Cycas ophiolitica

Cycas ophiolitica is a cycad of central Queensland, Australia, growing mainly on the red clays derived from serpentinite between Marlborough and Rockhampton. This species of the genus Cycas, described by Ken Hill in 1992, was already grown before then as Cycas ‘Marlborough Blue’, for the blue of its new leaves. Listed as Endangered under Australian federal and Queensland law and as Vulnerable by the IUCN, it is threatened by loss of habitat and by collection for the horticultural trade.

Key facts about Cycas ophiolitica

  • Accepted name: Cycas ophiolitica K.D.Hill (1992), accepted by The World List of Cycads (version 2026.08.15), the Flora of Australia and GBIF; POWO could not be consulted
  • Former names and synonyms: Cycas ‘Marlborough Blue’ (horticultural name); placed in the synonymy of Cycas angulata by de Laubenfels and Adema (1998), a treatment not followed; intermediate forms have been grown as Cycas normanbyana
  • Family: Cycadaceae, order Cycadales
  • Common names: “Marlborough blue” (Australia)
  • Natural range: Australia, central-eastern Queensland, Marlborough and Rockhampton area
  • IUCN status: Vulnerable (VU A2cd+4cd; B1ab(iii,v) according to The World List of Cycads); latest assessment by J.D. Bösenberg, published in 2023
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union; Endangered under the EPBC Act 1999 (Australia) and Queensland legislation
  • Documented hardiness: no measured value (see Cold hardiness)
  • Light and soil: in the wild, open, rocky eucalypt woodland on slopes and hilltops, on shallow red clays, mostly over serpentinite; sun and good drainage in cultivation
  • Habit and adult size: trunk to 2 m, rarely 4 m (7 m according to the Flora of Australia), 14 to 20 cm in diameter; leaves 0.95 to 1.40 m long
  • In the UK, US and Australia: grown in beds at the Royal Botanic Garden Sydney and at Mount Annan (wild-origin accessions from 1990–1991, new ones in 2021 and 2026); Montgomery Botanical Center (Florida) since at least 2003; declared in BGCI by Kew and by several American and Australian gardens
  • Toxicity: no data for the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas ophiolitica

Among the Australian cycads, Cycas ophiolitica is identified by its relatively broad, crowded, keeled and more or less glaucous leaflets, its grey- or white-felted petiole, the flaky orange down around the crown and its small seeds (Hill 1992, 1996). Typical forms have strongly blue new leaves that turn dark green with age, and narrow, stiff leaflets.

The trunk reaches 2 m, rarely 4 m, with a diameter of 14 to 20 cm; the online Flora of Australia gives up to 7 m. The leaves are 0.95 to 1.40 m long, keeled in section, with 170 to 220 leaflets; the rachis usually ends in a spine. The petiole, 18 to 35 cm long, is spiny or occasionally spineless. The median leaflets measure 14 to 24 cm by 6 to 7.5 mm and are glossy dark green, hairless or slightly downy; the original description calls them flat in section, whereas the Flora of Australia describes recurved margins. New growth is densely covered in grey-white and pale orange-brown hairs.

The male cones, ovoid and orange, measure about 17 cm by 8 cm; each microsporophyll ends in an upturned spine 7 to 11 mm long. The megasporophylls (the fertile leaves of female plants), 18 to 30 cm long and covered in brown down, carry 2 to 6 ovules; their narrowly triangular blade, 4 to 7 cm long, is regularly toothed and ends in a spine 8 to 20 mm long. The seeds are ovoid, green turning yellowish and usually bloomed, 29 to 33 mm by 28 to 32 mm. A 1990 field description reproduced on the wiki of the Palm and Cycad Societies of Australia (PACSOA) adds a swollen trunk base, charcoal-grey bark marked with diamond-patterned leaf bases, and a bluish tint that extends to the rachis and the seeds.

