Encephalartos transvenosus

Encephalartos transvenosus, the Modjadji cycad, is a large tree-like cycad from north-eastern South Africa, where it grows in the mist belt of the Soutpansberg mountains and the Letaba district, in Limpopo province. It is the most imposing species of the genus Encephalartos in southern Africa: its trunk commonly reaches 5 to 8 m and, exceptionally, about 13 m. It is famous for the true cycad forest it forms on the hills of Modjadji, near the former Duiwelskloof (now Modjadjiskloof), long protected by the Rain Queens of the Lovedu people. Assessed as Near Threatened by the IUCN, it is reputed to be one of the fastest-growing cycads in cultivation, but it comes from a frost-free region and only suits the mildest climates outdoors.

Key facts about Encephalartos transvenosus

  • Accepted name: Encephalartos transvenosus Stapf & Burtt Davy (1926), accepted by The World List of Cycads (version 2026.08.15), GBIF and Species+
  • Synonyms: none; Hutchinson and Rattray (1933) had reduced it to Encephalartos altensteinii
  • Family: Zamiaceae, order Cycadales
  • Common names: Modjadji cycad (PlantZAfrica, Species+); Modjadji broodboom in Afrikaans (PlantZAfrica)
  • Natural range: South Africa, Limpopo province (Soutpansberg and Letaba district), between 600 and 1,000 m
  • IUCN status: Near Threatened (NT B1b(iii,v)+2b(iii,v)), assessment by J.D. Bösenberg dated 27 April 2020 and published in 2022
  • CITES and other protection: CITES Appendix I since 1977, like the whole genus; Annex A in the European Union, with a positive EU opinion (2011) for artificially propagated plants from South Africa with a caudex up to 15 cm in diameter
  • Documented hardiness: frost-free region of origin (PlantZAfrica); a young potted plant came through −5 °C (23 °F) in Brittany, north-west France, in February 2012; a Californian nursery claims an absolute limit of about −5 to −5.6 °C (22 to 23 °F) (see Cold hardiness)
  • Light and soil: full sun or light shade, sheltered from the prevailing winds; well-drained soil, regular watering in the dry season (PlantZAfrica)
  • Habit and adult size: trunk usually 5 to 8 m tall and 40 to 65 cm in diameter, up to about 13 m; leaves 1 to 2.5 m long (Dyer, 1965; PlantZAfrica)
  • In the UK, US and Australia: Kew, the Royal Botanic Garden Edinburgh and the Eden Project (BGCI); the Montgomery Botanical Center (five accessions), Fairchild, the Huntington, Lotusland, the Missouri Botanical Garden and some fifteen other American gardens; Royal Botanic Gardens Victoria (outdoor bed in Melbourne) and Adelaide in Australia
  • Toxicity: seeds toxic, as in all cycads (see Toxicity and precautions)

How to recognise Encephalartos transvenosus

It is a giant Encephalartos, with a tall, rarely branched trunk crowned with long, glossy dark green leaves whose leaflets spread from the rachis and then curve backwards. R.A. Dyer (1965) describes it as follows, completed by PlantZAfrica:

  • Trunk: single or sometimes branched, often 5 to 8 m tall and 40 to 65 cm in diameter, reaching about 13 m in exceptional cases; crown with woolly brown hairs; many dormant buds appear at the base of the trunk (PlantZAfrica);
  • Leaves: 1 to 2.5 m long (1.5 to 2.5 m on adults according to PlantZAfrica), fairly straight or slightly curved towards the tip, hairy at first, then hairless; young leaves light green, covered with fine brown hairs, adult leaves dark green and glossy;
  • Leaflets: the median ones spread almost at right angles from the rachis, then curve progressively backwards, sometimes slightly sickle-shaped, 10 to 20 cm long (16 to 25 cm according to PlantZAfrica) and 2 to 3.5 cm wide (up to 4.5 cm), usually toothed on both margins towards their base; they overlap; towards the base of the leaf, they are reduced to a few prickles;
  • Male cones: two to four together, almost cylindrical, 30 to 40 cm long and 13 to 15 cm in diameter, rounded at the top, the face of the scales extended into a beak 1 to 1.5 cm long;
  • Female cones: two to four together, more or less ovoid, 50 to 80 cm long and 20 to 30 cm in diameter, with wrinkled or almost smooth scales projecting about 2.5 cm; Dyer gives their weight as about 75 lb (34 kg) when ripe, PlantZAfrica more than 40 kg; they are golden brown and appear at the end of the southern summer;
  • Seeds: red, 4 to 5.5 cm long and about 2.5 cm in diameter.

