Cycas wadei

Cycas wadei is a tree-like cycad endemic to Culion Island, north of Palawan in the Philippines, where it dominates a vast, frequently burnt Imperata grassland. Described in 1936 by Elmer D. Merrill, this species of the genus Cycas is the type of section Wadeae, a small, isolated Philippine group with ribbed seeds. Its exceptionally narrow leaflets make it recognisable at a glance. The IUCN lists it as Critically Endangered.

Key facts about Cycas wadei

  • Accepted name: Cycas wadei Merr. (1936), accepted by The World List of Cycads (version 2026.08.15) and by GBIF; the World Checklist of Vascular Plants (WCVP), on which POWO is based, also accepts it (consulted through GBIF on 31 October 2026)
  • Former names and synonyms: reported as Cycas sp. aff. cairnsiana (Foxworthy 1911), then as Cycas cairnsiana (Merrill 1923); Lindström et al. (2008) refer Cycas circinalis subsp. riuminiana var. curranii forma graminea J.Schust. (1932) to this species
  • Family: Cycadaceae, order Cycadales
  • Common names: “Wade’s pitogo” in English (Species+); in Tagalog bayit and oliva for the plant, pitógo for the seed
  • Natural range: Philippines, Culion Island (Palawan province)
  • IUCN status: Critically Endangered (CR B1ab(iii,v)), assessment by U. Ferreras and T. Marler 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: open Imperata grassland in full sun, on low hills with a marked dry season
  • Habit and adult size: trunk to 5 m, 10 to 20 cm across; crown of 30 to 100 leaves 0.75 to 1.8 m long; according to the original description, the trunk is often branched, swollen at the base (30 to 48 cm) and less than 1 m tall in many adult plants
  • In the UK, US and Australia: Montgomery Botanical Center (Florida), eight accessions from 1977 to 2023; Royal Botanic Garden Sydney (online catalogue); declared to BGCI by Glasgow Botanic Gardens and by several American and Australian gardens
  • Toxicity: no data specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas wadei

By the combination of very narrow leaflets, only 3 to 8 mm wide, and seeds whose hard shell carries symmetrical lengthwise ribs. The male cones are soft and waxy, without an upturned terminal spine, and the megasporophylls are deeply comb-like, as in the other species of section Wadeae. The description below follows Lindström, Hill and Stanberg (2008).

  • Trunk: tree-like, to 5 m, 10 to 20 cm in diameter; 30 to 100 leaves in the crown.
  • Leaves: 75 to 180 cm, dark green or grey-green, semi-glossy, slightly to moderately keeled, with 160 to 208 leaflets; rachis usually ending in a spine of 2 to 30 mm; petiole 20 to 40 cm, hairless, spiny for 60 to 100 % of its length.
  • Mid-leaf leaflets: 15 to 29 cm long and 3 to 8 mm wide, markedly paler beneath, narrowed to 2.5 to 3 mm at the base, 5 to 8 mm apart; margins flat; tip sharply pointed.
  • Cataphylls: narrowly triangular, soft, hairy, 70 to 90 mm long.
  • Male cones: spindle-shaped, green or cream, 40 to 70 cm long and 7 to 10 cm across; microsporophylls waxy, 21 to 30 mm, with no spine or only a rudimentary, folded one.
  • Megasporophylls: 14 to 22 cm, brown-felted, bearing 2 to 4 hairless ovules; blade rounded, 70 to 100 mm long and 55 to 80 mm wide, deeply comb-like, with 20 to 30 soft lateral spines 14 to 35 mm long; apical spine 26 to 45 mm.
  • Seeds: almost round to ovoid, 17 to 40 mm long and 15 to 30 mm across; sarcotesta yellow, 3 to 4 mm thick; sclerotesta ribbed lengthwise; no spongy layer.

