Cycas balansae

Cycas balansae is a trunkless cycad of the evergreen forests of south-eastern Guangxi, in China, and of northern Vietnam, where it grows in the deep shade of the understorey. Described by Otto Warburg in 1900 from a plant collected in the courtyard of a pagoda near Hanoi, this member of the genus Cycas is named after the French naturalist Benedict Balansa. It has also been known as Cycas shiwandashanica and Cycas palmatifida, both now treated as synonyms, and the IUCN classes it as Endangered (assessment of 2010, confirmed in 2023).

Key facts about Cycas balansae

  • Accepted name: Cycas balansae Warb. (1900), 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: Cycas siamensis subsp. balansae (Warb.) J.Schust. (1932); Cycas shiwandashanica Hung T.Chang & Y.C.Zhong (1995); Cycas palmatifida Hung T.Chang, Y.Y.Huang & Y.C.Zhong (1998)
  • Family: Cycadaceae, order Cycadales
  • Common names: “Balansa’s sago”, a trade name used by a British nursery; “Tue da voi” in Vietnamese, according to Species+ (see Common names)
  • Natural range: China (Shiwandashan mountains, south-eastern Guangxi) and northern Vietnam (Lang Son, Quang Ninh, Thai Nguyen and Vinh Phuc provinces)
  • IUCN status: Endangered (EN); first assessed by Nguyễn Tiến Hiệp (2010, criteria A2acd+4acd), reassessed by Nguyễn Tiến Hiệp and A. Lindstrom in version 2023-1 of the Red List
  • CITES and other protection: CITES Appendix II (seeds exempt under annotation #4); Annex B in the European Union
  • Documented hardiness: no measured value; a British nursery places it in USDA zone 9b, without cultivation data to back it up (see Cold hardiness)
  • Light and soil: deep shade beneath tall, closed evergreen forest; loamy soils over schist or granite
  • Habit and adult size: underground stem 12 to 20 cm across; 4 to 9 leaves 1.2 to 2.6 m long
  • In the UK, US and Australia: listed by Montgomery Botanical Center (Florida) and the Royal Botanic Garden Sydney in their online catalogues; no record in British gardens (see In cultivation in the UK, US and Australia)
  • Toxicity: no analysis specific to the species; treat it as poisonous, like all Cycas (see Toxicity and precautions)

How to recognise Cycas balansae

It is recognised by its few, very long leaves, carried on long petioles armed with slender spines and covered in a dark purple-brown felt that often persists. Ken Hill, in his revision of the genus in China (2008), adds mid-sized male cones whose rounded microsporophylls lack an apical spine, reduced megasporophylls with a few long, slender divisions, and small seeds. His description:

  • Stem: underground (acaulescent), 12 to 20 cm in diameter at the narrowest point; 4 to 9 leaves in the crown.
  • Leaves: dark green, highly glossy to semi-glossy, 120 to 260 cm long, slightly keeled or flat in section (opposite leaflets at an angle of 160 to 180°), with 90 to 160 leaflets; the rachis always ends in a pair of leaflets.
  • Petiole: 40 to 160 cm, i.e. 30 to 40 % of the leaf; downy, with dark purple-brown felt, spiny along its whole length, with spines 4 to 10 mm long.
  • Median leaflets: simple, strongly two-toned, 22 to 30 cm long and 10 to 15 mm wide, set at 75 to 85° to the rachis, narrowed to 3 to 4 mm at the base, 11 to 21 mm apart; stiff in texture, margins flat or barely recurved, tip softly acuminate, not spiny.
  • Cataphylls: narrowly triangular, soft, hairy, 6 to 7 cm long.
  • Male cones: spindle-shaped, yellow, 20 to 25 cm long and 4 to 7 cm across; microsporophylls soft, with no apical spine.
  • Megasporophylls: 8 to 12 cm long, with brown felt, bearing 2 to 4 hairless ovules; blade ovate, 4 to 6 cm, deeply comb-like, with 14 to 24 soft spines 25 to 40 mm long; apical spine not distinct from the lateral ones.
  • Seeds: ovoid, 25 to 27 mm long and 20 mm wide; sarcotesta yellow, without a waxy bloom or fibrous layer; sclerotesta slightly warty.

