Macrozamia occidua

Macrozamia occidua is a small cycad with no visible trunk from southern Queensland, in eastern Australia, known only from a few small stands in Sundown National Park, close to the New South Wales border, where it grows in dry eucalypt woodland on stony soils. This species of the genus Macrozamia, described in 1994, was brought to the attention of botanists by a park ranger. It is listed as Vulnerable, and no cultivation experience has been published.

Key facts about Macrozamia occidua

  • Accepted name: Macrozamia occidua D.L.Jones & P.I.Forst. (1994), accepted by The World List of Cycads (version 2026.08.15) and the Australian Plant Census
  • Former names and synonyms: none
  • Family: Zamiaceae, order Cycadales; section Parazamia, Macrozamia plurinervia complex
  • Common names: no English or Aboriginal name specific to the species is recorded
  • Natural range: southern Queensland, Australia: Sundown National Park, south-west of Stanthorpe; 800 to 1,000 m according to WildNet
  • IUCN status: Vulnerable (VU D2), assessment by J.D. Bösenberg dated 14 August 2020 and published in 2022
  • CITES and other protection: CITES Appendix II (annotation #4); Annex B in the European Union; Vulnerable under the federal EPBC Act and under Queensland law
  • Documented hardiness: no cultivation data; frequent frosts in its region, with −10.6 °C (12.9 °F) the lowest temperature recorded at Stanthorpe (see Cold hardiness)
  • Light and soil: in the wild, open forest and dry woodland on thin, sandy, stony soils derived from volcanic and sedimentary rocks (“traprock”)
  • Habit and adult size: underground stem 10 to 20 cm across, unbranched; 1 to 5 leaves 40 to 75 cm long
  • In the UK, US and Australia: no botanic garden declares it to BGCI or lists it in the online catalogues checked
  • Toxicity: not documented for the species; seeds and leaves toxic throughout the genus (see Toxicity and precautions)

How to recognise Macrozamia occidua

Macrozamia occidua is recognised by its short leaves, twisted in a spiral, its short and fairly broad leaflets, dark green above and glaucous beneath, whose tips sometimes carry two or three teeth, and its bluish-grey (glaucous) cones. The original description (Jones and Forster, 1994) gives the following characters.

  • Stem: underground, more or less ovoid, 10 to 20 cm across, unbranched.
  • Leaves: 1 to 5 in a sparse, obliquely erect crown, 40 to 75 cm long, dark green; the expanded base densely covered in soft fawn to grey-green wool; petiole 10 to 25 cm long; axis spirally twisted two to four times.
  • Leaflets: 80 to 120 per leaf, linear, 6 to 20 cm long and 3 to 10 mm wide, dark green above, glaucous and powdery beneath, crowded; tip tapering, sometimes with two or three teeth; callous base greenish-yellow to yellow, rarely pink; the lowest leaflets do not become spines.
  • Male cones: more or less cylindrical, 10 to 24 cm long and 3.5 to 5 cm across, straight, glaucous.
  • Female cones: ovoid, 10 to 14 cm long and 5 to 7 cm across, glaucous; each scale ends in a spine, the longest, near the top, about 2 cm long.
  • Seeds: ellipsoid to ovoid, 1.8 to 2.5 cm long and 1.5 to 2 cm wide, with orange to red flesh.

The Flora of Australia (Hill, 1998) gives slightly different figures: leaflets 4 to 10 mm wide, dull to semi-glossy, and female cones 5 to 8 cm across.

Hybrids

No hybrid involving Macrozamia occidua has been documented, in the wild or in cultivation.

Possible confusion

Its closest relative is Macrozamia cranei, which grows near Texas, also on the Darling Downs. According to Jones and Forster (1994), Macrozamia occidua differs in its shorter leaves, its shorter, dull leaflets and its glaucous female cones, whereas those of Macrozamia cranei are green. Their habitats differ too: Macrozamia occidua grows in open forest on traprock, Macrozamia cranei near limestone outcrops, in open forest or semi-evergreen vine thicket.

The Flora of Australia places the species in the group of Macrozamia plurinervia, where it stands out by its short leaves with short, broad leaflets. On the Darling Downs, the origin of a plant is a strong clue to its identity.

Taxonomy

Macrozamia occidua D.L.Jones & P.I.Forst. is accepted by The World List of Cycads and the Australian Plant Census. David L. Jones and Paul I. Forster described it in 1994 in the journal Austrobaileya (vol. 4, no. 2, p. 278, fig. 5), in a paper describing seven new species of section Parazamia from Queensland. The type, a male plant, was collected in Sundown National Park on 8 January 1993 by P.I. Forster and P. Machin (no. 12663B); the holotype is held in Brisbane (BRI), with an isotype in Canberra (CBG).

