In May 1954, Joy Adamson — the Austrian-born naturalist and author who would later become world-famous for Born Free, her account of raising and releasing the lioness Elsa — was exploring the Matthews Range in Kenya’s Rift Valley Province when she collected a cycad specimen from the slopes of Mount Lololokwe, at approximately 2100 m elevation. Three years later, Ronald Melville at Kew described it as Encephalartos tegulaneus — a new species, and the largest Encephalartos in East Africa. With trunks reaching 7–10 m in height and up to 1 m in diameter, fronds exceeding 3 m in cultivation, and massive golden-yellow cones, Encephalartos tegulaneus is a genuine tree cycad — a plant so large and so palm-like in silhouette that it has been repeatedly mistaken for a palm by casual observers. It is not a palm. It is something far older: a gymnosperm, a living fossil, a member of a lineage that predates the flowering plants by 150 million years.
For the gardener with the space, the climate, and the patience, Encephalartos tegulaneus offers something extraordinary: one of the most spectacular cycads on Earth, a species that combines the stature of a palm with the primeval architecture of a cycad, and that — unlike many rare Encephalartos — adapts well to cultivation and grows with genuine vigour once established.
Taxonomy and nomenclature
Encephalartos tegulaneus Melville was described in 1957 in the Kew Bulletin, based on Joy Adamson’s 1954 collection from Mount Lololokwe in the Matthews Range, about 35 miles north of Isiolo, Kenya, at 7000 feet (approximately 2130 m). The holotype is deposited at Kew (K), with isotypes at Berlin (B), Brussels (BR), and the East African Herbarium (EA).
The epithet tegulaneus is derived from the Latin tegula (tile), referring to the overlapping microsporophylls (pollen-bearing cone scales) that resemble the overlapping tiles on a roof — a character visible when the male cones are examined closely and that distinguishes the species from the smoother-scaled cones of related East African species.
Two subspecies are recognised:
Encephalartos tegulaneus subsp. tegulaneus
Encephalartos tegulaneus subsp. tegulaneus — the nominate subspecies, from the Matthews Range (Ndoto, Warges, and Lololokwi Hills) and near Barsaloi in the Rift Valley Province of central Kenya. This is the large, widespread form with an estimated population of 5000–10 000 mature individuals. It is assessed as Least Concern (LC) on the IUCN Red List — one of the very few Encephalartos not currently considered threatened. The remote, inaccessible terrain of the Matthews Range provides natural protection, and populations appear stable.
Encephalartos tegulaneus subsp. powysii
Encephalartos tegulaneus subsp. powysii Miringu & Beentje — described in 1999 from a single hill in the Meru District of central Kenya (near Mount Kenya). This subspecies was first observed by a local administration officer in the 1950s but remained unknown to science until 1989, when Henk Beentje made the first incomplete collections. It was named for Gilfrid Powys, a former District Officer and avid plantsman who brought the population to scientific attention. Subsp. powysii differs from the nominate form in cone scale morphology and is known from only a single hill — it is assessed as Critically Endangered (CR) and is threatened by illegal collection of seedlings by cycad enthusiasts. The contrast between the two subspecies — one Least Concern, the other Critically Endangered — illustrates how dramatically conservation status can vary within a single species depending on population size and accessibility.
Encephalartos tegulaneus belongs to the East African complex of large, green-leaved Encephalartos that also includes Encephalartos hildebrandtii, Encephalartos kisambo, Encephalartos bubalinus, Encephalartos gratus, and Encephalartos sclavoi. It shares characters with all of these but is distinguished by its combination of extreme size (the tallest in the complex), tile-like microsporophylls, and montane habitat at 1200–2300 m.
Common names: Kenyan giant cycad (English).
