Bowenia sp. ‘Tinaroo’

Bowenia sp. ‘Tinaroo’ is a provisional name for the population of Bowenia that grows at Tinaroo, on the Atherton Tableland in north-eastern Queensland, Australia, a population that some botanists have regarded as an undescribed species. It belongs to the genus Bowenia, fern-like cycads with twice-divided leaves. David Jones treated it as a distinct, undescribed species in 1993, but no formal description has ever been published, The World List of Cycads does not recognise the name, and the Australian Plant Census places it in the synonymy of Bowenia spectabilis. In the trade, plants are sold as Bowenia ‘Tinaroo’ or Bowenia spectabilis ‘Tinaroo’.

Key facts about Bowenia sp. ‘Tinaroo’

  • Name status: phrase name, Bowenia sp. Tinaroo (Jones, 1993), for a population suspected of being an undescribed species; not formally described; absent from The World List of Cycads (version 2026.08.15) and from the World Checklist of Vascular Plants; synonym of Bowenia spectabilis in the Australian Plant Census
  • Related accepted species: Bowenia spectabilis Hook. ex Hook.f. (1863)
  • Family: Zamiaceae according to The World List of Cycads and the Australian Plant Census; Stangeriaceae in CITES nomenclature
  • Common names: none attested; trade names Bowenia ‘Tinaroo’, Bowenia sp. Tinaroo and Bowenia spectabilis ‘Tinaroo’
  • Natural range: Tinaroo, on the Atherton Tableland, north-eastern Queensland; the Flora of Australia cites a specimen from near Tinaroo Dam
  • IUCN status: no assessment of its own; Bowenia spectabilis, in which the Australian Plant Census includes it, is Least Concern (LC, assessment published in 2022)
  • CITES and other protection: as a Bowenia, CITES Appendix II (annotation #4) and Annex B in the European Union
  • Documented hardiness: no measured value; two nurseries give contradictory ratings (see Cold hardiness)
  • Light and soil: shade or light shade; a free-draining soil, acidic according to one nursery
  • Habit: underground stem; toothed leaflets and a stem described as larger and more branched than in typical Bowenia spectabilis; adult dimensions of the population not documented
  • Mediterranean experience: grown in a pot since 2024 at the Jardin zoologique tropical (south-eastern France), where it develops slowly
  • Toxicity: treat the whole plant, and above all the seeds, as toxic, as for all cycads (see Toxicity and precautions)

How to recognise Bowenia sp. ‘Tinaroo’

The Tinaroo plants are recognised by leaflets with regularly toothed margins on fronds otherwise like those of Bowenia spectabilis. Hsiao and Oberprieler (2022) summarise the characters that made the Kuranda and Tinaroo populations seem intermediate between the two species of the genus: toothed leaflets, as in Bowenia serrulata, and an underground stem that is large and branched, as in that species, whereas typical Bowenia spectabilis has leaflets with entire margins and a small, sparsely branched stem.

These characters are not reliable on their own. The Flora of Australia notes that individuals with toothed leaflets occur occasionally in most populations of Bowenia spectabilis, and Hill and Osborne (2001), cited by Hsiao and Oberprieler, found them in all its populations. In his thesis on the genus, G.W. Wilson (2004) found that six populations, representing the two species and both forms of north Queensland, could not readily be told apart by the number or measurements of leaves, pinnae and leaflets, or by the size and branching of the underground stem. No published source gives measurements specific to the Tinaroo plants.

Possible confusion

  • Bowenia serrulata, of the Byfield area in central-eastern Queensland, several hundred kilometres further south: also has toothed leaflets, and its stem bears 5 to 20 crowns. For a cultivated plant, the documented origin is the best clue.
  • Typical Bowenia spectabilis, of the Wet Tropics: leaflets usually with entire margins, but individuals with toothed leaflets occur in its populations, so a toothed leaflet alone does not prove that a plant comes from Tinaroo.
  • The Kuranda plants, also on the Atherton Tableland, which share the toothed leaflets and were studied alongside those of Tinaroo; they are known in the literature as Bowenia ‘Kuranda’ (Kokubugata and colleagues, 2001).

