At Hanging Rock in the upper Hunter Valley of New South Wales, at an elevation of approximately 900 m, frosts are frequent and heavy snowfalls occur occasionally during winter. It is not a place where you would expect to find a cycad. But Macrozamia concinna grows here — a small, tidy, spirally twisted Parazamia species that has adapted to conditions more commonly associated with snow gums than with gymnosperms of Gondwanan ancestry. In 1990, PACSOA authors Craig Thompson and Paul Kennedy escorted Dr Piet Vorster, then President of the Cycad Society of South Africa, on a tour of New South Wales cycads. Vorster photographed several M. concinna plants at Hanging Rock — a South African cycad specialist, in an Australian snowfield, looking at a plant that should not exist there. The species was formally described in 1998 by David Jones, who named it concinna — Latin for “neat and trim” — after its prim, compact appearance. It had previously been hidden within the genus Macrozamia under the umbrella of M. pauli-guilielmi subsp. plurinervia. It is now recognised as geographically isolated from all other cycad species — no hybrids are known. And it pollinates via one of the most elegant mechanisms in the plant kingdom: a push-pull system mediated by cone thermogenesis and the specialist thrips Cycadothrips chadwicki.
Quick Facts
| Scientific name | Macrozamia concinna D.L.Jones |
| Family | Zamiaceae |
| Origin | Upper Hunter Valley to Nundle/Hanging Rock, New South Wales, Australia |
| Adult size | Subterranean stem, 8–15 cm diam.; 1–5 leaves, 50–90 cm long |
| Hardiness | −6 to −9 °C (21 to 16 °F) / USDA zone 8b (zone 8a with protection) |
| IUCN | Not Evaluated (NE) — threatened by habitat loss, fire, and potential reproductive failure |
| CITES | Appendix II (all cycads) |
| Cultivation difficulty | 3/5 |
Taxonomy and Nomenclature
Macrozamia concinna was described by David L. Jones in 1998 in the Flora of Australia volume 48 (page 718). It was segregated from Macrozamia pauli-guilielmi subsp. plurinervia, under which it had previously been classified.
Etymology: from Latin concinna (“neat, trim, well-arranged”) — referring to the compact, orderly appearance of the plant.
Affinities: PACSOA notes that M. concinna “relates in varying degrees to each of the other three New South Wales cycads possessing multi-twisted stems” — M. fawcettii, M. flexuosa, and M. plurinervia. It is closest to the larger M. plurinervia (from which it was segregated), but more similar in size and general appearance to M. flexuosa (the Hunter Valley twisted-leaf species).
Section: Parazamia — subterranean stem, few leaves, veins thick and prominent, basal pinnae not reduced to spines.
Geographic isolation: M. concinna is geographically isolated from all other cycad species. No hybrids are known. This isolation, combined with its restricted montane habitat, makes it an evolutionary island within the genus.
Morphological Description
Macrozamia concinna is a small, dioecious, evergreen cycad — one of the most compact species in the genus.
Stem: subterranean, 8–15 cm diameter — among the smallest caudices in the genus.
Leaves: 1–5 in the crown (a very sparse rosette), 50–90 cm long. The number of fronds is genetically determined, not habitat-dependent. Petiole ± terete (rounded in cross-section), 9–24 cm long.
Rachis: strongly spirally twisted — twisting through multiple complete 360° revolutions. The number of twists varies: from a single twist to multiple twists. Occasionally, some fronds do not twist at all. The pinnae appear to radiate from the rachis in all directions (like the branches of a tree), but this is an illusion created by the spiralling rachis.
Pinnae: 80–120 per leaf, dark green, semi-glossy, simple. Longest pinnae 14–21 cm long, 4–6 mm wide. Margins incurved. Apex not spinescent (rounded, not pungent). Basal pinnae not reduced to spines. The apical pinnae extend at a more acute angle than the rest.
Male cones: 14–22 cm long, 4–4.5 cm diameter; spines 0–1.3 cm. Males produce 1–2 cones on an irregular basis.
Female cones: usually solitary.
Seeds: reddish sarcotesta.
The Push-Pull Pollination System
Macrozamia concinna is pollinated by the specialist thrips Cycadothrips chadwicki — the same species involved in the landmark push-pull pollination study published in Science (Terry et al. 2007) on the related M. lucida. The mechanism, now documented across multiple Cycadothrips-pollinated Macrozamia, works as follows:
Push phase: male cones undergo thermogenesis (self-heating) during the day, raising cone temperature dramatically above ambient. This triggers a massive increase in volatile emissions — dominated by β-myrcene. At high concentrations, β-myrcene repels thrips, driving them out of the male cone en masse. The departing thrips are covered in pollen.
