Cycas apoa

Cycas apoa is a cycad of the humid lowland forests of northern New Guinea, known from the Huon Peninsula, in Papua New Guinea, to the area around Lake Sentani, in Indonesian Papua. Described by Ken Hill in 1994, this species of the genus Cycas takes its name from the word used by speakers of the Kaka language, near the mouth of the Sepik. Long misnamed Cycas circinalis in this region, it is recognised by its very long, glossy leaves with wavy leaflets and by its megasporophylls, which are almost without teeth.

Key facts about Cycas apoa

  • Accepted name: Cycas apoa K.D.Hill (1994), accepted by The World List of Cycads (version 2026.08.15); POWO could not be consulted directly
  • Former names and synonyms: no synonym; formerly referred to Cycas circinalis in northern New Guinea, then included in Cycas scratchleyana by de Laubenfels and Adema (1998)
  • Family: Cycadaceae, order Cycadales
  • Common names: no English name attested; “apoa” in Kaka and “handambo” in Sentani (New Guinea)
  • Natural range: northern New Guinea, from the Huon Peninsula (Papua New Guinea) to Jayapura Regency (Indonesia); The World List of Cycads also lists North Maluku and East Nusa Tenggara (see In the wild)
  • IUCN status: Least Concern (LC); assessment by Ken Hill (2010), reassessment by J. D. Bösenberg published in Red List version 2023-1, LC according to GBIF
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union
  • Documented hardiness: no data (see Cold hardiness)
  • Light and soil: more or less closed mesophyll forest in humid lowlands, often on small ridges, sometimes on ground flooded for part of the year
  • Habit and adult size: trunk up to 2.5 m; leaves 1.8 to 2.5 m long
  • In the UK, US and Australia: declared by four botanic gardens (Glasgow, San Diego, Atlanta, Cairns) in BGCI PlantSearch (see In cultivation in the UK, US and Australia)
  • Toxicity: no data specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas apoa

According to Lindström, Hill and Stanberg (2009), Cycas apoa stands out by its thin leaflets, very narrow at the base and with strongly wavy margins, and by the small sterile blade of its megasporophylls, which has no clear lateral teeth. Their description:

  • Trunk: upright, up to 2.5 m tall.
  • Leaves: 180 to 250 cm long, bright, very glossy green, flat, covered with white and orange down when they emerge, which later falls; ending in a spine or a pair of leaflets; petiole hairless, 35 to 60 cm long, spiny along 80 to 100% of its length.
  • Median leaflets: 22 to 32 cm by 11 to 15 mm, inserted at 70 to 80°, about 13 mm apart, narrowed to 2.5 mm at the base, distinctly paler beneath; margins slightly recurved and often wavy; tip softly acuminate.
  • Cataphylls (the scales protecting the growing point): linear, soft, hairy.
  • Male cones: narrowly ovoid, orange; terminal spine of the microsporophylls barely developed.
  • Megasporophylls (the fertile leaves of female plants): 20 to 26 cm long, with orange and grey down, carrying 2 to 8 ovules; sterile blade lanceolate, about 35 mm by 16 mm, without developed lateral teeth; terminal spine 15 to 30 mm.
  • Seeds: flattened-ovoid, 45 to 50 mm by 40 mm, with an orange-brown fleshy coat without bloom and no inner spongy layer.

The authors note that some cultivated plants bear small teeth on either side of the terminal spine of the megasporophylls, but never on the rest of the blade.

Hybrids

No natural or garden hybrid is documented.

Possible confusion

  • Cycas scratchleyana, from southern New Guinea, under which de Laubenfels and Adema had placed it: the same thin, wavy leaflets, but a much larger and broader sterile blade on the megasporophylls (45 to 80 mm by 38 to 50 mm), with 28 to 40 distinct lateral teeth;
  • Cycas rumphii, which occupies roughly the same region but lives on the coast: seeds with a spongy layer that lets them float, and broad, stiff, arching leaflets;
  • Cycas circinalis, a name long misapplied to this plant in New Guinea: it is a species endemic to south-western India.

Taxonomy

Cycas apoa is accepted by The World List of Cycads; POWO could not be consulted directly. Ken Hill described it in 1994 in Australian Systematic Botany (volume 7, pages 553 and 554), in his revision of the Cycas rumphii complex in New Guinea and the western Pacific, which also named Cycas bougainvilleana and Cycas micronesica. The plants of northern New Guinea had until then been called Cycas circinalis, a name that Lindström and Hill (2007) showed had been applied indiscriminately to populations from many regions.

