Cycas nongnoochiae

Cycas nongnoochiae is a cycad of the limestone hills of north-central Thailand, around Tak Fa in Nakhon Sawan province, where it grows on cliffs and open slopes. This species of the genus Cycas was described in 1999 by Ken Hill and named after Nong Nooch Tropical Garden, near Pattaya, a major supporter of the study of Thai cycads. Its grey to bluish green foliage and its black, deeply fissured bark set it apart. The IUCN lists it as Vulnerable.

Key facts about Cycas nongnoochiae

  • Accepted name: Cycas nongnoochiae K.D.Hill (1999), 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: no English vernacular name; “Nong Nooch sago” used commercially by a British nursery; ปรงตากฟ้า (prong Tak Fa, “Tak Fa cycad”) in Thai
  • Natural range: Thailand (Nakhon Sawan and Uthai Thani provinces); The World List of Cycads also cites Laos (Vientiane province)
  • IUCN status: Vulnerable (VU A2d; B1ab(v)), assessment by T. Marler and A. Lindström dated 2020 (Red List version 2022-1)
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union; protected plant in Thailand (Plant Varieties Act of 1975)
  • Documented hardiness: no measured data (see Cold hardiness)
  • Light and soil: in the wild, cliffs and open slopes of limestone hills, on sandy soils mixed with limestone, in full sun; no published growing results
  • Habit and adult size: trunk upright, sometimes reclining, up to about 5 m (Thai source); other dimensions not documented in the sources read
  • In the UK, US and Australia: declared in BGCI by Montgomery Botanical Center (Florida), Houston Botanic Garden (Texas) and the United States Botanic Garden (Washington, DC); no British or Australian record found
  • Toxicity: no data for the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas nongnoochiae

The original description by Hill (1999) could not be consulted. The characters below come from the 2019 report of Thailand’s Department of Agriculture (DOA) on the country’s cycads, written in Thai, and remain summary: it gives no measurements of leaves or cones.

Cycas nongnoochiae has an upright, sometimes reclining trunk up to about 5 m tall, with black, deeply fissured bark. Its pinnate leaves, numerous and spreading, are grey to bluish green and slightly hairy beneath; the lowest leaflets are reduced to spines, and the midrib is flat above and raised below. The cataphylls (the scale leaves that protect the growing point) are triangular and covered with short brown hairs. The male cones, narrowly ovoid, are pale yellow or green and end in sharp points. The megasporophylls (the fertile leaves of female plants) carry a white to yellow felt and a blade edged with very distinct, comb-like teeth. The seeds, ovoid and flattened, have a yellow, fibrous coat and no spongy layer.

The wiki of the Palm and Cycad Societies of Australia (PACSOA) describes it as a solitary cycad with dark, deeply fissured bark on a slim trunk to about 5 m, and grey-green or blue, semi-glossy leaves. Hobbyists in France were exchanging seed of a form called “Orange fruit”, with orange seeds, in 2009; this trade name has no botanical standing.

Hybrids

No hybrid is documented for this species. The PACSOA wiki states that it is “thought to have originated” as a hybrid between two other Thai cycads, but cites no study, and no published work consulted supports this idea; it is not followed here.

Possible confusion

In Thailand, several cycads with comb-like megasporophylls grow on limestone or sandstone hills. Cycas petraea, from the limestone cliffs of Loei province, has, according to the same DOA report, smooth yellow to grey bark and basal leaflets that are not reduced to spines, whereas Cycas nongnoochiae has black, fissured bark and spiny basal leaflets. Cycas pectinata (in the sense of the report), a tall cycad of the humid forests of the west and north, has almost smooth brown bark, a swollen base and a midrib raised on both surfaces of the leaflets.

The diagnostic characters used by Hill (1999) in his revision of the Thai cycads could not be read: for a reliable identification, cones and known provenance remain essential.

Taxonomy

Cycas nongnoochiae is a name accepted by The World List of Cycads and by GBIF; POWO could not be consulted (a search extract indicates that it is accepted there). The species was described by Ken Hill in “The genus Cycas (Cycadaceae) in Thailand”, a revision co-written with Yang S.-L. and published in Brittonia in 1999 (51(1): 48–73; the species on pages 60–62, fig. 7). Before that revision, Thai cycads were often given names applied too broadly, such as Cycas circinalis in the works of Smitinand (1971, 1972), according to Lindström and Hill (2007).