Pull phase: as thermogenesis declines, volatile emissions diminish. Female cones, which produce lower levels of the same volatiles, now attract the pollen-laden thrips with lower concentrations of β-myrcene and ocimene. The thrips enter the female cone, depositing pollen on the micropyle of each ovule.
This push-pull system is one of the most elegant pollination mechanisms known — a gymnosperm using thermogenesis and volatile chemistry to manipulate insect behaviour with a precision that rivals angiosperm pollination syndromes. The relationship is obligate: without Cycadothrips, no pollination occurs. When both wind and insects are excluded from female cones, no seeds are produced.
Comparison with Related Multi-Twisted Species
| Character | M. concinna | M. plurinervia | M. flexuosa | M. spiralis |
|---|---|---|---|---|
| Leaf length | 50–90 cm | >70 cm | 45–100 cm | 35–100 cm |
| Leaves in crown | 1–5 | Variable | 1–6 | 2–12 |
| Rachis twist | Strongly multi-twisted | Strongly twisted | Strongly multi-twisted | Moderately twisted (≤360°) |
| Pinnae width | 4–6 mm | Broader | 3–7 mm | 5–9 mm |
| Pinnae margins | Incurved | Variable | Involute | Flat |
| Altitude | 800–1,200 m | Variable | Low–moderate | Low |
| Hybrids | None (isolated) | Unknown | With M. reducta & M. communis | None documented |
Distribution and Natural Habitat
Macrozamia concinna grows in the upper Hunter Valley, extending north to the Nundle/Hanging Rock region and out to the Liverpool Plains. It is found on steep hillsides and slopes at high altitude — 800 to 1,200 m — under a eucalypt canopy with a medium to dense understorey, in dry sclerophyll woodland.
Climate (Murrurundi, elevation 466 m, ~40 km SW of Nundle):
| Parameter | Murrurundi |
|---|---|
| Annual rainfall | 830 mm (87 rain days) |
| January days above 35 °C | 4 days average |
| July days below 0 °C | 13 days average |
| Extreme low (2006) | −6.5 °C |
| Extreme high (2006) | 40.7 °C |
At the actual habitat elevation of 800–1,200 m (200–700 m higher than Murrurundi), conditions are significantly colder — frosts are frequent and heavy snowfalls occur occasionally. This places M. concinna among the most cold-exposed cycads in Australia, alongside M. stenomera (Mt Kaputar, to 1,450 m) and M. montana (Blue Mountains, −9.3 °C records).
Conservation
Macrozamia concinna has not been formally evaluated by the IUCN. However, its restricted montane distribution, sparse populations, geographic isolation, and dependence on a specialist pollinator make it vulnerable to:
- Fire: as with all Macrozamia, adults resprout from the subterranean caudex, but seedlings and seed banks are destroyed. Fire can also eliminate the Cycadothrips pollinator population.
- Reproductive failure: the obligate dependence on Cycadothrips chadwicki means that any event that eliminates the pollinator (fire, pesticide drift, habitat degradation) prevents reproduction entirely.
- Habitat loss: agricultural expansion and grazing in the Upper Hunter and Liverpool Plains threaten montane woodland habitat.
- Climate change: montane species on relatively low ranges are vulnerable to upward range shifts — at 800–1,200 m on the Great Dividing Range, there is limited space to move higher.
Cultivation
| Hardiness | −6 to −9 °C (21 to 16 °F) / USDA zone 9a (zone 8b with protection) |
| Light | Partial shade to full sun |
| Soil | Well-drained; montane soils, acid |
| Watering | Moderate; 830 mm at Murrurundi, higher at habitat altitude |
| Adult size | Compact: 50–90 cm fronds, 1–5 leaves |
| Growth rate | Very slow |
| Difficulty | 3/5 |
Cold hardiness: with recorded lows of −6.5 °C at Murrurundi (which is 200–700 m lower than the habitat) and occasional snowfall at Hanging Rock, M. concinna is among the most frost-hardy Parazamia species. Applying the standard half-zone safety margin: USDA zone 9a is the safe outdoor planting zone; zone 8a may be achievable with winter protection (horticultural fleece, canopy shelter, dry root zone, 15–20 cm mulch). For Mediterranean Europe (Var, Hérault, Alpes-Maritimes), outdoor planting is feasible in well-drained, sheltered positions at moderate elevation. European cold events (February 1956 at −12 to −16 °C, January 1985, January 2012) remain a risk, but the subterranean caudex provides critical thermal insurance — soil temperature at 10 cm depth is several degrees warmer than air temperature during a radiation frost.