Some popular descriptions speak of thin, papery leaflets; Hill’s revision describes them as stiff in texture.

Hybrids

No named natural hybrid has been described, but genetics points to exchanges with related species. A RADseq study of six Cycas species from southern China (Tao and colleagues, Frontiers in Genetics, 2021) found little admixture between species overall, except in the individuals of Cycas dolichophylla, which show substantial genetic admixture with Cycas bifida, Cycas changjiangensis and Cycas balansae. No garden hybrid has been documented.

Possible confusion

The likeliest confusion is with the other trunkless Cycas of section Stangerioides, a group that ranges from northern Thailand and Myanmar to Laos, Vietnam and southern China. In Hill’s key (2008), Cycas balansae is separated as follows:

  • Cycas dolichophylla: broader leaflets (14 to 25 mm), abruptly rounded at the base, and a shorter petiole (20 to 35 % of the leaf); Cycas balansae has leaflets 10 to 15 mm wide, narrowed and tapering at the base, and a long petiole (30 to 40 %).
  • Cycas tanqingii: microsporophylls with a distinct terminal spine, which Cycas balansae lacks.
  • Cycas collina: larger and often more numerous leaves, with more leaflets, and larger male cones. This is the species of southern Yunnan (the Xishuangbanna region) and north-western Vietnam to which Chinese authors long applied the name Cycas balansae.
  • Cycas ferruginea: it shares part of the range (Lang Son and Thai Nguyen in Vietnam, western Guangxi in China), but it grows on bare limestone cliff faces, whereas Cycas balansae lives on loamy soils in forest shade.

The literature also shows that the name has been applied to different plants: de Laubenfels and Adema (1998) included some of them in a broadly defined Cycas tonkinensis, so distribution data from Chinese publications should be read with care (see Taxonomy).

Taxonomy

Cycas balansae is an accepted species, but what it covers has changed several times. Warburg described it in 1900 in Monsunia (1: 179); in 1932 Josef Schuster reduced it to a subspecies of Cycas siamensis (Cycas siamensis subsp. balansae), a combination now treated as a synonym. Ken Hill’s revisions of the genus in Vietnam (with Nguyen Tien Hiep and Phan Ke Loc, 2004) and in China (2008) restored it as a species and placed it in section Stangerioides, defined by soft male cones, comb-like megasporophylls, hairless ovules and yellow seeds whose sarcotesta comes away easily.

Two Chinese species from Guangxi have been sunk into its synonymy:

  • Cycas shiwandashanica Hung T.Chang & Y.C.Zhong (1995), described from plants in the broadleaved forest at Nasuo, near Fangchenggang; included in Cycas balansae by Chen and Stevenson in the Flora of China (1999), then by Hill (2008).
  • Cycas palmatifida Hung T.Chang, Y.Y.Huang & Y.C.Zhong (1998), described from a plant grown in the Nanning arboretum and originating from Fangcheng county; Hill studied the living plant and placed the name in synonymy.

The World List of Cycads follows this treatment. The delicate point is the use of the name in China. According to Hill (2008), the plants of southern Yunnan that some Chinese authors called Cycas balansae (Wang 1996; Chen and Stevenson 1999) belong to Cycas collina. In 2006 a genetic study using ISSR markers on 158 plants from all the Chinese populations of the “Cycas balansae complex” (Xiao and Gong, Annals of Botany) recognised five groups, matching Cycas balansae in the strict sense, Cycas parvula, Cycas shiwandashanica, Cycas tanqingii and Cycas simplicipinna. That study therefore treats as distinct the Shiwandashan plants, which for Hill and for the world checklist are Cycas balansae itself; the authors’ “Cycas balansae in the strict sense” probably corresponds to the Chinese use of the name, but no source says so explicitly.

Etymology and history

The epithet honours Benedict Balansa (1825–1892), a French naturalist and plant explorer who collected widely for the Muséum national d’Histoire naturelle in Paris and who spent the years 1885 to 1892 in Tonkin, northern Vietnam, where he died (Hill 2008; Haynes 2022).

