Macrozamia conferta

Macrozamia conferta is a small cycad from south-eastern Queensland, in eastern Australia, confined to a few state forests west of Warwick, on the Darling Downs, where it grows in open eucalypt forest at 600 to 750 m. A species of the genus Macrozamia described in 1994, it is one of the smallest cycads of Queensland: a few stiff leaves 35 to 60 cm long, spirally twisted, set with narrow, bright green, shiny leaflets so tightly packed on the axis that they gave the plant its name. It is listed as Vulnerable in Australia and on the IUCN Red List.

Key facts about Macrozamia conferta

  • Accepted name: Macrozamia conferta 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; before its description, the informal name Macrozamia sp. (Warwick K.Hill 3825)
  • Family: Zamiaceae, order Cycadales; section Parazamia, Macrozamia plurinervia complex
  • Common names: no common name attested in English or any other language
  • Natural range: endemic to south-eastern Queensland, Australia: Darling Downs, between Inglewood, Leyburn and Warwick, at 600 to 750 m
  • IUCN status: Vulnerable (VU A2c; B1ab(iii,v)+2ab(iii,v)), 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 Queensland law and under the federal EPBC Act
  • Documented hardiness: no cultivation data (see Cold hardiness)
  • Light and soil: in the wild, open eucalypt forest, on grey-white floury silty loam or on skeletal soils on steep slopes; in cultivation, not documented
  • Habit and adult size: branched underground stem, up to 12 crowns per clump; 1 to 5 leaves 35 to 60 cm long per crown
  • In the UK, US and Australia: grown at the Royal Botanic Garden Sydney and, from wild collections of 2023, at the Australian Botanic Garden Mount Annan; no garden in the United Kingdom or the United States declares it to BGCI
  • Toxicity: not documented for the species; seeds and leaves toxic throughout the genus (see Toxicity and precautions)

How to recognise Macrozamia conferta

It is recognised by its small size, its stiff, erect leaves twisted two or three times along their length, and its narrow leaflets, 2 to 6 mm wide, bright green and shiny on both surfaces and so crowded on the axis that they almost touch. The original description by David Jones and Paul Forster (1994) gives the following characters.

  • Stem: underground, more or less ovoid, 15 to 30 cm across, branched, with up to 12 growths in a clump.
  • Leaves: 1 to 5 per crown, erect, 35 to 60 cm long, dark green and shiny, silky on the axis and petiole when young; leaf base covered in soft, light fawn wool; petiole 7 to 21 cm long; axis twisted two or three times.
  • Leaflets: 90 to 160 per leaf, linear, 6 to 30 cm long and 2 to 6 mm wide, bright green and shiny on both surfaces, channelled above, crowded (1 to 17 mm apart), with a greenish to greenish-yellow, rarely reddish, base; the lowest leaflets are not reduced to spines.
  • Male cones: more or less cylindrical, 7 to 18 cm long and 2.5 to 4 cm across, straight or slightly curved.
  • Female cones: ovoid, erect, 6 to 12 cm long and 3.5 to 6 cm across, on a woolly stalk 10 to 15 cm long.
  • Seeds: ovoid, 2 to 2.5 cm long and 1.6 to 2 cm wide, with red flesh.

The Flora of Australia gives a stem 9 to 15 cm across and leaflets 7 to 21 cm long with inrolled margins, and sums the species up by its stiff, strongly spirally twisted leaves with short, broad, often hairy petioles, and its stiff, crowded, mid-green leaflets.

Hybrids

No hybrid has been reported.

Possible confusion

Jones and Forster (1994) place the species in the complex of Macrozamia plurinervia, a species of northern New South Wales. Macrozamia conferta is easily told from it by its much narrower, bright green, shiny and crowded leaflets, and by its green, much smaller cones and much smaller seeds; Macrozamia plurinervia has grey-green leaflets 4 to 9 mm wide, very glaucous beneath, and glaucous cones.

In their key to the Queensland species, the same authors contrast it with Macrozamia fearnsidei, whose leaflets, also channelled, are much larger (20 to 60 cm long and 6 to 11 mm wide) and widely spaced. The other small species of the Darling Downs, Macrozamia cranei, Macrozamia machinii, Macrozamia occidua and Macrozamia viridis, look similar; each lives in its own area, so the origin of a plant is a strong clue to its identity.

Taxonomy

Macrozamia conferta D.L.Jones & P.I.Forst. is accepted by The World List of Cycads and the Australian Plant Census, with no synonym. It was published in 1994 in the journal Austrobaileya (vol. 4, no. 2, pp. 271–273), in a paper describing seven new species of section Parazamia from south-eastern Queensland. This section brings together small plants with an underground stem, usually twisted leaves, no lower leaflets reduced to spines and no mucilage canals in the leaflets (Johnson, 1959, as summarised by the authors). Within it, Macrozamia conferta belongs to the complex of Macrozamia plurinervia, whose species have moderately broad to broad, usually shallowly channelled leaflets.

