Macrozamia douglasii

Macrozamia douglasii, the Great Sandy Zamia, is a large cycad from south-eastern Queensland, in eastern Australia, that grows in tall forest and on rainforest margins on the deep sands of the old dunes of K’gari (formerly Fraser Island) and the neighbouring Cooloola coast. A species of the genus Macrozamia, it forms a dense crown of 30 to 90 glossy, dark green leaves 2 to 3.5 m long on an underground or short trunk, and is recognised by the brilliant white base of its leaflets and by the few spines at the base of the leaf. It was also published in 1883 as Encephalartos douglasii. It is not threatened, and its seeds, made edible by long soaking, were a food of the Aboriginal people of the island.

Key facts about Macrozamia douglasii

  • Accepted name: Macrozamia douglasii W.Hill ex F.M.Bailey (1883), accepted by The World List of Cycads (version 2026.08.15) and the Australian Plant Census
  • Former names and synonyms: Macrozamia tridentata var. douglasii J.Schust. (1932); Encephalartos douglasii F.Muell. (1883), a synonym according to Jones, Forster and Sharma (2001) and the Australian Plant Census, but not according to The World List of Cycads (see Taxonomy)
  • Family: Zamiaceae, order Cycadales; section Macrozamia, Macrozamia miquelii group
  • Common names: Great Sandy Zamia (Flora of Australia); “Goulbine” (Walter Hill, 1879) and “Coobine” (F.M. Bailey, 1883), recorded as local names
  • Natural range: endemic to south-eastern Queensland, Australia: K’gari and the Cooloola coast north of Noosa (Wide Bay district), at 10 to 80 m
  • IUCN status: Least Concern (LC), assessment by J.D. Bösenberg dated 24 August 2020 and published in 2022
  • CITES and other protection: CITES Appendix II (annotation #4); Annex B in the European Union; Special least concern under Queensland law; not listed under the federal EPBC Act
  • Documented hardiness: no cultivation data (see Cold hardiness)
  • Light and soil: in the wild, tall open forest, stream banks and rainforest margins, on deep grey to white sands over a permanent water table; in cultivation, not documented
  • Habit and adult size: trunk underground or emergent, up to 1 m tall and 70 cm across, unbranched; 30 to 90 leaves (up to 100 according to the Flora of Australia) 1.6 to 3.5 m long
  • In the UK, US and Australia: declared to BGCI by Kew; four accessions at Montgomery Botanical Center; one wild-collected plant at the Royal Botanic Garden Sydney
  • Toxicity: seeds toxic when raw, formerly eaten after long soaking; leaves toxic to livestock throughout the genus (see Toxicity and precautions)

How to recognise Macrozamia douglasii

It is a large Macrozamia with a very full crown, recognised by its lustrous dark green leaves, by the extremely conspicuous, intensely white callus at the base of each leaflet and by its few spines: only the lowest 1 to 4 pairs of leaflets are reduced to rigid spines. The revision by David Jones, Paul Forster and Ish Sharma (2001), who redescribed the species from plants studied in the field, gives the following characters.

  • Trunk: underground or emergent, up to 1 m tall and 70 cm across, unbranched.
  • Leaves: 30 to 90 in a dense crown, 2 to 3.5 m long, erect to widely spreading and arching, bright green to dark green, light green when young; leaf base covered in soft, greyish-white wool; petiole 40 to 60 cm long; axis straight, not or slightly twisted.
  • Leaflets: 120 to 200 per leaf, flat, 25 to 35 cm long and 8 to 12 mm wide, set at about 40° to the axis, dark green and glossy above, paler beneath, with a sharply pointed tip and a prominent white callus at the base; the lowest leaflets are gradually reduced to 1 to 4 pairs of rigid, yellowish spines.
  • Male cones: 1 to 3, cylindrical, 20 to 35 cm long and 5 to 7 cm across, green, on a stalk 20 to 35 cm long; each scale ends in an erect spine 0.5 to 4 cm long.
  • Female cones: 1 to 3, cylindrical to barrel-shaped, 35 to 45 cm long and 10 to 18 cm across, green, on a stalk 25 to 45 cm long; the scales near the top carry spines 3 to 4 cm long.
  • Seeds: oblong, 2.8 to 4 cm long and 1.8 to 2.5 cm wide, with orange to red flesh.

The Flora of Australia (Hill, 1998) gives a trunk up to 0.6 m tall, 30 to 100 leaves 1.6 to 3.4 m long, leaflets 27 to 38 cm long and 7 to 12 mm wide, 4 to 8 lower leaflets reduced to spines, female cones 40 to 50 cm long and seeds 3.6 to 4 cm long; it states that the male cones were not seen. Jones et al. (2001) note numerous discrepancies between their measurements and those of the Flora, and point out that the male cones had been described in 1883 and illustrated in 1936; they are rarely collected because weevil larvae destroy them soon after pollen release (see In the wild).