Morphological description
Habit and caudex: Encephalartos tegulaneus is the largest Encephalartos in East Africa and one of the largest in the genus. The trunk is very large, usually unbranched, erect (sometimes becoming procumbent in the oldest specimens), reaching 7 m in height and 50 cm in diameter as a standard — but exceptional specimens have been recorded at 10 m in length and 60–100 cm in diameter. The trunk is covered in persistent leaf scars and narrows slightly toward the crown. In its natural habitat, the silhouette is strikingly palm-like — a tall, columnar trunk topped by a dense rosette of long, pinnate fronds. It is not surprising that the species has been mistaken for a palm by non-botanists; the resemblance is remarkably close until one examines the reproductive structures.
An extraordinary ethnobotanical detail: in some communities within the species’ range, the trunks have been hollowed out and used as cattle drinking troughs. This destructive practice demonstrates both the massive size of the trunks and the economic pressures on rural communities that coexist with the species.
Leaves: Fronds are 1.2–1.8 m long in wild specimens, but can reach up to 3 m in cultivation under optimal conditions — one of the most dramatic responses to garden culture observed in any Encephalartos. The fronds are oblanceolate (widest above the middle, tapering gradually toward the base), light green to bright green or blue-green, semi-glossy, and flat in cross-section (opposing leaflets inserted at 180° on the rachis — not keeled). The rachis is distinctly grooved between the leaflets. The petiole is 15–20 cm long. The indumentum (woolly covering) of the cataphylls and petiole bases is buff-brown and softly woolly. Leaflets are oblong-lanceolate, 16–22 cm long and 1.6–2.8 cm wide, rigid, leathery, with a pungent (sharp-pointed) apex. Leaflet margins are reflexed (turned downward) and edentate (without teeth) or with 1–3 teeth on the upper side near the base. The lower surface is distinctly striate, with 26–40 parallel nerves — a useful diagnostic character. Lower leaflets progressively reduce in size toward the petiole base, becoming spiny and eventually trifurcate (three-pronged) near the petiole — the armed petiole and lower leaflets make handling mature fronds an unpleasant experience.
The crown typically holds many fronds, forming a dense, bowl-shaped or umbrella-shaped rosette that faces inward — LLIFLE describes the crown as “grey green, about 1.2–2 m long and form[ing] a bowl-shaped, inward-facing leaf crown.” This bowl-shaped crown is a distinctive silhouette character: from a distance, the living fronds form a dense, concave dome atop the trunk, quite different from the flat or convex crowns of most South African species.
Reproductive structures: Male cones are produced 3–6 per stem, subcylindrical to fusiform, bright yellow to creamy yellow, 40–50 cm long and 12–14 cm in diameter, on peduncles up to 20 cm long. The microsporophylls overlap like roof tiles — the diagnostic character that gives the species its name. Female cones are produced 1–4 per stem, ovoid, golden yellow to orange, 40–70 cm long and 19–30 cm in diameter — among the largest and most impressive female cones in the genus. Seeds are ovoid to oblong, with a yellow to orange sarcotesta. Reproduction in the wild is reportedly slow, with many seeds eaten by baboons or wild pigs. The estimated generation length is approximately 70 years — a sobering number that underscores the species’ vulnerability to any disruption of its reproductive cycle.
Distribution and natural habitat
Encephalartos tegulaneus is endemic to Kenya — the only Encephalartos restricted to Kenya alone (kisambo extends into Tanzania, and hildebrandtii spans both countries). The nominate subspecies (subsp. tegulaneus) occurs in the Matthews Range of the Rift Valley Province, in fairly remote and inaccessible terrain. The main populations are on the Ndoto, Warges, and Lololokwi Hills and near Barsaloi. Subsp. powysii is known from a single hill in the Meru District, near Mount Kenya.
The altitude range is 1200–2300 m — the broadest elevational range of any East African Encephalartos, spanning from the lower montane zone to near the upper limit of forest. The habitat is steep mountain slopes and exposed rock outcrops in two contrasting vegetation types: open bushland (savanna) with scattered cycads on rocky outcrops, and thick dry forest where the cycads grow as canopy or sub-canopy components. The substrate is rocky, well-drained, and mineral-rich.
