-1, LC according to GBIF; the Flora of Australia gives Near Threatened (NT, 2022) (see Conservation status)
  • 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: savanna woodland; soil not documented
  • Habit and adult size: trunk up to 8 m; leaves 1 to 1.2 m long
  • In the UK, US and Australia: no botanic garden found in any of the three countries
  • Toxicity: no data specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas badensis

Ken Hill distinguishes Cycas badensis by its short, soft cataphylls covered in thick orange wool, its large leaves with broad leaflets and its long megasporophylls. The description is based on a small number of herbarium collections; according to Hill (1996) and the Flora of Australia:

  • Trunk: up to 8 m; diameter not given.
  • Leaves: 100 to 120 cm long, moderately keeled, usually ending in a spine, with 200 to 230 leaflets; petiole hairless, 24 to 26 cm long (20 to 25% of the leaf), unarmed or spiny along 5 to 50% of its length; basal leaflets not reduced to spines.
  • Median leaflets: 11 to 22 cm by 5 to 7.5 mm, hairless, mid to dark green and semi-glossy above, distinctly paler beneath, inserted at 50 to 70°, 8 to 9 mm apart, with slightly recurved margins and a sharp tip.
  • Young growth: loose orange-brown down; cataphylls (the scales protecting the growing point) narrowly triangular, soft, 5 to 9 cm long, densely orange-woolly.
  • Male cones: not seen when the species was described; microsporophyll about 40 mm by 15 mm, with a terminal spine of about 4 mm.
  • Megasporophylls (the fertile leaves of female plants): 23 to 28 cm long, brown-felted, carrying 4 to 6 ovules; sterile blade triangular, 50 to 55 mm, regularly toothed (22 to 24 lateral spines of 1 to 4 mm), terminal spine 21 to 25 mm.
  • Seeds: flattened-ovoid, 30 to 35 mm by 27 to 29 mm, orange-brown, without bloom.

Hybrids

No natural or garden hybrid is documented.

Possible confusion

  • Cycas yorkiana, from the northern Cape York Peninsula, its closest relative: larger sterile blade on the megasporophylls (60 to 100 mm), with more lateral spines (24 to 32) that are longer (3 to 6 mm), a shorter terminal spine (11 to 18 mm), a woollier crown and leaflets usually curved rather than straight; the wiki of the Palm and Cycad Societies of Australia (PACSOA) also describes the two as very similar;
  • Cycas tuckeri and Cycas semota, of the same series, on Cape York: crown and cataphylls covered in very short grey to white down, not orange wool;
  • Cycas media, from eastern Queensland: hard, pungent cataphylls.

Taxonomy

Cycas badensis is accepted by The World List of Cycads; POWO could not be consulted directly. Ken Hill described it in 1996 in his revision of the Australian Cycas (Telopea 7(1), pages 20 and 21), as one of six new species. He placed it in series Yorkianosae, which he created at the same time: leaves openly keeled to almost flat, basal leaflets not reduced to spines, soft, non-pungent cataphylls. In Australia this series of about five species is confined to the Cape York Peninsula, and it has two species in New Guinea.

De Laubenfels and Adema (Blumea, 1998) placed it in the synonymy of Cycas angulata, within a very broad concept of that species; the Australian Plant Census and The World List of Cycads have not followed them.

Etymology and history

The epithet badensis refers to Badu Island, in the Torres Strait, where the species was collected (Haynes 2022, taken up by The World List of Cycads).

The type was collected on 29 October 1981 on Badu Island by John Clarkson (no. 4007); the holotype is kept at the Queensland Herbarium in Brisbane (BRI), with an isotype in Darwin (DNA). Another collection from the island, made by Harris on 2 November 1974, is cited in the revision. Unlike most of the species he described, Ken Hill gave no indication of habitat or conservation status in the original description.

Common names

No common name is attested for this species, in English or in the languages of the Torres Strait, in the sources consulted.

In the wild

Cycas badensis is endemic to Badu and Moa islands, in the Torres Strait, between Cape York and New Guinea. The Flora of Australia describes it as locally common but restricted to these two islands, in savanna woodland. Soil, altitude, phenology, pollinators and seed dispersers are not documented.

Conservation status and regulation

Cycas badensis is listed as Least Concern (LC) by the IUCN, but the sources do not all agree. The World List of Cycads gives LC, citing the assessment by Ken Hill (2010). A reassessment by John Donald Bösenberg was published in Red List version 2023-1 (reference checked on Crossref), and the IUCN data relayed by GBIF give the LC category (consulted on 21 October 2026). The Flora of Australia, updated in 2025, states instead “Listed as Near Threatened, 2022”; the sources consulted do not explain this difference. The Red List itself could not be consulted directly. Whatever its category, a range confined to two islands leaves the species exposed to any local disturbance.