Bailey’s short original description of 1883 gives much smaller leaves, 2 to 4 feet long (about 60 to 120 cm), a trunk rarely more than 3 feet (about 90 cm) above the ground, and spineless cone scales. According to Jones et al. (2001), the early descriptions were compiled from material sent by several collectors. Len Butt, writing in 1988 for the Palm and Cycad Societies of Australia (PACSOA), found the leaf colour variable: the plants he saw on the island were generally blue-grey, the seedlings dark green.

Hybrids

No natural or cultivated hybrid has been reported.

Possible confusion

The most likely confusion is with Macrozamia miquelii, from central-eastern Queensland. According to Jones et al. (2001), the female cones of the two species are very similar, but Macrozamia miquelii has 6 to 16 pairs of prominent spines towards the base of the leaf, against 1 to 4 pairs in Macrozamia douglasii, whose leaves are also more lustrous and whose leaflet bases are a more intense white.

Macrozamia cardiacensis, from Mount Walsh National Park near Biggenden, is its closest relative on morphological characters, and a limited allozyme (enzyme) analysis tends to support this. It has fewer leaves in the crown, a pale yellow callus at the base of the leaflets, more spines at the base of the leaf, smaller cones and longer spines on the upper scales of the female cone.

Taxonomy

Macrozamia douglasii belongs to the Macrozamia miquelii group of section Macrozamia: medium to large plants with leaves not or only slightly twisted and lower leaflets reduced to spines. The revision by Jones, Forster and Sharma (2001) recognises seven species in this group. L.A.S. Johnson had taken an extremely conservative view in 1959, reducing all the published names of the complex to synonyms of Macrozamia miquelii; Macrozamia douglasii is treated as a species in the Flora of Australia (1998) and is accepted by The World List of Cycads and the Australian Plant Census.

The history of the name is complicated. Walter Hill, director of the Brisbane Botanic Garden, used the name Macrozamia douglasii in 1879 without a description, so it had no formal standing (a nomen nudum). The name was then validated twice in 1883, apparently independently: by Ferdinand von Mueller as Encephalartos douglasii (14 February 1883), and by Frederick Manson Bailey as Macrozamia douglasii, which takes precedence in the genus Macrozamia. Bailey cited no type specimen, so Jones et al. (2001) chose two lectotypes: for Bailey’s name, a pressed leaf collected on Fraser Island by Sheridan, Collector of Customs and Police Magistrate at Maryborough, and sent to Kew by James Pink of the Brisbane Botanic Gardens on 24 April 1882; for Mueller’s name, seeds, cone remnants and a photograph sent in January 1883 by A. McDowall, of Maryborough (National Herbarium of Victoria, Melbourne).

The sources do not fully agree on Encephalartos douglasii. Jones et al. (2001) and the Australian Plant Census treat it as a synonym of Macrozamia douglasii. The World List of Cycads cites only an Encephalartos douglasii F.Muell. published in 1882 in the Systematic Census of Australian Plants, which it treats as an invalid name under Macrozamia miquelii; the only synonym it attaches to the species is Macrozamia tridentata var. douglasii, published by Julius Schuster in 1932.

Etymology and history

The epithet honours John Douglas (1828–1904), a politician and administrator in Queensland and British New Guinea, briefly Premier of Queensland, after whom Port Douglas is also named (Jones et al., 2001). The World List of Cycads, following Haynes (2022), describes him as the collector of the type specimen. Jones et al. (2001) disagree: none of the early collections of the species is his, and his only specimens in the Queensland Herbarium are ferns from Thursday Island; Bailey, by naming the plant “after the Hon. John Douglas”, was validating Walter Hill’s name, and the authors interpret the naming as political patronage, Douglas being active in the same learned societies as Hill and Bailey. The genus name Macrozamia combines the Greek makros, “large”, with the genus name Zamia.

In 1879, after a visit to Fraser Island in April of that year, Walter Hill reported collecting seeds and plants of “Macrozamia douglasii, W. H. (Goulbine)”, adding that “the nuts of this tree are largely used as an article of food by the aborigines”. Live plants were then grown at the Brisbane Botanic Garden: one of the early specimens at the National Herbarium of Victoria is labelled “ex horto bot. Brisbane 1881”.

Common names

The Flora of Australia gives the English name Great Sandy Zamia; K’gari and Cooloola are both protected within the Great Sandy National Park. Two local names were recorded in the 19th century: “Goulbine” by Walter Hill in 1879, and “Coobine”, given as the “native name” by Bailey in 1883. Neither source names the language, and no later published source has been found to confirm them.