Its placement in a section of the genus is not stated in the sources consulted. No synonym is known.

Etymology and history

The epithet honours Nong Nooch Tropical Botanical Garden, near Pattaya (Chonburi province), which supported the study of Thailand’s cycads (Haynes 2022, cited by The World List of Cycads). The garden belongs to Kampon Tansacha, its director; Anders Lindström, co-author of many species in the genus, worked there (Lindström et al. 2008).

The type was collected by Ken Hill and P. Vatcharakorn on 29 April 1994 near the Wat Suk Sam Ran temple, 5 km north of Tak Fa, in Nakhon Sawan province (Hill 4643; holotype in Sydney, NSW; isotypes in Bangkok, BKF, and at Kew). Plants have circulated among European collectors since at least 2007, when young plants were offered for exchange on the French forum Fous de palmiers.

Common names

No English vernacular name is attested. The British nursery Trebrown uses “Nong Nooch sago”, a commercial name built from the epithet. In Thai, the species is called ปรงตากฟ้า (prong Tak Fa), “Tak Fa cycad”, after the district where it grows; “prong” is the general Thai word for cycads (DOA 2019).

In the wild

Cycas nongnoochiae grows on the limestone hills of the upper central basin of Thailand, on sandy soils mixed with limestone, in the provinces of Nakhon Sawan and Uthai Thani (DOA 2019). In a survey published in 2019, the DOA recorded two sites with a total of 270 plants, on the cliffs and open parts of limestone hills in Lam Phayon sub-district (Tak Fa district, Nakhon Sawan) and in Lan Sak district (Uthai Thani); local people reported past illegal collection. The PACSOA wiki describes it growing in full sun in low scrub on steep limestone bluffs near Tak Fa, locally abundant but with a very restricted range.

The World List of Cycads also cites Vientiane province, in Laos; no source consulted gives details of this occurrence. Pollination and phenology are not documented.

Conservation status and regulation

The IUCN lists Cycas nongnoochiae as Vulnerable (VU, criteria A2d; B1ab(v)), in the assessment by T. Marler and A. Lindström dated 2020 and published in version 2022-1 of the Red List; the previous assessment, by K.D. Hill (2010), already listed it as Vulnerable, and the Red List data relayed by GBIF confirm the current category (consulted on 21 October 2026). The criteria reflect a population reduction due to exploitation (A2d) and a small range in which the number of mature plants is declining (B1ab(v)).

In Thailand, all Cycas species are “protected plants” under the Plant Varieties Act of 1975 (B.E. 2518) and its amendments (DOA 2019). The DOA report lists Cycas nongnoochiae among the endemic species with limited dispersal whose wild populations are declining and highly threatened, notably by collection for ornamental use.

Like every species in the genus except Cycas beddomei, Cycas nongnoochiae 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 exempt, 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 and confirms this status (searches of 3 and 12 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 nongnoochiae

In short: Cycas nongnoochiae is grown by a few collectors and declared by several American botanic gardens, but no grower’s report describing its behaviour has been published. The only growing advice found, on the PACSOA wiki, is brief: a sunny, well-drained position, preferably in a limestone-based potting mix or soil, which matches its wild habitat on limestone bluffs.

Outdoor and in-ground cultivation

No planting result has been published. Its habitat, under the frost-free tropical climate of central Thailand, points to warm, frost-free climates for planting out, in full sun and on very free-draining ground; this is a deduction, not a documented result.

Container cultivation

In temperate climates it is a plant for a pot under glass, in a mineral, free-draining mix; the PACSOA wiki suggests a limestone-based mix. Young plants and germinated seeds appeared in exchange lists on the French forum Fous de palmiers in 2007 and 2009, and an Italian hobbyist listed it in his collection on the forum Tropicamente in 2009, but none of these messages describes how it grows. 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

In the United States, BGCI PlantSearch lists Cycas nongnoochiae at Montgomery Botanical Center (Coral Gables, Florida), Houston Botanic Garden (Texas) and the United States Botanic Garden (Washington, DC) (search of 21 October 2026); no accession under this name appears, however, in Montgomery’s online catalogue. A BGCI entry shows that a garden has declared a plant, not that it is alive today, and it does not say whether the plant grows outdoors or under glass; in Washington, DC, it can only be under glass.