For PlantZAfrica, the backward curve of the leaflets is one of the distinguishing features; Dyer adds the size, unmatched among the cycads of southern Africa. Jungle Music, a nursery in southern California, also describes two-toned leaflets, dark green above and light lime green beneath, with up to ten teeth that are not very rigid, and yellow male cones.

Hybrids

No natural hybrid of Encephalartos transvenosus has been described. In cultivation, hybrids obtained by cross-pollination circulate among collectors: on the French Fous de palmiers forum, one grower showed a seedling of Encephalartos transvenosus × Encephalartos latifrons in 2013 and 2014, and another reported in 2015 hybrids of Encephalartos transvenosus with Encephalartos woodii that look like the latter. The Huntington, in California, declares an Encephalartos transvenosus × woodii hybrid to BGCI. As with other Encephalartos, a plant raised from collection seed is therefore not necessarily pure.

Possible confusion

The closest species is Encephalartos paucidentatus, described in the same 1926 publication, which grows further south, near Barberton (Mpumalanga) and in Eswatini. According to Dyer (1965) and PlantZAfrica, they can be told apart as follows:

  • Leaflets: curved backwards from the rachis and proportionately broader in Encephalartos transvenosus; straight or slightly sickle-shaped, and narrower, in Encephalartos paucidentatus;
  • Veins: Encephalartos paucidentatus has some twenty to thirty prominent longitudinal veins on the underside of the leaflets, which Encephalartos transvenosus lacks;
  • Size: Encephalartos paucidentatus hardly exceeds 6 m, whereas many Encephalartos transvenosus are taller.

Dyer notes that confusion is most likely at intermediate heights, before the plants reach their adult size. The other related species is Encephalartos altensteinii, from the Eastern Cape and KwaZulu-Natal, to which Hutchinson and Rattray had reduced it in 1933. Henderson (1945) acknowledged a general resemblance of the leaves, but in Encephalartos transvenosus the leaflets are broader, abruptly narrowed at the base, inserted almost at right angles on the rachis rather than in a V, less clearly veined beneath, and those at the base of the leaf are reduced to prickles; the beaks of the male cone scales all point downwards, whereas only those at the top and bottom of the cone do so in Encephalartos altensteinii. Dyer (1965) uses the same criterion of the basal leaflets reduced to prickles.

Taxonomy

Encephalartos transvenosus was described in 1926 by Otto Stapf and Joseph Burtt Davy in the first part of Burtt Davy’s Manual of the flowering plants and ferns of the Transvaal with Swaziland (pages 40 and 99, figure 4b), together with Encephalartos paucidentatus (figure 4a). The type is a collection by Burtt Davy (no. H3086) made in 1906 from the Modjadji mountains, in the former Zoutpansberg district, and cultivated at Tzaneen; the holotype is kept in Pretoria (PRE), with isotypes at Kew (K) and the Compton Herbarium (NBG), according to The World List of Cycads.

In the Flora Capensis (1933), Hutchinson and Rattray reduced it to a synonym of Encephalartos altensteinii. Henderson (1945) reinstated it as a species, judging it “sufficiently distinct in foliage, cones and habitat”; he also thought that plate 7162 of Curtis’s Botanical Magazine, published as Encephalartos altensteinii, rather showed Encephalartos transvenosus. Dyer (1965) and all current checklists treat it as a separate species, and The World List of Cycads records no synonym: the species has never changed name, but old plants may appear in collections or herbaria under the name Encephalartos altensteinii.

Etymology and history

The epithet comes from the Latin trans (“across”) and venosus (“veined”), in reference to the “transverse veinlets” said to link the longitudinal veins of the leaflets (Haynes, 2022, via The World List of Cycads). PlantZAfrica, and Palmer and Pitman (1972, quoted by the Gymnosperm Database), describe a network of fine veins visible when a leaflet is held up against the light. Haynes calls these veinlets “purported”, and Dyer stresses that the leaflets have no prominent veins beneath.