Hybrids

Natural hybrids are well documented. Hill (1992, 1996) describes extensive zones of intergradation with Cycas media to the north of the range, between Mackay and St Lawrence, and with Cycas megacarpa to the south, between Rockhampton and Mount Morgan: throughout the range, plants may show characters of these species. Hill attributes this to repeated hybridisation and introgression, which might also explain some unusual characters of Cycas ophiolitica within its group. Some of this intermediate material is grown as Cycas normanbyana, although the type of that name belongs to Cycas media.

Possible confusion

Its two geographical neighbours are the easiest to confuse with it. Cycas media and Cycas megacarpa have broader, more widely spaced leaflets, leaves that end as often in a pair of leaflets as in a spine and, in Cycas media, more ovules per megasporophyll (Hill 1992). Cycas megacarpa also has large seeds, as its name suggests.

With its narrow, stiff, bluish leaflets, Cycas ophiolitica also recalls Cycas platyphylla and Cycas couttsiana, from northern Queensland. The former has shorter leaflets and leaves, with more orange down around the cataphylls; the latter keeps persistent white hairs and has more strongly keeled leaves.

Taxonomy

Cycas ophiolitica is a name accepted by The World List of Cycads, the Flora of Australia and GBIF; POWO could not be consulted. Ken Hill described it in 1992 in his preliminary account of the cycads of Queensland (Telopea 5(1): 177–206). In his 1996 revision he placed it in section Cycas, subsection Endemicae, series Cairnsianosae, with Cycas cairnsiana, Cycas couttsiana, Cycas desolata and Cycas platyphylla, the glaucous cycads of north-central Queensland. He noted that it departs from this series in its broader leaflets and in an anatomical character (an interrupted lower hypodermis) found in the Cycas media series, perhaps acquired through introgression.

De Laubenfels and Adema (1998), who took a very broad view of species, placed Cycas ophiolitica in the synonymy of Cycas angulata. This treatment has not been followed: the Flora of Australia and The World List of Cycads maintain the species.

Etymology and history

The epithet is formed from the Greek ophis, “serpent”, and lithos, “stone”, as in the word “ophiolite”, used for serpentinite: it recalls that the species grows mainly on soils derived from this rock (Hill 1992; Haynes 2022).

The type was collected by Ken Hill and Lyn Stanberg on 1 October 1991, 48.6 km south of Marlborough on the Bruce Highway (holotype in Sydney, NSW; isotypes in Brisbane, Canberra, Kew and Darwin). The plant was known to collectors before it was described: Hill notes that the “core” form was already in cultivation, mostly as wild-collected plants, under the name Cycas ‘Marlborough Blue’.

Common names

In Australia the species is called “Marlborough blue”, the name used by the Royal Botanic Garden Sydney and Mount Annan in their online catalogues and derived from the horticultural name Cycas ‘Marlborough Blue’ (Hill 1992); the PACSOA wiki gives “Cycas sp. ‘Marlborough Blue’”. The British nursery Trebrown uses “Marlborough Blue Sago”, a commercial variant.

In the wild

Cycas ophiolitica is endemic to central-eastern Queensland. It reaches its best development on red clays over serpentinite between Marlborough and Rockhampton; plants with intermediate characters extend north towards Mackay and south towards Mount Morgan (Hill 1992, 1996). The Flora of Australia confirms this preference for red clays over serpentinite.

The 1990 field account on the PACSOA wiki describes the main habitat as rocky, sloping, open eucalypt forest (ironbark country) with little undergrowth, on very poor soils with hard magnesite rock, along hilly outcrops and in lower areas near creeks; most large plants have trunks no taller than 1.5 m, although two plants of 3 m were measured in the largest colony seen, and the species grows near Macrozamia miquelii and Cycas media. Pollination and phenology are not documented in the sources consulted.

Conservation status and regulation

The IUCN lists Cycas ophiolitica as Vulnerable. The World List of Cycads gives the criteria A2cd+4cd; B1ab(iii,v) and still cites the 2010 assessment by P. Forster; the most recent assessment, by J.D. Bösenberg, was published in 2023 (Red List version 2023-1), and the Red List data relayed by GBIF confirm the category VU (consulted on 21 October 2026). These criteria reflect a decline linked to loss of habitat and collection, and a restricted, declining range.

