Cycas brunnea

Cycas brunnea is a cycad of north-western Queensland and the far east of the Northern Territory, in Australia, known from a few populations around the headwaters of Lawn Hill Creek and on Wollogorang Station. Described by Ken Hill in 1992, this species of the genus Cycas owes its name to the dark brown down covering its new growth. Its bluish leaflets and large, bloomed seeds link it to Cycas angulata, with which it forms a small series. The IUCN lists it as Near Threatened (2022), and Queensland protects it as a Vulnerable species.

Key facts about Cycas brunnea

  • Accepted name: Cycas brunnea K.D.Hill (1992), 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), and treated under that name in the Northern Territory (see Taxonomy)
  • Family: Cycadaceae, order Cycadales
  • Common names: no name attested, in English or any other language
  • Natural range: Australia, north-western Queensland (headwaters of Lawn Hill Creek and its tributaries) and north-eastern Northern Territory (Wollogorang Station)
  • IUCN status: Near Threatened (NT), criterion B1a, assessment by J. D. Bösenberg published in 2022, NT according to GBIF
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union; Vulnerable in Queensland (Nature Conservation (Plants) Regulation 2020)
  • Documented hardiness: no measured data; the PACSOA wiki says it tolerates light frosts, without figures (see Cold hardiness)
  • Light and soil: exposed sites on limestone or limestone-derived alluvium (Lawn Hill); sandy alluvium in sandstone gorges (Wollogorang)
  • Habit and adult size: trunk to 2 m, rarely 5 m, 17 to 23 cm across in the original description; herbarium labels record plants to 6 and even 8 m; leaves 1.2 to 1.7 m long
  • In the UK, US and Australia: only Naples Botanical Garden (Florida) 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 brunnea

According to Ken Hill, three characters identify Cycas brunnea in Australia: relatively broad, bluish leaflets with slightly recurved to almost flat margins, on openly keeled leaves; dark brown hairs on the new growth; and large, strongly bloomed seeds. In detail, after the original description (1992) and the Flora of Australia:

  • Trunk: up to 2 m, rarely 5 m, 17 to 23 cm across. Later herbarium collections record taller plants: “cycad to 6 m” on the labels of Hill and Stanberg (1991), and plants to 8 m, some with several heads and trunks up to 50 cm across at the base in old plants, on a 1997 collection from Queensland.
  • Leaves: 120 to 170 cm, moderately keeled (the two ranks of leaflets at 90 to 135° to each other), with 160 to 240 leaflets, grey-green or blue and dull; the rachis usually ends in a short spine; petiole 28 to 60 cm, spiny along 20 to 50% of its length, rarely unarmed.
  • Median leaflets: 17 to 27 cm by 6 to 7.5 mm, inserted at 40 to 50°, 9 to 13 mm apart, with slightly recurved margins; distinctly blue when new, later greyish green.
  • New growth: densely covered with brown hairs; cataphylls (the scales protecting the growing point) pungent, 7 to 10 cm, orange-brown felted.
  • Male cones: ovoid to almost globular, about 21 cm by 13 cm, yellow; microsporophylls with a fine, upturned terminal spine about 28 mm long.
  • Megasporophylls (the fertile leaves of female plants): 28 to 32 cm, orange-felted, carrying 4 to 6 ovules; blade narrowly triangular, 45 to 80 mm, finely toothed, terminal spine 16 to 32 mm.
  • Seeds: ovoid, green turning orange, bloomed, 36 to 39 mm by 28 to 32 mm.

As in Cycas angulata, the leaflets have a continuous layer of cells beneath the epidermis, stomata sunk in deep pits and a thick cuticle (Hill 1996).

Hybrids

No natural or garden hybrid is documented. Hill’s 1996 revision, which lists the known hybrid populations between Australian Cycas, records none for this species.

Possible confusion

  • Cycas angulata, its closest relative: the same habit, the same dark brown down, the same large, almost globular male cones and finely toothed megasporophylls; but narrower leaflets (4.5 to 6.5 mm), more crowded (6 to 9 mm apart) and more strongly recurved, less blue foliage, and larger seeds (45 to 60 mm) without bloom;
  • Cycas megacarpa, from central-eastern Queensland, which also has pungent cataphylls but a slender trunk (less than 15 cm across) and shorter leaves;
  • Cycas couttsiana and the other blue Cycas of Queensland, whose cataphylls are soft, not pungent.