Whether a plant sold as ‘Tinaroo’ actually descends from the Tinaroo population cannot be checked from the published sources.

Taxonomy

Bowenia sp. ‘Tinaroo’ has no formal botanical rank: no description of a species, subspecies or variety has been published under this name. The sources set out four positions, which have not been reconciled by a formal treatment.

  • An undescribed species: David Jones, in Cycads of the World (1993, pp. 108–109, and the second edition of 2002), treated the Tinaroo population as a distinct species not yet described, under the phrase name Bowenia sp. Tinaroo.
  • A variety: Norstog and Nicholls (1997) regarded it as an infraspecific variety of Bowenia spectabilis, according to Hsiao and Oberprieler (2022); no varietal name has been published.
  • Variation within Bowenia spectabilis: Wilson (2004) concluded that the plants with toothed leaflets of north-eastern Queensland are examples of phenotypic variation within Bowenia spectabilis, and, according to Hsiao and Oberprieler (2022), that the Kuranda and Tinaroo populations are probably ecotypes rather than subspecies, the shape of the leaflets and stem depending on the environment, especially temperature. The Flora of Australia cites a specimen collected 2 km past Tinaroo Dam (K.D. Hill 3770 and L. Stanberg) under Bowenia spectabilis, and McKenzie (2006) writes that the population near Tinaroo Dam, previously considered a possible separate species, is included in that species.
  • The Australian Plant Census lists Bowenia sp. Tinaroo (Jones, 1993) and Bowenia sp. (Tinaroo), a phrase name used by Cooper and Cooper (2004) in Fruits of the Australian Tropical Rainforest, among the heterotypic synonyms of Bowenia spectabilis, together with Bowenia sp. (Mt. Haig) from the same book. The World List of Cycads accepts only two species in the genus and does not mention the name.

What the chromosomes show

Kokubugata and colleagues (2000) compared the chromosomes of Bowenia serrulata, Bowenia spectabilis and Bowenia sp. ‘Tinaroo’. All three have 2n = 18 chromosomes. Bowenia serrulata has ten chromosomes with a median centromere, whereas Bowenia spectabilis and the Tinaroo plants have eight; the pattern of ribosomal DNA signals, however, differs between the three. A second study (Kokubugata and colleagues, 2001) described the Kuranda and Tinaroo plants as undescribed taxa and concluded that they are cytologically closer to Bowenia spectabilis than to Bowenia serrulata.

What the pollinating weevils show

Bowenia are pollinated by weevils of the genus Miltotranes, which breed in the male cones. In their 2022 revision of the genus, Yun Hsiao and Rolf Oberprieler examined weevils collected at Tinaroo (by G. Wilson in November 1994, among others), at Kuranda and at Cooktown, and found that all belong to Miltotranes prosternalis, the pollinator of Bowenia spectabilis. Since the ranges of the weevil species match those of their host plants, they conclude that these plant populations also represent Bowenia spectabilis. Only the isolated McIlwraith Range population, on Cape York Peninsula, has its own weevil, Miltotranes wilsoni, which suggests to them that it, rather than Tinaroo, may be a third, undescribed species.

Etymology and history

The name refers to the locality of the population, Tinaroo, on the Atherton Tableland. The Australian Plant Census treats it as an informal name: it has no standing as a formally published botanical name. According to the Australian Plant Census, the name Bowenia sp. Tinaroo appears in David Jones’s Cycads of the World (1993), and the variant Bowenia sp. (Tinaroo) in Cooper and Cooper (2004). Kokubugata and colleagues wrote Bowenia sp. ‘Tinaroo’ (2000) and Bowenia ‘Tinaroo’ (2001). The genus name honours Sir George Bowen, first Governor of Queensland (see Bowenia spectabilis).

Common names

No common name is attested for the Tinaroo plants in any language. The trade uses the botanical phrase name, written Bowenia ‘Tinaroo’, Bowenia sp. Tinaroo or Bowenia spectabilis ‘Tinaroo’ depending on the seller. The English name “zamia fern” belongs to Bowenia spectabilis as a whole.

