For 163 years, Macrozamia spiralis wore another plant’s clothes. When Richard Anthony Salisbury described Zamia spiralis in 1796 from a collection made near Port Jackson (Sydney), his description — based on a plant with relatively few, small, twisted leaves — was subsequently applied to the large, abundant Burrawang that dominated the Sydney Basin understorey. The real spiralis was pushed aside, known only as Macrozamia corallipes (Hooker, 1872). It was not until 1959, when Lawrie Johnson re-examined Salisbury’s original description, that the confusion was resolved: the name spiralis belonged to the small cycad, and the large one needed a new name — Macrozamia communis. The irony is rich: the species that bore the name “spiralis” for over a century and a half was the one whose rachis is not twisted.
The actual Macrozamia spiralis — the real owner of the name — is a modest, slow-growing, acaulescent cycad with just 2–12 leaves, each with a rachis twisted up to 180° (sometimes 360°), growing as scattered individuals (not dense colonies) in dry sclerophyll forest on poor soils across the western Sydney Basin, the lower Blue Mountains, and the Goulburn River valley. It belongs to the genus Macrozamia — the largest exclusively Australian cycad genus, with around 40 species — and within that genus it is the archetype of section Parazamia: the small, twisted-leaf, ground-hugging species that are so different from the palm-like giants of section Macrozamia.
Quick Facts
| Scientific name | Macrozamia spiralis (Salisb.) Miq. |
| Family | Zamiaceae |
| Origin | Central New South Wales, Australia (Sydney Basin, Blue Mountains, Goulburn River valley) |
| Adult size | Acaulescent; 2–12 leaves, 35–100 cm long; plant 30–60 cm above ground |
| Hardiness | −4 to −5 °C (25 to 23 °F) / USDA zones 9a–11 |
| IUCN | Least Concern (LC) |
| CITES | Appendix II (all cycads) |
| Cultivation difficulty | 2/5 |
Taxonomy and Nomenclature
Richard Anthony Salisbury described this species as Zamia spiralis in 1796, from a collection made somewhere in the vicinity of Port Jackson (Sydney). No type specimen is extant. Friedrich Anton Wilhelm Miquel transferred it to Macrozamia in 1842.
Meanwhile, Joseph Dalton Hooker described Macrozamia corallipes from a plate in 1872 — unwittingly creating a second name for the same small cycad. For many years the two names coexisted in confusion: M. spiralis applied (wrongly) to the large Burrawang, and M. corallipes applied (correctly, but redundantly) to the small twisted-leaf species.
The 1959 resolution: Lawrie Johnson examined Salisbury’s original description and determined that it matched the smaller species, not the large Burrawang. He created Macrozamia communis for the large plant and restored M. spiralis to its rightful owner — the small, twisted-leaf cycad. This nomenclatural correction is one of the most consequential in Australian cycad taxonomy, and confusion between the two species persists to this day, particularly outside Australia.
The Macrozamia elegans segregation: in 1998, Ken Hill and David Jones described Macrozamia elegans — previously known as “robust M. spiralis” in Sydney botanical circles — as a separate species. Macrozamia elegans shares the twisted rachis and reddish callouses at the leaflet base but has larger, more numerous fronds, pinnae, cones, and seeds.
Etymology: spiralis from the Latin for “spiral” or “coiled,” referring to the twisted rachis.
Synonyms: Zamia spiralis Salisb. (1796) — the basionym; Macrozamia corallipes Hook.f. (1872).
Common names: no widely established common name distinct from the generic “Burrawang” (which properly refers to M. communis).
Morphological Description
Macrozamia spiralis is a small, dioecious, evergreen cycad — one of the most compact species in the genus and the archetype of section Parazamia.
Stem: entirely subterranean, 8–20 cm in diameter. Never forms an aerial trunk.
Leaves: 2–12 per crown (typically 6–8), 35–100 cm long. The rachis is the species’ most diagnostic character: twisted up to 180°, sometimes up to 360°, though occasionally untwisted. The twist gives the leaf a distinctive spiral profile that is immediately recognisable in the field. Petiole 15–40 cm long.
