Cycas simplicipinna

Cycas simplicipinna is a small cycad whose trunk almost always stays underground, living in the understorey of humid evergreen forest in northern Indochina: the mountains of northern and north-eastern Thailand, Laos, central Vietnam and, according to most authors, southern Yunnan in China. This member of the genus Cycas was described in 1971 by the Thai botanist Tem Smitinand as Cycas micholitzii var. simplicipinna, a variety with undivided leaflets of a species whose leaflets are forked; Ken Hill raised it to species rank in 1995. It carries only a few large, upright, glossy leaves with broad, well-spaced leaflets. The IUCN lists it as Near Threatened.

Key facts about Cycas simplicipinna

  • Accepted name: Cycas simplicipinna (Smitinand) K.D.Hill (1995), accepted by The World List of Cycads (version 2026.08.15); 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: basionym Cycas micholitzii var. simplicipinna Smitinand (1971); included by de Laubenfels and Adema (1998) in a broadly defined Epicycas tonkinensis; placed with doubt in the synonymy of Cycas balansae by the Flora of China (1999)
  • Family: Cycadaceae, order Cycadales; section Stangerioides
  • Common names: no English common name attested; in Thai มะพร้าวเต่า (ma phrao tao), plong and phrao tao
  • Natural range: northern and north-eastern Thailand, Laos (Saravan), Vietnam (Quang Tri), China (Yunnan, presence disputed); Myanmar uncertain
  • IUCN status: Near Threatened (NT); assessment by J. D. Bösenberg (2020, published in 2023), following that of H. T. Nguyen (2010)
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union
  • Documented hardiness: no published, verifiable data (see Cold hardiness)
  • Light and soil: in the wild, the shade of humid evergreen forest, often near streams, from 600 to 1,500 m in Thailand
  • Habit and adult size: underground trunk 8 to 14 cm across; 2 to 5 upright leaves, with a petiole of 35 to 140 cm and a rachis of 90 to 250 cm (LLIFLE)
  • In the UK, US and Australia: no garden found in the UK or Australia; in the US, Montgomery Botanical Center (4 accessions, 1994 to 2011), with Fairchild and San Diego Botanic Garden in BGCI
  • Toxicity: no analysis specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas simplicipinna

Look for a very sparse crown of a few large, upright leaves that seem to rise straight out of the ground, with undivided, broad and widely spaced leaflets, and small, narrow male cones. According to the description taken up by the online encyclopaedia LLIFLE, this combination, together with small megasporophylls with short spines and small seeds, sets it apart at once from the other Thai cycads.

Smitinand (1971) described it as a normally trunkless shrub that, in extreme cases, forms at most a short stem of about 20 cm above the ground. Its leaves were 115 to 150 cm long, with 18 or 19 leaflets on each side, 20 to 22 cm by 1.4 to 1.8 cm, with wavy margins and a papery texture, and a petiole of about 24 cm. More recent figures, taken up by LLIFLE from Ken Hill’s pages on cycads, cover a wider range of variation:

  • Trunk: 8 to 14 cm across (exceptionally 7 to 20 cm), almost always underground, rarely at the surface and creeping for a short distance; bark almost smooth, pale grey to yellowish.
  • Leaves: 2 to 5 at a time, pinnate, upright to ascending, bright to deep green and very glossy, covered when they emerge with an orange down that falls as they open; petiole 35 to 140 cm (40 to 60% of the leaf), armed with short spines; rachis 90 to 250 cm, always ending in a pair of leaflets.
  • Leaflets: 18 to 38 (up to 45) on each side, 20 to 56 cm by 1.4 to 2 cm, spaced 20 to 40 mm apart on the rachis; flat, with flat or wavy margins and a midrib raised on the upper side.
  • Cataphylls (the scales that protect the growing point): soft and hairy, 4 to 5 cm.
  • Male cones: spindle-shaped, cream-yellow, 15 to 21 cm by 2 to 4 cm, measurements already given by Smitinand; microsporophylls 12 to 14 mm, without an apical spine.
  • Megasporophylls (the fertile leaves of female plants): 7 to 12 cm, with brown felt, carrying 2 hairless ovules; sterile part oval, 45 to 55 mm by 18 to 35 mm, deeply comb-like, with lateral spines of 15 to 25 mm, the terminal spine not distinct from the others.
  • Seeds: egg-shaped, 25 to 27 mm by 18 to 21 mm; yellow sarcotesta (fleshy coat), without bloom or fibrous layer; warty shell.