Taxonomy

Cycas brunnea is accepted by The World List of Cycads; POWO could not be consulted directly. Ken Hill described it in 1992 in Telopea (volume 5, pages 200 and 201), in a preliminary account of the Cycas of Queensland that added six new species. In 1996 he placed it with Cycas angulata in series Angulatosae, within subsection Endemicae of section Cycas: keeled leaves, glaucous leaflets with recurved margins, hard, pungent cataphylls and large, almost globular male cones.

De Laubenfels and Adema (Blumea, 1998) sank it into the synonymy of Cycas angulata, within a very broad concept of that species. This view has not been followed by the Australian Plant Census or by The World List of Cycads. The Flora of Australia nevertheless notes that plants in the Northern Territory are treated as Cycas angulata, without giving the reason. A possible origin is a 2004 review of the gymnosperms of the Northern Territory by Dale Dixon (The Beagle 20: 1–24), cited to that effect in an observer’s note on iNaturalist; the review itself could not be consulted, so this remains unconfirmed.

Etymology and history

The epithet brunnea comes from the late Latin brunneus, “brown”, referring to the brown hairs on the new growth that distinguish the species from its neighbours; the explanation is given in the original description.

The type was collected on 16 November 1972 by John Maconochie at Running Waters, on Lawn Hill Creek (Burke district, Queensland); the holotype is at the Northern Territory Herbarium in Darwin (DNA), with isotypes in Brisbane (BRI) and Canberra (CANB). His labels describe plants growing on loamy levee banks of watercourses, among eucalypts, paperbarks and ghost gums, at the foot of sandstone ridges, with trunks of 0.75 to 1.85 m. Ken Hill and Leonie Stanberg collected the species in September 1991 on Colless Creek, in Lawn Hill National Park, and on Wollogorang Station, in the Northern Territory.

Common names

No common name is attested for this species, in English or in an Aboriginal language, in the sources consulted.

In the wild

Cycas brunnea is known from only a few populations, in a small area straddling the border between Queensland and the Northern Territory. In Queensland it grows at the headwaters of Lawn Hill Creek and its tributaries, on limestone or on alluvium derived from limestone, in exposed sites along small open valleys; herbarium labels mention open shrubland on skeletal grey clay over limestone outcrops (1991), a gully running into Colless Creek (1995) and a narrow valley between limestone bluffs, in open woodland of Corymbia capricornia, with numerous seedlings (1997). In the Northern Territory, on Wollogorang Station, it forms small relict stands on sandy alluvium in gorges of siliceous sandstone, in vine thicket according to a 1991 label.

In 1996 Ken Hill noted that several of the known populations are large, under little threat and protected in national parks. The pollinator, phenology and seed dispersers are not documented for the species.

Conservation status and regulation

Cycas brunnea is listed as Near Threatened (NT) by the IUCN, under criterion B1a (small range, few populations), in the assessment by John Donald Bösenberg published in 2022; the IUCN data relayed by GBIF confirm the NT category (consulted on 21 October 2026). An earlier assessment by K. D. Hill (2010) also exists, according to Crossref. In 1992 Ken Hill gave it the code 3RC in the Australian system for rare plants (rare, present in a conservation reserve), and the PACSOA wiki describes it as “restricted but not threatened”. In Queensland, the Flora of Australia states that it is listed as Vulnerable in the November 2022 list of the Nature Conservation (Plants) Regulation 2020. The Red List itself could not be consulted directly.

Like every species in the genus except Cycas beddomei, Cycas brunnea 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 brunnea

In short: a sun-loving cycad of the seasonally dry tropics, for very well-drained soil. The only species-specific advice is a short note on the PACSOA wiki; no institution has published growing guidance, and no grower’s report has been found.

Outdoor and in-ground cultivation

The PACSOA wiki recommends a sunny, very well-drained position and describes the species as slow-growing; it prefers a seasonally dry tropical climate, although, according to the same note, it will tolerate light frosts, with no temperature given. Its natural habitat, limestone soils or sandy alluvium in exposed sites, with a long dry season, points the same way: full sun and moderate watering. It is not known from any outdoor planting outside its range.

Container cultivation

In the United Kingdom and other temperate regions, it would be a plant for a glasshouse. The French nurseryman Simon Lavaud, in a 2021 note on growing Australian Cycas in a European climate, does not name Cycas brunnea, but his general advice applies to the group: a very mineral substrate, full sun or the brightest spot in the glasshouse, a glasshouse to lengthen the growing season, and generous watering in hot weather, reduced when temperatures fall below 20 °C (68 °F) and stopped when nights drop below 10 °C (50 °F), because of a very high risk of root rot. 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

In short: a single, undated record.