Merrill’s original description (1936) gives partly different figures. The trunk reaches 5.3 m but is often much shorter (under 1 m in many adult plants), frequently branched, swollen at the base (30 to 48 cm across), then narrowing to 10 to 20 cm below the crown and marked with conspicuous rings. The leaves are about 75 cm long and 25 to 30 cm wide, on a petiole of about 20 cm armed with two rows of short spines 1.5 mm long; young leaves carry cinnamon hairs, later shed. The leaflets, about 90 on each side, are stiff, flat and only 4 to 5 mm wide, those in mid-leaf 15 to 20 cm long, the lowest 8 cm. Male cones measure 40 to 70 cm by 9 to 10 cm, with microsporophylls of about 3 cm; megasporophylls reach 22 cm, are covered in reddish hairs, usually bear two ovules (one to three) and have an oval blade up to 10 cm by 8 cm, divided into about fifteen lobes on each side, at most 3.5 cm long. The fruits, ovoid to ellipsoid, brown and glossy, measure 3.2 to 4 cm by 2.5 to 3 cm, with a woody shell marked by 9 to 15 lengthwise ribs. Merrill already singled out the exceptionally narrow leaflets and the strongly ribbed shell as the most obvious characters. He also noted that a male plant set out at the Bureau of Science in Manila had branched several times, each head bearing a cone, with no sign of injury.

The two accounts differ in the number of megasporophyll lobes (about fifteen on each side against 20 to 30 lateral spines), the number of ovules (usually two against two to four), leaf length (about 75 cm against 75 to 180 cm) and trunk diameter, which Merrill also measured at the swollen base. The published sources do not comment on these differences.

Hybrids

No hybrid has been documented for this species.

Possible confusion

  • Cycas curranii, from Palawan: it also has ribbed seeds, but they are twice as large, and its leaflets are about twice as wide. Zamora and Co (1986) had grouped under the name Cycas wadei plants from Palawan that belong to this species.
  • Cycas saxatilis, from the limestone cliffs of Palawan: wider leaflets (10 to 14 mm) and less keeled leaves.
  • Cycas cairnsiana, from Australia, to which Merrill first compared it: another section, with smooth seeds.

Taxonomy

Cycas wadei is an accepted name in The World List of Cycads; the World Checklist of Vascular Plants (WCVP), on which POWO is based, also accepts it (consulted through GBIF on 31 October 2026). Lindström, Hill and Stanberg (2008) made it the type of a new section, Wadeae, defined by soft, waxy male cones, comb-like megasporophylls, hairless ovules and yellow seeds with a strongly ribbed shell. The section, with only three species endemic to the Philippines (Cycas wadei, Cycas curranii and Cycas saxatilis), is taxonomically isolated: it shows links with groups on the Asian mainland, from which it would have been separated by crustal rifting early in the Tertiary. Hill had earlier called it subsection Wadeanae (1993), without a valid description.

Before it was described, the species went under other names: Cycas sp. aff. cairnsiana (Foxworthy 1911), then Cycas cairnsiana (Merrill 1923). In 1932 Schuster coined, for Merrill’s 1902 collection, a four-part name under Cycas circinalis (subsp. riuminiana var. curranii forma graminea), which Lindström and colleagues refer to this species, designating a lectotype. De Laubenfels and Adema (1998) kept the species; according to Lindström et al., it is in fact the only Philippine name they applied correctly. Merrill himself placed the species in section Indosinenses, close to Cycas inermis, and regarded as mistaken both his own earlier comparison with Cycas cairnsiana and Schuster’s placement under Cycas circinalis, two species he put in section Lemuriae.

Etymology and history

The epithet honours H. Windsor Wade (1886–1968), an American-born physician who settled in the Philippines and brought the species to Merrill’s attention (Lindström et al. 2008; Haynes 2022). According to Merrill, Wade had for many years directed research at the Culion leper colony and supplied him with almost all his information on the plant: photographs, ripe fruits, other material and measurements of wild plants. He had also transplanted several plants to the colony.

Elmer D. Merrill had already collected a sterile plant on 11 February 1902, on an excursion inland from Halsey Harbour (Merrill 657). Several attempts to find it again failed, because they set out from the leper colony on the east coast, whereas Merrill had walked eastwards from the west coast. On 4 April 1923, H. W. Wade and G. A. Perkins finally relocated it after some seven hours’ walk and sent a leaf and some microsporophylls to Manila. W. H. Brown then gathered abundant material (male cones, megasporophylls, ripe fruits), and A. W. Herre collected leaves with megasporophylls and fruits on 27 April 1931 (no. 1061). Two of the plants transplanted by Wade were set out in Manila, in the grounds of the Bureau of Science; by 1936 seedlings were growing at the New York Botanical Garden and at the Coconut Grove Palmetum in Florida, and viable seed had been sent to Kew and to Berlin. Merrill described the species in 1936 (Philippine Journal of Science 60(3): 234–236, pls 1–4) from W. H. Brown’s collection in the “Cogonal Grande”; the Manila holotype has been lost, probably destroyed during the Second World War, and The World List of Cycads gives a lectotype in New York.