Like every species in the genus except Cycas beddomei, Cycas badensis 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): seeds, pollen, seedlings or tissue cultures obtained in vitro and transported in sterile containers, and cut flowers of artificially propagated plants, are not subject to CITES, 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, names the species and confirms this status. 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 provenance and prefer plants raised from seed in cultivation.

Growing Cycas badensis

In short: no published growing result has been found for Cycas badensis, and the species does not appear to be in the European trade. The only growing advice is a short note on the PACSOA wiki.

Outdoor and in-ground cultivation

The PACSOA wiki recommends a sunny, moist but well-drained position. Its habitat of tropical island savanna points to a plant for frost-free tropical climates; no outdoor planting is documented anywhere, and no trial has been published in a Mediterranean or temperate climate.

Container cultivation

In the United Kingdom and other temperate regions, it would be a plant for a heated glasshouse, given its tropical origin and the size of the adult plant. No account of pot culture has been found. The Jardin zoologique tropical at La Londe-les-Maures, in the south of France, has published no observation on Cycas badensis.

In cultivation in the UK, US and Australia

In short: no record. The species is absent from BGCI PlantSearch (consulted in October 2026) and from the online catalogues consulted: Montgomery Botanical Center and Fairchild Tropical Botanic Garden in Florida, the Royal Botanic Garden Sydney, the Australian Botanic Garden Mount Annan, the Royal Botanic Gardens Victoria, Cambridge, Edinburgh and the Chelsea Physic Garden. No first-hand report from a private grower in these countries could be read; PalmTalk and Dave’s Garden could not be consulted.

Propagation

Like all Cycas, Cycas badensis is dioecious: a male and a female plant are needed for fertile seed. No germination data specific to the species have been published. Seeds are exempt from CITES under annotation #4; ask for seed from cultivated plants.

Pests and diseases

No pest or disease specific to the species is documented. Scale insects, including Aulacaspis yasumatsui, threaten all cultivated Cycas, but no attack has been reported on this species in particular.

Cold hardiness

No cold-tolerance data exist for Cycas badensis. Its range, in the Torres Strait, is entirely tropical; nothing suggests that it can take frost.

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. A search of the French forum Fous de palmiers and the Italian forum Tropicamente found no report for this species.

United Kingdom, United States and Australia

No cold reading and no growing report were found, either on forums or from botanic gardens. Treat it as frost-tender; no USDA zone can be given without a documented trial.

Toxicity and precautions

No toxicity analysis specific to Cycas badensis 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 is documented for this species.

Frequently asked questions

Where does Cycas badensis grow?

Only on Badu and Moa islands, in the Torres Strait, north of Queensland.

Where does its name come from?

From Badu Island, where the type was collected in 1981.

How can it be told from Cycas yorkiana?

By its megasporophylls, whose sterile blade is shorter, with fewer lateral spines and a longer terminal spine, and by a slightly less woolly crown.

Is it a form of Cycas angulata?

No. A 1998 revision placed it there, but current reference checklists keep it as a distinct species, in a different series from Cycas angulata.

Is it endangered?

Probably not, but its range is tiny. The IUCN data relayed by GBIF give Least Concern after the 2023 reassessment, whereas the Flora of Australia gives Near Threatened; it is covered by CITES.

Can it be grown outdoors in the UK?

No, almost certainly not. No cold data exist and its range is tropical.

Is it poisonous?

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

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Hill, K.D. (1996). A taxonomic revision of the genus Cycas (Cycadaceae) in Australia. Telopea 7(1): 1–64. doi:10.7751/telopea19963040 [Original description (pp. 20–21); full text consulted.]
  • Hill, K.D. (1998). Cycadaceae. In McCarthy, P.M. (ed.), Flora of Australia 48: 597–635. CSIRO Publishing, Melbourne. [Consulted in its updated online version (profiles.ala.org.au).]
  • de Laubenfels, D.J. & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Very broad species concept; not consulted directly, cited after The World List of Cycads and the Flora of Australia.]
  • Hill, K.D. (2010). Cycas badensis. The IUCN Red List of Threatened Species: e.T41970A10613527. doi:10.2305/IUCN.UK.2010-3.RLTS.T41970A10613527.en [Previous assessment; reference checked on Crossref, Red List page not consulted (access blocked).]
  • Bösenberg, J.D. (2023). Cycas badensis. The IUCN Red List of Threatened Species 2023: e.T41970A67336287. doi:10.2305/IUCN.UK.2023-1.RLTS.T41970A67336287.en [Current assessment; reference checked on Crossref, LC category relayed by GBIF; page 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 [Source of the etymologies taken up 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.]