The authors saw these narrowly localised species as the result of long geographical isolation. Melinda Laidlaw and Paul Forster (2012) note that the five species of this group on the Darling Downs (Macrozamia conferta, Macrozamia cranei, Macrozamia machinii, Macrozamia occidua and Macrozamia viridis) may result from a fairly recent, probably post-Pleistocene, speciation, or may be five metapopulations of a single, highly variable “superspecies”; the five species are still recognised separately.

The type was collected near Warwick on 20 April 1992 by Paul Forster and Peter Machin (male plant, Forster 9800B); the holotype is held at the Queensland Herbarium in Brisbane and an isotype at the Australian National Herbarium in Canberra. The World List of Cycads gives the collection number as “98008”, apparently a transcription error.

Etymology and history

The epithet comes from the Latin confertus, “crowded, pressed together”, and alludes to the crowded leaflets of the leaf (Jones and Forster, 1994; Haynes, 2022, as given by The World List of Cycads). The genus name Macrozamia combines the Greek makros, “large”, with the genus name Zamia. According to the authors, the plant appears to have been discovered in 1987 by the botanist A.R. Bean while he was collecting eucalypts near Warwick, but no specimen was lodged in a herbarium at the time.

Common names

No common name is attested for Macrozamia conferta, in English or in any other language; the Flora of Australia, WildNet (the Queensland Government’s wildlife database) and the Atlas of Living Australia give none. The scientific name is used.

In the wild

Macrozamia conferta lives only on the Darling Downs, in south-eastern Queensland. In 1994 it was known from two state forests near Warwick; WildNet now places it between Inglewood, Leyburn and Warwick, and a management plan of 2022 places most known populations within an area of about 25 km² that includes Durikai, Bringalily and Devine State Forests, west of Warwick (Queensland Herbarium, 2008, as cited by the plan). It grows at 600 to 750 m in open eucalypt forest (Eucalyptus fibrosa, Eucalyptus melliodora, Eucalyptus crebra, Eucalyptus moluccana), either on flat ground or low ridges in ash-grey to white, floury silty loam, or on steep slopes with grey-white skeletal soils.

The cones mature in October and November and the seeds ripen in February and March. Pollination is carried out by a weevil of the genus Tranes, in an obligate mutualism (Forster et al., 1994). Laidlaw and Forster (2012) note that the male and female cones of these Darling Downs species produce heat. According to the 2022 plan, which draws on Laidlaw and Forster (2012), the heavy seeds are rarely dispersed more than 100 m and a generation lasts 20 to 25 years.

Surveys made before the construction of a wind farm west of Warwick give an idea of the populations: from 1 to 592 plants per hectare, one female for every eight males on average, and 96% adult plants.

Conservation status and regulation

Macrozamia conferta is listed as Vulnerable (VU) on the IUCN Red List under criteria A2c and B1ab(iii,v)+2ab(iii,v), which refer to a past decline of its habitat and a very small range with continuing decline. 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). It is also listed as Vulnerable in Queensland and under the federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC), effective from 16 July 2000 according to the Flora of Australia.

The threats identified by the federal conservation advice of 2008, as summarised in the 2022 plan, are the illegal removal of adult plants, the past poisoning of cycads by graziers (kerosene, arsenic or herbicides applied to the growing point to protect livestock), intense fires in years of heavy seed production, logging and the loss of pollinators. Laidlaw and Forster (2012) found that, unlike the other four species of the group, its range depends on land zone and vegetation rather than on temperature: their models predict that its suitable habitat will contract around the present populations as the climate warms, but that the part of it within protected areas will remain largely stable.

In 2022, the building of the MacIntyre wind farm and its power line was to affect 3,664 plants that could not be avoided, about 3,517 of them adults. The federal approval required their translocation to a nearby site, the collection and sowing of their seeds, and the establishment within 20 years of a viable population at least equal to the one affected.

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 conferta

No published source describes the cultivation of Macrozamia conferta by amateurs, in Australia or elsewhere. The only practical indications come from the 2022 translocation plan, which describes how seedlings are raised in a nursery. The Palm and Cycad Societies of Australia (PACSOA) advise, briefly, a sunny, well-drained position. Its habitat suggests a poor, very free-draining soil and the bright light of open forest. It is a small plant, well suited to a pot.

Outdoor and in-ground cultivation

  • Light: sunny, according to the PACSOA; in the wild, the light shade of open eucalypt forest.
  • Soil: poor and very free-draining; in the wild, silty loam or shallow skeletal soils.
  • Water: no published data for the species.
  • Space: very little; a clump of small crowns, with leaves at most 60 cm long.