The history of the species is bound up with that of the Rain Queens (Modjadji) of the Lovedu people, north-east of Tzaneen. Dyer (1965) reports that the species enjoys “royal protection” there and forms, uniquely in southern Africa, a true forest: plants are counted “in thousands” on the hills near the royal kraal, and damaged trunks are the exception, whereas elsewhere cycad trunks often bear the marks of harvesting by traditional healers. He adds that it is not known how long this protection has been in force, but that it no doubt explains the density of the population. PlantZAfrica writes that the Rain Queens have protected this locally common species “for centuries”, and Palmer and Pitman (1972) describe a pure forest on two hills, “the only cycad forest in southern Africa”. The site is now the Modjadji Nature Reserve, where a community nursery raises plants from seed collected on the spot (Donaldson, 2003).

Common names

In English, PlantZAfrica and Species+ use “Modjadji cycad”; Palmer and Pitman (1972) also give “Modjadji’s palm”, and Dyer (1965) notes the use of “Modjadji Palm”; Jungle Music writes “Modjaji cycad”. In Afrikaans, PlantZAfrica gives “Modjadji broodboom”, “Modjadji bread tree”, broodboom being the Afrikaans name for Encephalartos, from which a meal was once made.

In the wild

Encephalartos transvenosus is endemic to Limpopo province, South Africa, according to The World List of Cycads; Henderson (1945) extended its range to the Lydenburg district (eastern former Transvaal) on the strength of a herbarium collection, which neither Dyer nor the current checklists follow. It grows in the mist belt of the Soutpansberg mountains and the Letaba district (Dyer, 1965), between 600 and 1,000 m above sea level, in a region that receives more than 1,500 mm of rain a year, where frequent mists bring cool, humid summers, and that is frost-free (PlantZAfrica). The PlantZAfrica page places the Letaba district in Mpumalanga, whereas its own attributes and The World List of Cycads place it in Limpopo. Jungle Music gives altitudes of 600 to 1,500 m.

As with other Encephalartos, ripe female cones attract animals: according to PlantZAfrica, porcupines can ring-bark trunks and strip the cones, baboons break off immature cones, and the caterpillars of the leopard magpie moth eat the young leaves; seed-eating weevils can destroy an entire seed crop. The fleshy coat of the seeds is eaten by squirrels, baboons, monkeys, dassies (rock hyraxes) and birds (louries, parrots, trumpeter hornbills), which discard the seed itself.

Conservation status and regulation

Encephalartos transvenosus is assessed as Near Threatened (NT) on the IUCN Red List, under criteria B1b(iii,v)+2b(iii,v), which reflect a restricted range in which habitat quality and the number of mature individuals are declining. The assessment, by J.D. Bösenberg, is dated 27 April 2020 and was published in 2022 (The World List of Cycads, GBIF, Crossref). In 2003 the IUCN cycad action plan (Donaldson, 2003) still classed it as Least Concern, with 20,000 to 50,000 plants, a population in a reserve, a slight decline and minor habitat loss; PlantZAfrica (2005) described it as not threatened.

The main threat documented since then is a disease: Nesamari, Coutinho and Roux (2017) identified the oomycete Phytophthora cinnamomi on dead Encephalartos transvenosus in the Modjadji Nature Reserve, and experimental inoculations reproduced the symptoms, making it very probably the cause of these deaths.

Regulation, according to Species+ (consulted through its public API on 26 October 2026):

  • CITES: Appendix I since 4 February 1977, like the whole genus;
  • European Union: Annex A, current list in Regulation (EU) 2026/1383 (in force since 29 June 2026); for artificially propagated plants from South Africa (source codes A and D), a negative EU opinion covering the whole genus, issued on 3 December 2010, was lifted on 11 March 2011; a positive opinion specific to the species, limited to plants with a caudex up to 15 cm in diameter, has applied since 20 June 2011, and a new consultation on the whole genus has been open since 16 September 2026;
  • South Africa: the collection of wild cycads (plants and seeds) has been prohibited since 2012, except for conservation purposes (Government Notice no. 371, cited by SANBI’s non-detriment finding for Encephalartos horridus).