Common names

Species+, the CITES database, gives the English name “Wade’s pitogo”; no other English name is attested in the botanical sources. In Tagalog the plant is called bayit (in preference to bait or vait) or oliva (oliba, uliba, uliva), and the seed pitógo (bitogo, patubo, pitugo, potago), according to Amoroso (1986) and Bonta and Osborne (2007), cited by Lindström et al. (2008). These names are not specific to the species.

In the wild

Cycas wadei is known only from Culion Island, on the low hills inland from Halsey Harbour, in the west of the island. It grows in an extensive open Imperata grassland, known locally as the “cogonal grande” or “patag grande”, with a marked dry season and frequent fires. The narrow leaflets are thought to be an adaptation to these seasonally dry conditions, parallel to that of Australian species such as Cycas cairnsiana and Cycas calcicola or the Indian Cycas beddomei (Lindström et al. 2008). A report from Mindoro (Mansalay), with no herbarium specimen, remains to be confirmed. On his 1902 visit, Merrill saw plants 1 to 2 m tall on the gentle, open slopes of the grassland.

In 2008 the population exceeded 5,000 plants, showed no sign of decline and was actively regenerating, with all age classes well represented. The Asian cycad scale, Aulacaspis yasumatsui, which devastates cultivated Cycas on Luzon, appeared to be kept in check on Culion by native predators (Lindström et al. 2008).

Conservation status and regulation

The IUCN lists Cycas wadei as Critically Endangered (CR) under criteria B1ab(iii,v): a tiny range, with a decline in habitat quality and in the number of mature individuals. The assessment is by Ulysses Ferreras and Thomas Marler: according to Crossref it is dated 12 May 2020 and was published in 2022, The World List of Cycads cites it, and GBIF relays the CR category. The species already appeared in the 1997 IUCN Red List of Threatened Plants and was listed as Critically Endangered in the 2011 Red List (Agoo and Madulid 2012). In 2008, by contrast, Lindström and colleagues judged the population stable and suggested Near Threatened, while noting that the land, apparently privately owned, enjoys no protection and that any change in land use would seriously threaten the species.

Like every species in the genus except Cycas beddomei, Cycas wadei 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 only 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 wadei

Cycas wadei is one of the Philippine Cycas best represented in cultivation. Its seed has been widely distributed: adult plants exist in collections around the world, Fairchild Tropical Botanic Garden in Miami has in recent years distributed seed from its cultivated plants, and large quantities of wild-collected seed circulated in the early 1990s, from which many cultivated plants derive (Lindström et al. 2008). It has also been grown in Manila since the 1920s or 1930s: in 1936 Merrill recorded adult plants at the Bureau of Science and at the Culion leper colony, and seedlings at the New York Botanical Garden and the Coconut Grove Palmetum in Florida.

No cultivation guidance specific to Cycas wadei has been published. Its natural setting, an open tropical grassland, dry for part of the year and often burnt, suggests a very free-draining mineral mix and full light: these are cautious inferences, not tested results.

Outdoor and in-ground cultivation

Only frost-free tropical climates can reasonably be considered for planting out, such as southern Florida, where Montgomery Botanical Center grows its cycads in the open ground and where its first accession of the species dates from 1977, or Manila, where Merrill already recorded planted specimens in 1936. The published sources do not say whether the plants held in other American and Australian gardens grow outdoors or under glass.

Container cultivation

Elsewhere, grow it in a pot, in a gritty mineral compost and in full light, and keep it in a heated glasshouse or conservatory in winter. There is no documented experience of its behaviour in a pot.

In cultivation in the UK, US and Australia

In short: well represented in American collections, present in at least one Australian catalogue and declared by one British garden.