No British or Australian garden declares the species in the sources checked (BGCI PlantSearch and the inventory of cycads in British, American and Australian gardens compiled for this site, 19 October 2026). 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 to obtain seed. Exchanges of germinated seeds among hobbyists show that it can be raised from seed, but no germination time or rate has been published. Seeds are exempt from CITES under annotation #4; collecting them in the wild remains subject to Thai law.

Pests and diseases

No pest or disease specific to the species is documented. Cycad scale insects, including the Asian cycad scale, Aulacaspis yasumatsui, can attack all cultivated species.

Cold hardiness

No measured cold-tolerance data exist for Cycas nongnoochiae. It lives under the tropical climate of the central Thai plain, without frost, and nothing allows us to say that the plant tolerates frost. The British nursery Trebrown rates it USDA zone 9b (average annual minimum of −3.9 to −1.1 °C, or 25 to 30 °F), a commercial rating not backed by any published growing observation.

Mediterranean experience

No growing result has been published in Europe, in the ground or in a pot, and no dated frost event concerns the species; the Jardin zoologique tropical in the Var has published nothing on it. Readers in comparable climates, such as California or southern Australia, have no European result to go on.

United Kingdom, United States and Australia

No cold reading or dated growing report was found, either on forums or from botanic gardens; the American gardens that declare it have published no observation. In the UK, and in most of the United States and Australia outside the tropics, keep it under glass with frost protection.

Toxicity and precautions

No toxicity analysis specific to Cycas nongnoochiae 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 is documented. The main current use is ornamental: the DOA (2019) cites collection from the wild for garden landscaping among the threats facing Thai cycads.

Frequently asked questions

Where does Cycas nongnoochiae grow?

In north-central Thailand, on the limestone hills of Nakhon Sawan (Tak Fa district) and Uthai Thani provinces; The World List of Cycads also cites Vientiane province, in Laos.

Where does the name nongnoochiae come from?

From Nong Nooch Tropical Garden, near Pattaya, which supported the study of Thailand’s cycads.

What is its Thai name?

ปรงตากฟ้า, prong Tak Fa, “Tak Fa cycad”, after the district where it grows.

How can it be told from Cycas petraea?

By the bark and the base of the leaves: Cycas nongnoochiae has black, deeply fissured bark and basal leaflets reduced to spines; Cycas petraea has smooth, yellow to grey bark and no spines at the base of the leaves.

Is it endangered?

Yes. The IUCN lists it as Vulnerable: a 2019 survey found only 270 plants at two sites, and illegal collection has taken place.

Can it be grown outdoors in the UK?

Almost certainly not. No measured cold data exist and its range is frost-free; the nursery rating of zone 9b is not backed by observations. Grow it in a pot under glass.

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

  • Hill, K.D. & Yang, S.-L. (1999). The genus Cycas (Cycadaceae) in Thailand. Brittonia 51(1): 48–73. doi:10.2307/2666557 [Revision containing the original description (pp. 60–62, fig. 7); not consulted (paywalled), cited after The World List of Cycads and Crossref.]
  • Sonsuphap, Y., Sripotha, D., Thuamsomboon, P. & Thongdon-ae, S. [names transliterated from Thai] (2019). วิจัยสถานภาพพืชอนุรักษ์สกุลปรง (Cycas spp.) — Non-Detriment Findings for Cycas spp. Department of Agriculture, Bangkok. [Report in Thai; read directly.]
  • Marler, T. & Lindström, A. (2022). Cycas nongnoochiae. The IUCN Red List of Threatened Species 2022: e.T42060A68906763. doi:10.2305/IUCN.UK.2022-1.RLTS.T42060A68906763.en [Red List assessment (dated 2020); reference found on The World List of Cycads and Crossref, category VU relayed by GBIF, page not consulted (access blocked).]
  • Lindström, A.J. & Hill, K.D. (2007). The genus Cycas (Cycadaceae) in India. Telopea 11(4): 463–488. doi:10.7751/telopea20075745 [Remark on the use of the name Cycas circinalis in Thailand; 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 [Affiliations and acknowledgements (Nong Nooch garden); full text 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.]