Seeds are covered in the same way as plants. Any plant offered for sale must come from cultivation and carry the CITES documents required by the countries concerned (and, in the European Union, the EU documents). These notes do not replace the official texts: check Species+ and the national authorities before any purchase or import.

Growing Encephalartos transvenosus

This is a cycad for mild climates and, for the genus, a fast grower. According to PlantZAfrica, a seedling becomes a decorative plant with leaves about 1 m long in four to five years, and the species responds well to cultivation in frost-free areas, with regular watering in the dry months. PlantZAfrica recommends it for South Africa’s frost-free coastal zones, in both summer- and winter-rainfall regions, and for the bushveld zone with light frost.

Outdoor and in-ground cultivation

PlantZAfrica’s advice:

  • Position: full sun or light shade, in a place sheltered from the prevailing winds; in very hot areas, protection from the sun prevents leaf scorch;
  • Soil: good drainage is essential;
  • Watering: regular during the dry season; irrigation systems can be harmful, both through the pressure of the water on leaves and trunk and through overwatering;
  • Transplanting: adult plants transplant easily, preferably with all their leaves removed beforehand, which makes handling easier and reduces water loss;
  • Space: allow room for a tree, as the crown can spread over 5 m.

Jungle Music, at Encinitas near San Diego, finds it more tolerant of soil moisture than some Encephalartos; on the coast it takes full or part-day sun, and in desert areas it should be grown in filtered light. The nursery adds that leaves are shorter in bright sun, that plants usually produce one flush of leaves a year, and that they can form offsets while usually keeping one main stem.

Container cultivation

Young plants can be grown in containers and later planted out (PlantZAfrica); Jungle Music writes that it can easily be grown on a patio given enough light. The plant soon outgrows its pot, which mainly serves to shelter it in winter where frosts occur. In France, a grower at Concarneau (Finistère, Brittany) reported on the Fous de palmiers forum that in 2011 his young potted Encephalartos transvenosus had produced two leaves, whereas his other recently planted Encephalartos had produced none.

In cultivation in the UK, US and Australia

BGCI PlantSearch lists 54 institutions holding the species. In the United Kingdom, Kew, the Royal Botanic Garden Edinburgh and the Eden Project in Cornwall declare it; no source says whether it grows in a glasshouse or a biome. In the United States, the Montgomery Botanical Center (Coral Gables, Florida) lists five accessions in its online catalogue, two of whose numbers point to the early 1960s; BGCI also lists Fairchild, the Huntington, Lotusland, the Los Angeles County Arboretum, Descanso Gardens, the San Diego Botanic Garden, the San Diego Zoo and its Safari Park, the Cal State Fullerton Arboretum, UC Berkeley, the Missouri Botanical Garden, the United States Botanic Garden, the Marie Selby and Naples gardens in Florida and several Hawaiian gardens. In Australia, Royal Botanic Gardens Victoria grows it in an outdoor bed at Melbourne Gardens according to its living collection census, and the Adelaide Botanic Garden declares it. A BGCI listing records a declaration by the garden, not a living plant on display today. In Italy, the Naples botanic garden grew two specimens in 1993–1994 (Gaudio et al., 1997), and the Messina botanic garden listed the species in 2009. In a tropical climate, by contrast, the Nong Nooch Tropical Botanical Garden in Thailand finds that the species does poorly, growing slowly and producing no cones, which the garden attributes to the lack of cool winter weather (Lindstrom, CYCADS, 2022). Jungle Music describes the species as rare but affordable for a South African cycad, and usually has it in sizes from seedlings to coning specimens.

Propagation

Propagation is mainly from seed. The species being dioecious, a male and a female plant must cone at the same time, or the cones must be hand-pollinated. In the Modjadji reserve, a community nursery raises plants from seed collected on the spot (Donaldson, 2003). On the Fous de palmiers forum, a grower pointed out in 2013 that in some species, including Encephalartos transvenosus, unfertilised seeds still colour up: colour is therefore no guarantee that an embryo is present. For sowing, see the article on growing cycads from seed.