Leaflets: 45–120 per leaf, spreading, simple, the longest 12–20 cm long and 5–10 mm wide. Rather dull green (rarely glaucous), with 5–10 prominent veins visible on the underside. A distinctive character: the leaflets have a pinkish to red or orange callous at the base where they join the rachis — the “coral foot” that gave rise to the synonym M. corallipes. Unlike M. communis, the basal leaflets are not reduced to spines.
Cones: small by Macrozamia standards.
- Male cones: fusiform (spindle-shaped), 15–20 cm long, 5–6 cm diameter. Spines to 1.5 cm long. A male plant develops 1–4 cones.
- Female cones: oval, 12–20 cm long, 6–9 cm diameter. Spines to 3 cm long. Usually a single cone per plant.
Coning cycle: erratic, occurring approximately every 3–4 years, often with a large percentage of plants in a population coning simultaneously (a masting event). In intervening years, few cones are produced.
Seeds: 2.5–3 cm long, 2–2.5 cm diameter. Sarcotesta orange to scarlet. Ripe in April–May. Highly toxic.
Growth: extremely slow — both in terms of seedling development and the production of new fronds on mature plants. Plants do not reproduce until 10–20 years of age and are thought to live over 60 years.
Similar Species and Common Confusions
| Character | Macrozamia spiralis | Macrozamia communis | Macrozamia elegans | Macrozamia flexuosa |
|---|---|---|---|---|
| Leaves per crown | 2–12 | 50–100 | Numerous | Few |
| Leaf length | 35–100 cm | 70–200 cm | 90–150 cm | Variable |
| Rachis twisted? | Yes (180–360°) | No | Yes (moderate) | Yes (multi-twisted) |
| Leaflet base callous | Pinkish-red | White | Reddish | Variable |
| Basal leaflets reduced to spines? | No | Yes | Variable | No |
| Growth pattern | Scattered individuals | Dense colonies | Scattered | Scattered |
| Overall size | Small (30–60 cm) | Large (1–2 m crown) | Medium | Small |
The key diagnostic vs. M. communis is size: M. spiralis is a small cycad with 6–8 fronds standing ~60 cm above ground; M. communis is a large plant with 100+ fronds reaching 2 m. The twisted rachis, the reddish callous at the leaflet base, and the non-spiny basal leaflets confirm the identification. Macrozamia elegans is the “robust M. spiralis” — same twisted rachis and reddish callouses but larger in all parts. Macrozamia flexuosa (from the NSW central coast) has multi-twisted fronds — occasionally a M. spiralis plant produces one or two similar multi-twisted fronds, but this is considered aberrant.
Distribution and Natural Habitat
Macrozamia spiralis is endemic to central New South Wales. The distribution extends from Dunedoo and the Goulburn River valley eastwards over the Blue Mountains and into the Sydney Basin, south to Waterfall, Wallacia, and north to Maroota and Putty. Near Richmond (western Sydney), it grows on flat, poor-quality, sometimes sandy soil.
The species grows as scattered, often depauperate individuals in dry sclerophyll forest — not in the dense, extensive colonies typical of M. communis. Specimens from the lower Blue Mountains (Wheeney Creek to the Mellong Range) differ in being larger with more or less glaucous leaves and broader leaflets.
Conservation areas where the species is protected include Werakata National Park, Windsor Downs Nature Reserve, Agnes Banks Nature Reserve, and Castlereagh Nature Reserve.
Climate in the native range:
| Parameter | Western Sydney Basin / lower Blue Mountains |
|---|---|
| Mean annual temperature | 16–19 °C |
| Mean winter minimum | 3–7 °C |
| Historical absolute minimum | −4 to −5 °C (regular frost in western Sydney and Blue Mountains) |
| Mean summer maximum | 28–35 °C (western Sydney is one of the hottest parts of the Basin) |
| Annual rainfall | 700–1,000 mm |
| Köppen classification | Cfa (humid subtropical) to Cfb (oceanic, higher elevations) |
This is a temperate to warm-temperate climate with regular frost — similar to the range of M. communis, making M. spiralis one of the more cold-hardy Macrozamia species.