The description by Hill and Yang (1999), the source of these figures, could not be consulted; only Smitinand’s figures have been checked against the original description.

Hybrids

No hybrid, natural or horticultural, is documented. A genetic study published in 2025 even looked for hybrids between Cycas simplicipinna and Cycas pectinata in three populations in Yunnan where the two species grow together, and found none, not even among seedlings (Zheng and colleagues 2025, see In the wild).

Possible confusion

The most direct confusion is with Cycas micholitzii, of which the species was long treated as a variety. The difference is clear: Cycas micholitzii has forked leaflets, which give it a fern-like look, whereas those of Cycas simplicipinna are undivided. Smitinand also separated his variety by its narrower leaflets and megasporophylls with only two ovules. LLIFLE presents the two species, together with Cycas bifida (leaflets forked once) and Cycas multipinnata (leaflets divided several times), as a series running from undivided to repeatedly divided leaflets. Cycas debaoensis also has repeatedly divided leaves.

The distinction is harder with the other Sino-Vietnamese cycads that have no aerial trunk and undivided leaflets. Cycas balansae is so close that the Flora of China tentatively merged the two. Cycas collina is recognised, according to Hill (2008), by its larger and often more numerous leaves carrying more leaflets, and by its larger male cones (25 to 60 cm), with rounded microsporophylls without an apical spine; the name Cycas simplicipinna has in fact been applied in China to plants of Cycas collina (see Taxonomy). Cycas pectinata, which shares part of its range in Yunnan, is easy to tell apart: it has a true aerial trunk and hard male cones, and belongs to another section of the genus (Indosinenses).

In the trade, the species also serves as a point of comparison: on the French forum Fous de palmiers, a grower reports in January 2020 that a plant bought young as Cycas multipinnata never produced a divided leaflet and looked more like photographs of Cycas simplicipinna.

Taxonomy

Cycas simplicipinna is accepted by 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). Tem Smitinand described the plant in 1971 in the Natural History Bulletin of the Siam Society (24: 164), in his revision of the cycads of Thailand, as Cycas micholitzii var. simplicipinna: having found in Thailand only plants with undivided leaflets, he made them a new variety. He designated two types in Chiang Mai province: a male plant from Chiang Dao, at 600 m, in evergreen forest (Smitinand and Alsterlund 6768, 24 April 1960), and a female plant from Doi Suthep, at 1,100 m, in lower montane forest (Smitinand 4757, 19 July 1958), both in the Forest Herbarium in Bangkok (BKF). Ken Hill raised the variety to species rank in 1995, in the proceedings of the Third International Conference on Cycad Biology (p. 150).

The history of the name has been eventful. De Laubenfels and Adema (1998), in the revision that set up the genus Epicycas, included Smitinand’s variety in a broadly defined Epicycas tonkinensis, together with Cycas balansae and other names, and chose the female plant from Doi Suthep as lectotype. A year later, the Flora of China (Chen and Stevenson 1999) placed Cycas simplicipinna, with a question mark, in the synonymy of Cycas balansae, adding that it might deserve species rank but that more fertile material was needed to decide. The regional revisions by Hill and Yang (1999, Thailand) and by Hill, Nguyen and Loc (2004, Vietnam) treated it instead as a separate species, the treatment followed today.

The species belongs to section Stangerioides, which groups the cycads of China and Vietnam with soft male cones, a fleshy seed coat without a fibrous layer that comes away easily, and a warty shell (Hill 2008; Zheng and colleagues 2017).

Its presence in China remains disputed. For Hill (2008), the Chinese plants called Cycas simplicipinna by Wang (1996) and by the Flora of China are in fact Cycas collina, and his revision of the cycads of China does not include the species. The World List of Cycads, on the other hand, lists Yunnan in its range, and botanists at the Kunming Institute of Botany treat the populations of Xishuangbanna and Pu’er as Cycas simplicipinna (Zheng and colleagues 2017 and 2025). Species+, the CITES database, does not count China among its range countries. Plants or seed of Chinese origin sold under this name should therefore be treated with caution.

Etymology and history

The epithet combines the Latin simplex, “simple”, and pinna, “leaflet”: it recalls that the leaflets are undivided, unlike the divided leaflets of Cycas micholitzii, of which the plant was first considered a variety (Haynes 2022, as taken up by The World List of Cycads).

Smitinand already noted the wide distribution of the plant in Thailand, between 600 and 1,500 m, and cited a single specimen from western China (Wilson 5420, at Kew); he expected it to occur in Myanmar and Laos. The specimens he listed, collected in Chiang Mai province (Doi Suthep, Chiang Dao, Doi Inthanon, Fang), in Phrae, on Phu Kradueng (Loei) and on Phu Tong, many of them by the botanist Kerr, show that the plant was known to herbaria long before it was described.

