Cycas zambalensis

Cycas zambalensis is a tree-like cycad of the grassy hills of Zambales province, in north-western Luzon (Philippines), where it grows in full sun and wind, close to the sea, on chromium-rich ultrabasic soils. Described in 2005 by Domingo Madulid and Esperanza Agoo, this species of the genus Cycas is recognised by its short, stiff leaflets set in a V and by the brown hairs that persist on its leaves. Young plants resemble the familiar sago palm, Cycas revoluta. The IUCN lists it as Critically Endangered.

Key facts about Cycas zambalensis

  • Accepted name: Cycas zambalensis Madulid & Agoo (2005), accepted by The World List of Cycads (version 2026.08.15) and by GBIF; POWO could not be consulted
  • Former names and synonyms: none
  • Family: Cycadaceae, order Cycadales
  • Common names: none attested
  • Natural range: Philippines, north-western Luzon, Zambales province (San Antonio, Kawag, Bucao)
  • IUCN status: Critically Endangered (CR A4acd), assessment by J.D. Bösenberg dated 2020 and published in 2022
  • 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: hill grassland in full sun, exposed to wind, on ultramafic soils (peridotite and gabbro)
  • Habit and adult size: small tree to 3 m, 15 to 30 cm across; leaves 1 to 1.9 m long
  • In the UK, US and Australia: no record in BGCI or in the online catalogue of Montgomery Botanical Center; the only garden declaring it to BGCI is in the Philippines
  • Toxicity: no data specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas zambalensis

It is the only Philippine Cycas whose leaflets and rachis remain covered in hairs, which persist even on herbarium specimens. The leaflets are short, stiff and brittle, set in a V on either side of the rachis, and on young leaves they form a very marked channel (Madulid and Agoo 2005). The description below follows the original description and Lindström, Hill and Stanberg (2008).

  • Trunk: to 3 m, 15 to 30 cm in diameter, usually single, sometimes branched; base not swollen.
  • Leaves: 100 to 190 cm (at most 105 cm in the original description), dark green, semi-glossy, keeled, with 99 to 260 leaflets; persistent brownish hairs; petiole 30 to 44 cm, hairy, armed for 60 to 80 % of its length with small yellowish spines under 5 mm long.
  • Mid-leaf leaflets: 12 to 26 cm long and 5 to 8 mm wide, narrowed to 2.5 mm at the base, 5 to 10 mm apart, stiff, with straight margins; midrib flat above, raised beneath; scattered brown hairs on both faces.
  • Cataphylls: narrowly triangular, needle-like, stiff, hairy, 60 to 70 mm long.
  • Male cones: orange-brown, ovoid to long-ovoid, tapering, up to 36 cm long and 18 cm across; microsporophylls firm, 30 to 50 mm, with a distinct, upturned apical spine of 5 to 25 mm.
  • Megasporophylls: 22 to 35 cm, with a thick, persistent brown woolly covering, bearing 4 to 6 hairless ovules; blade ovate to lanceolate, 70 to 80 mm long and 40 to 50 mm wide, shallowly comb-like, with 20 to 34 pungent lateral spines 6 to 14 mm long; apical spine 30 to 35 mm.
  • Seeds: ovoid, slightly flattened, up to 43 mm long and 36 mm across; sarcotesta yellow when ripe, without a fibrous layer; sclerotesta smooth; spongy layer present but thin. The endocarp, translucent and watery when young, becomes white and floury when ripe.

Hybrids

No hybrid has been described. Lindström, Hill and Stanberg (2008), however, observed a spongy layer in a cultivated plant (Fernando 1605): it could indicate hybridisation, present or past, with subsection Rumphiae, the Cycas with floating seeds.

Possible confusion

  • Cycas riuminiana, also Philippine and its closest relative according to the authors of the species: the same long petiole and woolly megasporophylls, but wider, hairless leaflets, a shorter sterile part to the megasporophylls and a smaller apical spine (Madulid and Agoo 2005).
  • Cycas revoluta, widely grown in the Philippines: young Cycas zambalensis resemble it in their stiff leaflets and channelled leaves, but the ovules and seeds of Cycas revoluta are hairy. The original description compares the plant with Cycas taitungensis, “more commonly called Cycas revoluta”.
  • Cycas furfuracea and Cycas calcicola, from Australia, which also have hairy leaflets and rachis, but on another continent and on other soils.