The history of the type is unusual. Warburg cited a single collection by Balansa, no. 4084: cones from the courtyard of a temple near Hanoi, kept in the Barbey herbarium. The Berlin specimen, which should have been the type, was evidently destroyed during the Second World War. Two sheets survive in Paris, one with part of a male cone and one with part of a leaf; the label reads “Dioique. Frondes de deux mètres de hauteur” and “Village du papier près de Hanoi, dans la cour d’une pagode”, April 1889. Hill designated them as the lectotype in his Chinese revision of 2008, with isolectotypes at Geneva and Kew. The World List of Cycads also cites the typification in the Vietnamese revision of 2004.

The type itself therefore came from a cultivated plant. Hill (2008) lists other cultivated specimens: in gardens at Hai Phong as early as 1885 (Balansa 563), at Nanning, in a village in Fangcheng county, and even in a restaurant garden in Tuyen Quang province.

Common names

No traditional English name is attested. The British nursery Trebrown offers it under the trade name “Balansa’s sago”. Species+, the CITES database, records the Vietnamese name “Tue da voi”, written without diacritics; no other published source confirms it. The Chinese name could not be checked in a flora.

In the wild

Cycas balansae grows in the deep shade of tall, closed evergreen forest, in the most sheltered spots, where it is locally frequent but never forms dense stands (Hill 2008). It favours loamy soils over schist or granite.

According to Hill and The World List of Cycads, the range covers the Shiwandashan mountains, in coastal south-eastern Guangxi, and extends in Vietnam to the regions north-west and north-east of Hanoi: the provinces of Lang Son, Quang Ninh, Thai Nguyen and Vinh Phuc. Hill also mentions a plant grown in Tuyen Quang province, collected on the north-western slopes of the Tam Dao range.

Chinese sources paint a different picture. A modelling study published in 2025 (Zhang and colleagues, Plants) describes a plant of tropical rainforest or monsoon forest on limestone in the valleys of Yunnan and Guangxi, between 100 and 800 m, and places the core of its distribution in and around Xishuangbanna, in southern Yunnan, on the basis of 87 records gathered from Chinese databases and GBIF. These Yunnan records probably correspond to the plants that Hill assigns to Cycas collina; the study does not discuss the point.

The same study identifies temperature seasonality, the mean temperature of the coldest quarter, isothermality and the rainfall of the warmest quarter as the main factors shaping the distribution, and predicts a slight shrinking of the suitable area and a shift northwards with climate change.

Conservation status and regulation

Cycas balansae is classed as Endangered (EN) on the IUCN Red List. The first assessment, by Nguyễn Tiến Hiệp (2010), used criteria A2acd+4acd, repeated by The World List of Cycads: a population decline caused by loss of habitat and by collection. A reassessment by Nguyễn Tiến Hiệp and A. Lindstrom was published in version 2023-1 of the Red List (reference found on Crossref) and kept the Endangered category, which is the one the IUCN currently publishes (checked through GBIF). Earlier, Donaldson’s assessment (2003), cited by Hill in 2008, regarded it as Near Threatened (NT). In China it is listed as Endangered in the Red List of China’s higher plants, according to Zhang and colleagues (2025), who report sharply declining populations, increasingly fragmented habitat and low seed production, and propose a priority protected area in the city of Simao, in Yunnan.

Like every species in the genus except Cycas beddomei, Cycas balansae is listed in CITES Appendix II, where the family Cycadaceae has been included since 4 February 1977. The listing carries annotation #4 (CoP20 version, in force since 5 March 2026): seeds, pollen, seedlings and tissue cultures obtained in vitro and transported in sterile containers, and cut flowers of artificially propagated plants, are not covered by CITES, whereas international trade in plants requires an export permit. The United Kingdom, the United States and Australia 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, confirms this status (consulted on 12 October 2026).

This general information does not replace the official texts: check the rules in force before any purchase or exchange, ask the seller for proof of origin and prefer plants raised from seed in cultivation.

Growing Cycas balansae

In short: a shade-loving cycad for a frost-free glasshouse or conservatory, or for the open garden in a warm, frost-free climate; no published trial gives precise rules. No institution has published growing recommendations specific to Cycas balansae. The species has, however, long been grown in its home countries: the type itself came from a pagoda courtyard near Hanoi, and Hill (2008) mentions plants grown at Hai Phong, at Nanning and in several villages. According to Zhang and colleagues (2025), it is also grown in China in Sichuan and Guangdong provinces and in Taiwan, valued for its appearance.