  • United States: Naples Botanical Garden (Florida) declares the species in BGCI PlantSearch (consulted in October 2026); the garden grows its cycads outdoors, but no source names this species there.
  • United Kingdom and Australia: no garden declares it in BGCI, 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; PalmTalk and Dave’s Garden could not be consulted.

Propagation

Like all Cycas, Cycas brunnea is dioecious: a male and a female plant are needed for fertile seed. No germination data specific to the species have been published; a 1997 herbarium label notes numerous seedlings in the wild. 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. Cycad scale insects, including Aulacaspis yasumatsui, can affect any cultivated Cycas, and root rot in a cool, wet substrate is the cause of failure most often cited for Australian Cycas in Europe (Lavaud 2021).

Cold hardiness

No measured cold-tolerance data exist for Cycas brunnea. Its range lies entirely in the tropics of northern Australia. The PACSOA wiki says it will tolerate light frosts, but gives no temperature, duration or source of observation; treat this as an indication only.

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 cold report for this species.

United Kingdom, United States and Australia

No cold reading and no dated growing report were found, either on forums or from botanic gardens. Without a documented trial, no USDA zone can be given; in temperate climates, keep it frost-free under glass.

Toxicity and precautions

No toxicity analysis specific to Cycas brunnea 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. In Cycas angulata, its closest relative, a 2026 study found high levels of toxins in both the kernel and the orange flesh of the seeds (Lloyd et al. 2026). 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

Why is it called brunnea?

Because its new growth is covered with dark brown hairs: brunneus means “brown” in late Latin.

Where does it grow?

In a small area of northern Australia: at the headwaters of Lawn Hill Creek, in Queensland, and on Wollogorang Station, in the Northern Territory.

How can it be told from Cycas angulata?

By its broader, flatter leaflets, more widely spaced on the rachis, its bluer foliage and its smaller, bloomed seeds.

Is it a form of Cycas angulata?

No, according to current reference checklists. A 1998 revision placed it under Cycas angulata, and the Flora of Australia notes that it is still treated that way in the Northern Territory.

Is it endangered?

Partly. The IUCN lists it as Near Threatened (2022) because of its small range, and Queensland protects it as a Vulnerable species.

Can it be grown outdoors in the UK?

No, almost certainly not. Its range is tropical, and the light frosts it is said to tolerate are not quantified; it needs a glasshouse.

Is it poisonous?

It must be assumed so. No analysis specific to the species exists, but the Cycas studied, including its close relative Cycas angulata, contain dangerous toxins.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Hill, K.D. (1992). A preliminary account of Cycas (Cycadaceae) in Queensland. Telopea 5(1): 177–206. doi:10.7751/telopea19924964 [Original description (pp. 200–201); full text consulted.]
  • Hill, K.D. (1996). A taxonomic revision of the genus Cycas (Cycadaceae) in Australia. Telopea 7(1): 1–64. doi:10.7751/telopea19963040 [Reference revision for Australia; 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; cited after The World List of Cycads and the Flora of Australia.]
  • Dixon, D. (2004). A review of the gymnosperms of the Northern Territory. The Beagle: Records of the Museums and Art Galleries of the Northern Territory 20: 1–24. doi:10.5962/p.286319 [Reference checked on Crossref; text not consulted (Biodiversity Heritage Library not accessible).]
  • Hill, K.D. (2010). Cycas brunnea. The IUCN Red List of Threatened Species: e.T41971A10613719. doi:10.2305/IUCN.UK.2010-3.RLTS.T41971A10613719.en [Earlier assessment; reference checked on Crossref, category not checked.]
  • Bösenberg, J.D. (2022). Cycas brunnea. The IUCN Red List of Threatened Species 2022: e.T216580742A67337723. doi:10.2305/IUCN.UK.2022-1.RLTS.T216580742A67337723.en [Current assessment (a later version of the same assessment carries the identifier e.T216580742A243415050); references checked on Crossref, NT category relayed by GBIF; page not consulted (access blocked).]
  • Lloyd, G.R., Holt, P., Maher, K. & Gleadow, R.M. (2026). Integrated LC/MS–MS approaches reveal toxicity differences across seed layers of Cycas angulata. Annals of Botany. doi:10.1093/aob/mcag169 [Toxins of the closest relative; abstract 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 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.]