Cycas edentata

Cycas edentata is a coastal cycad of South-East Asia, growing on beaches, dunes and rocky headlands from southern Vietnam and Thailand to Malaysia, Sumatra, Java, northern Borneo and the Philippines. This member of the genus Cycas, long confused with Cycas rumphii, is also known as Cycas litoralis, a name published in 1999 for the same plant and now a synonym. It forms a trunk up to 10 m tall, carries flat, very glossy leaves and produces seeds that float. The IUCN lists it as Endangered.

Key facts about Cycas edentata

  • Accepted name: Cycas edentata de Laub. (1998), accepted by The World List of Cycads (version 2026.08.15); POWO could not be consulted directly
  • Former names and synonyms: Cycas litoralis K.D.Hill (1999); Cycas circinalis subsp. riuminiana var. curranii forma maritima J.Schust. (1932); long misidentified as Cycas rumphii or Cycas circinalis
  • Family: Cycadaceae, order Cycadales
  • Common names: no established English name; prong thale (“sea cycad”, Thai), kwale pahang, paku laut and pokok sakat (Malay), bayit and pitógo (Tagalog), oliva (Philippine Spanish)
  • Natural range: coasts of southern Vietnam, southern Myanmar and Thailand, Malaysia (Peninsular Malaysia and northern Borneo), Singapore, Indonesia (Sumatra, Java, Bali) and the Philippines
  • IUCN status: Endangered (EN), in the assessment published in 2023, according to the Red List data relayed by GBIF; Near Threatened in the previous assessment (see Conservation status)
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union
  • Documented hardiness: no measured value; a tropical coastal species, reported as very tender (see Cold hardiness)
  • Light and soil: full sun to part shade, on beach sand or very thin soils over granite or limestone headlands, by the sea
  • Habit and adult size: trunk up to 10 m tall and 20 cm in diameter; leaves 1.3 to 2.3 m long
  • In the UK, US and Australia: Montgomery Botanical Center (Florida) and several other American gardens; Royal Botanic Garden Sydney and Cairns Botanic Gardens in Australia; no British garden record found
  • Toxicity: no data for the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas edentata

Three characters identify Cycas edentata, according to Lindström, Hill and Stanberg (2008, 2009): flat, clear green, very glossy leaves; microsporophylls (the scales of the male cone) ending in a long, stout spine that is sharply upturned; and megasporophylls (the fertile leaves of female plants) without distinct lateral teeth, hence the name. Its large seeds with an inner spongy layer place it in the Cycas rumphii group. In detail:

  • Trunk: tree-like, up to 10 m tall and 20 cm in diameter at the narrowest point; many leaves in the crown.
  • Leaves: 130 to 230 cm long, bright green to dark green, very glossy, flat (leaflets held opposite at 180°), with 100 to 200 leaflets; rachis ending in a pair of leaflets; petiole 30 to 90 cm, hairless, spiny over 5 to 100% of its length.
  • Median leaflets: 22 to 37 cm long and 11 to 19 mm wide, clearly paler beneath, inserted at 45 to 80°, spaced 12 to 35 mm apart, with slightly recurved margins; midrib broad.
  • Cataphylls (the scale leaves protecting the crown): narrowly triangular, soft, hairy, 4 to 7 cm long.
  • Male cones: narrowly ovoid or spindle-shaped, orange, 35 to 60 cm long and 11 to 17 cm wide; microsporophylls with an apical spine 9 to 24 mm long, strongly upturned.
  • Megasporophylls: 24 to 50 cm long, with white, yellow or brown felt, bearing 2 to 8 hairless ovules; blade lanceolate, 43 to 120 mm by 20 to 40 mm, with short or indistinct lateral teeth; apical spine 14 to 40 mm.
  • Seeds: flattened-ovoid, 45 to 66 mm by 35 to 50 mm; fleshy coat orange-brown, not powdery; no fibrous layer; inner spongy layer present.

According to the 2019 report of the Thai Department of Agriculture, Thai plants are 5 to 10 m tall, with a straight, rarely branched trunk, grey or brown, finely fissured bark and yellow male cones.

Hybrids

No natural or garden hybrid is documented for this species in the revisions consulted.