In the wild

Macrozamia douglasii grows on K’gari, where it is extremely abundant, and on the adjacent coast near Cooloola, north of Noosa, both in the Wide Bay district (Jones et al., 2001). The island has officially borne its traditional Butchulla name, K’gari, since 7 June 2023 (Queensland Government media statement). The plant grows at 10 to 80 m in tall open forests on old coastal dunes, along streams and on the margins of rainforest, with some plants within the rainforest canopy. The soils are deep grey to white sands with a permanent water table. Len Butt (PACSOA, 1988) also saw it in moist sandy places near freshwater swamps and on dry ridges under banksias, eucalypts and grass trees. The localities recorded in WildNet, the Queensland Government’s wildlife database, span about 110 km from north to south.

Pollen is shed in November, when the male cones are attended by hordes of Tranes weevils, specific to the species, whose larvae then quickly destroy the cones; male cones are therefore absent from the plants once the season is over (Forster et al., 1994, as cited by Jones et al., 2001). Ripe seeds are dispersed from March to April. The plants grow in scattered, sometimes dense colonies with strong seedling recruitment; according to Len Butt, females carry mostly a single cone, sometimes up to three, seedlings often grow around the base of female plants, and marsupials eat the seeds.

Conservation status and regulation

Macrozamia douglasii is not threatened: it is listed as Least Concern (LC) on the IUCN Red List, in an assessment by J.D. Bösenberg dated 24 August 2020 and published in 2022 (The World List of Cycads, GBIF and Crossref, checked on 26 October 2026). In 2001, Jones and his co-authors considered it “very well conserved” in the Cooloola and Fraser Island national parks, today sections of the Great Sandy National Park.

In Queensland it is listed as Special least concern under the Nature Conservation Act 1992, and WildNet flags it as a sensitive species. WildNet records no listing under the federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC).

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 seed-raised plants with their papers.

Growing Macrozamia douglasii

No published source describes the cultivation of Macrozamia douglasii outside Australia. The only grower’s account found is that of Len Butt (PACSOA, 1988): the seed germinates well, even lying beneath the parent plant; the seedling has a single leaf at first, then one or two more in its second year, and the crown forms and hardens at about five years, after which growth speeds up if the plant is grown in a container. Its habitat gives a few pointers, to be taken as hypotheses only.

Outdoor and in-ground cultivation

  • Space: one of the largest Macrozamia with a short trunk; Len Butt measured a crown about 3 m tall and 4 m in circumference.
  • Soil: deep, poor, very free-draining sand; in the wild, never dry at depth, as the water table is permanent.
  • Light: tall forest and rainforest margins in the wild; bright partial shade seems closer to its habitat than harsh full sun, but this is not documented in cultivation.
  • Climate: subtropical coast at low altitude; no data on its tolerance of cold (see Cold hardiness).

Container cultivation

According to Len Butt, young plants grow faster in a container once the crown has formed. A deep pot of sandy, free-draining compost that never dries out completely matches its habitat. Its adult size, with leaves up to 3.5 m long, makes long-term container culture difficult.

In cultivation in the UK, US and Australia

  • United Kingdom: the Royal Botanic Gardens, Kew, declares it to BGCI.
  • United States: Montgomery Botanical Center (Coral Gables, Florida) lists four accessions in its online catalogue, and the San Diego Botanic Garden (Encinitas, California) declares it to BGCI.
  • Australia: the Garden Explorer of the Royal Botanic Garden Sydney lists one plant of wild origin (accession S1992-3819, bed 65g); the Botanic Garden of Adelaide and the System Garden of the University of Melbourne declare it to BGCI. It is not listed at the Australian Botanic Garden Mount Annan.

In all, ten institutions declare the species to BGCI (checked on 26 October 2026), including, in continental Europe, the Prague Botanical Garden, the Marimurtra Botanical Garden in Blanes (Spain) and the Pinetum Blijdenstein in Hilversum (Netherlands), and the Fairy Lake Botanical Garden in Shenzhen. A BGCI listing records a declaration by the garden, not necessarily a living plant today.

Propagation

Macrozamia douglasii is propagated by seed, as the plants are male or female; both sexes are needed and, in cultivation, hand pollination. According to Len Butt, the seed germinates readily. The trunk is unbranched and no source mentions offsets, so division is not an option. Wear gloves to clean the seeds, whose flesh is toxic.

Pests and diseases

No pest or disease specific to the species is documented in cultivation. In the wild, the larvae of Tranes weevils destroy the male cones after pollen release, with no known harm to the plant. For Macrozamia grown in Europe, growers’ forums mainly mention scale insects and rot in cold, wet soil (see the genus page).