Section Parazamia brings together small species with an underground stem, usually twisted leaves, no spiny leaflets and no mucilage canals. The authors placed Macrozamia occidua in the Macrozamia plurinervia complex, which includes several narrowly localised species of the Darling Downs. The species has no synonym and has never been known under another name.

Etymology and history

The epithet comes from the Latin occiduus, “going down, setting”, which Jones and Forster (1994) call “an oblique reference to the Sundown country where the type specimen was collected” (see also Haynes, 2022). The genus name Macrozamia combines the Greek makros, “large”, with the genus name Zamia.

The species was discovered by Peter Hazelgrove, ranger at Sundown National Park, who brought it to the authors’ attention; the oldest specimen cited in the description was collected in October 1990.

Common names

No common name specific to Macrozamia occidua is recorded in English, and no Aboriginal name is attested for it. Gardeners and botanists use the scientific name.

In the wild

Macrozamia occidua was known from two populations in Sundown National Park, in south-eastern Queensland, when it was described (Jones and Forster, 1994); the Flora of Australia speaks of a few small stands, and WildNet places it in a small area south-west of Stanthorpe, between 800 and 1,000 m. According to the original description, it grows in sandy soil derived from acid to intermediate volcanic rocks, greywacke and mudstone, the “traprock” of the region, in open forest dominated by Eucalyptus prava and Eucalyptus sideroxylon. The understorey includes Dampiera purpurea, Goodenia delicata, Hibbertia stricta, Persoonia sericea and Olearia microphylla. WildNet, after a federal profile of 2008, describes skeletal sandy soils and granite on slopes, in dry woodland and open forest.

The cones mature from September to January and the seeds ripen from February to April. According to WildNet, young seedlings and seeds lying on the surface are killed by fire. Nothing has been published on the pollinators of the species.

Conservation status and regulation

Macrozamia occidua is listed as Vulnerable (VU) on the IUCN Red List under criterion D2, which applies to a species known from a very restricted area or very few locations, exposed to a sudden threat. The assessment, by J.D. Bösenberg, is dated 14 August 2020 and was published in 2022 (The World List of Cycads, GBIF and Crossref, checked on 26 October 2026).

In Australia, it is listed as Vulnerable under the federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC), effective 16 July 2000, and under the Queensland Nature Conservation (Plants) Regulation 2020 (Flora of Australia; WildNet, checked on 26 October 2026). WildNet also treats it as a restricted plant and a sensitive species. All known populations lie within the national park, but the authors of the description expected in 1994 “some poaching pressures”.

Like other Macrozamia, it has been listed in CITES Appendix II since 4 February 1977, with annotation #4: seeds and pollen are exempt, but plants are not. In the European Union it falls under Annex B of Regulation (EC) No 338/97, as amended by Regulation (EU) 2026/1383, applicable since 29 June 2026 (Species+, checked on 26 October 2026). Check the regulations in force before any purchase or import, and buy only plants whose cultivated origin is proven.

Growing Macrozamia occidua

No cultivation experience with Macrozamia occidua has been published. Its habitat gives a few pointers: dry slopes with thin, sandy soils, an upland climate with cold, frosty winters and most rain in summer. These are assumptions drawn from the wild, not tested advice.

Outdoor and in-ground cultivation

  • Light: in the wild, dry woodland and open forest; a bright position is a deduction from the habitat.
  • Soil: in the wild, thin, sandy, stony soils; a very free-draining gritty mix is the logical choice.
  • Water: no published data; at Stanthorpe, the nearest weather station, about 765 mm of rain falls a year, more in summer than in winter.
  • Space: a small plant, with a few leaves up to 75 cm long.

Container cultivation

No container culture has been described. Its size suits a deep pot of gritty compost. A plant in a pot loses the protection that the soil gives to its underground stem in winter (see Cold hardiness).

In cultivation in the UK, US and Australia

No botanic garden in Britain, the United States or Australia declares Macrozamia occidua to BGCI, and neither the Royal Botanic Garden Sydney, Mount Annan nor Montgomery Botanical Center in Florida lists it in its online catalogue (checked on 26 October 2026). No grower in the English-speaking world has published a cultivation result.

Propagation

Macrozamia occidua is propagated by seed. A male and a female plant are needed, and outside Australia the female cone must be hand-pollinated. The seeds of this protected species must come from a legal, documented source. Wear gloves to clean the seeds, whose flesh is toxic.