Possible confusion

  • Cycas rumphii, from eastern Indonesia and New Guinea: same group and the same seeds with a spongy layer, but microsporophylls with a short spine and ridged seeds.
  • Cycas thouarsii, from the western Indian Ocean: microsporophylls also with a long spine, but narrower leaflets, clearly bluish-grey when young.
  • Cycas zeylanica, from Sri Lanka and the Andaman Islands: longer, narrower megasporophylls, more widely spaced leaflets, and more numerous cataphylls that are long, prickly and covered with redder down.
  • Cycas macrocarpa, from Thailand and Peninsular Malaysia, which grows in forest understorey away from the coast: flattened yellow seeds with a fibrous layer, and a narrow, raised midrib.
  • Cycas falcata, from Sulawesi: megasporophylls with long lateral spines, keeled leaves and sickle-shaped leaflets.

Taxonomy

Cycas edentata is the name accepted by The World List of Cycads; POWO could not be consulted directly. David de Laubenfels published it in 1998 in Blumea (volume 43, page 372), in the revision he co-authored with Frits Adema, on a type from the Sulu Islands (Philippines), collected on Mount Cabucan in 1957 (Kondo & Edaño 38877, holotype at L). His concept of the species was, however, confused, and also took in Cycas glauca, Cycas rumphii and other plants.

Ken Hill had recognised this coastal cycad as a distinct taxon as early as 1995 and described it in April 1999 as Cycas litoralis (Brittonia 51: 70), on a type from Narathiwat province, Thailand. De Laubenfels’s name, published a few months earlier, has priority: Lindström, Hill and Stanberg (2008, 2009) therefore placed Cycas litoralis in synonymy under Cycas edentata, and clarified the limits of the species. This is why the name Cycas litoralis still turns up in books and the nursery trade, and why many older floras list the plant under Cycas rumphii or Cycas circinalis. A form described by Schuster in 1932 (Cycas circinalis subsp. riuminiana var. curranii forma maritima) also belongs here.

The species belongs to subsection Rumphiae of section Cycas: mostly coastal cycads whose seeds have a spongy layer beneath the hard shell, which lets them float. Dispersal by sea explains the wide range of the group.

Etymology and history

The epithet edentata combines the Latin prefix e-, “without”, with dentatus, “toothed”: it refers to the blade of the megasporophylls, which lacks distinct teeth. The synonym litoralis means “of the shore”.

Present in the earliest accounts of the flora of the Philippines, this cycad was referred to Cycas rumphii by many authors from Kurz (1877) onwards, and to Cycas circinalis by Foxworthy and Merrill in the early 20th century. It was only recognised as a species at the end of the 1990s.

Common names

No established English name has been found; plants are often sold under the name Cycas litoralis. The revisions of Lindström and colleagues (2008, 2009) record several local names: kwale pahang (“shore wood”, Malay), prong thale (“sea cycad”, Thai; ปรงทะเล in the report of the Thai Department of Agriculture), sauang or sawang (Ilocano), bait, bayit or pitógo (Tagalog) and oliva (Philippine Spanish). The Malaysia Biodiversity Information System gives paku laut in Malay, and a checklist of the plants of the Setiu Wetlands, Malaysia (2020), gives pokok sakat. The Royal Botanic Garden Sydney labels its plant “Bayit”.

In the wild

Cycas edentata grows only on the coast: often dry beach-front scrub on sand, and rocky headlands with very thin soils, over granite as well as limestone, in full sun or part shade. According to Lindström and colleagues (2009), it occurs in southern Vietnam, southern Myanmar and Thailand, Peninsular Malaysia, Sumatra, Java and northern Borneo, and in western and central Philippines. The World List of Cycads adds Bali, Singapore (Changi) and the Vietnamese province of Kien Giang. The Thai report describes it in beach forest, on sand, or near mangroves.

Like the other species in its group, it owes its coastal range to seeds that float and are dispersed by the sea. Its pollinator is not documented. The caterpillars of the butterfly Luthrodes pandava feed on its leaves: in 2019, larvae were collected from a large coastal population at Mansalay, on the island of Mindoro (Philippines), for feeding trials (Marler 2025).

