Cycas zeylanica

Cycas zeylanica is a cycad of tropical coastal forest, found on the south coast of Sri Lanka and in the Andaman and Nicobar Islands of India, on either side of the Bay of Bengal. Long confused with Cycas rumphii and first described in 1932 as Cycas rumphii subsp. zeylanica, this species of the genus Cycas was raised to species rank in 2002. Its seeds float and are dispersed by the sea. The Andaman plants described in 2014 as Cycas sainathii are included in it by The World List of Cycads, the reference checklist. The IUCN lists it as Critically Endangered: in Sri Lanka, no natural population remains.

Key facts about Cycas zeylanica

  • Accepted name: Cycas zeylanica (J.Schust.) A.Lindstr. & K.D.Hill (2002), accepted by The World List of Cycads (version 2026.08.15) and by GBIF; POWO could not be consulted
  • Former names and synonyms: Cycas rumphii subsp. zeylanica J.Schust. (1932, basionym); Cycas sainathii R.C.Srivast. (2014), a synonym according to The World List of Cycads; the Sri Lankan plants were long called Cycas rumphii, and de Laubenfels and Adema (1998) included them in Cycas thouarsii
  • Family: Cycadaceae, order Cycadales; section Cycas, subsection Rumphiae (Lindström and Hill 2007)
  • Common names: no English name attested; maha-madu in Sinhala (Sri Lanka)
  • Natural range: Sri Lanka (south coast) and India (Andaman and Nicobar Islands)
  • IUCN status: Critically Endangered (CR A2ac), assessment by A. Lindström dated 2020 and published in Red List version 2022-1; the Red List assesses Cycas sainathii separately, as Vulnerable (VU, 2022) (see Conservation status)
  • CITES and other protection: CITES Appendix II; Annex B in the European Union; India bans the commercial export of wild-collected specimens of CITES-listed species
  • Documented hardiness: no data (see Cold hardiness)
  • Light and soil: in the wild, coastal forest close to the sea, on sandy soil
  • Habit and adult size: trunk 2.3 to 3.1 m tall and 13 to 20 cm across; leaves 1.4 to 1.9 m long
  • In the UK, US and Australia: Montgomery Botanical Center (Florida), one accession of 2016; Naples Botanical Garden (Florida) and Cairns Botanic Gardens (Queensland), declared to BGCI; no British record
  • Toxicity: no data specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas zeylanica

Two characters separate it from its relatives, according to Lindström and Hill (2007): numerous long, pungent cataphylls (the scales that protect the tip of the trunk) and leaflets set far apart along the rachis. Like all the cycads of the Cycas rumphii group, it has seeds with an inner spongy layer that makes them float. The measurements below come from their description, based on plants from Sri Lanka and the Andamans:

  • Trunk: tree-like, 2.3 to 3.1 m tall and 13 to 20 cm in diameter, slightly swollen at the base, with thin, smooth bark; about thirty leaves in the crown; cataphylls and leaf bases not persistent.
  • Leaves: 1.4 to 1.9 m, bright to dark green, semi-glossy, flat, with 70 to 100 leaflets; white or orange felt that falls as the leaf expands; rachis ending in a pair of leaflets; petiole hairless, 50 to 70 cm (30 to 40 % of the leaf), spiny for 30 to 100 % of its length.
  • Mid-leaf leaflets: 18 to 30 cm long and 12 to 15 mm wide, narrowed to 6 to 7 mm at the base, markedly paler beneath, set at 50 to 60° to the rachis and 22 to 27 mm apart; margins slightly recurved, tip sharp but not pungent. The basal leaflets, 19 to 20 cm long, do not grade into spines.
  • Cataphylls: linear, pungent, hairy, 10 to 12 cm long.
  • Male cones: spindle-shaped, orange-brown, about 30 to 40 cm long and 10 cm across; microsporophylls 35 to 45 mm long and 17 to 19 mm wide, ending in a distinct, clearly upturned spine of 3 to 10 mm.
  • Megasporophylls: 17 to 30 cm, covered in persistent brown felt, bearing 2 to 4 hairless ovules; blade lanceolate, 60 to 120 mm long and 10 to 17 mm wide, barely toothed (6 to 12 small bumps or spines of at most 2 mm); apical spine 40 to 60 mm.
  • Seeds: flattened-ovoid, 60 to 70 mm long and 45 to 55 mm across; sarcotesta orange-brown, without a fibrous layer; sclerotesta smooth; inner spongy layer (endotesta) present.