Container cultivation

In the 2022 plan, seedlings are moved into 140 mm pots once the first leaf appears, then, once the roots fill the pot (after 9 to 12 months), into 300 mm pots of the same mix; plants are planted out after about three years. This nursery schedule is the only published guide to growing the species in a pot. 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

  • Australia: the Royal Botanic Garden Sydney’s Garden Explorer lists a wild-collected accession of 1990 (S1990-2181/2) in bed 102i (updated 1 October 2026); the Australian Botanic Garden Mount Annan lists twelve wild-collected accessions of 2023, totalling about 150 plants (updated 15 October 2026).
  • United States: no garden declares it to BGCI, and it is not in the online catalogue of Montgomery Botanical Center.
  • United Kingdom: no British garden declares it to BGCI.

In all, three institutions declare the species to BGCI (checked on 26 October 2026): the two gardens of Sydney and the Fairy Lake Botanical Garden in Shenzhen, China. A BGCI listing records a declaration by the garden, not necessarily a living plant today. No English-language grower’s report has been found.

Propagation

Macrozamia conferta is propagated by seed, as the plants are male or female. According to Paul Forster, quoted in the 2022 plan, seeds collected when the cone breaks up, still in their flesh, are not ready to germinate: the embryo needs 8 to 12 months to develop. Older seeds whose flesh has gone, picked up from the ground, should be ready. Seeds are stored in paper bags, in a dry, well-ventilated place away from extremes of temperature; those that float in a bucket of water are discarded. Seeds germinate best in the warmer months; after cleaning, they are lightly pressed into the surface of a seed-raising mix, not buried, and kept watered. 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 foliage is eaten by native insects that depend on cycads, and grazing of the leaves by livestock or native animals can injure or kill the plants; adult plants resprout after fire, unlike seeds and seedlings (2022 plan).

Cold hardiness

No cultivation result is documented for Macrozamia conferta, 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 conferta among the “less hardy” species of inland Queensland, without giving a temperature.

United Kingdom, United States and Australia

The Darling Downs, where the species lives, have an annual mean temperature of 11.9 to 18.4 °C (53.4 to 65.1 °F) and an annual rainfall of 602 to 1,061 mm (Laidlaw and Forster, 2012), but no frost data have been published for its sites, and no hardiness rating, even commercial, has been found. Any figure would be a guess, so none is given here. The underground stem is protected by the thermal inertia of the soil, which a potted plant lacks. In Britain and in the colder parts of the United States, a pot kept frost-free in winter is the prudent choice.

Toxicity and precautions

No analysis specific to Macrozamia conferta 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; cycasin can cause debilitating symptoms or death in many mammals that eat enough of it (Halford, 1997, as cited by the 2022 plan). Cattle that eat the leaves of Macrozamia 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 2022 plan also recalls that graziers used to poison cycads to protect their stock.

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

No traditional use specific to Macrozamia conferta is documented. Other Macrozamia provided Aboriginal peoples with seeds that could be eaten after long processing (see the genus page).

Frequently asked questions

Why is it called conferta?

Because its leaflets are crowded. The Latin confertus means “crowded, pressed together”: the leaflets are only 1 to 17 mm apart on the axis of the leaf.

Is it endangered?

It is Vulnerable. The IUCN (2022), Queensland and the federal EPBC Act all list it as Vulnerable, because of its very small range and the threats to its populations.

What pollinates its cones?

A weevil of the genus Tranes. The plant and the insect depend on each other to reproduce, and the cones produce heat, as in the related species of the Darling Downs.

How can it be told from Macrozamia plurinervia?

By its leaflets and cones. Those of Macrozamia conferta are narrower, bright green, shiny and very crowded, and its cones are green and smaller, whereas Macrozamia plurinervia has grey-green leaflets, glaucous beneath, and glaucous cones.

How do you germinate its seeds?

By letting them mature first. Freshly fallen seeds need 8 to 12 months before they can germinate; they are then cleaned and pressed lightly into the surface of a seed-raising mix, preferably in the warm months.

Can it be grown in Britain or the United States?

Nobody knows yet. No grower has published any experience, and an Australian specialist ranks it among the less hardy Macrozamia; its small size makes it easy to grow in a pot kept frost-free in winter.

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, pp. 271–273; full text.]
  • Laidlaw, M.J. & Forster, P.I. (2012). Climate predictions accelerate decline for threatened Macrozamia cycads from Queensland, Australia. Biology 1(3): 880–894. doi:10.3390/biology1030880 [Climate of the Darling Downs, thermogenic cones, factors limiting the range, projected effects of warming; full text (Europe PMC).]
  • 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. [Weevil pollination; cited by the Flora of Australia and WildNet.]
  • Hill, K.D. (1998). Cycadophyta. In: McCarthy, P.M. (ed.), Flora of Australia 48: 597–661, 717–719. ABRS/CSIRO Publishing, Melbourne. [Description; online version.]
  • 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 conferta. The IUCN Red List of Threatened Species 2022: e.T41953A48715936. doi:10.2305/IUCN.UK.2022-1.RLTS.T41953A48715936.en [Vulnerable, criteria A2c and B1ab(iii,v)+2ab(iii,v); 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.]
  • 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.]