Conservation
Macrozamia spiralis is listed as Least Concern (LC) on the IUCN Red List. It is protected in New South Wales and occurs in several conservation reserves. The species is not currently threatened at a population level, but its scattered growth habit (single plants or small clumps, not dense colonies) makes individual populations potentially more vulnerable to local habitat loss from urban expansion — particularly in the rapidly developing western Sydney growth corridor.
Cultivation
| Hardiness | −4 to −5 °C (25 to 23 °F) / USDA zones 9a–11 |
| Light | Full sun to partial shade |
| Soil | Well-drained; tolerates very poor, sandy soils |
| Watering | Drought-tolerant; minimal supplemental watering |
| Adult size | 30–60 cm above ground; 6–8 fronds |
| Growth rate | Extremely slow |
| Difficulty | 2/5 |
Macrozamia spiralis is an easy cycad to grow — its challenge is not difficulty but patience. This is one of the slowest-growing cycads in cultivation, and it may be years before a seedling produces enough fronds to become an attractive garden plant. But for growers who value the quiet, sculptural beauty of a compact cycad with character, M. spiralis has few equals.
Light: full sun to partial shade. In habitat, it grows in dry sclerophyll forest — open, sun-exposed positions on poor soils. It adapts well to cultivation in any light condition from full sun to moderate shade.
Soil: very undemanding. The species naturally grows on flat, poor-quality, sandy soils — it is one of the least soil-sensitive cycads. Any well-drained substrate works. The coralloid root cyanobacteria fix nitrogen, allowing survival on extremely nutrient-poor ground.
Watering: drought-tolerant. In its native climate, annual rainfall is 700–1,000 mm but the soils dry rapidly. In cultivation, minimal supplemental watering is needed. Overwatering is more dangerous than neglect.
Cold hardiness: one of the hardier Macrozamia species. The native range includes western Sydney and the Blue Mountains, where frost is regular and winter minima reach −4 to −5 °C. The subterranean stem provides excellent thermal insulation. USDA zone 9a minimum for permanent outdoor planting, with the standard half-zone safety margin. In European Mediterranean climates, the species is suitable for open positions — its small size and subterranean caudex make it significantly more cold-tolerant than the arborescent species. Winter protection is unlikely to be necessary in zone 9b, but in zone 9a, a thick mulch over the root zone during cold spells is advisable.
Container culture: excellent — arguably the ideal use for this species outside its native range. The compact habit, slow growth, extreme drought tolerance, and tolerance of low light make M. spiralis a superb pot plant for terraces, courtyards, and indoor settings. A container specimen can be maintained indefinitely with minimal care.
Buying Advice
Availability: Macrozamia spiralis is less commonly offered than M. communis or M. miquelii — partly because it is smaller and less immediately showy, and partly because its extremely slow growth makes commercial propagation uneconomic. Seeds are occasionally available from Australian specialist nurseries. Outside Australia, it is rare in the trade. Plants sold as “M. spiralis” outside Australia should be verified carefully — the historical name confusion means they may actually be M. communis.
Propagation
Seed: the only practical method. Clean the orange-scarlet sarcotesta (gloves — toxic) and sow in well-drained mix at 25–30 °C. Germination is cryptocotylar. No pretreatment required. Germination and seedling growth are very slow — patience measured in years, not months.
Pests and Diseases
Scale insects: the most common pest. The low number of fronds and the open, well-ventilated growth habit mean that mealybug infestations are less problematic than in the dense-crowned arborescent species.
Root rot: in waterlogged substrates.
Toxicity: all parts are toxic (cycasin, macrozamin). Seeds are the most dangerous part. Toxic to dogs, cats, livestock, and humans.