  • United States: Montgomery Botanical Center, in Coral Gables (Florida), lists eight accessions in its online catalogue, numbered 77967 (1977), 94633 (1994), 981915 (1998), 20080079 (2008) and 20230325 to 20230329 (four accessions of 2023), according to the year given by the garden’s numbering (consulted on 24 October 2026). Fairchild Tropical Botanic Garden, San Diego Botanic Garden, the San Diego Zoo, Marie Selby Botanical Gardens (Sarasota), the New York Botanical Garden and, in Hawaii, Honolulu Botanical Gardens and the University of Hawaii botanic garden at Hilo also declare the species to BGCI.
  • Australia: the Royal Botanic Garden Sydney lists the species in its online catalogue (Garden Explorer, search of 19 October 2026), and the Cairns Botanic Gardens and the Botanic Garden of South Australia, in Adelaide, declare it to BGCI.
  • United Kingdom: Glasgow Botanic Gardens declares the species to BGCI; there it can only be a glasshouse plant. No other British record is documented. The British nursery Trebrown lists the species with a USDA zone 9b rating, its own commercial classification, not a documented trial.

A BGCI declaration shows that a garden held the plant at some point, not that it is alive today; in all, 21 gardens worldwide declare the species. No dated report from a private grower is documented.

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, such as those distributed by botanic gardens.

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, and on Culion native predators seemed to keep it in check (Lindström et al. 2008).

Cold hardiness

There is no cold-hardiness data for Cycas wadei. Culion 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. A 2010 message on the French Fous de palmiers forum, in a thread on cycads in Europe, mentions a plant obtained from another collector, with no growing details; no dated cold event concerns it. The Jardin zoologique tropical at La Londe-les-Maures, in the Var, has published no observation of this species.

United Kingdom, United States and Australia

Despite its wide presence in collections, no cold value and no dated cultivation report is documented, from forums or from botanic gardens. Trebrown’s zone 9b rating is a commercial classification, not a measured result.

Toxicity and precautions

No toxicity analysis specific to Cycas wadei has been published, but 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

No use specific to the species is documented. The existence of a Tagalog name for the seed (pitógo) is not enough to show that it was used.

Frequently asked questions

Who was Wade?

H. Windsor Wade (1886–1968), an American-born physician in charge of research at the Culion leper colony: he relocated the species in 1923 with G. A. Perkins, supplied Merrill with almost all his material and planted some specimens at the colony.

Where does Cycas wadei grow?

Only on Culion Island, north of Palawan (Philippines), in an open, frequently burnt grassland.

How can I recognise it?

By its very narrow leaflets (3 to 8 mm wide) and its seeds with a ribbed shell.

How does it differ from Cycas curranii?

Cycas curranii, from Palawan, has leaflets twice as wide and seeds twice as large.

Is it endangered?

Yes. The IUCN lists it as Critically Endangered: a single population, on unprotected land.

Is it in cultivation?

Yes. Its seed has circulated for decades, and adult plants grow in many collections, including Montgomery Botanical Center in Florida, whose first accession of the species dates from 1977.

Is it hardy in the UK?

No. There is no cold data for the species, and its island never sees frost: 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

  • Merrill, E.D. (1936). A new Philippine species of Cycas. Philippine Journal of Science 60(3): 233–237, pls 1–4. [Original description; history of the collections, Latin and English descriptions, specimens, plants in cultivation, etymology. Primary source.]
  • 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 [Section Wadeae, description, history, habitat, Tagalog names, status, cultivation.]
  • 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, 2011 Red List status.]
  • 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 concept.]
  • Ferreras, U. & Marler, T. (2022). Cycas wadei. The IUCN Red List of Threatened Species 2022: e.T42097A69828324. doi:10.2305/IUCN.UK.2022-1.RLTS.T42097A69828324.en [Assessment dated 12 May 2020; reference checked on The World List of Cycads and Crossref, CR category relayed by GBIF.]
  • Amoroso, V.B. (1986). Morphological study of the sporophylls of Philippine Cycas. Philippine Journal of Science 115(3): 177–198. [Vernacular names; cited by Lindström et al. (2008).]
  • 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.]
  • 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.]