Container culture: the very compact size (1–5 leaves, stem 8–15 cm diameter) and multi-twisted fronds make it a charming miniature — ideal for a small container on a bright terrace. Less visually spectacular than the larger twisted-leaf species (*M. flexuosa*, *M. pauli-guilielmi*) but more cold-tolerant and more manageable.
Buying Advice
Availability: Macrozamia concinna is extremely rare in cultivation. Its restricted montane range, sparse populations, and geographic isolation mean that material is almost never offered. If encountered, verify provenance: Upper Hunter Valley / Nundle / Hanging Rock area, 800–1,200 m, multi-twisted fronds with incurved margins, very small caudex (8–15 cm).
Propagation
Seed: the only method. Seeds with reddish sarcotesta. Sow in well-drained mix at 18–25 °C (cooler than tropical species). Delayed fertilisation: 12 months. Growth extremely slow. Without the specialist pollinator Cycadothrips chadwicki, hand pollination is required in cultivation.
Pests and Diseases
Root rot: in poorly drained soils.
Scale insects: occasional.
Toxicity: all parts are toxic. Contains cycasin and macrozamin.
Landscape Use
Macrozamia concinna is a montane miniature — a snow-country cycad that contradicts every expectation of what a cycad should be. The multi-twisted, dark green fronds with incurved margins, emerging from a caudex barely wider than a fist, growing on a slope where snow falls in winter — it is a plant that rewards close observation and rewards patience. Use it:
- As the cold-hardiest twisted-leaf Macrozamia in a collection — paired with M. stenomera (the coldest overall, from Mt Kaputar at 1,450 m) to show the montane extreme of the genus.
- As a miniature container specimen — the 1–5 fronds and 8–15 cm caudex are the smallest proportions in the genus.
- As a conservation piece — geographically isolated, reproductively dependent on a specialist thrips, and growing in a climate that will shift with warming. Ex situ cultivation is genetic insurance.
Frequently Asked Questions
Does it really grow where it snows?
Yes. At Hanging Rock (~900 m), heavy snowfalls occur occasionally during winter. The nearby Murrurundi weather station recorded −6.5 °C in 2006. The actual habitat at 800–1,200 m is colder still. This is one of the most cold-exposed cycads in Australia.
How does it pollinate without its thrips?
In the wild, Cycadothrips chadwicki is the sole pollinator. In cultivation, hand pollination is necessary. The push-pull system (thermogenesis driving thrips away from male cones, volatile decline attracting them to female cones) does not function without the insect partner.
Why are there no hybrids?
Because M. concinna is geographically isolated from all other Macrozamia species. The nearest related species (*M. plurinervia*, *M. flexuosa*) do not grow at these elevations or in this region.
Authority Websites and Databases
POWO — Plants of the World Online (Kew)
https://powo.science.kew.org/taxon/…
Accepted species. First published in Flora of Australia 48: 718 (1998). Native range: New South Wales.
PlantNET — New South Wales Flora Online
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/…
Stem subterranean, 8–15 cm diam. Leaves 1–5, 50–90 cm, rachis strongly spirally twisted. Pinnae 80–120, dark green, semi-glossy, margins incurved, 14–21 cm × 4–6 mm. Basal pinnae not reduced to spines. Petiole ± terete, 9–24 cm.
PACSOA — Palm and Cycad Societies of Australia
https://www.pacsoa.org.au/wiki/index.php/Macrozamia_concinna
Section Parazamia. Named 1998 by Jones, segregated from M. pauli-guilielmi subsp. plurinervia. Upper Hunter to Nundle/Hanging Rock, 800–1,200 m. Murrurundi: 830 mm, −6.5 °C, frosts frequent, occasional snowfall. Multi-twisted rachis. Geographically isolated, no hybrids. Cycadothrips chadwicki pollination. Related to M. plurinervia, M. flexuosa, M. fawcettii.
Bibliography
Hill, K. D. (1998). Cycadophyta. Flora of Australia, 48, 597–661.
Jones, D. L. (1998). Macrozamia concinna. Flora of Australia, 48, 718.
Jones, D. L. (2002). Cycads of the World (2nd ed.). New Holland Publishers, Sydney.
Terry, I., Walter, G. H., Moore, C., Roemer, R., & Hull, C. (2007). Odor-mediated push-pull pollination in cycads. Science, 318(5847), 70.
Terry, I., Walter, G. H., Donaldson, J. S., Snow, E., Forster, P. I., & Machin, P. J. (2005). Pollination of Australian Macrozamia cycads: effectiveness and behavior of specialist vectors in a dependent mutualism. American Journal of Botany, 92(6), 931–940.
Whitelock, L. M. (2002). The Cycads. Timber Press, Portland.