Taxonomy

Cycas zambalensis is an accepted name in The World List of Cycads; POWO could not be consulted. It was described in 2005 by Domingo A. Madulid, of the National Museum of the Philippines, and Esperanza M.G. Agoo, of De La Salle University (Blumea 50(3): 519–522, fig. 1), who placed it in de Laubenfels’s subgenus Pectinata. Lindström, Hill and Stanberg (2008) place it in section Cycas, subsection Cycas, that of the species with no spongy layer or only a thin one.

Etymology and history

The epithet refers to Zambales province, on the island of Luzon, to which the species is endemic (Madulid and Agoo 2005; Haynes 2022).

The authors discovered the population during a survey of the distribution of Cycas riuminiana on Luzon, funded by the Threatened Species Programme of the Haribon Foundation. The type was collected in 2005 at San Antonio (Madulid & Agoo PNH 173358; holotype in Manila). In March 2006 Anders Lindström collected it on the slopes of Mount Anawangan, in barangay Pundakit, at about 300 m.

Common names

No common name is attested for this species, in English, in any language of the Philippines or in any other language, in the sources consulted.

In the wild

Cycas zambalensis is known only from the grassy hills of the Zambales peninsula (San Antonio, Kawag, Bucao), a distinct biogeographical region of western Luzon. The soils are ultramafic and rich in chromite; the San Antonio massif is made of peridotite and gabbro. The climate has two clear seasons: dry from November to April, wet for the rest of the year, with a peak from June to September during the south-west monsoon. The plants, widely scattered on steep, hard-to-reach slopes, grow in full sun and exposed to strong wind, close to the sea (Madulid and Agoo 2005; Lindström et al. 2008).

The grassy slopes are reportedly burnt at least once a year to encourage new grass growth for cattle and goats; the effect of these fires on the population has not been assessed. Pollination and seed dispersal are not documented.

Conservation status and regulation

The IUCN lists Cycas zambalensis as Critically Endangered (CR) under criterion A4acd: an observed or projected population reduction linked to habitat loss and exploitation. The assessment is by J.D. Bösenberg, cited by The World List of Cycads: according to Crossref it is dated 12 November 2020 and was published in 2022, and GBIF relays the category; the Red List itself could not be consulted. As early as 2005 the authors considered it critically endangered: a very small range, changes in land use and growing pressure from the horticultural trade, which removes seedlings and young plants to sell them in markets.

Like every species in the genus except Cycas beddomei, Cycas zambalensis is listed in CITES Appendix II, where the family Cycadaceae has appeared since 4 February 1977. The listing carries annotation #4 (the version adopted at CoP20, in force since 5 March 2026): seeds, pollen, seedlings and tissue cultures obtained in vitro and transported in sterile containers, as well as cut flowers of artificially propagated plants, are not covered by CITES; international trade in the plants themselves requires an export permit. In the European Union the species falls under Annex B of Regulation (EC) No 338/97, whose current annexes are set by Regulation (EU) 2026/1383, applicable since 29 June 2026. Species+, the official CITES database, lists the species, with the Philippines as its range state, and confirms this status (consulted on 24 October 2026).

This summary does not replace the official texts: check the regulations in force before any purchase or exchange, ask the seller for proof of origin and choose nursery-raised plants grown from seed.

Growing Cycas zambalensis

In the Philippines, Cycas zambalensis is grown locally: Lindström collected it in 2006 in the town of San Antonio and in the hotels of the former Subic Bay naval base, and Fernando had already collected it in 2001 at a hotel in the Subic free port zone. Around 2014, seed merchants offered it for sale in Europe.

No cultivation guidance has been published. Its native setting, a sunny, windy grassland, dry for part of the year, on ultrabasic soil, suggests full light and a very free-draining mineral mix: these are cautious inferences, not tested results.

Outdoor and in-ground cultivation

Only frost-free tropical climates can reasonably be considered for planting out, as in its home region, where it is planted in hotel grounds around Subic Bay. No planted specimen with a documented history is known outside the Philippines.

Container cultivation

Elsewhere, grow it in a pot, in full light and in a gritty mineral compost, and keep it in a heated glasshouse or conservatory in winter. The only European experience found comes from France: a grower in Dirinon (Finistère, Brittany, France) reported on the Fous de palmiers forum in October 2015 that four young plants were being raised in pots, in a heated growing room under LED lighting, where they were growing steadily; no later results were published, and the trial says nothing about cold tolerance.