Common names

No English common name is attested. In Thailand, the Department of Agriculture report on the country’s cycads (2019) calls it มะพร้าวเต่า (ma phrao tao); Smitinand (1971) recorded the local names plong and phrao tao in Chiang Mai, and ma phrao tao in Phrae. LLIFLE gives the Chinese name 單羽蘇鐵 (dan yu su tie), which no flora consulted confirms.

In the wild

Cycas simplicipinna is one of the most widely distributed cycads of Indochina. The World List of Cycads records it in Yunnan, Laos (Saravan province), Thailand (Chiang Mai, Loei, Mae Hong Son, Phrae), central Vietnam (Quang Tri province) and, with doubt, Myanmar. In Thailand, a survey by the Department of Agriculture (2019) counted 520 plants at four sites: the districts of Chat Trakan (Phitsanulok province), Nam Nao (Phetchabun), Seka (Bueng Kan) and Phu Ruea (Loei).

It is a plant of shade and moisture. Smitinand collected it in evergreen forest and lower montane forest, between 600 and 1,500 m; the Thai report describes it as scattered in the humid evergreen forests of the north and north-east, often along streams or in damp places near water. LLIFLE speaks of sheltered sites in the dense shade of the understorey of tall evergreen forest, with plants scattered and rarely in dense stands.

In China, the species lives in the basin of the Lancang (Mekong), in Yunnan. Zheng and colleagues (2025) studied three populations in Xishuangbanna and the Pu’er region where it grows with Cycas pectinata, and compared the habitat of 16 of its populations with that of 13 populations of Cycas pectinata: it occupies higher positions on the slopes and less acid soils. It is pollinated by only two species of beetles of the genus Cycadophila (family Erotylidae), different from the pollinators of Cycas pectinata, and its male cones shed pollen from April to September, with a peak in April and May.

A genetic study of seven Chinese populations (Feng, Wang and Gong 2014, BMC Plant Biology) found high genetic diversity at the species level but low diversity within each population, strong differentiation between populations and a clear genetic structure; the data point to a population contraction during the last glacial period, without retreat to a single refuge. The authors see these features as guidelines for conservation, since each population carries part of the diversity of the species.

Conservation status and regulation

The IUCN lists Cycas simplicipinna as Near Threatened (NT). The first assessment, by H. T. Nguyen, dates from 2010; the most recent, by J. D. Bösenberg (2020, published in 2023), keeps the category according to GBIF, and The World List of Cycads gives the criteria A2cd, that is, an estimated decline linked to habitat loss and collecting. According to the LLIFLE summary, which takes up the 2010 assessment, the populations number more than 10,000 mature individuals, remain numerous throughout the range and are partly within protected areas, but logging could become a threat.

In Thailand, during the 2019 survey, local people reported illegal collecting in the wild, and the Department of Agriculture report concludes that export should be allowed for no Thai cycad except Cycas chamaoensis and Cycas siamensis. In China, the species occurs in three protected areas in Yunnan (the Naban River and Xishuangbanna national nature reserves, and the Nuozhadu provincial reserve), and the main threat is habitat fragmentation (Zheng and colleagues 2017).

Like every species in the genus except Cycas beddomei, Cycas simplicipinna is covered by CITES Appendix II, where the family Cycadaceae has been listed since 4 February 1977. Annotation #4 (version from CoP20, in force since 5 March 2026) exempts in particular seeds, pollen, and seedlings or tissue cultures obtained in vitro in sterile containers, while international trade in live plants still requires permits. In the European Union, the species is listed in Annex B of Regulation (EC) No 338/97, in the version set by Regulation (EU) 2026/1383, applicable since 29 June 2026. Species+ confirms this status (consulted on 13 October 2026). This information does not replace the official texts: check the regulations in force before any purchase or exchange, ask the seller for proof of origin, and prefer seed-grown plants raised in cultivation.

Growing Cycas simplicipinna

No institution has published growing results specific to Cycas simplicipinna. The only guidance available comes from the LLIFLE entry, a secondary source: a species suited to tropical regions with a dry season, easy to grow and able to cope with short droughts, suitable for pots; it prefers bright but filtered light to full sun, which bleaches its foliage, should be shaded from the afternoon heat and needs a deep, free-draining soil. LLIFLE advises feeding only when the terminal bud starts to swell, at the start of the annual growth cycle. This advice, consistent with a humid understorey habitat, is not confirmed by any other source.