Conservation status and regulation

Cycas edentata is listed as Endangered (EN) by the IUCN, under criteria A2acde+4acde (past and projected population decline), according to The World List of Cycads. The Red List data relayed by GBIF (consulted on 21 October 2026) confirm the category, and Crossref dates this assessment, by A. Lindström, to version 2023-1 of the Red List. The previous assessment, by Osborne, Hill, Nguyen and Phan (2010), is quoted as Near Threatened by the 2019 report of the Thai Department of Agriculture and by the Setiu Wetlands checklist (2020), which gives the same category for the Malaysian Red List. Lindström and colleagues had themselves recommended Near Threatened for the Philippines (2008) and Indonesia (2009).

The threats are well described. Once abundant on the coasts of southern Thailand, it has disappeared from many sites; its shores face population growth, development and, increasingly, aquaculture. In the Philippines, historical populations have vanished, and cultivated plants nearby were dying, according to Lindström and colleagues (2008), from attacks by the Asian cycad scale, Aulacaspis yasumatsui. In Peninsular Malaysia, the Malaysia Biodiversity Information System names it among the cycads whose wild populations are declining through trade in ornamental plants.

Like every species in the genus except Cycas beddomei, Cycas edentata 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 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, confirms this status and links the synonym Cycas litoralis to it (search of 3 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 edentata

In short: a tropical seashore cycad for frost-free climates, full sun and very free-draining soil. No institution has published a growing guide for it, but it is grown in several tropical and subtropical collections.

Outdoor and in-ground cultivation

In the Philippines, physiological studies have used trees planted in an agroforestry setting at Angeles City (Marler and Krishnapillai 2020), and seedlings were used in an experiment showing that its roots recognise related plants (summarised by Gorelick and Marler 2014). Its native habitat points to a plant for full sun, a humid tropical climate and very sharply drained soil; in the wild it lives exposed to salt spray. No account of open-ground cultivation outside the tropics has been found.

Container cultivation

In cooler countries it can only be grown under glass or indoors. On the French forum Fous de palmiers, a collector based in Belley and Montpellier offered a few seeds in 2009 and, in 2012, described the species as very tender. 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

  • United States: the online catalogue of Montgomery Botanical Center (Coral Gables, Florida) lists Cycas edentata under four accession numbers, which date from 1978, 1993, 1995 and 2000 (catalogue consulted on 21 October 2026). BGCI PlantSearch also lists Brooklyn Botanic Garden (New York), Houston Botanic Garden (Texas), San Diego Botanic Garden and San Diego Zoo (California), and Marie Selby Botanical Gardens (Sarasota, Florida), the last under the name Cycas litoralis; these are declarations by the gardens, which do not prove that a plant is alive today.
  • Australia: the Royal Botanic Garden Sydney lists a plant of garden origin (accession S1992-4327/1) in bed 102j, labelled “Bayit” (Garden Explorer, updated 1 October 2026). BGCI PlantSearch also lists Cairns Botanic Gardens (Queensland), under the name Cycas litoralis.
  • United Kingdom: no record in BGCI PlantSearch or in the inventory of cycads in British, American and Australian gardens compiled for this site.

Elsewhere, BGCI PlantSearch lists it in botanic gardens in the Netherlands, Belgium, Spain and France (Lyon, and Château Pérouse at Saint-Gilles), as well as in Singapore, the Philippines and Thailand. 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 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

The Asian cycad scale, Aulacaspis yasumatsui, is the main documented pest: in the Philippines, Lindström and colleagues (2008) reported cultivated plants dying from it near wild populations that had disappeared. The caterpillars of Luthrodes pandava (long known as Chilades pandava) feed on its leaves in the Philippines, both in the wild and in collections (Marler 2025).

Cold hardiness

No cold-tolerance value has been published for Cycas edentata. It is a plant of tropical shores, and its whole range lies within the tropics; nothing suggests it can survive frost.

European experience

No growing result in the open ground has been published in Europe, and no dated frost event concerns this species. On the French forum Fous de palmiers, a grower based in Belley (Ain) and Montpellier (Hérault) simply stated in March 2012 that the species is very tender, without giving a temperature or a trial site. A search of the Italian forum Tropicamente found no report.