Its habitat gives the safest guidance. Unlike Cycas revoluta and many sun-loving Cycas, it is a plant of the shady understorey of moist evergreen forest, on loamy soils: filtered light or bright shade and a rich but free-draining substrate therefore suit it. This advice is inferred from its natural environment, not from published cultivation trials.

Outdoor and in-ground cultivation

No result of open-ground cultivation outside its native range has been published, in the Mediterranean, the United States, Australia or Britain. A plant listed in a numbered bed at the Royal Botanic Garden Sydney (see below) shows that the species is grown in a garden setting there, but the catalogue does not say how it has fared. Without measured data on cold, planting out is a gamble anywhere frosts occur.

Container cultivation

In a pot, the same principles apply: bright shade or filtered light rather than full sun, a rich but free-draining mix, and a frost-free place in winter. A grower in Monza (Lombardy, Italy) listed it in October 2009, on the Italian forum Tropicamente, among some thirty small cycads kept indoors in winter, while asking which of them would cope with a cold glasshouse; no answer gave any information on Cycas balansae. That is the only cultivation record found in Europe.

In cultivation in the UK, US and Australia

In short: the species is rare in public collections; one American and one Australian garden list it in their own catalogues, and no British garden does. A garden listed in the BGCI PlantSearch database (consulted in October 2026) has declared the species at some point, which does not prove that a living plant is there today.

  • United States: the online catalogue of Montgomery Botanical Center (Coral Gables, Florida) lists one accession of Cycas balansae; its short number does not allow the year of entry to be read. BGCI PlantSearch also lists the species for Denver Botanic Gardens (Colorado).
  • Australia: the Royal Botanic Garden Sydney grows one plant of wild origin from China (accession of 1999) in bed 51k, according to its Garden Explorer (updated 1 October 2026).
  • United Kingdom: no British garden lists the species. The Trebrown nursery offers it with a USDA zone rating (see Cold hardiness).

No report from a grower in the United Kingdom, the United States or Australia has been published on English-language forums.

Propagation

Like all Cycas, Cycas balansae is dioecious: a male and a female plant are needed to obtain fertile seed. Zhang and colleagues (2025) point out that low seed production limits its natural spread. No germination data specific to the species has been published, nor any experience of propagation from offsets. Seeds are exempt from CITES under annotation #4; ask for seed collected from cultivated plants.

Pests and diseases

No pest or disease specific to the species is documented. Scale insects, including Aulacaspis yasumatsui, threaten all cultivated Cycas, and collar rot affects cycads kept in a substrate that stays too wet, but no attack on this species in particular has been reported.

Cold hardiness

There is no measured figure for the cold tolerance of Cycas balansae. The British nursery Trebrown places it in USDA zone 9b, which corresponds to average annual minimums of −3.9 to −1.1 °C (25 to 30 °F); this is a commercial rating, not supported by cultivation observations. No forum message reports a temperature that the species has survived.

In Europe, no result of open-ground cultivation has been published, and no dated frost episode concerns it. The only Italian plant known, the Monza grower’s mentioned above, was kept indoors in winter. On the French forum Fous de palmiers, whose members garden largely in the south of France, the species is never mentioned, and the Jardin zoologique tropical has published no observation of it. In its natural setting, beneath the tall forests of northern Vietnam and Guangxi, the plant lives under the shelter of the canopy; the study by Zhang and colleagues (2025) confirms that the temperature of the coldest quarter is one of the factors limiting its distribution, without giving a frost threshold. Without data, grow it in a pot, protected from frost.

Toxicity and precautions

No toxicity analysis specific to Cycas balansae is documented, 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 Cycas revoluta among plants poisonous to dogs, cats and horses. 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

Zhang and colleagues (2025) report that in traditional Chinese medicine the roots, stems and leaves of Cycas balansae are regarded as anti-inflammatory, analgesic and antihypertensive, that the starch-rich pith has food value and that the plant is prized as an ornamental. These uses concern the plants given this name in China, probably in part Cycas collina (see Taxonomy), and none has been validated by modern pharmacology: given the toxins of the genus, they must not be copied under any circumstances.

