Cycas diannanensis

Cycas diannanensis is a cycad from southern Yunnan, in China, where it grows on the steep slopes of the Red River valley, between about 600 and 2,000 m above sea level. Described in 1995, this member of the genus Cycas is recognised by its very long, glossy leaves and its narrow, spiny cataphylls. Its name now also covers plants described under other names, Cycas parvula and Cycas multiovula, which causes confusion in the literature and in the trade. Listed as Endangered, it is rare in cultivation in Europe and North America, and its cold hardiness is still poorly documented, despite the claims made by some sellers.

Cycas diannanensis
Cycas diannanensis in the garden of the Serre de la Madone, Menton (France).
Cycas diannanensis
Leaflets of Cycas diannanensis.

Key facts about Cycas diannanensis

  • Accepted name: Cycas diannanensis Z.T.Guan & G.D.Tao (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)
  • Synonyms: Cycas parvula S.L.Yang ex D.Yue Wang (1996), Cycas multiovula D.Yue Wang (1996) and Cycas pectinata subsp. manhaoensis C.J.Chen & P.Yun (1995), according to The World List of Cycads; other sources place Cycas multiovula under Cycas guizhouensis (see Taxonomy)
  • Family: Cycadaceae, order Cycadales; section Stangerioides (Hill 2008)
  • Common names: no English name attested; in Chinese 滇南苏铁 (protologue)
  • Natural range: China, central and eastern Yunnan, along the Red River; presence in northern Vietnam doubtful
  • IUCN status: Endangered (EN B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)), assessment by J. D. Bösenberg published in 2023
  • CITES and other protection: CITES Appendix II; Annex B in the European Union; first-class state protection in China (2021 national list)
  • Documented hardiness: no published measurement; a few reports on young plants in France and Italy, from −4 °C (24.8 °F) under fleece without damage to losses in the cold spell of winter 2012 (see Cold hardiness)
  • Light and soil: in the wild, steep slopes on limestone, schist or mudstone, in former cloud forest that is now often degraded
  • Habit and adult size: trunk up to 3 m and 25 to 40 cm across; leaves 1.4 to 3.3 m long
  • In the UK, US and Australia: Montgomery Botanical Center (accessions from 1994 to 2026); listed by the Missouri Botanical Garden, San Diego Botanic Garden, the San Diego Zoo, Glasgow Botanic Gardens and James Cook University in BGCI PlantSearch (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 diannanensis

The first thing to look at is the cataphylls, the scale leaves that alternate with the leaves at the top of the trunk: linear and spiny, they are 12 to 20 cm long, much longer than in the other Chinese cycads of the same group. Ken Hill (2008) adds small seeds, broad leaflets lying flat on the rachis and not twisted, with slightly recurved and sometimes wavy margins, and a large megasporophyll blade ending in a broad spine.

According to Hill (2008), the trunk, aerial or underground, reaches 3 m and 25 to 35 cm in diameter and carries 12 to 50 leaves. These, bright or dark green and very glossy, are 140 to 330 cm long and bear 160 to 300 leaflets. The petiole, 45 to 100 cm long, is spiny along almost its whole length. The median leaflets are 13 to 32 cm long and 9 to 16 mm wide, with a midrib raised on both faces.

The male cones, narrowly ovoid and yellow, are 50 to 65 cm long and 9 to 13 cm across. The megasporophylls, 16 to 24 cm long and covered in grey down, bear 4 to 8 hairless ovules and an oval or rounded blade 6.5 to 14 cm long, divided into 30 to 52 soft lobes. The ovoid seeds are 28 to 40 mm by 20 to 32 mm, with a yellow fleshy coat and a warty inner shell. The French nursery Cycadales.eu describes male cones “up to 1 meter” tall, which the published descriptions do not confirm.

The original description (Guan and Tao 1995) gives similar values for the type plant: a trunk 1 to 3 m tall and 30 to 40 cm across, marked with rings of leaf scars; leaves about 2.5 m long on a petiole of 70 to 80 cm armed with 36 to 40 pairs of spines about 3 mm long; about 138 pairs of leaflets 35 to 38 cm by 1.5 cm; and megasporophylls 26 to 30 cm long bearing 3 to 7 pairs of ovules, usually hairless.