Hill first placed the species in subsection Rumphiae, defined by seeds with a spongy layer, on the basis of a few seed collections that were apparently mixed. Later collections showed that its seeds lack this layer, so Lindström, Hill and Stanberg (Telopea, 2009) moved it to subsection Cycas, alongside Cycas scratchleyana and Cycas javana, which extended the known range of that group well to the east. De Laubenfels and Adema (Blumea, 1998), for their part, had included it in Cycas scratchleyana, a view that has not been followed.

Etymology and history

The epithet is the name of the plant in Kaka, a language spoken around the Sepik estuary, in the north of New Guinea; it is pronounced “AP-wah”, with the first syllable stressed but short (Lindström et al. 2009, after Hill 1994).

The type was collected on 4 April 1957 by G. Iwanggin at Babrongko, on the southern shore of Lake Sentani, in Papua (no. BW 5245); the holotype is kept in Canberra (CANB), with isotypes at Harvard (A), Brisbane (BRI), Lae (LAE) and Leiden (L).

Common names

No English common name is attested. Ken Hill recorded two vernacular names in New Guinea: “apoa” in Kaka (Kasmin village, Sepik region) and “handambo” in Sentani, around Lake Sentani (Hill 1994, quoted by Lindström et al. 2009).

In the wild

According to Lindström, Hill and Stanberg (2009), Cycas apoa is known from northern New Guinea, from the Huon Peninsula (Morobe Province) west to Jayapura Regency. It shares this region with Cycas rumphii, but the latter lives on the coast, whereas Cycas apoa grows away from the shore. It is a scattered plant of more or less closed mesophyll forest in the humid lowlands, sometimes on ground flooded for part of the year but more often on small ridges.

The World List of Cycads gives a wider range, which includes, in Indonesia, North Maluku and East Nusa Tenggara as well as the two provinces of Papua. The sources consulted do not explain this extension, and the 2009 distribution map does not show it. Pollinators and seed dispersers are not documented.

Conservation status and regulation

Cycas apoa is listed as Least Concern (LC) by the IUCN. The World List of Cycads cites the assessment by Ken Hill (2010); a reassessment by John Donald Bösenberg was published in Red List version 2023-1 (reference checked on Crossref), and the IUCN data relayed by GBIF give the LC category (consulted on 21 October 2026). Lindström and colleagues already recommended this category in 2009, whereas Donaldson (2003) had rated the species Near Threatened; they estimated the population at more than 10,000 individuals. The Red List itself could not be consulted directly.

Like every species in the genus except Cycas beddomei, Cycas apoa is listed in CITES Appendix II, where the family Cycadaceae has been 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 not subject to CITES, 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. 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 provenance and prefer plants raised from seed in cultivation.

Growing Cycas apoa

In short: no institution has published growing advice specific to Cycas apoa. It is in cultivation, since Lindström and colleagues describe cultivated plants, and the wiki of the Palm and Cycad Societies of Australia (PACSOA) gives it “a bit of a reputation for being difficult”.

Outdoor and in-ground cultivation

Its habitat of humid equatorial lowland forest points to a plant for permanently warm, humid conditions, more tolerant of shade and of moist soil than the savanna Cycas. The PACSOA wiki recommends light shade and a well-drained position. Outdoor planting can only be considered in frost-free tropical climates; no outdoor trial has been published in a Mediterranean or temperate climate.

Container cultivation

In the United Kingdom and other temperate regions, it is a plant for a heated, humid glasshouse. Young plants can be kept in pots, in bright light without scorching sun, in a free-draining compost. No published account gives watering or temperature regimes for this species. The Jardin zoologique tropical at La Londe-les-Maures, in the south of France, has published no observation on Cycas apoa.

In cultivation in the UK, US and Australia

In short: four botanic gardens in the three countries declare the species, but none of their own online catalogues consulted lists it. A garden listed in the BGCI PlantSearch database (consulted in October 2026) has declared the species at some point, which does not prove that a living plant is there today, nor whether it grows under glass or outdoors.