In Sri Lanka, the shape of the megasporophylls varies greatly from plant to plant, which makes identification harder (see Hybrids).

Hybrids

No named hybrid has been documented. In Sri Lanka, however, Mudannayake and colleagues (2019, Scientific Reports) examined 25 female plants and found such diversity of megasporophylls, falling into six groups, that they speak of a “Cycas zeylanica complex”. They explain it by crossing between forms that arrived repeatedly from South-East Asia, as seeds carried by ocean currents; the genetic diversity measured on a chloroplast marker (trnH-psbA), on the other hand, is very low.

Some plants recall, in the sterile part of their megasporophylls, Cycas pschannae, Cycas edentata, Cycas javana or Cycas falcata. These are resemblances noted by the authors, who interpret them as traces of hybridisation: no hybrid has been demonstrated.

Possible confusion

The most frequent confusions are confusions of names. In the nineteenth century the Sri Lankan plants were called Cycas rumphii (Trimen 1898), and de Laubenfels and Adema (1998) placed them in Cycas thouarsii, whose range they extended to Sri Lanka. Lindström and Hill (2007) do indeed compare Cycas zeylanica with Cycas thouarsii and Cycas edentata, with which it shares seeds without an apical crest and microsporophylls ending in a spine; it differs from them in its long, pungent cataphylls and widely spaced leaflets. Compared with Cycas rumphii, Mudannayake and colleagues point to a character of the ripe seed: the lack of an apical crest in Cycas zeylanica.

Sri Lanka is also home to Cycas nathorstii, which is recognised by its more crowded, thinner leaflets, its shorter, softer and less hairy cataphylls and its seeds without a spongy layer; it grows in the forests of the interior and the hills of the north of the island, in drier conditions (Lindström and Hill 2007).

In the Andamans, The World List of Cycads recognises three Cycas: Cycas zeylanica, Cycas pschannae (of which Cycas andamanica is a synonym) and Cycas dharmrajii. According to its authors, Cycas pschannae is recognised by the triangular sterile part of its megasporophylls, bearing two horn-like lateral teeth, whereas the blade of Cycas zeylanica is lanceolate and barely toothed.

Taxonomy

Cycas zeylanica is the name accepted by The World List of Cycads; POWO could not be consulted. Julius Schuster described the taxon in 1932, in Engler’s Pflanzenreich (IV.1, Heft 99, p. 75), as a subspecies of Cycas rumphii. In 2002 Anders Lindström and Ken Hill raised it to species rank in the journal Novon (12(2): 238; IPNI 20006946-1). Schuster’s specimens, kept in Berlin, were destroyed during the Second World War, so a sheet of megasporophylls from Thwaites’s collection (Sri Lanka, 1866, no. 3862), kept in Geneva in the Barbey-Boissier herbarium, was chosen as lectotype (Lindström and Hill 2007).

The broader treatment of de Laubenfels and Adema (1998), who took a very wide view of species, placed Cycas rumphii subsp. zeylanica in the synonymy of Cycas thouarsii and gave Sri Lanka as part of the range of that species, alongside Madagascar, the Comoros and the coast of East Africa. Lindström and Hill (2002, 2007) separated the Sri Lankan and Andaman plants as Cycas zeylanica; The World List of Cycads, which this site follows, adopts their treatment and restricts Cycas thouarsii to East Africa, Madagascar and the Comoros.

In the classification followed by Lindström and Hill, the species belongs to section Cycas, subsection Rumphiae, defined by the spongy layer inside the seed. This group stretches from East Africa to Fiji and Tonga, and Cycas zeylanica is its only representative in India, confined to the Andaman and Nicobar Islands. Its taxonomy is difficult: every species of the Cycas rumphii complex has at one time or another been called Cycas circinalis (Lindström and Hill 2007).