In the wild

The Tinaroo plants grow on the Atherton Tableland, in north-eastern Queensland. Hsiao and Oberprieler (2022) mention two populations of Bowenia on the tableland whose status had been uncertain, one at Kuranda and the other at Tinaroo, within the Wet Tropics range of Bowenia spectabilis, and the Flora of Australia specimen comes from near Tinaroo Dam. The Queensland government’s WildNet profile states that Bowenia spectabilis grows up to 700 m (2,300 ft) on the Atherton Tableland, in and around rainforest, vine forest and coastal forest, and keeps the locality records of the species confidential.

No published source read describes the habitat, the size or the trend of the Tinaroo population itself. A seed nursery, Rare Palm Seeds, places the plant on the “cool” Atherton Tableland at 700 m (2,300 ft): a commercial statement, not a field study.

Pollination is carried out by the weevil Miltotranes prosternalis: Hsiao and Oberprieler list specimens collected at Tinaroo in November 1966 and November 1994, the season when the weevil breeds in the male cones.

Conservation status and regulation

The Tinaroo population has no IUCN assessment of its own. Bowenia spectabilis, in which the Australian Plant Census includes it, is listed as Least Concern (LC) on the IUCN Red List, in an assessment by J.D. Bösenberg dated 1 April 2021 and published in 2022. In Queensland, WildNet lists Bowenia spectabilis as “special least concern” under the Nature Conservation (Animals/Plants) Regulation 2020; the species is not listed under the federal EPBC Act. If the population were one day described as a separate species, its status would have to be assessed anew.

Like all Bowenia, plants sold as ‘Tinaroo’ fall under CITES Appendix II, with annotation #4: live plants need an export permit, while seeds, pollen and seedlings in sterile containers are exempt. In the European Union they fall under Annex B of Regulation (EC) No 338/97 (Species+, checked on 31 October 2026 for Bowenia spectabilis). Check the regulations in force before any purchase abroad, and buy seed-grown plants of known origin.

Growing Bowenia sp. ‘Tinaroo’

The only cultivation advice specific to the Tinaroo plants comes from two nurseries, and their advice differs; the documented advice for Bowenia spectabilis (filtered sun or shade, a moist but free-draining soil, high humidity) therefore remains the safest guide.

  • Rare Palm Seeds recommends light shade in all climates, deep shade for young plants and in hot, dry climates, rates the water requirement as high and the wind tolerance as low, and the growth rate as moderate.
  • A French cycad nursery, cycadales.eu, calls it a tropical plant that needs an acidic substrate and acidic water, good drainage and tropical conditions, and says that it grows fast if these conditions are met.

Outdoor and in-ground cultivation

No result of growing the Tinaroo plants in the open ground has been found in the published sources. For Bowenia spectabilis, the Australian Native Plants Society reports success in tropical and subtropical areas, in moist, semi-shaded or shaded positions, and possibly in frost-free temperate climates. In the ground, the plant is therefore only an option in frost-free climates, in shade, in a soil that never dries out completely and never becomes waterlogged.

Container cultivation

In other climates, grow it in a deep pot with a free-draining, humus-rich mix kept slightly moist, in shade or bright indirect light, and overwinter it frost-free in a heated glasshouse, a conservatory or a bright room without direct sun. PACSOA describes Bowenia spectabilis as a very good pot plant. At the Jardin zoologique tropical in La Londe-les-Maures (Var, south-eastern France), a Bowenia ‘Tinaroo’ has been grown in a pot since 2024 and develops slowly. This Mediterranean experience may guide growers in comparable climates, such as coastal California or southern Australia, without giving a temperature limit.

Propagation

No method specific to the Tinaroo plants is documented; those of Bowenia spectabilis apply. Propagation is from seed: the Australian Native Plants Society notes that it germinates without pretreatment but may take up to 12 months, and the Australian Tropical Rainforest Plants key gives 89 to 243 days. PACSOA advises pressing the seed halfway into the mix and notes that large plants can be divided. Plants are male or female and the pollinating weevil is absent outside Queensland, so fertile seed in cultivation requires plants of both sexes and hand-pollination. Clean the seeds with gloves.