Outdoor and in-ground cultivation

No result in the ground has been published outside its native range, in Europe, the United States or Australia. The underground trunk keeps the growing point in the soil, which in theory protects it, but no observation documents a plant growing back after frost.

Container cultivation

The only reports found come from the Fous de palmiers forum and concern plants under glass. A collector who grows under glass in the Ain and in the Hérault (France) followed his plants in 2010 and 2011: the species usually produced 3 or 4 leaves at each flush, with growth resuming at the end of winter; one plant made only one leaf in the autumn, and in August 2011, a year when most of his cycads had grown little, another had produced only two. None of these posts gives a minimum temperature. On the same forum, a grower in Barcelona describes in 2015 a pair of plants with trunks about 20 cm across, which put out new leaves in August (the male) and early October (the female), and which he moved into an unheated greenhouse for the winter without knowing how cold-tolerant they were; he did not report the result. In Italy, the species appears only once on the Tropicamente forum, in October 2009, in the list of a collection whose owner asked which species would tolerate a cold greenhouse; a grower near Ravenna replied that these Chinese and Vietnamese cycads were still little known.

In cultivation in the UK, US and Australia

  • United Kingdom: no garden is known to list it, in BGCI PlantSearch or in the online catalogues consulted.
  • United States: the online catalogue of Montgomery Botanical Center (Coral Gables, Florida) lists four accessions, whose numbers date them to 1994 (2), 1995 (1) and 2011 (1). Fairchild Tropical Botanic Garden and San Diego Botanic Garden list it in BGCI PlantSearch, which shows a declaration, not necessarily a living plant.
  • Australia: no garden is known to list it; it is absent from the online catalogue of the Royal Botanic Garden Sydney (updated on 1 October 2026). The page of the Palm and Cycad Societies of Australia (PACSOA) wiki shows only a photograph of a seedling, without growing information.

No English-language growing report is documented.

Propagation

The plant is dioecious, and LLIFLE notes that it is not self-fertile: a male and a female plant are needed to obtain seed and, in cultivation, usually hand pollination. No germination data specific to the species have been published. LLIFLE indicates, in general terms, slow germination of 6 to 18 months, and advises cleaning the seeds of their pulp and storing them for a few months before sowing, the embryo completing its development after harvest. The same entry mentions removing offsets as a maintenance task, without data on their use for propagation. Seeds are exempt from CITES under annotation #4.

Pests and diseases

No pest or disease specific to the species is documented. As for all cycads grown in pots or under glass, standing water remains the main danger for the underground trunk.

Cold hardiness

No published, verifiable cold tolerance data exist for Cycas simplicipinna. LLIFLE judges it “probably tropical in its requirements”.

European experience

No result in the ground has been published in France, Italy or elsewhere in Europe, and no dated frost episode concerns the species. The only reports concern plants under glass, without a recorded temperature (see Container cultivation). The Jardin zoologique tropical at La Londe-les-Maures, in the Var, has published no observations on this species.

United Kingdom, United States and Australia

No cold value and no dated outdoor growing report has been published. In the UK, treat it as a plant for a heated glasshouse; in subtropical gardens, a shaded, sheltered spot with free drainage matches its habitat, but no trial has been published.

Toxicity and precautions

It should be treated as poisonous, even though no analysis specific to Cycas simplicipinna exists. The risk is well documented in the genus: the tissues of Cycas, and above all their seeds, contain cycasin, which digestion converts into methylazoxymethanol, toxic to the liver and nervous system, along with a neurotoxic amino acid, BMAA. The ASPCA lists the sago palm (Cycas revoluta) among plants toxic to dogs, cats and horses. Keep seeds and leaves out of reach of children and pets, 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 traditional use specific to the species is documented. In Thailand, according to the 2019 report, the cycads sold on the domestic market come largely from collecting in the wild, but the report gives no details for this species.

Frequently asked questions

What does simplicipinna mean?

“With simple leaflets”, in Latin: the name recalls that the leaflets are undivided, unlike the divided leaflets of Cycas micholitzii, of which the plant was first a variety.

Are Cycas simplicipinna and Cycas micholitzii the same plant?

No. Smitinand described it in 1971 as a variety of Cycas micholitzii, but it has been treated as a separate species since 1995. Cycas micholitzii has divided leaflets, Cycas simplicipinna undivided ones.

Does it have a trunk?

Hardly ever a visible one. The trunk normally stays underground and the few leaves seem to rise straight from the soil; it only rarely reaches the surface, over about twenty centimetres.

