Cycas yorkiana

Cycas yorkiana is a cycad of northern Cape York Peninsula, in Queensland, Australia, growing in the understorey of open eucalypt woodland on sandy soils. Described in 1996 by Ken Hill, this species of the genus Cycas is named after the peninsula. It is recognised by its bright green, keeled leaves and by the thick crown of orange wool around its cataphylls. Extremely abundant within its range but very localised, it is listed as Near Threatened by the IUCN.

Key facts about Cycas yorkiana

  • Accepted name: Cycas yorkiana K.D.Hill (1996), accepted by The World List of Cycads (version 2026.08.15) and by GBIF; POWO could not be consulted
  • Former names and synonyms: none; de Laubenfels and Adema (1998) sank it into Cycas angulata, a treatment not followed; the Cape Melville population was formerly referred to Cycas media
  • Family: Cycadaceae, order Cycadales
  • Common names: none attested
  • Natural range: Australia, Queensland: northern Cape York Peninsula (north of the Wenlock River) and Cape Melville
  • IUCN status: Near Threatened (NT B1b(iii)), assessment by J.D. Bösenberg dated 2020 and published in 2022
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union; “special least concern” and restricted plant in Queensland, according to WildNet
  • Documented hardiness: no data (see Cold hardiness)
  • Light and soil: understorey of open Eucalyptus miniata and Eucalyptus tetrodonta woodland on flat ground, sandy soils over laterite; the PACSOA wiki recommends a sunny, moist but well-drained position
  • Habit and adult size: trunk usually to 1.5 m, up to 3 or 4 m depending on the source, 14 to 20 cm across; leaves 0.9 to 1.4 m long
  • In the UK, US and Australia: Montgomery Botanical Center (Florida), three accessions (1994 and 2004); James Cook University, Townsville (declared to BGCI); no British record
  • Toxicity: no data specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas yorkiana

By a combination of characters that no other Australian Cycas shares: bright green, keeled leaves, with leaflets that are themselves keeled and almost always curved like a sickle, short soft cataphylls, a thick crown of orange wool around the cataphylls and leaf bases, and no waxy bloom on the leaves or seeds (Hill 1996, 2004). The description below combines Hill (1996, 2004) and the Flora of Australia.

  • Trunk: to 1.5 m, rarely 3 m (4 m according to the Flora), 14 to 20 cm in diameter.
  • Leaves: 90 to 140 cm, openly keeled to almost flat (opposite leaflets set at 150 to 180° to each other), mid-green, semi-glossy, with 160 to 220 leaflets, ending in a spine of 5 to 20 mm; petiole 15 to 30 cm, loosely covered in orange-brown wool.
  • Mid-leaf leaflets: 14 to 20 cm long and 5.5 to 7.5 mm wide, narrowed to 4 to 5 mm at the base, 9 to 11 mm apart, hairless or loosely woolly, mostly sickle-shaped, keeled, with recurved margins. New growth is densely woolly and orange-brown.
  • Cataphylls: narrowly triangular, soft, 6 to 8 cm long, densely covered in orange-brown wool.
  • Male cones: about 20 cm long and 9 cm across; microsporophylls about 35 mm, with a spine of about 6 mm.
  • Megasporophylls: 20 to 32 cm, felted grey and orange, bearing 2 to 6 ovules; blade narrowly triangular, 60 to 100 mm long and 16 to 32 mm wide, regularly toothed with 24 to 32 teeth 3 to 6 mm long; apical spine 11 to 18 mm.
  • Seeds: flattened-ovoid, green turning orange, not bloomed, 28 to 37 mm long and 26 to 32 mm across; sarcotesta 2 to 3 mm thick.

Hybrids

No hybrid has been documented for this species.

Possible confusion

  • Cycas badensis, from the Torres Strait islands, its closest relative: a smaller megasporophyll blade with fewer, shorter lateral spines, a shorter apical spine, less orange wool and mostly straight leaflets (Hill 1996).
  • Cycas campestris, from New Guinea: also has keeled leaflets, but they are rarely sickle-shaped and more narrowed at the base, and its megasporophyll blade is broader, with longer teeth.
  • Cycas xipholepis, further south: flat, dark green leaves and long, hard, pungent cataphylls.
  • Cycas cairnsiana, Cycas ophiolitica, Cycas maconochiei and Cycas lane-poolei, which also carry orange wool around the cataphylls, but without the combination of characters described above (Hill 2004).

