Where the Nguruman Hills descend toward the alkaline flats of Lake Natron — that otherworldly body of soda-crusted water famous for its flamingos and its lethal chemistry — a medium-sized cycad grows among quartzite outcrops and open bushland at altitudes of 1300 to 2150 m. Encephalartos bubalinus is one of the most geographically striking cycads in Africa: its entire range straddles the Kenya–Tanzania border in the eastern arm of the Great Rift Valley, in a landscape of volcanic escarpments, Maasai pasturelands, and the rain shadow of Mount Kilimanjaro. It is a handsome, vigorous, multi-stemmed species that produces disproportionately large cones for its size, grows faster than most Encephalartos, and remains one of the more poorly known members of the genus — protected as much by the remoteness and ruggedness of its habitat as by any formal conservation law.
Encephalartos bubalinus belongs to the East African Encephalartos complex — the group of species distributed across Kenya, Tanzania, and Uganda that includes Encephalartos hildebrandtii, Encephalartos kisambo, Encephalartos sclavoi, and Encephalartos tegulaneus. Among these, it occupies a distinctive ecological niche: montane grassland and open bushland on quartzite ridges, at altitudes well above the coastal and sub-montane habitats of hildebrandtii and kisambo, and in a drier, more seasonal climate than the cloud-forest habitat of sclavoi.
Taxonomy and nomenclature
Encephalartos bubalinus Melville was first published in 1957 in the Kew Bulletin (volume 12(2): 252, fig. 4), as part of Ronald Melville’s landmark paper “Encephalartos in Central Africa” (Kew Bulletin 12: 237–257). This paper — one of the most important early treatments of the non-South African Encephalartos species — also described Encephalartos tegulaneus from Kenya in the same volume. The species was based on material collected by Peter Bally (collection number 10600) between Loliondo and Lake Natron, at approximately 2°11’S, 35°40’E, in what was then Tanganyika Territory. The holotype is deposited at the Royal Botanic Gardens, Kew (K), with an isotype at Berlin (B).
The epithet bubalinus derives from the Latin for “of cattle” or “buff” — a reference not to the African buffalo but to the buff-brown colour of the tomentum (dense covering of fine hairs) on the cataphylls (bud scales) and leaf bases. This woolly, tawny covering is conspicuous on emerging leaves and gives the crown a distinctly warm-toned appearance during flushing, contrasting with the dark green of the mature foliage.
Encephalartos bubalinus has no taxonomic synonyms. In the dichotomous key to the East African Encephalartos complex, the species is separated from its nearest relative, Encephalartos kisambo, by having smaller leaves and leaflets, smaller male cones with proportionately broader median sporophylls, and female cones with broader bullae (the raised facets on the outer surface of the sporophylls). The relationship between bubalinus and kisambo was discussed in detail by Faden & Beentje (1989) in the original description of E. kisambo, where kisambo was distinguished from bubalinus by its larger dimensions throughout.
Common names: Lake Natron cycad (informal); buff cycad (translation of the epithet).
Morphological description
Habit and caudex: Encephalartos bubalinus is a medium-sized cycad with a stout, cylindrical trunk that grows erect when young but may become procumbent (reclining) with age, reaching 1.4–2 m in height and 33–45 cm in diameter. The species suckers vigorously from the base, and mature specimens typically develop 6 or more stems over time, forming a multi-headed clump — a growth habit that distinguishes it from the predominantly single-stemmed species such as Encephalartos tegulaneus and Encephalartos sclavoi. The crown and stem are covered with buff-brown cataphylls and persistent leaf bases, giving the upper trunk a shaggy, woolly texture.
Leaves: The fronds are oblanceolate, 60–165 cm long and 20–30 cm wide, tapering gradually toward the base. They are dark green, semiglossy, and slightly keeled (the opposing leaflets inserted at an angle of 120–160°, creating a shallow V-shape). In exposed habitats, the fronds tend to be shorter and more compact; in sheltered or shaded locations, they can reach 170 cm or more. Each frond consists of 50–90 pairs of tough, leathery leaflets arranged alternately along the rachis at approximately 45°. The leaflets are closely spaced, lanceolate, with a rounded or obtuse apex ending in a fine sharp point. The lower leaflets are reduced to spines along the petiole. The overall appearance is of a dense, well-armed crown — dark green and glossy when mature, but flushing with the characteristic buff-brown tomentum that gives the species its name.
Phil Bergman at Jungle Music describes the leaflets as “cupped” and “slightly plumose or out of plane” on larger specimens — a subtle three-dimensionality in the leaf architecture that adds textural interest. The leaflets are moderately armed but not aggressively sharp.
Reproductive structures: The cones of Encephalartos bubalinus are large relative to the plant’s overall stature and serve as a key diagnostic character.
Male cones are erect, greenish, almost sessile (without a noticeable stalk), measuring 27.5–55 cm long and 5–13 cm in diameter. Their near-sessile attachment is a distinguishing feature: in many East African Encephalartos, male cones are distinctly stalked or even pendulous (as in Encephalartos whitelockii).
Female cones are ovoid, greenish, distinctly stalked (in contrast to the sessile males), measuring 32–45 cm long and 20–25 cm wide. Each cone produces ovoid seeds approximately 30–40 mm long, enclosed in a red-orange sarcotesta.
The contrast between the sessile male cones and the stalked female cones is one of the most reliable characters for separating Encephalartos bubalinus from related species in the field.