Cycas sainathii, described by R.C. Srivastava in 2014 in the Indian Journal of Plant Sciences (3(1): 109–110) for plants from the Andamans, was placed in the synonymy of Cycas zeylanica by the revision of the Cycas of the Andaman and Nicobar Islands by Lal Ji Singh and Dharam Raj Misra (2020), followed by The World List of Cycads; only the abstract of that revision has been read. The IUCN Red List does not follow this treatment (see Conservation status). In practice, for The World List of Cycads, plants labelled Cycas sainathii, like the Sri Lankan plants once called Cycas rumphii, are Cycas zeylanica.

Etymology and history

The epithet comes from Zeylona, a Latinised form of Ceylon, the former name of Sri Lanka, where the type was collected (Lindström and Hill 2007; The World List of Cycads, after Haynes’s etymological compendium, 2022).

The plant was known to botanists long before it had a name of its own: Trimen’s flora of Ceylon (1898) recorded it as Cycas rumphii. Among the specimens cited by Lindström and Hill is a plant grown at Kew from seed collected in the Nicobar Islands in 1875 and pressed in 1881: the oldest trace of cultivation in Europe found. The modern description rests mainly on Lindström’s collections in Sri Lanka in June 2000 and in the Andamans in December of the same year.

Common names

No English common name is attested. In Sri Lanka the plant is called maha-madu in Sinhala (Lindström and Hill 2007; Species+). The published sources give no name of its own in the Andamans.

In the wild

The species lives in two regions separated by the Bay of Bengal: the south coast of Sri Lanka and the Andaman and Nicobar Islands. Its habitat is coastal forest close to the sea, on sandy soil (Lindström and Hill 2007). In the Andamans, the herbarium specimens come from South Andaman (including the beach vegetation of Kodiaghat), from Havelock Island, where the plant grows in littoral evergreen forest a few metres above the sea, and from Rangat, in Middle Andaman; for the Nicobars, the only record cited is the seed collected in 1875.

In Sri Lanka, Mudannayake and colleagues (2019) found 53 plants of the group, all in the low-country wet zone apart from two cultivated at higher altitude; the plants are more frequent near the coast than inland. Their ecological niche model indicates favourable climatic conditions also in the Andaman and Nicobar Islands, northern Sumatra, southern Thailand, northern Peninsular Malaysia and, to a lesser extent, the southern Western Ghats: this is a climatic prediction, not an observed presence.

Thanks to their spongy layer, the seeds float: dispersal by sea has been put forward to explain the variability of the group, with successive colonisations producing different forms a short distance apart (Lindström and Hill 2007).

Conservation status and regulation

The species is Critically Endangered. The IUCN Red List lists it as CR under criterion A2ac, that is, for a severe population reduction already observed and linked to habitat decline; the assessment, by A. Lindström, is dated 2020 and was published in version 2022-1 (The World List of Cycads; DOI metadata on Crossref), and the Red List data relayed by GBIF confirm the CR category (consulted on 24 October 2026). The same data, however, treat Cycas sainathii as a separate species, assessed as Vulnerable (VU) in 2022: for the IUCN, part of the Andaman plants therefore falls under another assessment. The Red List itself could not be consulted.

The situation is very different in the two countries. In Sri Lanka, Lindström had found, even before 2004, no population capable of regenerating, only large, old, scattered plants, none of them in a protected area; the Indian Ocean tsunami (dated 2005 in the article) then struck the narrow coastal strip where they survived, and the authors thought it likely that most had died, suggesting for the island the category CR, or even “extinct” (Lindström and Hill 2007). In 2019 Mudannayake and colleagues, after surveying the whole wet zone, found no natural population, only scattered individuals, mostly planted by local people, and estimate that probably fewer than 200 remain in the country.

In the Andaman and Nicobar Islands, by contrast, the species was described in 2007 as widespread and common, with large populations in several places. It has, however, suffered badly from repeated cyclones, and the building of seaside tourist resorts has wiped out several once-large populations; some lie within protected areas or restricted military zones. For India, the authors suggested the category Vulnerable (Lindström and Hill 2007).

Like every species in the genus except Cycas beddomei, Cycas zeylanica 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+ also records a stricter national measure: India bans the export for commercial purposes of wild-collected specimens of CITES-listed species, except cultivated varieties (CITES Notification No. 2018/031; consulted on 13 and 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 zeylanica

The species is grown mainly in its countries of origin. In Sri Lanka, most surviving plants were planted by local people (Mudannayake and colleagues 2019); Lindström collected specimens from cultivated plants along roads, at Hikkaduwa and at Peradeniya (Lindström and Hill 2007). Outside Asia, the oldest record found is the nineteenth-century Kew plant; today the species is declared by a few botanic gardens in Florida, Queensland and Sweden (see below), but no cultivation report has been published.