The Matthews Range is a remote, rugged mountain block rising from the semi-arid Samburu lowlands of northern Kenya. It is sparsely populated, difficult to access, and has historically received limited botanical attention — Joy Adamson’s 1954 collection was one of the first scientific visits. This remoteness has been the species’ greatest protection: the inaccessible terrain makes large-scale collection logistically difficult (though not impossible), and the populations appear to be stable and not declining. The Matthews Range is also home to endemic birds, mammals, and other plants — it is a centre of endemism in its own right, though less well-known than the Eastern Arc Mountains to the south.
The climate at 1200–2300 m in the Matthews Range is equatorial montane: warm days (18–28 °C), cool nights (8–15 °C), with no true winter — temperature variation is diurnal rather than seasonal. Rainfall is moderate to high, falling in two seasons (long rains March–May, short rains October–December). Mist and cloud are frequent on the upper slopes. Frost is not recorded at the species’ sites, though the highest elevations (above 2000 m) may occasionally experience near-zero temperatures.
Conservation status
The conservation picture is unusual for an Encephalartos — split between secure and critical:
Subsp. tegulaneus: Least Concern (LC). The population is estimated at 5000–10 000 mature individuals across 6 locations. Populations appear stable, with no known decline. The remote, inaccessible terrain of the Matthews Range provides effective natural protection. This is one of only a handful of Encephalartos classified as LC — a remarkable status for a genus in which over 70 % of species are threatened.
Subsp. powysii: Critically Endangered (CR). Known from only a single hill in the Meru District. The population is small and declining due to illegal collection by cycad enthusiasts. The subspecies was described in 1999, and — as with Encephalartos hirsutus — the publication of its existence and location has attracted the attention of collectors. The IUCN assessment notes that “to protect this taxon from collection” the precise locality should not be disclosed publicly.
Additional threats to the species overall include habitat degradation from traditional stem-hollowing for cattle troughs (subsp. tegulaneus), honey gathering and small-mammal hunting in the forest habitat, and the general expansion of human activity into montane forest zones across East Africa. However, the core populations of subsp. tegulaneus remain large and intact — a genuinely positive conservation story in a genus where positive stories are rare.
Cold hardiness — the montane equatorial equation
Encephalartos tegulaneus grows at 1200–2300 m on the equator — a wide altitudinal range that implies a wide thermal tolerance. At the lower end (1200 m), temperatures are warm year-round (20–30 °C days, 12–18 °C nights). At the upper end (2300 m), temperatures are cooler (15–22 °C days, 5–10 °C nights), and near-zero temperatures are conceivable during exceptional cold events.
The cultivation sources are consistent:
LLIFLE: “Needs a moist, well-drained, frost-free position.” “Frost-free conditions” is emphasised.
Jungle Music (Phil Bergman, San Diego): Describes the species as growing well in the mild, frost-free climate of southern California.
Practical cold hardiness estimate: USDA Zone 10a (−1 to 0 °C) as a safe minimum for outdoor cultivation. Zone 9b (−1 to −4 °C) may be tolerable for brief events if the plant is dry, sheltered, and well-established — but this is extrapolation from habitat climate, not tested in cultivation. The species has no evolutionary exposure to sustained freezing. In Mediterranean climates with occasional light frost (Côte d’Azur, coastal California, coastal Portugal), outdoor cultivation in sheltered positions is realistic, with fleece protection on the coldest nights. In climates with regular frost, a large greenhouse or conservatory is required.
The high-altitude origin (to 2300 m) does provide a meaningful degree of cool tolerance — the species is adapted to nighttime temperatures of 5–10 °C, which means it will not suffer in an unheated but frost-free conservatory during a European winter. This is an advantage over the strictly lowland tropical species (hildebrandtii at 0–350 m) which may struggle in cool indoor conditions.
Cultivation guide
Difficulty: 2/5 — adaptable, vigorous, and rewarding. “One of the most spectacular of all cycad species and quite adaptable in cultivation” (LLIFLE).