Hybrids

No natural hybrid has been described with certainty. Hill (2008) reports that plants grown at the Fairy Lake Botanical Garden in Shenzhen are thought to be hybrids between Cycas bifida and Cycas diannanensis, without a voucher specimen. In the trade, a grower mentioned in 2020 on the French Fous de palmiers forum a hybrid with Cycas debaoensis, of undocumented origin.

Possible confusion

Several names for one plant

The main difficulty lies in the names. Along the Red River, three very similar cycads were described: Cycas diannanensis (1995), Cycas parvula and Cycas multiovula (1996). According to Liu, Zhou and Gong (2015), they differ only in the shape of the megasporophyll blade (more deeply divided in parvula) or in the number of ovules and the size of the megasporophylls (larger in multiovula), and are almost impossible to tell apart without reproductive organs. Their genetic study of 15 populations found no clear boundary between them: they propose uniting them all under Cycas diannanensis, which The World List of Cycads follows.

The name Cycas multiovula is a special case, because its type is a plant cultivated at Gejiu. Hill (2008) placed it under Cycas guizhouensis, and the Flora of China (1999) under Cycas szechuanensis. Species+ and the Kew classification relayed by GBIF still place it under Cycas guizhouensis. A plant labelled “Cycas multiovula” may therefore belong to one species or another depending on the source.

The Flora of China (1999) went further and placed Cycas diannanensis itself in the synonymy of Cycas taiwaniana. That is no longer the view of Hill (2008) or of The World List of Cycads.

How to tell it from related species

  • Cycas taitungensis, from Taiwan, the species with which the authors compared it: shorter, keeled leaves, narrow leaflets (6 to 8 mm) with recurved margins, a short petiole and hairy ovules (Guan and Tao 1995; Hill 2008).
  • Cycas taiwaniana, from south-eastern China: hairy ovules according to the protologue; Hill (2008) separates it by a petiole spiny down to its swollen base and male cones under 50 cm.
  • Cycas dolichophylla, from the same region: short, broad leaflets, clearly rounded at the base, and long, slender petiole spines (Hill 2008).
  • Cycas panzhihuaensis, from Sichuan and northern Yunnan: bluish, upright leaves 70 to 150 cm long, leaflets 5 to 7 mm wide and red to orange seeds (Hill 2008).

Taxonomy

Guan Zhongtian, of the Sichuan forestry survey and planning institute, and Tao Guoda, of the Xishuangbanna Tropical Botanical Garden, described Cycas diannanensis in 1995 in a “preliminary report on a new cycad from Yunnan”. The type, collected by Tao (no. 95014) near the town of Manhao, south of Gejiu, between 700 and 1,120 m, is stated in the protologue to be kept at the forestry institute in Chengdu; Hill (2008) and The World List of Cycads cite a holotype at the herbarium of the South China Botanical Garden (IBSC). This discrepancy could not be resolved.

Hill (2008) places the species in section Stangerioides: soft male cones, yellow seeds with a non-fibrous, freely peeling flesh and a warty shell. He puts it in a subgroup with a robust aerial trunk, together with Cycas taiwaniana, Cycas hainanensis and Cycas dolichophylla. He reduced Cycas parvula to synonymy after studying an isotype and living plants, along with Cycas pectinata subsp. manhaoensis, already treated as a synonym by Guan and Tao. Liu, Zhou and Gong (2015) added Cycas multiovula. Zheng and colleagues (2017) therefore speak of a “Cycas diannanensis complex”.

Etymology and history

According to Haynes (2022), cited by The World List of Cycads, and to Hill (2008), the epithet refers to Diannan, in Gejiu district (Yunnan). The protologue gives the Chinese name 滇南苏铁; since 滇 is the usual abbreviation for Yunnan and 南 means “south”, the name can also be read as “cycad of southern Yunnan”, but no published source comments on this.