  • United Kingdom: Glasgow Botanic Gardens declares the species in BGCI PlantSearch.
  • United States: San Diego Botanic Garden, in Encinitas, California, and Atlanta Botanical Garden, in Georgia, declare it in BGCI PlantSearch. It does not appear in the online catalogue of Montgomery Botanical Center or in the Garden Explorer of Fairchild Tropical Botanic Garden, both in Florida.
  • Australia: the Cairns Botanic Gardens, in tropical Queensland, declare it in BGCI PlantSearch. It does not appear in the Garden Explorer of the Royal Botanic Garden Sydney or in the online census of the Royal Botanic Gardens Victoria.

No first-hand report from a private grower in these countries could be read; PalmTalk and Dave’s Garden could not be consulted.

Propagation

Like all Cycas, Cycas apoa is dioecious: a male and a female plant are needed for fertile seed. No germination data specific to the species have been published. Seeds are exempt from CITES under annotation #4; ask for seed from cultivated plants.

Pests and diseases

No pest or disease specific to the species is documented. Scale insects, including Aulacaspis yasumatsui, threaten all cultivated Cycas, but no attack has been reported on this species in particular.

Cold hardiness

No cold-tolerance data exist for Cycas apoa. It is a plant of equatorial lowland rainforest; nothing suggests that it can take frost.

European experience

No cultivation result has been published in Europe, in the open ground or in a pot, and no dated frost episode concerns the species. A search of the French forum Fous de palmiers and the Italian forum Tropicamente found no report of cold tolerance. In the absence of data, grow it under heated glass.

United Kingdom, United States and Australia

No cold reading and no dated growing report were found, either on forums or from botanic gardens. Treat it as frost-tender; no USDA zone can be given without a documented trial.

Toxicity and precautions

No toxicity analysis specific to Cycas apoa 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 use is documented for this species in the sources consulted. The vernacular names recorded in Kaka and Sentani show only that the plant is known to local people.

Frequently asked questions

What does the name apoa mean?

It is the name of the plant in Kaka, the language of the Sepik estuary, in New Guinea; it is pronounced “AP-wah”.

Where does it grow?

In northern New Guinea, from the Huon Peninsula to the Lake Sentani area, in humid lowland forest, away from the coast.

Is it a Cycas circinalis?

No. The name was misapplied to it; the true Cycas circinalis is endemic to south-western India.

How can it be told from Cycas rumphii?

By its megasporophylls with a small sterile blade lacking clear lateral teeth, its thin, wavy leaflets and its seeds without a spongy layer; Cycas rumphii also lives on the coast.

Is it endangered?

No. The IUCN lists it as Least Concern, and its population was estimated at more than 10,000 individuals in 2009.

Can it be grown outdoors in the UK?

No, almost certainly not. No cold data exist; it is a plant of equatorial forest that needs a heated glasshouse.

Is it poisonous?

It must be assumed so. No toxicity analysis specific to the species exists, but the Cycas studied contain dangerous toxins, especially in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Hill, K.D. (1994). The Cycas rumphii complex (Cycadaceae) in New Guinea and the western Pacific. Australian Systematic Botany 7(6): 543–567. doi:10.1071/SB9940543 [Original description; abstract only consulted (paywall).]
  • Lindström, A.J., Hill, K.D. & Stanberg, L.C. (2009). The genus Cycas (Cycadaceae) in Indonesia. Telopea 12(3): 385–418. doi:10.7751/telopea20095826 [Full text consulted.]
  • Lindström, A.J. & Hill, K.D. (2007). The genus Cycas (Cycadaceae) in India. Telopea 11(4): 463–488. doi:10.7751/telopea20075745 [Misapplications of the name Cycas circinalis; full text consulted.]
  • de Laubenfels, D.J. & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Very broad species concept; not consulted directly, cited after The World List of Cycads.]
  • Hill, K.D. (2010). Cycas apoa. The IUCN Red List of Threatened Species: e.T42068A10642573. [Red List assessment; reference taken from The World List of Cycads and Crossref, Red List page not consulted (access blocked).]
  • Bösenberg, J.D. (2023). Cycas apoa. The IUCN Red List of Threatened Species 2023: e.T42068A67334966. doi:10.2305/IUCN.UK.2023-1.RLTS.T42068A67334966.en [Reassessment; reference checked on Crossref, LC category relayed by GBIF; page not consulted (access blocked).]
  • 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 taken up 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.]