Frequently asked questions

Is Cycas balansae frost-hardy?

Nobody knows. No measurement has been published; a British nursery places it in USDA zone 9b, −3.9 to −1.1 °C (25 to 30 °F), but without cultivation data to support the rating.

Can it be grown outdoors in the UK?

There is no evidence that it can. No outdoor result has been published anywhere outside its native range, and the only European plant on record was kept indoors in winter; grow it in a pot and keep it frost-free.

Does it need shade?

Yes, judging by its habitat. In the wild it grows in the deep shade of tall, closed evergreen forest, unlike Cycas revoluta; no trial of cultivation in full sun has been published.

How does it differ from Cycas revoluta?

Clearly. Cycas balansae has no above-ground trunk, carries only 4 to 9 leaves up to 2.6 m long with flat leaflets 10 to 15 mm wide and long spiny petioles, and grows in shade; Cycas revoluta forms a trunk and has shorter leaves with leaflets whose margins roll under.

Is Cycas shiwandashanica the same species?

Yes, under current taxonomy. The Flora of China (1999), Hill (2008) and The World List of Cycads treat it as a synonym of Cycas balansae; a 2006 genetic study, however, treated it as a distinct unit.

Is it threatened?

Yes. The IUCN has classed it as Endangered since 2010, a category kept in the 2023 reassessment, because of habitat loss and collection, and it is protected by CITES (Appendix II) and, in the European Union, by Annex B.

Is it poisonous?

Yes, it should be treated as such. There is no analysis of this species, but every Cycas studied contains toxins dangerous to people and animals, especially in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Warburg, O. (1900). Monsunia: Beiträge zur Kenntniss der Vegetation des Süd- und Ostasiatischen Monsungebietes 1: 179. [Protologue; reference taken from Hill (2008) and The World List of Cycads.]
  • Hill, K.D., Nguyen, H.T. & Loc, P.K. (2004). The genus Cycas (Cycadaceae) in Vietnam. The Botanical Review 70(2): 134–193. doi:10.1663/0006-8101(2004)070[0134:TGCCIV]2.0.CO;2 [Revision for Vietnam; reference checked on Crossref.]
  • Hill, K.D. (2008). The genus Cycas (Cycadaceae) in China. Telopea 12(1): 71–118. doi:10.7751/telopea20085804 [Reference revision for China: description, key, lectotypification, synonyms, distribution, habitat, use of the name by Chinese authors.]
  • Xiao, L.-Q. & Gong, X. (2006). Genetic differentiation and relationships of populations in the Cycas balansae complex (Cycadaceae) and its conservation implications. Annals of Botany 97(5): 807–812. doi:10.1093/aob/mcl039 [ISSR study of 158 Chinese plants.]
  • Nguyen, H.T. (2010). Cycas balansae. The IUCN Red List of Threatened Species 2010: e.T42069A10642849. doi:10.2305/IUCN.UK.2010-3.RLTS.T42069A10642849.en [First Red List assessment (EN); reference checked on Crossref, category taken from The World List of Cycads.]
  • Nguyễn, T.H. & Lindstrom, A. (2023). Cycas balansae. The IUCN Red List of Threatened Species 2023: e.T42069A67336462. doi:10.2305/IUCN.UK.2023-1.RLTS.T42069A67336462.en [Current assessment (EN); reference checked on Crossref, category checked through GBIF.]
  • Tao, Y., Chen, B., Kang, M., Liu, Y. & Wang, J. (2021). Genome-wide evidence for complex hybridization and demographic history in a group of Cycas from China. Frontiers in Genetics 12: 717200. doi:10.3389/fgene.2021.717200 [RADseq study of six species from southern China.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology of cycad names; used through The World List of Cycads.]
  • Zhang, H., Zhou, Y., Zhang, S., Wang, Z. & Liu, Z. (2025). Adaptive distribution and priority protection of endangered species Cycas balansae. Plants 14(5): 815. doi:10.3390/plants14050815 [MaxEnt modelling of the distribution in China, traditional uses, Chinese status. Based on the Chinese use of the name.]
  • 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.]