What follows is deduced from its habitat, not from published trials: a cycad of tropical coastal forest probably needs warmth all year round, plenty of light, a sandy, free-draining compost and regular watering in the growing season, more widely spaced when temperatures fall. With a trunk of 2 to 3 m, it remains a medium-sized tree cycad.

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 holds one accession of this species, or tropical Queensland, where the Cairns Botanic Gardens declare it. The published sources do not say how these plants are grown.

Container cultivation

In a temperate climate it needs a heated glasshouse: grow it in a pot, in a sandy, free-draining mix and in full light, keeping it warm all year round or at least through the winter.

In cultivation in the UK, US and Australia

In short: two American collections and one Australian one; no British record.

  • United States: Montgomery Botanical Center, in Coral Gables (Florida), lists one accession in its online catalogue, numbered 20160147, from 2016 according to the garden’s numbering (consulted on 24 October 2026); Montgomery and Naples Botanical Garden (Florida) declare the species to BGCI.
  • Australia: the Cairns Botanic Gardens, in tropical Queensland, declare the species to BGCI.
  • United Kingdom: no record in BGCI or in the British catalogues checked in October 2026; the plant grown at Kew in the nineteenth century is known only from a herbarium sheet of 1881. The British nursery Trebrown lists the species with a USDA zone 9b rating, its own commercial classification, not a documented trial.

In Europe, the botanic garden of Lund University, in Sweden, also declares the species to BGCI. A BGCI declaration shows that a garden held the plant at some point, not that it is alive today. No report from a private grower is documented.

Propagation

From seed, like other Cycas; no germination data specific to the species has been published. The plant is dioecious, so a male and a female are needed to obtain seed, and in cultivation hand pollination. The fleshy sarcotesta is removed before sowing, wearing gloves. In subsection Rumphiae, seed takes about two years to ripen, but this has been confirmed only for Cycas seemannii, Cycas thouarsii and Cycas bougainvilleana, not for Cycas zeylanica (Lindström and Hill 2007). Given the rarity of the species, look only for seed or plants of legal, documented origin.

Pests and diseases

No pest has been documented specifically on Cycas zeylanica. In the Andamans, the cycad blue butterfly, Luthrodes pandava, whose caterpillars eat the young leaves, was recorded in 2022 on other Cycas of the archipelago, Cycas pschannae and Cycas dharmrajii (Purti and colleagues 2022). In cultivation, its enemies are those of all cycads, including the Asian cycad scale, Aulacaspis yasumatsui, and trunk and root rot when the compost stays too wet.

Cold hardiness

There is no data on the cold tolerance of Cycas zeylanica. The species lives on humid tropical coasts with no cold season, and nothing suggests that it 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. Searches of the French Fous de palmiers forum and of the Italian Tropicamente forum, under the names zeylanica and sainathii, return only other plants with the same epithet, and the species appears under neither name in the published inventories of the Italian botanic gardens consulted. The Jardin zoologique tropical at La Londe-les-Maures, in the Var, has published no observation of it.

United Kingdom, United States and Australia

No cold measurement has been published in any country. The gardens that hold it in Florida and Queensland have tropical or subtropical climates, which say nothing about its frost tolerance, and Trebrown’s zone 9b rating is a commercial classification, not a measured result.

Toxicity and precautions

No toxicity analysis specific to Cycas zeylanica 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, with vomiting, diarrhoea and liver damage that can be fatal. 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 food or medicinal use specific to Cycas zeylanica is documented. In Sri Lanka the plant is mainly cultivated: Mudannayake and colleagues (2019) report very old plants at historic sites, such as old Catholic churches in the south of the wet zone, and put forward the hypothesis that seeds were brought from South-East Asia by traders during the Portuguese and Dutch colonial periods (sixteenth and seventeenth centuries). This is the authors’ hypothesis, not an established fact.

Frequently asked questions

Are Cycas zeylanica and Cycas sainathii the same plant?