The 1995 description is short: it compares the species with Cycas taitungensis and Cycas taiwaniana and calls it rare and “in urgent need of protection”. The two other names of the complex were published the following year in the collective work Cycads in China. No published source covers the species’ introduction into cultivation in the West. Montgomery Botanical Center, in Florida, holds accessions whose numbers point to 1994 and 1995, and seed sold as “Mountain form” was circulating among French amateurs by 2008 (see Growing).

Common names

No English common name is attested: the British nursery Trebrown gives “None known”. The Chinese name given by the authors is 滇南苏铁 (diannan sutie).

In the wild

Cycas diannanensis is widespread in central and eastern Yunnan, along the Red River valley (Hong He), from Hekou to Shuangbai (Hill 2008). It grows on a range of substrates, from limestone to schist, usually on steep slopes high on ridges, between about 600 and 1,800 m. Its original vegetation is closed evergreen cloud forest, now often reduced to secondary grassland or scrub. Liu, Zhou and Gong (2015) studied 15 populations between 900 and 2,000 m, in the districts of Chuxiong, Shuangbai, Nanhua, Xinping, Gejiu, Yuanjiang and Yuanyang.

The protologue describes the type locality, at Manhao, as steep limestone mountains between the Lüshui and Qingshui rivers, at 700 to 1,120 m, with Woodfordia fruticosa and Imperata cylindrica var. major. It gives coning in January and February and seed ripening in November and December. The World List of Cycads mentions a doubtful presence in northern Vietnam.

Genetics shows low diversity and a long decline, which began during the Quaternary glaciations. The populations fall into two geographical groups, and those downstream, with the most distinctive haplotypes, should be protected first (Liu, Zhou and Gong 2015). No climate data for the species’ localities is published.

Conservation status and regulation

The IUCN lists Cycas diannanensis as Endangered (EN B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)), in the assessment by J. D. Bösenberg published in 2023. These criteria mean a restricted extent of occurrence and area of occupancy, fragmented or few populations, and a continuing decline in range, habitat, number of populations and number of mature plants (category checked through GBIF and The World List of Cycads). The previous assessment, by K. D. Hill, dates from 2010. Hill (2008) considered the species “moderately abundant over a considerable area”, but with many depleted populations.

Liu, Zhou and Gong (2015) cite habitat fragmentation, ploughing and grazing as threats. Zheng and colleagues (2017) report protected populations in the Dawei Shan nature reserve, in a reserve in Yuanjiang district and, under the name Cycas parvula, in other reserves of Honghe; they also note very small populations near Majie and the Huashiban hydroelectric station, which they attribute to ineffective management and trade.

In China, all Cycas species are in the first class of the 2021 national list of protected wild plants. Like the whole family Cycadaceae, the species has been listed in CITES Appendix II since 4 February 1977, with annotation #4 (CoP20 version, in force since 5 March 2026): seeds, pollen and seedlings in sterile containers are not covered by CITES. 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 are set by Commission Regulation (EU) 2026/1383, applicable since 29 June 2026. Databases consulted on 19 October 2026: check the rules in force before any purchase, and prefer plants raised from seed in cultivation.

Growing Cycas diannanensis

In short: still rare in cultivation, with no published growing guide; the general rules for Cycas apply, and its tolerance of cold is not established.

Outdoor and in-ground cultivation

No source describes its cultivation in detail. Without specific data, the general rules for cycads apply: a very free-draining soil, sun or bright light, watering during growth and a drier soil in winter. In the wild it receives mostly summer rain and grows on slopes where water does not lie; that is a deduction from its habitat, not a growing result. On the French Riviera, the plant shown above grows in the garden of the Serre de la Madone, in Menton; its age and winter behaviour are not documented. The Jardin zoologique tropical at La Londe-les-Maures, in the Var, has published no observation on the species. These Mediterranean sites are the closest European equivalents to coastal California or southern Australia, but no in-ground trial has been reported from either.