The many dormant buds at the base of the trunk (PlantZAfrica) and the offsets that some plants produce (Jungle Music) also allow vegetative propagation, but no published source gives a method specific to the species.

Pests and diseases

The best documented disease is the rot caused by Phytophthora cinnamomi, identified on dead plants in the Modjadji reserve (Nesamari et al., 2017). The same study recorded on cultivated Encephalartos in Gauteng and Limpopo, all species together, the weevil Amorphocerus talpa and several scale insects and mealybugs, including Aonidiella aurantii, Pseudaulacaspis pentagona and Pseudococcus longispinus. PlantZAfrica cites, for the species, the caterpillars that eat the young leaves and the seed weevils. In cultivation, a well-drained soil and avoiding overwatering are the best prevention against rot.

Cold hardiness

Encephalartos transvenosus comes from a frost-free region, and PlantZAfrica recommends it for frost-free or lightly frosted horticultural zones. No published data allow a cold limit to be set for an adult plant in the ground. As with all Encephalartos, survivals in cold areas often concern young plants whose caudex is still underground, protected by the thermal inertia of the soil; an adult plant with an aerial trunk does not benefit from this protection.

Mediterranean and European experience

  • Brittany (north-west France, mild oceanic climate): a grower at Concarneau reported on the Fous de palmiers forum in January 2009 that his Encephalartos transvenosus had “felt the cold a little” at −4 °C (24.8 °F) in winter 2007–2008, without describing the damage, and that he had then put it in a pot; he brought it indoors in winter 2008–2009, so that it escaped the −5 to −6 °C of that winter. In April 2012 the same grower reported that this small plant, in a pot for five years and left outdoors during the cold spell of February 2012, when his garden fell to −5 °C (23 °F), had stood up “very, very well”, with only a slight yellow tinge on the leaves.
  • Mediterranean coast: no result is documented, in France or in Italy. The Jardin zoologique tropical in La Londe-les-Maures (Var, south-east France) received a plant from a French nursery in 2014, with the CITES formalities handled through the regional environment authority (DREAL Provence-Alpes-Côte d’Azur), but no temperature record has been published for it.

These observations concern a young plant in a mild oceanic climate; they say nothing about the hardiness of an adult. For readers in comparable climates, such as coastal California or southern Australia, a very well-drained soil and a sheltered position are essential, and a large container overwintered frost-free remains the safe option wherever frosts are regular.

United Kingdom, United States and Australia

  • United States: Jungle Music writes that the species “easily withstands a freeze” and claims an absolute cold tolerance of about −5 to −5.6 °C (22 to 23 °F); this is a nursery’s rating, not accompanied by dated observations.
  • Australia: a plant grows in an outdoor bed in Melbourne (Royal Botanic Gardens Victoria census), without published winter data.
  • United Kingdom: no source says whether the plants declared by Kew, Edinburgh and the Eden Project grow under glass or outdoors, and no outdoor result is documented.

No USDA hardiness zone is documented for Encephalartos transvenosus in a botanical source.

Toxicity and precautions

Like other cycads, Encephalartos transvenosus contains toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived, a toxin affecting the liver and the nervous system; the seeds are the most dangerous part. According to Palmer and Pitman (1972), the children of Modjadji used to eat the thin ripe flesh around the seed; this account does not make the plant safe. Wear gloves to handle the seeds, and keep plants and seeds out of reach of children and pets. If any part is swallowed, contact a poison centre, a doctor or a vet without delay.

Traditional uses

PlantZAfrica recalls that the pith of cycad trunks was once removed, wrapped in an animal skin, fermented and ground into a meal used to make bread, hence the Afrikaans name broodboom; the page does not say whether this use concerned this species in particular. Dyer (1965) notes that, away from Modjadji, cycad trunks often bear the marks of harvesting by traditional healers. No other use specific to the species is described.

Frequently asked questions

Is Encephalartos transvenosus frost-hardy?

Only slightly. It comes from a frost-free region; a young potted plant came through −5 °C (23 °F) at Concarneau, in Brittany, in February 2012, but no measurement exists for an adult plant in the ground. Outdoors, it should be tried only in the mildest climates, in a very free-draining soil.