In Australia the species is listed as Endangered under the federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), effective 16 July 2000, and under Queensland’s Nature Conservation (Plants) Regulation 2020 (November 2022 list), according to the online Flora of Australia (re-checked on 21 October 2026). Hill (1992, 1996) already stressed that its habitat was poorly conserved, or not at all, and that the species was under significant commercial collecting pressure. It is covered by the national multi-species recovery plan for Queensland cycads (Queensland Herbarium 2007).

Like every species in the genus except Cycas beddomei, Cycas ophiolitica is listed in CITES Appendix II, through the listing of the family Cycadaceae, included since 4 February 1977. The listing carries annotation #4 (CoP20 version, in force since 5 March 2026): seeds, pollen, seedlings or tissue cultures obtained in vitro and transported in sterile containers, and cut flowers of artificially propagated plants, are exempt, whereas international trade in the plants themselves requires an export permit. Australia, the United Kingdom and the United States apply CITES through their own national legislation; in the European Union the species is in Annex B of Regulation (EC) No 338/97, whose annexes in force are set by Commission Regulation (EU) 2026/1383, applicable since 29 June 2026. Species+, the official CITES database, names the species and confirms this status (searches of 3 and 12 October 2026).

This general information does not replace the official texts: check the rules in force before buying or exchanging plants, ask the seller for proof of origin and prefer plants raised from cultivated seed.

Growing Cycas ophiolitica

In short: Cycas ophiolitica has been grown in Australia for longer than it has had a name, but older plants were mostly collected from the wild (Hill 1992); buy only seed-raised plants with documentation. It needs sun and very good drainage. Among the Australian Cycas, the French nurseryman Simon Lavaud ranks it in his “medium” difficulty class and notes that it “tolerates slightly cooler conditions”, without giving a temperature; European growers nevertheless report slow growth and root rot.

Outdoor and in-ground cultivation

The 1990 account on the PACSOA wiki recommends a sunny, moist but well-drained position and describes the species as drought and frost tolerant, without giving any value. It also notes that offsets severed from the parent plant are extremely slow to produce new leaves. In Australia, the Royal Botanic Garden Sydney and the Australian Botanic Garden Mount Annan grow it in numbered garden beds (see below), but neither garden has published an observation on its behaviour.

Container cultivation

In a 2021 note on growing Australian Cycas in a European climate, Simon Lavaud (Cycadales.eu) places Cycas ophiolitica in his “medium” difficulty class, with Cycas media, Cycas megacarpa and Cycas silvestris, adding of this species alone that it “tolerates slightly cooler conditions”; the other species he lists are rated difficult or very difficult. For the group as a whole, he advises a mix with a high mineral content, full sun or the brightest place in the glasshouse, and generous watering in warm weather (nights of 18–20 °C, or 64.4–68 °F, and days around 30 °C, or 86 °F), reduced when temperatures fall below 20 °C (68 °F) and stopped when nights drop below 10 °C (50 °F), since watering in cool conditions carries a very high risk of root rot.

European reports are few and not encouraging. A grower in the Deux-Sèvres, in western France, reported on the French forum Fous de palmiers in October 2010 partial root rot on a young potted plant, of unstated cause, which he tried to save by cutting away the affected parts, treating it with fungicide and repotting it in pure perlite, kept warm. On the Italian forum Tropicamente, a collector whose location is not given reported in February 2013 that his plants sown “in the last century” had stayed “microscopic”; he found all Australian cycads “very difficult to keep alive”, with perhaps only Cycas media adapting reasonably well, and blamed low temperatures rather than wetness. The Jardin zoologique tropical at La Londe-les-Maures, in the south of France, has published no observation on this species.