Seed sold under the label “Mountain form” was distributed in 2008 among members of the French forum Fous de palmiers: the seller presented it as coming from a high-altitude form collected between 1,200 and 1,800 m in the Red River valley. This is a sales argument with no taxonomic value, although it matches the published altitude range of the species.

Container cultivation

The few European growers who report on it keep it in a pot, under cover in winter. A grower in southern Vendée (France) who has kept it in a pot for several years reports slow but steady growth (2015) and has not yet dared plant it out. In the United Kingdom, a frost-free glasshouse or conservatory is the prudent choice until in-ground trials are published.

In cultivation in the UK, US and Australia

In short: present in a few American collections, rare elsewhere. 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 six accessions of Cycas diannanensis, whose numbers point to 1994, 1995 (three) and 2026, plus one older number whose year cannot be read, and two plants of 2003 entered as Cycas sp. (diannanensis). The Missouri Botanical Garden (St Louis), whose cycads are grown under glass, San Diego Botanic Garden, the San Diego Zoo, the Gardens of Golden Gate Park (San Francisco) and Mercer Arboretum and Botanic Gardens (Texas) list the species in BGCI PlantSearch.
  • United Kingdom: Glasgow Botanic Gardens list the species in BGCI PlantSearch; no other British garden does.
  • Australia: James Cook University, in Townsville, lists the species in BGCI PlantSearch; it does not appear in the online catalogues of the Royal Botanic Garden Sydney, Mount Annan or the Royal Botanic Gardens Victoria.

No dated report from a grower in the United Kingdom, the United States or Australia has been published. Two nurseries give USDA ratings, both commercial: zone 9b for Trebrown in Britain, zone 9a for the French nursery Cycadales.eu, which adds that damage may occur at higher temperatures.

Propagation

Cycas diannanensis is propagated from seed; a male and a female plant are needed, and in the wild the seeds ripen at the end of the year (November and December according to the protologue). A grower in Agen (Lot-et-Garonne, France) reports on the Fous de palmiers forum (2009) germination after about 60 days on a bed of sand, at 30 °C (86 °F) by day and 19 °C (66.2 °F) by night; another member of the forum obtained germination in 22 days (2008). A grower in Ravenna (Emilia-Romagna, Italy), on the Tropicamente forum (2009), ranks the species among the cycads that germinate easily, while reporting rotten seed elsewhere. No protocol specific to the species is published.

Pests and diseases

No pest or disease specific to Cycas diannanensis has been documented. Like other Cycas, it can host scale insects, including the Asian cycad scale, Aulacaspis yasumatsui, and it can rot in waterlogged soil: a risk known at the level of the genus.

Cold hardiness

No measurement of cold hardiness has been published for Cycas diannanensis. Its altitude, up to 2,000 m, suggests some tolerance of cold, but no climate data for its localities is published, and the few cultivation reports concern young plants.

The only dated reports come from France and Italy, a Mediterranean and Atlantic experience useful to readers in comparable climates:

  • a grower in Nantes (Loire-Atlantique, France) reports on the Fous de palmiers forum (September 2013) that their seedlings spent the winter of 2012-2013 in a polytunnel that fell to −4 °C (24.8 °F), under horticultural fleece, without damage;
  • a grower in Agen (Lot-et-Garonne, France) reports on the same forum (July 2012) the loss of all their young plants, about three years old, in the cold spell of winter 2012, without giving the temperature or the growing conditions;
  • a grower in Sabaudia (Lazio, Italy) reports on the Tropicamente forum in November 2011 that their Cycas diannanensis, like their Cycas panzhihuaensis and Cycas guizhouensis, had “no problems” at the −7 °C (19.4 °F) of the previous December, which killed many palms in the garden; neither the size of the plants nor any protection is stated.

A visitor also recorded the species at the Palermo botanic garden in December 2010 (Tropicamente). These are isolated reports, still to be confirmed. No adult plant growing in the ground is documented in Europe, and none in the United Kingdom: in Britain, keep it frost-free under glass.