Taxonomy

Cycas yorkiana is an accepted name in The World List of Cycads; POWO could not be consulted. Ken Hill described it in his revision of the Australian Cycas (Telopea 7(1): 18–19, fig. 8) and made it the type of series Yorkianosae, in subsection Endemicae: a tropical series of about five species, confined in Australia to Cape York, with two species endemic to New Guinea, characterised by flat or weakly keeled leaves and short, non-pungent cataphylls. It also includes Cycas badensis, Cycas tuckeri and Cycas semota.

In 2004 Hill published an amended description: the Cape Melville population, until then reported as Cycas media, belongs to Cycas yorkiana. De Laubenfels and Adema (1998), by contrast, had placed the species in the synonymy of Cycas angulata, a treatment followed neither by The World List of Cycads nor by the Flora of Australia.

Etymology and history

The epithet refers to Cape York Peninsula, to which the species is endemic (Hill 1996; Haynes 2022).

The type was collected on 11 July 1994 by Ken Hill and Leonie Stanberg, 20.5 km north of the Wenlock River crossing on the road to Bamaga (Hill & Stanberg 4711; holotype in Sydney, isotypes in Brisbane, Canberra, Darwin, at Kew, in Leiden, Melbourne and New York). Older collections exist: near Moreton Telegraph Station (J.R. Maconochie, 1981; K.D. Hill, 1986) and a specimen from Rokeby, north-west of Coen (J. Gordon, 1966). The collection from Bathurst Bay, at Cape Melville (Wannan 926, 1998), was identified in 2004.

Common names

No common name is attested for this species, in English or in any other language, in the sources consulted; WildNet, the Queensland wildlife database, gives none either.

In the wild

Cycas yorkiana is extremely abundant in northern Cape York Peninsula but very localised, north of the Wenlock River; it grows in the understorey of open Eucalyptus miniata and Eucalyptus tetrodonta woodland on flat ground, on sandy soils over laterite (Hill 1996; Flora of Australia). A second area, at Cape Melville, lies within Cape Melville National Park (Hill 2004). The Rokeby specimen, within the range of Cycas xipholepis, remains isolated. Pollination and seed dispersal are not documented.

Conservation status and regulation

The IUCN lists Cycas yorkiana as Near Threatened (NT) under criterion B1b(iii): a restricted range, with a decline in habitat quality. The assessment is by J.D. Bösenberg, cited by The World List of Cycads and the Flora of Australia: according to Crossref it is dated 17 September 2020 and was published in 2022, and GBIF relays the category; the Red List itself could not be consulted. Judgements have changed over time: in 1996 Hill considered it abundant but localised (code 2R); in 2004, after the discovery of the protected Cape Melville population, he regarded it as not threatened.

In Queensland, the state’s WildNet database lists it as “special least concern” under the Nature Conservation (Animals/Plants) Regulation 2020 (a listing recorded in April 2025), as a restricted plant and as a confidential taxon whose locations are not published; it also flags the species as recorded within a protected area, which agrees with Hill’s account of the Cape Melville population. No listing under the national EPBC Act appears in WildNet.

Like every species in the genus except Cycas beddomei, Cycas yorkiana is listed in CITES Appendix II, where the family Cycadaceae has appeared since 4 February 1977. The listing carries annotation #4 (the version adopted at CoP20, in force since 5 March 2026): seeds, pollen, seedlings and tissue cultures obtained in vitro and transported in sterile containers, as well as cut flowers of artificially propagated plants, are not covered by CITES; international trade in the plants themselves requires an export permit. In the European Union the species falls under Annex B of Regulation (EC) No 338/97, whose current annexes are set by Regulation (EU) 2026/1383, applicable since 29 June 2026. Species+, the official CITES database, lists the species, with Australia as its range state, and confirms this status (consulted on 24 October 2026).

This summary does not replace the official texts: check the regulations in force before any purchase or exchange, ask the seller for proof of origin and choose nursery-raised plants grown from seed.

Growing Cycas yorkiana

Cycas yorkiana is grown at least in the Darwin botanic garden, in the Northern Territory, where a member of the French Fous de palmiers forum photographed plants in 2016. The wiki of the Palm and Cycad Societies of Australia (PACSOA) recommends a sunny, moist but well-drained position. No other published cultivation guidance was found. Its habitat, sandy soil over laterite under open eucalypt woodland in a monsoonal climate, points to a free-draining sandy mix: a deduction from the habitat, not a tested result.