In cultivation in the UK, US and Australia

In Australia, the online catalogue of the Royal Botanic Garden Sydney (updated on 1 October 2026) lists Cycas ophiolitica, under the name “Marlborough Blue”, in beds 65h and 65i (accession S1990-2179, wild origin), plus a more recent wild-origin accession, S2021-0668. The catalogue of the Australian Botanic Garden Mount Annan (updated on 15 October 2026) lists 21 entries: two plants in bed 14b (accessions A1990-2179/1 and A1991-2858/1, wild origin) and a series of new wild-origin accessions numbered from A2026-0350, from 2026. The catalogues do not say whether these beds are in the open; the species is also declared in BGCI PlantSearch by the Australian National Botanic Gardens (Canberra), the Adelaide Botanic Garden and Mackay Regional Botanic Gardens (Queensland).

In the United States, the online catalogue of Montgomery Botanical Center (Coral Gables, Florida), whose collection is grown outdoors, lists three accessions (8854, 20030067 and RM976), one of them dating from 2003 by the garden’s numbering (search of 21 October 2026). The species is also recorded in the online catalogue of Fairchild Tropical Botanic Garden (inventory compiled for this site, 19 October 2026) and declared in BGCI by the San Diego Botanic Garden (California), the University of California Botanical Garden at Berkeley, Honolulu Botanical Gardens, the National Tropical Botanical Garden (Hawaii) and Mercer Arboretum and Botanic Gardens (Texas).

In the United Kingdom, Kew declares the species in BGCI PlantSearch; Kew’s cycads are grown under glass. A BGCI entry shows that a garden has declared a plant, not that it is alive today. No report from an English-speaking grower could be read; PalmTalk and Dave’s Garden could not be consulted.

Propagation

The plant is dioecious: a male and a female plant are needed to obtain seed. Seed is the normal route; seedlings grow slowly, according to the Italian report quoted above, and no germination figures have been published. Offsets can be removed, but they are very slow to re-establish, according to the PACSOA wiki. Seeds are exempt from CITES under annotation #4.

Pests and diseases

No pest specific to the species is documented. The only problem reported in cultivation is root rot in pots, mentioned above. Like all cycads, it can be attacked by the Asian cycad scale, Aulacaspis yasumatsui.

Cold hardiness

No measured minimum temperature has been published for Cycas ophiolitica. The indications available contradict one another: the 1990 account on the PACSOA wiki calls it “frost tolerant”, without any value; the Florida nursery Top Tropicals gives USDA zones 9 to 10 (average annual minima of about −6.7 to 4.4 °C, or 20 to 40 °F) while describing it as “frost sensitive”; the British nursery Trebrown rates it zone 9b (−3.9 to −1.1 °C, or 25 to 30 °F). Simon Lavaud (2021) says only that it “tolerates slightly cooler conditions”, without a temperature. None of these statements rests on a measurement: they are not enough to establish its hardiness.

Mediterranean experience

No growing result has been published in Europe, in the ground or in a pot, and no dated frost event concerns the species. The only French report, from the Deux-Sèvres in 2010, concerns a potted plant with root rot, with no established link to cold; the Italian grower quoted above blamed low temperatures for the failure of his seedlings, without giving any values. The Jardin zoologique tropical in the Var has published nothing on it. For readers in comparable climates, such as California or southern Australia, this European experience points to caution rather than to a hardiness figure.

United Kingdom, United States and Australia

No cold reading or dated growing report was found on forums. The gardens that grow it in beds or outdoor collections, in Sydney, Mount Annan and southern Florida, have published no observation of cold damage or survival; the nursery zone ratings above are commercial and attributed as such. In the UK it should be kept under glass with frost protection.

Toxicity and precautions

No toxicity analysis specific to Cycas ophiolitica has been found. The risk is, however, well documented in the genus: Cycas tissues, and the seeds above all, contain cycasin, which is converted during digestion into methylazoxymethanol, toxic to the liver and nervous system, along with a neurotoxic amino acid, BMAA. The ASPCA lists the sago palm (Cycas revoluta) as poisonous to dogs, cats and horses. Until proven otherwise, treat the plant as poisonous: keep seeds and leaves out of reach of children and pets, and wear gloves to clean the seeds. If any part is swallowed, contact a poison centre, a doctor or a vet straight away.