Light: Full sun or shade — the species performs well in both. In its native habitat, it grows in open savanna outcrops (full sun) and in thick dry forest (shade). In cultivation, full sun produces stiffer, more compact fronds; shade produces longer, more graceful fronds (up to 3 m in cultivation, compared to 1.2–1.8 m in the wild). The choice depends on the aesthetic desired and the space available.
Soil: Well-drained, gritty, and fertile. The species responds well to rich soil — unlike the nutrient-shunning arid-habitat blues. A mix of loam, coarse sand, and compost in roughly equal parts provides an ideal growing medium. Excellent drainage is still required (no waterlogging), but the substrate can be richer and more moisture-retentive than for the South African arid species.
Watering: Regular and generous. The montane equatorial habitat receives moderate to high rainfall with no extreme dry season. In cultivation, water consistently throughout the year, reducing somewhat in the cooler months but never withholding completely. “Regular watering during the dry months” is emphasised by multiple sources. The species is more moisture-tolerant than most South African Encephalartos.
Feeding: Responds very well to regular fertilisation. Growth rate improves dramatically with balanced NPK and supplemental trace elements. Apply granular fertiliser in spring and feed through the growing season. Mulch with compost for additional organic nutrition.
Growth rate: Among the fastest in the genus. LLIFLE notes that seedlings develop into “an attractive garden plant with 1 m long leaves in four to five years.” After the initial slow seedling phase (the first 3–5 years), the species grows “more rapidly” and “responds well to cultivation.” In optimal conditions (warm, moist, well-fed, frost-free), the growth rate is described as competing with Encephalartos kisambo for the title of fastest-growing Encephalartos — high praise in a genus where most species are measured in millimetres per year.
Container culture: Practical when young, but the species’ ultimate size (trunk to 7–10 m, crown span to 5+ m, fronds to 3 m in cultivation) means that container culture is a temporary phase. Use deep, large containers to accommodate the taproot. Seedlings in 50-litre pots grow well for the first 5–10 years. Eventually, the species must be planted in the ground or in a very large raised bed if it is to reach anything approaching its potential.
Landscape use: In frost-free gardens, Encephalartos tegulaneus is a landscape plant of the first order. Its palm-like stature, massive crown, and vigorous growth make it suitable as a specimen tree, an avenue planting, or a focal point in a tropical or subtropical garden. It has the scale to anchor a landscape composition — something that few cycads outside the Lepidozamia and the largest Macrozamia can claim. Plant where it has unrestricted vertical and horizontal space, in a position that allows the full silhouette to be appreciated.
Comparison with other large East African Encephalartos
| Character | Encephalartos tegulaneus | Encephalartos hildebrandtii | Encephalartos kisambo |
|---|---|---|---|
| Distribution | Kenya only (Matthews Range) | Kenya / Tanzania coast | S. Kenya / N. Tanzania (hills) |
| Altitude | 1200–2300 m (widest range) | Sea level to 350 m | 800–1800 m |
| Trunk height | 7–10 m (tallest in E. Africa) | 8–10 m | 1.2–2.5 m |
| Trunk diameter | 50–100 cm | 40–60 cm | 45–70 cm (barrel-shaped) |
| Leaf length | 1.2–1.8 m (to 3 m in cultivation) | 3–6 m | 2.4–3.6 m |
| Leaf colour | Light green to blue-green | Green | Silvery-green to blue-green |
| Crown shape | Bowl-shaped, inward-facing | Spreading, open | Dense, architectural |
| Male cones | 3–6, bright yellow, 40–50 cm | 2–6, yellow-orange | 2–5, creamy yellow, 49–64 cm |
| Female cones | 1–4, golden yellow, 40–70 cm | 1–3, orange | 2–5, yellow-orange, 42–60 cm |
| Cone diagnostic | Microsporophylls tile-like (tegula) | — | — |
| Growth rate | Fast (among fastest in genus) | Fast | Fast (competes with tegulaneus) |
| Cold hardiness | Zone 10a (frost-free) | Zone 10b (strictly tropical) | Zone 10a (frost-sensitive) |
| Wild population | 5000–10 000 (subsp. tegulaneus: LC) | Declining (NT) | ~5000 (EN) |
| Subspecies | 2 (tegulaneus LC + powysii CR) | None | None (but synonyms voiensis, kanga) |
| Discoverer | Joy Adamson (1954) | J.M. Hildebrandt (1877) | R.B. Faden (1971) |
Propagation
Seed: The species is easily grown from seed, and seeds are among the most readily germinated in the genus. Sow cleaned seeds in a free-draining medium at 27–28 °C. Germination is relatively fast. Seedlings are slow for the first 3–5 years, then accelerate dramatically. Use deep containers to accommodate the developing taproot.