Cold hardiness

No cultivation result is documented for Macrozamia douglasii, anywhere in the world.

Mediterranean and European experience

No result has been published in Europe, in the ground or in a pot. In 2014, a member of the French Fous de palmiers forum relayed the ranking of an Australian cycad specialist, who placed Macrozamia douglasii in the last of his four groups, the “less hardy” species of the Queensland coast, without giving a temperature.

United Kingdom, United States and Australia

The species lives on a subtropical coast at 10 to 80 m, and no frost data have been published for its habitat. Any hardiness figure would be a guess, so none is given here. The declarations of Kew, Montgomery and San Diego say nothing about the conditions in which the plants are kept. In Britain and in the colder parts of the United States, it should be treated as a frost-tender plant, although its size makes winter protection difficult.

Toxicity and precautions

The seeds of Macrozamia douglasii are toxic when raw, like those of other Macrozamia. No chemical analysis specific to the species has 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. The long processing that Aboriginal people gave the seeds (see Traditional uses) shows that they could not be eaten as they were.

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

Traditional uses

The seeds of Macrozamia douglasii were an important food on K’gari. Walter Hill noted in 1879 that its “nuts” were “largely used as an article of food by the aborigines”. According to the review by the archaeologist Brit Asmussen (2011), prolonged leaching appears to have been the only technique used on the island: Bracewell, an escaped convict, reported that the kernels were soaked in a running stream for two days and nights (Simpson, 1843), and another account (Miller, in Devitt, 1979) states that after soaking they were dried, ground, made into cakes and cooked. Do not attempt to reproduce these preparations.

Frequently asked questions

Where does Macrozamia douglasii grow?

On K’gari (formerly Fraser Island) and the Cooloola coast, in south-eastern Queensland. It grows on the sands of old dunes, in tall forest and on rainforest margins, at 10 to 80 m.

How can it be told from Macrozamia miquelii?

By the base of the leaf. Macrozamia douglasii has only 1 to 4 pairs of leaflets reduced to spines, against 6 to 16 in Macrozamia miquelii; its leaves are also glossier, and the base of each leaflet is brilliant white.

Did John Douglas collect the plant?

Probably not. The World List of Cycads describes him as the collector of the type, but the 2001 revision found no collection by him and reads the name as a tribute to a politician.

Is it endangered?

No. The IUCN lists it as Least Concern (2022); it is abundant on K’gari and protected in the Great Sandy National Park.

Are its seeds edible?

Not raw. They are toxic; the Aboriginal people of the island ate them only after soaking them for days in running water, then drying, grinding and cooking them.

Can it be grown in Britain or the United States?

No outdoor experience has been published. Kew, Montgomery and San Diego declare it, but none says how the plants are kept, and an Australian specialist ranks it among the least hardy Macrozamia; its large size also makes winter protection difficult.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Bailey, F.M. (1883). A Synopsis of the Queensland Flora. Government Printer, Brisbane, p. 500. [Protologue of Macrozamia douglasii W.Hill ex F.M.Bailey; full text (PDF from The Cycad Society).]
  • Jones, D.L., Forster, P.I. & Sharma, I.K. (2001). Revision of the Macrozamia miquelii (F.Muell.) A.DC. (Zamiaceae section Macrozamia) group. Austrobaileya 6(1): 67–94. [Redescription, typification, habitat, affinities, etymology; full text.]
  • Hill, K.D. (1998). Cycadophyta. In: McCarthy, P.M. (ed.), Flora of Australia 48: 597–661, 717–719. ABRS/CSIRO Publishing, Melbourne. [Description and range; online version.]
  • Forster, P.I., Machin, P., Mound, L. & Wilson, G. (1994). Insects associated with the reproductive structures of cycads in Queensland and north-east New South Wales, Australia. Biotropica 26: 217–222. [Tranes weevils of the male cones; cited by Jones et al. (2001).]
  • Asmussen, B. (2011). Changing perspectives in Australian archaeology, part X. “There is likewise a nut…”: a comparative ethnobotany of Aboriginal processing methods and consumption of Australian Bowenia, Cycas, Macrozamia and Lepidozamia species. Technical Reports of the Australian Museum, Online 23(10): 147–163. doi:10.3853/j.1835-4211.23.2011.1575 [Processing methods recorded on Fraser Island; full text.]
  • 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.]
  • Bösenberg, J.D. (2022). Macrozamia douglasii. The IUCN Red List of Threatened Species 2022: e.T42001A48716693. doi:10.2305/IUCN.UK.2022-1.RLTS.T42001A48716693.en [Least Concern; assessment dated 24 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.]
  • 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.]