Outdoor and in-ground cultivation

The plants seen in the Darwin botanic garden show that the species can be grown in a frost-free tropical climate such as that of the Top End. No planted specimen with a documented history is known from a climate with cool winters.

Container cultivation

Elsewhere, grow it in a pot, in a gritty, sandy mineral compost and in full light, and keep it in a heated glasshouse or conservatory in winter. Australian Cycas in general have a reputation in Europe for declining on their own roots through root rot in cool, wet spells; there is no documented experience for this species.

In cultivation in the UK, US and Australia

In short: one American collection and two Australian ones; no British record.

  • United States: Montgomery Botanical Center, in Coral Gables (Florida), lists three accessions in its online catalogue, numbered 941306 (1994) and 20040258 and 20040259 (2004), according to the year given by the garden’s numbering, and declares the species to BGCI (both consulted on 24 October 2026).
  • Australia: James Cook University, on its Townsville campus, declares the species to BGCI; plants were photographed in the Darwin botanic garden in 2016 (Fous de palmiers forum).
  • United Kingdom: no record in BGCI or in the British catalogues checked in October 2026. The British nursery Trebrown lists the species with a USDA zone 9b rating, its own commercial classification, not a documented trial.

A BGCI declaration shows that a garden held the plant at some point, not that it is alive today. No report from a private grower was found.

Propagation

The plant is dioecious: a male and a female are needed to obtain seed. No germination data specific to the species has been published; Cycas seed is usually sown fresh, in a free-draining mix and in warmth. 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 has been documented.

Cold hardiness

There is no cold-hardiness data for Cycas yorkiana. Northern Cape York has a monsoonal tropical climate without frost: nothing supports the idea that the plant can withstand frost.

Mediterranean and European experience

No cultivation result has been published from southern France or Italy, outdoors or in a pot, and no dated cold event concerns the species. The only message on the species on the French Fous de palmiers forum concerns the Darwin plants; the Jardin zoologique tropical at La Londe-les-Maures, in the Var, has published no observation of this species.

United Kingdom, United States and Australia

Cultivation in the tropical Darwin botanic garden says nothing about cold tolerance. No cold value and no dated cultivation report was found elsewhere. Trebrown’s zone 9b rating is a commercial classification, not a measured result.

Toxicity and precautions

No toxicity analysis specific to Cycas yorkiana has been found, 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. In the absence of evidence to the contrary, treat the plant as poisonous: keep seeds and leaves out of reach of children and animals and wear gloves to clean 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.

Frequently asked questions

Where does the name yorkiana come from?

From Cape York Peninsula, in Queensland, to which the species is endemic.

Where does Cycas yorkiana grow?

North of the Wenlock River, in northern Cape York, and at Cape Melville, in the understorey of open eucalypt woodland on sand.

How can I recognise it?

By its bright green, keeled leaves, its often curved leaflets and the crown of orange wool at the top of the trunk.

How does it differ from Cycas badensis?

Cycas badensis has a smaller, less spiny megasporophyll blade, less orange wool and mostly straight leaflets.

Is it endangered?

Not immediately. It is listed as Near Threatened: abundant, but localised; part of its range lies within a national park.

Is it hardy in the UK?

Nothing suggests so. There is no cold data for the species, and its range is tropical: in Britain it should be grown under glass.

Is it poisonous?

It should be assumed so. No analysis exists for this species, but all the Cycas studied contain serious toxins, especially in their 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. 18–19), series Yorkianosae; reference revision for Australia; full text consulted.]
  • Hill, K.D. (2004). Cycas candida (Cycadaceae), a new species from Queensland together with an extension of range and amended description of Cycas yorkiana. Telopea 10(2): 607–611. [Cape Melville population, amended description, status; 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).]
  • Laubenfels, D.J. de & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Very broad species concept; synonymy under Cycas angulata; full text consulted.]
  • Bösenberg, J.D. (2022). Cycas yorkiana. The IUCN Red List of Threatened Species 2022: e.T41977A69828759. doi:10.2305/IUCN.UK.2022-1.RLTS.T41977A69828759.en [Assessment dated 17 September 2020; reference checked on The World List of Cycads and Crossref, NT category relayed by GBIF; Red List page 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 etymology 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.]