Offsets: The trunk is usually unbranched and does not produce basal suckers as freely as the South African species. Offset propagation is not the primary method of multiplication — seed is far more practical.
Pests and diseases
Scale insects are the primary pest. The long fronds with numerous leaflet pairs and the woolly cataphylls create sheltered microhabitats for pest establishment. Root rot is a risk in waterlogged substrates, though the species’ tolerance for moist conditions reduces this risk compared to the arid-habitat species. In the wild, baboons and wild pigs eat a significant proportion of the seeds — a natural limitation on recruitment that has been sustained for millennia but becomes problematic when combined with other anthropogenic pressures.
Why Encephalartos tegulaneus matters
In a genus where nearly every species story is one of decline, poaching, and approaching extinction, Encephalartos tegulaneus subsp. tegulaneus stands as a rare example of a species that is holding its ground. The Matthews Range of northern Kenya — remote, rugged, sparsely populated, and difficult to access — has provided the kind of natural fortress that most Encephalartos habitats no longer enjoy. The population of 5000–10 000 mature individuals is stable. The habitat is intact. The species is not declining. This is what conservation success looks like for a cycad: a species that has survived not because of heroic human intervention but because its habitat has not yet been destroyed.
The contrast with subsp. powysii — known from a single hill, already declining from collection, Critically Endangered — is a warning. Even within the same species, the difference between survival and extinction can be measured by the distance from a road, the accessibility of a hillside, and the willingness of a few individuals to dig up plants for profit. The Matthews Range is safe today. Whether it will remain safe in 50 years, as Kenya’s population grows, as roads extend into remote areas, and as the international demand for rare cycads continues unabated, is an open question.
Joy Adamson, who discovered the species in 1954, would have understood the stakes. She spent her life advocating for the wild things of East Africa. The cycad she found on Mount Lololokwe — the largest, most palm-like, most magnificent Encephalartos of the East African mountains — is, for now, one of those wild things that endures.
Authority websites
POWO — Plants of the World Online: https://powo.science.kew.org…
IUCN Red List (subsp. tegulaneus): https://www.iucnredlist.org/…
World List of Cycads: https://cycadlist.org
Bibliography
Melville, R. (1957). Encephalartos tegulaneus. Kew Bulletin 12(2): 249. [Original description]
Miringu, B.W. & Beentje, H.J. (1999). Encephalartos tegulaneus subsp. powysii (Zamiaceae): a new cycad in Central Kenya. Journal of East African Natural History 88(1): 35–39. [Subspecies description]
Faden, R.B. & Beentje, H.J. (1989). Encephalartos kisambo, a new cycad from Kenya, with a note on Encephalartos tegulaneus. Kew Bulletin 44(2): 239–246.
Whitelock, L.M. (2002). The Cycads. Timber Press, Portland. 374 pp.
Jones, D.L. (2002). Cycads of the World. 2nd ed. Smithsonian Institution Press, Washington. 456 pp.
Donaldson, J.S. (ed.) (2003). Cycads: Status Survey and Conservation Action Plan. IUCN/SSC Cycad Specialist Group, IUCN, Gland.
Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31.
TRAFFIC East/Southern Africa (2003). Review of Significant Trade: Cycads. Report PC14 Doc. 9.2.2.