United Kingdom, United States and Australia

No cold reading or dated growing report was found, either on forums or from botanic gardens. No USDA zone can be given.

Toxicity and precautions

No toxicity analysis specific to Cycas edentata 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 specific to the species was found in the sources consulted. The Setiu Wetlands checklist (Malaysia, 2020) lists it among the wetland plants, without recording a use for it.

Frequently asked questions

Are Cycas edentata and Cycas litoralis the same plant?

Yes. Both names refer to the same species; Cycas edentata, published in 1998, has priority over Cycas litoralis, published in 1999. The second name is still common in the trade.

Why is it called edentata?

Because its megasporophylls have no distinct lateral teeth: edentatus means “toothless” in Latin.

Where does it grow?

On the coasts of South-East Asia, from southern Vietnam and Thailand to Malaysia, Sumatra, Java, Borneo and the Philippines, on beaches and rocky headlands.

How can it be told from Cycas rumphii?

By its microsporophylls with a long, stout spine and its seeds without a ridge. Both species have floating seeds and were long confused.

Is it endangered?

Yes. The IUCN lists it as Endangered: its shores are being developed and converted to aquaculture ponds, and the Asian cycad scale has killed plants in the Philippines.

Can it be grown outdoors in the UK?

No. It is a cycad of tropical shores, reported as very tender; in cool climates it needs a heated glasshouse or a place indoors.

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

  • Laubenfels, D.J. de & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Original description (pp. 372–374); cited after The World List of Cycads and Lindström et al. (2008, 2009).]
  • Hill, K.D. & Yang, S.L. (1999). The genus Cycas (Cycadaceae) in Thailand. Brittonia 51(1): 48–73. [Description of Cycas litoralis; not consulted directly, cited after Lindström et al. and The World List of Cycads.]
  • 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 [Description, synonymy, local names, threats; full text consulted.]
  • 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 [Description, range, habitat, status; full text consulted.]
  • Jutta, M., Chew, K.L. & Saw, L.G. (2010). A new species of Cycas (Cycadaceae) from Peninsular Malaysia. Blumea 55(3): 249–252. doi:10.3767/000651910X544438 [Key to the Cycas of Peninsular Malaysia, comparison with Cycas macrocarpa; full text consulted.]
  • Salim, J.M. et al. (2020). A checklist of vascular plants and uses of some species for livelihood-making in Setiu Wetlands, Terengganu, Malaysia. PhytoKeys 160: 7–43. doi:10.3897/phytokeys.160.52946 [Malay name pokok sakat, IUCN and Malaysian Near Threatened status; full text consulted.]
  • Gorelick, R. & Marler, T.E. (2014). Kin recognition by roots occurs in cycads and probably in conifers. Communicative & Integrative Biology 7: e28009. doi:10.4161/cib.28009 [Seedling experiment; full text consulted.]
  • Marler, T.E. & Krishnapillai, M.V. (2020). Vertical strata and stem carbon dioxide efflux in Cycas trees. Plants 9(2): 230. doi:10.3390/plants9020230 [Trees cultivated at Angeles City; full text consulted.]
  • Marler, T.E. (2025). Luthrodes pandava larvae can distinguish Cycas leaf quality in cafeteria experiments. Insects 16(9): 973. doi:10.3390/insects16090973 [Coastal population on Mindoro and butterfly larvae; full text consulted.]
  • Lindström, A. (2023). Cycas edentata. The IUCN Red List of Threatened Species: e.T216470314A68900236. doi:10.2305/IUCN.UK.2023-1.RLTS.T216470314A68900236.en [Current assessment (EN); reference checked on Crossref, category relayed by GBIF; Red List page not consulted (access blocked).]
  • Osborne, R., Hill, K.D., Nguyen, H.T. & Phan, K.L. (2010). Cycas edentata. The IUCN Red List of Threatened Species: e.T42091A10628022. doi:10.2305/IUCN.UK.2010-3.RLTS.T42091A10628022.en [Previous assessment, quoted as Near Threatened by the Thai report (2019) and Salim et al. (2020); reference checked on Crossref, 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 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.]