Where does it grow in the wild?

In the understorey of humid evergreen forest in northern and north-eastern Thailand, southern Laos, central Vietnam and southern Yunnan, often near streams. Its presence in Myanmar is not confirmed.

Is it easy to grow?

Perhaps, but no verified source shows it. LLIFLE calls it easy and suitable for pots, in filtered light and a free-draining compost; the forum reports concern only plants under glass.

Can it take full sun?

Better not. It is an understorey plant: according to LLIFLE, full sun bleaches its leaves, and bright but filtered light suits it better.

Can it be grown outdoors in the UK?

No. No verifiable cold data exist and no trial in the ground has been published: in the UK, grow it in a pot under heated glass.

Is it poisonous?

It should be assumed so. No analysis specific to the species exists, but every cycad studied contains serious toxins, especially in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Smitinand, T. (1971). The genus Cycas Linn. (Cycadaceae) in Thailand. Natural History Bulletin of the Siam Society 24: 163–175. https://archive.org/details/nhbss_024_1-2k_smitinand_thegenuscycasli [Original description of Cycas micholitzii var. simplicipinna (p. 164): types, description, localities, Thai names.]
  • Hill, K.D. (1995). [Cycas simplicipinna (Smitinand) K.D.Hill, comb. et stat. nov.] Proceedings of the Third International Conference on Cycad Biology: 150. [Raised to species rank; reference taken from The World List of Cycads and IPNI.]
  • Laubenfels, D.J. de & Adema, F. (1998). A taxonomic revision of the genera Cycas and Epicycas gen. nov. (Cycadaceae). Blumea 43(2): 351–400. [Inclusion of the variety in Epicycas tonkinensis and choice of lectotype.]
  • Chen, C.J. & Stevenson, D.W. (1999). Cycadaceae. In Wu, Z.Y. & Raven, P.H. (eds), Flora of China, vol. 4: 1–7. Science Press, Beijing; Missouri Botanical Garden Press, St Louis. [Doubtful synonymy with Cycas balansae; consulted on eFloras.]
  • Hill, K.D. & Yang, S.L. (1999). The genus Cycas (Cycadaceae) in Thailand. Brittonia 51(1): 48–73. [Description (pp. 50–52); reference taken from The World List of Cycads.]
  • Hill, K.D., Nguyen, T.H. & Loc, P.K. (2004). The genus Cycas (Cycadaceae) in Vietnam. The Botanical Review 70(2): 134–193. [Vietnamese populations (pp. 147–148); reference taken from The World List of Cycads.]
  • Hill, K.D. (2008). The genus Cycas (Cycadaceae) in China. Telopea 12(1): 71–118. doi:10.7751/telopea20085804 [Name applied in China to Cycas collina, distinguishing characters, section Stangerioides.]
  • Feng, X., Wang, Y. & Gong, X. (2014). Genetic diversity, genetic structure and demographic history of Cycas simplicipinna (Cycadaceae) assessed by DNA sequences and SSR markers. BMC Plant Biology 14: 187. doi:10.1186/1471-2229-14-187 [Seven Chinese populations, genetic structure, Pleistocene contraction; peer-reviewed article, consulted on 21 October 2026.]
  • Zheng, Y., Liu, J., Feng, X. & Gong, X. (2017). The distribution, diversity, and conservation status of Cycas in China. Ecology and Evolution 7(9): 3212–3224. doi:10.1002/ece3.2910 [Protected areas and threats in Yunnan.]
  • Zheng, F., Wang, Y., Xi, H., Xiao, S., Feng, X., Gong, X. & Liu, J. (2025). Ecological isolation maintains the species boundaries between two sympatric Cycas from Southwest China. Ecology and Evolution 15(7): e71769. doi:10.1002/ece3.71769 [No hybrids with Cycas pectinata, habitat, pollinators and phenology in Yunnan; peer-reviewed article.]
  • Nguyen, H.T. (2010). Cycas simplicipinna. The IUCN Red List of Threatened Species 2010: e.T42085A10625321. doi:10.2305/IUCN.UK.2010-3.RLTS.T42085A10625321.en [First assessment; reference taken from The World List of Cycads and Crossref.]
  • Bösenberg, J.D. (2023). Cycas simplicipinna. The IUCN Red List of Threatened Species 2023: e.T42085A69157953. doi:10.2305/IUCN.UK.2023-1.RLTS.T42085A69157953.en [Reassessment (dated 2020); Crossref metadata consulted, NT category from GBIF.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology taken up 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.]