Yes, for The World List of Cycads, which follows the revision by Singh and Misra (2020): Cycas sainathii is a synonym of Cycas zeylanica. The IUCN Red List, however, still assesses Cycas sainathii separately.

What does zeylanica mean?

“Of Ceylon”. The epithet comes from Zeylona, a Latinised form of the former name of Sri Lanka, where the type was collected.

Where does it grow in the wild?

On the south coast of Sri Lanka and in the Andaman and Nicobar Islands of India, in coastal forest on sand, close to the sea.

Why is it so threatened in Sri Lanka?

Because its natural populations have disappeared. Even before 2004 only old, scattered plants remained, which were then hit by the tsunami; the island probably has fewer than 200 today, mostly planted. In the Andamans the species is more common, but suffers from cyclones and tourist development.

Is it the same as Cycas thouarsii?

No, according to Lindström and Hill (2007) and The World List of Cycads, although de Laubenfels and Adema (1998) included the Sri Lankan plants in Cycas thouarsii. Cycas zeylanica differs in its long, pungent cataphylls and widely spaced leaflets.

Do its seeds float?

Yes. As in all the cycads of subsection Rumphiae, an inner spongy layer makes them float, allowing dispersal by sea.

Is it hardy in the UK?

No. There is no cold data, the plant comes from tropical coasts with no winter, and no outdoor cultivation is documented outside the tropics: in Britain it needs 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

  • Schuster, J. (1932). Cycadaceae. In: Engler, A. (ed.), Das Pflanzenreich IV.1 (Heft 99): 75, fig. 10 C–D, 11 M. [Basionym Cycas rumphii subsp. zeylanica; not consulted, reference taken from Lindström and Hill (2007) and The World List of Cycads.]
  • Laubenfels, D.J. de & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Cycas rumphii subsp. zeylanica in the synonymy of Cycas thouarsii, whose range includes Sri Lanka; full text consulted.]
  • Lindstrom, A.J. & Hill, K.D. (2002). Notes on the species of Cycas (Cycadaceae) from Sri Lanka and islands of the Andaman Sea. Novon 12(2): 237–240. doi:10.2307/3392960 [Raising to species rank and lectotypification; not consulted directly.]
  • Lindstrom, A.J. & Hill, K.D. (2007). The genus Cycas (Cycadaceae) in India. Telopea 11(4): 463–488. doi:10.7751/telopea20075745 [Description, type, Sinhala name, distinctions, range, habitat, conservation, subsection Rumphiae; full text consulted.]
  • Mudannayake, A., Ranaweera, L. and colleagues (2019). The morpho-genetic and ecological niche analyses reveal the existence of climatically restricted Cycas zeylanica complex in Sri Lanka. Scientific Reports 9: 16807. doi:10.1038/s41598-019-53011-w [Megasporophyll diversity, genetics, numbers, niche model; full text consulted.]
  • Singh, L.J. & Misra, D.R. (2020). Reappraisal of the genus Cycas L. (Cycadaceae) in Andaman and Nicobar Islands, India. Indian Journal of Forestry 43(1): 46–57. [Cycas sainathii as a synonym of Cycas zeylanica; abstract only consulted.]
  • Purti, N., Singh, L.J. & Pandey, A.K. (2022). New hosts for the cycad blue butterfly, Luthrodes pandava, Horsfield (Lepidoptera: Lycaenidae) in an island ecosystem. Feddes Repertorium 133(3): 234–243. doi:10.1002/fedr.202100024 [First record of Luthrodes pandava in the Andaman and Nicobar Islands, on Cycas pschannae and Cycas dharmrajii; abstract consulted.]
  • Lindström, A. (2022). Cycas zeylanica. The IUCN Red List of Threatened Species 2022: e.T42098A69829252. doi:10.2305/IUCN.UK.2022-1.RLTS.T42098A69829252.en [CR A2ac assessment dated 4 March 2020; reference found on The World List of Cycads and Crossref; Red List page not consulted.]
  • Singh, L.J. (2022). Cycas sainathii. The IUCN Red List of Threatened Species 2022: e.T103631608A243419871. doi:10.2305/IUCN.UK.2022-1.RLTS.T103631608A243419871.en [VU assessment under the name sainathii; reference found on Crossref, 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 [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.]