In cultivation in the UK, US and Australia

In short: no record. The species does not appear in the online catalogue of Montgomery Botanical Center, nor in the British, American and Australian gardens declared to BGCI (both consulted on 24 October 2026); the only garden declaring it to BGCI is a university botanic garden at Laoag, in Ilocos Norte (Philippines). The British nursery Trebrown has no page for it. No report from an English-speaking grower was found; PalmTalk and Dave’s Garden could not be consulted.

Propagation

The plant is dioecious: a male and a female are needed to obtain seed. No germination data specific to the species has been published; Cycas seed is usually sown fresh, in a free-draining mix and in warmth. Seeds are exempt from CITES under annotation #4: ask for seed from cultivated plants, never from wild collection.

Pests and diseases

No disease specific to the species has been documented. In the Philippines, the cycad scale Aulacaspis yasumatsui is spreading fast and seriously damages cultivated Cycas on Luzon, Negros and Panay; in 2008 its presence in wild populations had not been confirmed (Lindström et al. 2008).

Cold hardiness

There is no cold-hardiness data for Cycas zambalensis. The Zambales coast has a frost-free tropical climate: nothing supports the idea that the plant can withstand frost.

Mediterranean and European experience

No cultivation result has been published from southern France or Italy, outdoors or in a pot, and no dated cold event concerns the species. The young plants reported in 2015 were grown in Brittany, indoors and in warmth, and the Italian Tropicamente forum has nothing on the species; the Jardin zoologique tropical at La Londe-les-Maures, in the Var, has published no observation of it. Another message on the French forum, which suggested this name for a cycad photographed by the sea, has been set aside: the identification was not established.

United Kingdom, United States and Australia

No cold value and no dated cultivation report was found, from forums or from botanic gardens.

Toxicity and precautions

No toxicity analysis specific to Cycas zambalensis has been found. The original description notes that the ripe, slightly sweet endocarp is sometimes eaten: this observation does not show that the seed is harmless. The risk is 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. In the absence of evidence to the contrary, treat the plant as poisonous: keep seeds and leaves out of reach of children and animals and wear gloves to clean seeds. If any part is swallowed, contact a poison centre, a doctor or a vet straight away.

Traditional uses

According to Madulid and Agoo (2005), local people use the leaves in religious ceremonies during Lent, and the slightly sweet endocarp of the seeds is sometimes eaten. Young plants are also removed for the horticultural trade.

Frequently asked questions

Where does the name zambalensis come from?

From Zambales province, in north-western Luzon (Philippines), the only place where the species grows.

Where does Cycas zambalensis grow?

On the grassy hills of Zambales, in full sun and wind, close to the sea, on ultrabasic soils.

How can I recognise it?

By its short, stiff leaflets set in a V and by the brown hairs that persist on the leaflets and rachis.

Does it look like the sago palm?

Yes, when young. But its ovules and seeds are hairless, whereas those of Cycas revoluta are hairy.

Is it endangered?

Yes. The IUCN lists it as Critically Endangered: a tiny range, fires, changes in land use and collection for the trade.

Is it hardy in the UK?

No. There is no cold data for the species, and its range is tropical: in Britain it is a plant for a heated glasshouse.

Is it poisonous?

It should be assumed so. No analysis exists for this species, but all the Cycas studied contain serious toxins, especially in their seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Madulid, D.A. & Agoo, E.M.G. (2005). A new species of Cycas (Cycadaceae) from the Philippines. Blumea 50(3): 519–522. doi:10.3767/000651905X622770 [Original description, habitat, uses, threats; full text consulted.]
  • Lindström, A.J., Hill, K.D. & Stanberg, L.C. (2008). The genus Cycas (Cycadaceae) in the Philippines. Telopea 12(1): 119–145. doi:10.7751/telopea20085805 [Additional description, subsection, specimens, cultivation in the Philippines; full text consulted.]
  • Agoo, E.M.G. & Madulid, D.A. (2012). Cycas sancti-lasallei (Cycadaceae), a new species from the Philippines. Blumea 57(2): 131–133. doi:10.3767/000651912X657503 [Key to the Philippine Cycas; full text consulted.]
  • Bösenberg, J.D. (2022). Cycas zambalensis. The IUCN Red List of Threatened Species 2022: e.T178869A69829006. doi:10.2305/IUCN.UK.2022-1.RLTS.T178869A69829006.en [Assessment dated 12 November 2020; reference checked on The World List of Cycads and Crossref, CR category relayed by GBIF; Red List page not 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 etymology 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.]