Toxicity and precautions

No toxicity analysis specific to Cycas diannanensis 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 the sago palm (Cycas revoluta) among plants poisonous to dogs, cats and horses. Treat the plant as poisonous: keep seeds out of reach of children and pets, wear gloves to handle them and, if any part is swallowed, contact a poison centre, a doctor or a vet straight away.

Traditional uses

No traditional use specific to Cycas diannanensis is documented. Zheng and colleagues (2017) note only that Chinese cycads are grown as ornamentals and sold for medicinal uses, which contributes to the decline of wild populations.

Frequently asked questions

Where does Cycas diannanensis grow?

In China, in central and eastern Yunnan, along the Red River, on steep slopes between about 600 and 2,000 m. A presence in northern Vietnam is possible but unconfirmed.

Are Cycas parvula and Cycas multiovula the same plant?

Yes, in the taxonomy followed here. The World List of Cycads places them under Cycas diannanensis, following a 2015 genetic study. Note, however, that other sources still place Cycas multiovula under Cycas guizhouensis.

How can it be recognised?

By its narrow, spiny cataphylls 12 to 20 cm long, its very long glossy leaves and its flat leaflets 9 to 16 mm wide. The male cones are more than 50 cm long.

Is it frost-hardy?

Nobody really knows. Seedlings came through −4 °C (24.8 °F) under fleece in Nantes, but others died in Agen in the winter of 2012; an Italian grower reports plants unharmed at −7 °C (19.4 °F), without giving their size.

Can it be grown outdoors in the UK?

There is no evidence that it can. No in-ground trial is documented in Britain or northern Europe; keep it in a pot for its first years and protect it from frost.

Is it endangered?

Yes. It is listed as Endangered (2023): its populations are fragmented, genetically poor and declining. It is protected in China and covered by CITES.

Is it poisonous?

It must be assumed so. There is no analysis for the species itself, but all the Cycas studied contain serious toxins, especially in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Guan, Z.T. & Tao, G.D. (1995). A preliminary report of new cycad from Yunnan [云南新种苏铁初报]. Sichuan Forestry Survey and Design 1995(4): 1. [Protologue, in Chinese with a Latin diagnosis: description, type, locality, phenology, comparison with Cycas taitungensis and Cycas taiwaniana.]
  • Hill, K.D. (2008). The genus Cycas (Cycadaceae) in China. Telopea 12(1): 71–118. doi:10.7751/telopea20085804 [Description, synonymy (Cycas parvula, subsp. manhaoensis), distribution, habitat, altitude, section, suspected hybrids; Cycas multiovula under Cycas guizhouensis.]
  • Chen, C.J. & Stevenson, D.W. (1999). Cycadaceae. In Wu, Z.Y. & Raven, P.H. (eds), Flora of China 4. Science Press, Beijing and Missouri Botanical Garden Press, St Louis. [Cycas diannanensis in the synonymy of Cycas taiwaniana; online version.]
  • Liu, J., Zhou, W. & Gong, X. (2015). Species delimitation, genetic diversity and population historical dynamics of Cycas diannanensis (Cycadaceae) occurring sympatrically in the Red River region of China. Frontiers in Plant Science 6: 696. doi:10.3389/fpls.2015.00696 [Cycas parvula and Cycas multiovula united with Cycas diannanensis, 15 populations and altitudes, genetic diversity, threats.]
  • 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 [“Cycas diannanensis complex”, reserves, state of populations, national protection.]
  • Bösenberg, J.D. (2023). Cycas diannanensis. The IUCN Red List of Threatened Species 2023: e.T42052A68899786. doi:10.2305/IUCN.UK.2023-1.RLTS.T42052A68899786.en [Current assessment (EN); reference checked on Crossref.]
  • Hill, K.D. (2010). Cycas diannanensis. The IUCN Red List of Threatened Species 2010: e.T42052A10639287. doi:10.2305/IUCN.UK.2010-3.RLTS.T42052A10639287.en [Previous assessment; reference checked on Crossref.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. doi:10.11646/phytotaxa.550.1.1 [Etymology; used through 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.]