Pests and diseases

No pest or disease specific to the Tinaroo plants is documented. For the Bowenia he grew in Brisbane, Leonard Butt found a dark, hard-shelled scale insect to be the only trouble and advised controlling the ants that tend it. Cold, waterlogged soil rots the underground stem, and direct sun scorches the thin leaflets.

Cold hardiness

No measured cold-hardiness value has been published for the Tinaroo plants, by a garden, a grower or a study. The two nurseries that describe them contradict each other: Rare Palm Seeds presents the plant as the hardiest Bowenia, “tolerating moderate freezes”, and rates its frost tolerance as “moderate”, whereas cycadales.eu describes it as tropical, to be kept frost-free and preferably at 15 °C (59 °F) or above, tolerating cool conditions only if they are temporary. Neither gives a measured value or a dated observation.

Mediterranean and European experience

At the Jardin zoologique tropical in La Londe-les-Maures, the plant is grown in a pot, where it has developed slowly since 2024; no open-ground trial has been reported in Europe. In mild Mediterranean climates as in Britain, a pot that can be moved under cover in winter remains the only documented approach.

United Kingdom, United States and Australia

No dated cold report for the Tinaroo plants has been published in a source that can be read. No outdoor cultivation of a Bowenia is documented in Britain. For Bowenia spectabilis as a whole, see the species page.

Toxicity and precautions

Yes, it should be treated as poisonous. Like other cycads, Bowenia contain toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived. McKenzie (2006), who includes the Tinaroo Dam population in Bowenia spectabilis, notes that this species has been associated with field cases of poisoning in cattle, and describes the nervous disorder that cycads cause in cattle, known as “zamia staggers”, as irreversible. No analysis specific to the Tinaroo plants has been published.

Wear gloves to clean the seeds, keep plants and seeds out of reach of children, dogs, cats and livestock, and contact a poison centre, a doctor or a vet without delay in case of ingestion.

Traditional uses

No traditional use specific to the Tinaroo plants is documented. The use of the underground stem of Bowenia spectabilis by Aboriginal people, after cooking and leaching, is described on the species page; it relied on traditional knowledge, and the plant is not safe to eat.

Frequently asked questions

Is Bowenia sp. ‘Tinaroo’ a separate species?

It depends on the source. David Jones (1993, 2002) treated the Tinaroo population as an undescribed species, but no description has been published. The chromosome studies, Wilson’s thesis, the pollinating weevils and the Australian Plant Census all link it to Bowenia spectabilis, and The World List of Cycads accepts only two species of Bowenia.

Where does the name ‘Tinaroo’ come from?

From the locality of the population. Tinaroo lies on the Atherton Tableland in north-eastern Queensland; the Flora of Australia cites a specimen collected 2 km past Tinaroo Dam, filed under Bowenia spectabilis. The name is a provisional phrase name, not a formal botanical name.

How do I tell it from Bowenia serrulata?

Mainly by its origin. Both have toothed leaflets, but Bowenia serrulata comes from the Byfield area in central-eastern Queensland and has a large stem with many crowns. A plant of documented Tinaroo origin belongs to the Bowenia spectabilis group; without a documented origin, the leaflets alone are not enough.

Is it hardier than other Bowenia?

Not on present evidence. One seed nursery calls it the hardiest of the genus, tolerating moderate freezes, but another describes it as tropical and frost-tender, and no measured value has been published. Treat it as frost-tender.

Can it be grown outdoors in the UK?

No documented case exists. No Bowenia is documented outdoors in Britain. Grow it in a pot, in shade, and overwinter it frost-free in a glasshouse, a conservatory or indoors.

Does it grow fast?

Not in the only documented case. At the Jardin zoologique tropical, the plant grown in a pot since 2024 develops slowly. A French nursery claims fast growth in tropical conditions and Rare Palm Seeds a moderate rate; Wilson (2004) describes the genus as slow-growing.

Is it toxic?