Is it the tallest Encephalartos?

It is the tallest in southern Africa. Dyer (1965) describes it as the most majestic species of the region, up to about 13 m, and PlantZAfrica counts it among the tallest of all cycads; most plants, however, are 5 to 8 m tall.

How can it be told from Encephalartos paucidentatus?

By its leaflets. Those of Encephalartos transvenosus are broader and curve backwards; those of Encephalartos paucidentatus are straight and carry some twenty prominent veins beneath.

Does it grow fast?

Yes, for a cycad. According to PlantZAfrica, a seedling becomes a plant with leaves about 1 m long in four to five years.

What is the Modjadji forest?

A natural forest of Encephalartos transvenosus on hills near Modjadjiskloof, protected by the Rain Queens of the Lovedu people. Dyer counted the plants in thousands; it is now a nature reserve.

Can it be grown in a pot?

Yes, while young. PlantZAfrica advises growing it in a container before planting it in the garden; the pot allows it to be sheltered in winter, but the plant soon becomes too large to stay in it.

Is it poisonous?

Yes, especially its seeds, like all cycads.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Burtt Davy, J. (1926). A manual of the flowering plants and ferns of the Transvaal with Swaziland, South Africa, part I: 40, 99, fig. 4b. Longmans, Green & Co., London. [Protologue, with O. Stapf; cited by The World List of Cycads and Dyer (1965).]
  • Hutchinson, J. & Rattray, G. (1933). Cycadaceae. Flora Capensis 5(2): 24–44. [Treatment as a synonym of Encephalartos altensteinii (p. 39), cited by Henderson (1945) and The World List of Cycads.]
  • Henderson, M.R. (1945). Materials for a revision of the South African species of Encephalartos. Journal of South African Botany 11: 3–65. [Reinstatement of the species, distinction from Encephalartos altensteinii, collections, description (pp. 45–47); digitised text.]
  • Dyer, R.A. (1965). The cycads of southern Africa. Bothalia 8: 405–515. [Key, description, distribution, Modjadji forest, distinction from Encephalartos paucidentatus.]
  • Palmer, E. & Pitman, N. (1972). Trees of Southern Africa. Balkema, Cape Town. [Modjadji forest, names, seeds; quoted by the Gymnosperm Database.]
  • Osborne, R. (1989). Focus on Encephalartos transvenosus. Encephalartos 20: 10–18. [Journal of the Cycad Society of South Africa, members only.]
  • Grobbelaar, N. (1999). Coning frequency, gender ratio, and pollination of Encephalartos transvenosus (Zamiaceae) at the Modjadji Nature Reserve, South Africa, and the germination of this cycad’s seed. In: Chen, C.-J. (ed.), Biology and Conservation of Cycads. Academic Publishers, Beijing. [Cited by Donaldson (2003).]
  • Donaldson, J.S. (ed.) (2003). Cycads. Status Survey and Conservation Action Plan. IUCN/SSC Cycad Specialist Group, Gland and Cambridge. [Status table, Modjadji community nursery.]
  • Gaudio, L., Aceto, S., Caputo, P., Cozzolino, S., Siniscalco Gigliano, G., Moretti, A. & De Luca, P. (1997). Enzyme polymorphism in Encephalartos Lehmann (Zamiaceae). Delpinoa n.s. 35–36 (1993–1994): 55–64. [Specimens grown in Naples.]
  • Nesamari, R., Coutinho, T.A. & Roux, J. (2017). Investigations into Encephalartos insect pests and diseases in South Africa and identification of Phytophthora cinnamomi as a pathogen of the Modjadji cycad. Plant Pathology 66: 612–622. doi:10.1111/ppa.12619
  • Lindstrom, A. (2022). The cycad collection at Nong Nooch Tropical Botanical Garden, Thailand. CYCADS 6(1): 5–9. IUCN/SSC Cycad Specialist Group. [Growing Encephalartos in a tropical climate.]
  • Bösenberg, J.D. (2022). Encephalartos transvenosus. The IUCN Red List of Threatened Species 2022: e.T41945A51044061. [Assessment cited by The World List of Cycads and Crossref.]
  • Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31. [Etymology, via 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; consulted.]