Traditional uses

No traditional use is documented for this species. Its main use today is ornamental, and it is precisely collection for the horticultural trade that threatens it.

Frequently asked questions

What is Cycas ‘Marlborough Blue’?

It is Cycas ophiolitica. The horticultural name, taken from the town of Marlborough in Queensland and the blue of the new leaves, was in use before Ken Hill described the species in 1992.

What does ophiolitica mean?

The name comes from “ophiolite”, a term used for serpentinite: the species grows mainly on red clays derived from this rock.

Do its leaves stay blue?

No. The new leaves of typical forms are strongly blue, then turn dark green with age.

Is it endangered?

Yes. It is listed as Endangered under Australian federal and Queensland law, and as Vulnerable by the IUCN, because of habitat loss and collection for the trade.

How can it be told from Cycas media?

By its narrower, more crowded leaflets, its leaves usually ending in a spine and its fewer ovules; but intermediate forms exist where the two species meet.

Can it be grown outdoors in the UK or in a Mediterranean climate?

Not in the UK. No measured minimum temperature has been published; claims of frost tolerance are commercial or unquantified. Even in mild Mediterranean climates, the prudent course is a pot that can be moved into frost-free shelter.

Is it difficult to grow?

Fairly, although Simon Lavaud ranks it among the Australian cycads of only “medium” difficulty and notes that this species “tolerates slightly cooler conditions”, without giving a temperature. The few European reports describe slow growth and losses to root rot: a very free-draining mineral mix, full light and reduced watering in cool weather are advised.

Is it poisonous?

It must be assumed so. No analysis exists for the species, but all the cycads studied contain serious toxins, especially in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Hill, K.D. (1992). A preliminary account of Cycas (Cycadaceae) in Queensland. Telopea 5(1): 177–206. doi:10.7751/telopea19924964 [Original description (pp. 190–192, fig. 7), intergradation, horticultural name; full text consulted.]
  • Hill, K.D. (1996). A taxonomic revision of the genus Cycas (Cycadaceae) in Australia. Telopea 7(1): 1–64. doi:10.7751/telopea19963040 [Series Cairnsianosae, leaflet anatomy, hybrids; full text consulted.]
  • Hill, K.D. (1998). Cycadaceae. In: McCarthy, P.M. (ed.), Flora of Australia 48: 597–635. CSIRO Publishing, Melbourne. [Consulted in its updated online version (profiles.ala.org.au).]
  • Bösenberg, J.D. (2023). Cycas ophiolitica. The IUCN Red List of Threatened Species 2023: e.T41974A69153435. doi:10.2305/IUCN.UK.2023-1.RLTS.T41974A69153435.en [Latest Red List assessment; reference found on Crossref, category VU relayed by GBIF, page not consulted (access blocked).]
  • Forster, P. (2010). Cycas ophiolitica. The IUCN Red List of Threatened Species 2010: e.T41974A10614556. doi:10.2305/IUCN.UK.2010-3.RLTS.T41974A10614556.en [Earlier assessment, cited by The World List of Cycads; not consulted.]
  • Queensland Herbarium (2007). National Multi-species Recovery Plan for the cycads, Cycas megacarpa, Cycas ophiolitica, Macrozamia cranei, Macrozamia lomandroides, Macrozamia pauli-guilielmi and Macrozamia platyrhachis. Department of the Environment and Water Resources, Canberra. [Official recovery plan, cited after the Flora of Australia; the document could not be downloaded (connection reset on 21 October 2026).]
  • Laubenfels, D.J. de & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Very broad species concepts: Cycas ophiolitica placed in the synonymy of Cycas angulata (p. 363); full text consulted.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Source of the etymologies given by The World List of Cycads; not consulted directly.]
  • 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 checklist; consulted directly.]