Pests and diseases

No pest or disease specific to Macrozamia occidua is documented. In the wild, fire is the main danger to seedlings. For Macrozamia grown in Europe, growers’ forums mainly mention scale insects and rot in cold, wet soil (see the genus page).

Cold hardiness

The cold hardiness of Macrozamia occidua has not been tested in cultivation: no result has been published.

Mediterranean and European experience

No result has been published in Europe, in the ground or in a pot.

United Kingdom, United States and Australia

At Stanthorpe (815 m), the nearest weather station, some 20 to 45 km from the known localities, the lowest temperature recorded since 1957 is −10.6 °C (12.9 °F), on 23 June 1961; frost occurs on about 43 days a year on average, and the mean July minimum is 1.1 °C (34.0 °F) (Bureau of Meteorology). Sundown National Park, further west, has no station, and the cold the plants endure in the wild has never been measured. These figures describe the region, not the tolerance of the plant; in nature its stem is protected by the soil. In Britain and in the colder parts of the United States, a pot kept frost-free and dry in winter is the prudent choice.

Toxicity and precautions

No toxicity data specific to Macrozamia occidua have been published, but the risk is well documented for the genus. Macrozamia contain toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived, a poison of the liver; cattle that eat the leaves can develop a locomotor disorder of the hind legs (Healy, 1967), which McKenzie (2006) describes as irreversible, ending in paralysis of the hindquarters, with no treatment.

Treat the plant as toxic: wear gloves to handle the seeds and keep them out of reach of children and animals. In case of ingestion, contact a poison centre, a doctor or a vet without delay.

Traditional uses

No traditional use specific to Macrozamia occidua is recorded. Other Macrozamia provided Aboriginal peoples with seeds that could be eaten after long processing (see the genus page); never eat cycad seeds.

Frequently asked questions

What does occidua mean?

“Going down” or “setting”, in Latin. The name evokes the setting sun, an oblique reference to Sundown National Park, where the species was found.

Who discovered Macrozamia occidua?

Peter Hazelgrove, a ranger at Sundown National Park. The botanists David L. Jones and Paul I. Forster then described it in 1994.

How does it differ from Macrozamia cranei?

By its shorter leaves and leaflets, its dull leaflets and its glaucous female cones. The two species also live in different habitats: traprock soils for one, limestone outcrops for the other.

How hardy is it?

Nobody knows. No trial has been published, but its region has cold winters: frost occurs on more than 40 days a year at Stanthorpe, with a record low of −10.6 °C (12.9 °F).

Is it endangered?

Yes, it is Vulnerable. It is known only from a few stands in a single national park, which exposes it to a single fire or to poaching.

Is it poisonous?

Probably, like all cycads. No study deals with this species, but the seeds and leaves of Macrozamia are toxic to people and livestock.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Jones, D.L. & Forster, P.I. (1994). Seven new species of Macrozamia section Parazamia (Miq.) Miq. (Zamiaceae section Parazamia) from Queensland. Austrobaileya 4(2): 269–288. [Protologue of Macrozamia occidua, pp. 278–279: description, type, habitat, discovery, etymology; full text (PDF made available by The World List of Cycads).]
  • Hill, K.D. (1998). Cycadophyta. In: McCarthy, P.M. (ed.), Flora of Australia 48: 597–661, 717–719. ABRS/CSIRO Publishing, Melbourne. [Description, read in the online version of the flora.]
  • Bösenberg, J.D. (2022). Macrozamia occidua. The IUCN Red List of Threatened Species 2022: e.T41965A48869643. doi:10.2305/IUCN.UK.2022-1.RLTS.T41965A48869643.en [Vulnerable, criterion D2; assessment dated 14 August 2020, from Crossref.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology, as given by The World List of Cycads.]
  • Healy, P.J. (1967). Macrozamia poisoning. Institute of Inspectors of Stock of New South Wales Year Book. [Reprinted by Flock & Herd.]
  • McKenzie, R.A. (2006). Toxicology for Australian Veterinarians: cycads (Cycas, Macrozamia, Lepidozamia, Bowenia), pp. 282–288. Animal Health Australia, Australian Animal Pathology Standards Program (PDF): https://aapspextranet.animalhealthaustralia.com.au/wp-content/uploads/2019/04/tav7_17_unknowntoxins_pt2.pdf [Australian veterinary reference text; describes the cattle syndrome as irreversible, ending in paralysis of the hindquarters, with no treatment.]
  • 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 list.]