Landscape Use
Macrozamia spiralis is not a landscape showstopper — it is a landscape connoisseur’s plant. The small rosette of twisted, dark green fronds with their reddish-pink callouses at the leaflet bases has a subtle, sculptural beauty that rewards close observation. Use it in a rockery, in a native bush garden beneath eucalypts and banksias (mimicking its natural habitat), in a collection of section Parazamia species arranged to showcase the diversity of leaf form within the genus, or as a container specimen on a table or shelf where its modest scale and quiet elegance can be appreciated. It pairs naturally with Xanthorrhoea grass trees, Doryanthes gymea lilies, and other plants of the Sydney sandstone flora. For gardeners who have grown M. communis and M. moorei, adding M. spiralis completes the New South Wales Macrozamia trifecta — from the giant of the tablelands, through the Burrawang of the coast, to the small twisted cycad of the western Sydney bush.
Frequently Asked Questions
Is Macrozamia spiralis the same as Macrozamia communis?
No — despite the historical confusion. M. spiralis is a small cycad (2–12 leaves, 35–100 cm long, scattered individuals) with a twisted rachis and reddish callouses at the leaflet base. M. communis is a large cycad (50–100+ leaves, up to 200 cm long, dense colonies) with an untwisted rachis and white callouses. They are sympatric in the Sydney Basin but occupy different niches.
Why does the rachis twist?
The twist is a genetically determined character — it is present (to varying degrees) in all true M. spiralis plants but is not an environmental response. The degree of twist varies from 0° (occasionally) to 360° (rarely), with 180° being typical. The adaptive significance of the twist, if any, is unknown.
How cold-hardy is Macrozamia spiralis?
Reasonably hardy — frost is regular in its native range (western Sydney, Blue Mountains), with winter minima of −4 to −5 °C. The subterranean stem provides excellent thermal insulation. USDA zone 9a minimum. In European Mediterranean climates, this is one of the safer Macrozamia species for outdoor planting.
Why is it so slow?
Extremely slow growth is typical of section Parazamia species — small, conservative plants adapted to nutrient-poor soils and periodic disturbance (fire). Plants do not reproduce until 10–20 years of age and may live over 60 years. In cultivation, patience is essential.
Authority Websites and Databases
POWO — Plants of the World Online (Kew)
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:297206-1
The accepted nomenclatural record. Basionym: Zamia spiralis Salisb. (1796).
PACSOA — Palm and Cycad Societies of Australia
https://pacsoa.org.au/wiki/index.php/Macrozamia_spiralis
The most detailed English-language account. Section Parazamia, subterranean caudex, moderate spiral twist. History of nomenclatural confusion with M. communis (Johnson 1959). Distribution: outer southern, SW and W suburbs of Greater Sydney, lower Blue Mountains, Goulburn River Valley. Richmond populations on flat, poor, sandy soil. Coning every 3–4 years. Affinity with M. elegans (segregated 1998). Extremely slow growing.
NSW PlantNET — Macrozamia spiralis
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/…
Official NSW Flora: stem subterranean 8–20 cm diameter; leaves 2–12, 60–100 cm, rachis twisted to 180° (rarely 360°); pinnae 45–120, 12–20 cm × 5–10 mm; male cones 15–20 cm; female cones 12–20 cm; seeds orange to red.
Conifers.org — Macrozamia spiralis
https://conifers.org/za/Macrozamia_spiralis.php
Morphological description (Harden 1990, Jones 1993). Illustrated as M. corallipes in Botanical Magazine 98, tab. 5943 (1872). Lower Blue Mountains specimens larger with glaucous, broader-pinnae leaves. Scattered in dry sclerophyll forest.
Bibliography
Hill, K. D. (1998). Cycadophyta. Flora of Australia, 48, 597–661.
Hill, K. D., & Jones, D. L. (1998). Macrozamia elegans (Zamiaceae), a new species from New South Wales. Telopea, 8(1), 21–23.
Johnson, L. A. S. (1959). The families of cycads and the Zamiaceae of Australia. Proceedings of the Linnean Society of New South Wales, 84, 64–117.
Jones, D. L. (2002). Cycads of the World (2nd ed.). New Holland Publishers, Sydney.
Miquel, F. A. W. (1842). Monographia Cycadearum. Utrecht.
Salisbury, R. A. (1796). Zamia spiralis. Prodromus Stirpium in Horto ad Chapel Allerton Vigentium, 401.
Whitelock, L. M. (2002). The Cycads. Timber Press, Portland.