Yes, as far as is known. No analysis of the Tinaroo plants has been published, but all cycads contain toxic glycosides, and Bowenia spectabilis has been associated with poisoning in cattle. Keep it away from children and animals.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Jones, D.L. (1993). Cycads of the World. Reed Books, Chatswood (New South Wales); Smithsonian Institution Press, Washington, D.C. (two 1993 imprints of 312 pages), pp. 108–109. [Tinaroo population treated as an undescribed species, phrase name Bowenia sp. Tinaroo; after the Australian Plant Census and Hsiao and Oberprieler (2022).]
  • Norstog, K.J. & Nicholls, T.J. (1997). The Biology of the Cycads. Cornell University Press, Ithaca. [Tinaroo plants treated as a variety of Bowenia spectabilis; after Hsiao and Oberprieler (2022).]
  • Hill, K.D. (1998). Cycadophyta. In: McCarthy, P.M. (ed.), Flora of Australia 48: 597–661. ABRS/CSIRO Publishing, Melbourne. [Specimen from near Tinaroo Dam under Bowenia spectabilis; online version of the flora.]
  • Kokubugata, G., Kondo, K., Wilson, G.W., Randall, L.M., van der Schans, A. & Morris, D.K. (2000). Comparison of karyotype and rDNA-distribution in somatic chromosomes of Bowenia species (Stangeriaceae, Cycadales). Australian Systematic Botany 13(1): 15–20. doi:10.1071/SB98028 [2n = 18 and eight median-centromeric chromosomes in the Tinaroo plants, distinct rDNA pattern; peer-reviewed article.]
  • Hill, K. & Osborne, R. (2001). Cycads of Australia. Kangaroo Press, Sydney. [Toothed leaflets in all populations of Bowenia spectabilis; after Hsiao and Oberprieler (2022).]
  • Kokubugata, G., Hill, K.D., Wilson, G.W., Kondo, K. & Randall, L.M. (2001). A comparison of chromosome number and karyotype in somatic chromosomes of Stangeriaceae (Cycadales). Edinburgh Journal of Botany 58(3): 475–481. doi:10.1017/S0960428601000786 [Kuranda and Tinaroo plants cytologically closer to Bowenia spectabilis; peer-reviewed article.]
  • Jones, D.L. (2002). Cycads of the World, 2nd ed. Reed New Holland, Sydney. [Tinaroo population still treated as a distinct species; after Hsiao and Oberprieler (2022).]
  • Wilson, G.W. (2004). The biology and systematics of Bowenia Hook ex. Hook f. (Stangeriaceae: Bowenioideae). Master’s thesis (research), James Cook University. [Two species; plants with toothed leaflets of north-eastern Queensland as phenotypic variation of Bowenia spectabilis.]
  • Cooper, W.E. & Cooper, W.T. (2004). Fruits of the Australian Tropical Rainforest. [Phrase names Bowenia sp. (Tinaroo) and sp. (Mt. Haig); after the Australian Plant Census.]
  • McKenzie, R.A. (2006). Toxicology for Australian Veterinarians: cycads, pp. 282–288. Animal Health Australia (PDF): https://aapspextranet.animalhealthaustralia.com.au/wp-content/uploads/2019/04/tav7_17_unknowntoxins_pt2.pdf [Population near Tinaroo Dam included in Bowenia spectabilis; field cases in cattle.]
  • Bösenberg, J.D. (2022). Bowenia spectabilis. The IUCN Red List of Threatened Species 2022: e.T41980A48510061. doi:10.2305/IUCN.UK.2022-1.RLTS.T41980A48510061.en [Least Concern; assessment dated 1 April 2021.]
  • Hsiao, Y. & Oberprieler, R.G. (2022). Taxonomic revision of the genus Miltotranes Zimmerman, 1994 (Coleoptera: Curculionidae: Molytinae), the Bowenia-pollinating cycad weevils in Australia, with description of a new species and implications for the systematics of Bowenia. Insects 13(5): 456. doi:10.3390/insects13050456 [Kuranda and Tinaroo populations, history of their treatment, weevils of Tinaroo; peer-reviewed article, open access.]
  • 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; two species of Bowenia.]