Distribution and natural habitat
Encephalartos bubalinus is native to northern Tanzania (Arusha Province) and southern Kenya (Narok County). The core populations are found west of Lake Natron and south of the town of Loliondo, in the Nguruman Hills — the eastern escarpment of the Great Rift Valley. Two isolated populations are documented. The altitude range is 1300–2150 m above sea level, placing this species firmly in the montane zone — higher than most East African Encephalartos except Encephalartos tegulaneus subsp. tegulaneus (which reaches 2300 m in the Matthews Range, Kenya).
The habitat is open bushland and grassland on quartzite ridges, or montane forest with a few scattered trees on shallow soils over sandstone. The associated vegetation includes Acacia (sensu lato), Ziziphus, Dombeya, Dolichos, and Aloe volkensii — a characteristic dry montane assemblage of the East African Rift escarpments. The cycads grow on rocky slopes and ridges with thin, well-drained, mineral soils, exposed to strong sunshine and seasonal drought.
The climate is seasonally dry tropical with a pronounced dry season. Rainfall is moderate, estimated at 600–1000 mm per year, concentrated in two rainy seasons (March–May and October–December). Daytime temperatures are warm (20–30 °C), but nights at 1300–2150 m can be cool, particularly during the dry season (June–September), when temperatures may drop to 8–12 °C. Brief ground frost is conceivable at the upper altitudinal limit during clear, dry nights, though it would be exceptional.
The landscape is Maasai territory — traditional pastoreland for cattle, goats, and sheep. The cycad populations coexist with pastoral land use. Human population density is low, and the rocky quartzite ridges on which the cycads grow are largely unsuitable for cultivation, providing some degree of natural protection.
Lake Natron — a cycad on the edge of the alkaline world
Lake Natron, which lies at the foot of the Nguruman Hills at approximately 600 m elevation, is one of the most extreme aquatic environments on Earth. Its waters are heated by volcanic springs to temperatures exceeding 50 °C, with a pH approaching 12 — essentially caustic soda. The lake is the sole breeding site for the Lesser Flamingo (Phoeniconaias minor) in East Africa, and its shores are encrusted with trona (hydrated sodium carbonate). The cycad does not grow anywhere near the lake itself — the altitude gap of 700–1500 m between the lakeshore and the cycad habitat creates entirely different environments. But the geographic association gives Encephalartos bubalinus one of the most dramatic backdrops of any cycad: from the quartzite ridges where it grows, the alkaline flats of Lake Natron shimmer in the distance, and the active volcano Ol Doinyo Lengai — “Mountain of God” in the Maasai language — rises to the south.
Conservation status
Encephalartos bubalinus is assessed as Near Threatened (NT) on the IUCN Red List. The World List of Cycads confirms this assessment. The species is listed on CITES Appendix I.
The Near Threatened status reflects a population that currently appears stable, but is inherently vulnerable due to its narrow distribution and small number of locations. As the IUCN assessment notes, African cycads “have tended to decline rapidly once they become the targets of collectors” — a warning that the species’ current stability should not be taken for granted.
Threats: Habitat loss from agricultural expansion and settlement (though the rocky, high-altitude habitat is less threatened than lowland areas); potential collection for the horticultural trade (the species is described as “rare in cultivation” and therefore potentially valuable to collectors); fire (grassland burning for pastoral management); and climate change (shifts in rainfall patterns could alter the montane grassland habitat).
Protection: No specific conservation programme targets Encephalartos bubalinus. The remoteness and difficulty of access to the Nguruman Hills and the Loliondo area provide de facto protection. The broader landscape falls partly within the Ngorongoro Conservation Area and the Maasai-managed rangelands of southern Kenya, though none of these designations specifically protect cycad habitat.
Cold hardiness
The montane habitat (1300–2150 m) in the East African Rift creates a climate that is significantly cooler than the lowland and coastal environments inhabited by species such as Encephalartos hildebrandtii (sea level to 350 m). Cool-season nighttime temperatures of 8–12 °C are routine, and brief ground frost at the upper altitudinal limit cannot be entirely excluded.
LLIFLE: “Not too hardy to frost (doesn’t die, but leaves get damaged).”
Dave’s Garden/Jungle Music: “Being from central Africa, this is not one of the more cold-tolerant species and frosts can defoliate it. It tolerates humid warm climates like Miami probably better than in California.”
LLIFLE cultivation notes: USDA Zones 10–12; frost-sensitive.
Practical cold hardiness estimate: USDA Zone 9b–10a (−1 to −4 °C) for brief frost events on dry foliage. The montane origin provides more cold tolerance than the truly tropical lowland species (hildebrandtii, laurentianus), but less than the South African montane species adapted to regular frost (cycadifolius, ghellinckii). Frost will damage leaves but may not kill an established plant if the event is brief and the root zone is dry. In Mediterranean climates (Côte d’Azur, coastal southern California), outdoor cultivation with winter protection is feasible in sheltered microsites. In climates with regular frost, a greenhouse is recommended.
Cultivation guide
Difficulty: 2/5. The species is described as a vigorous grower, adaptable, and responsive to cultivation. LLIFLE calls it “one of the most spectacular of all cycad species” in garden settings and notes it will reach coning size in 8–10 years — fast by Encephalartos standards.
Light: Full sun to partial shade. The quartzite-ridge habitat is fully exposed to equatorial montane sunshine. In cultivation, full sun is ideal for compact growth and strong colouration. The species tolerates partial shade without significant loss of vigour. Phil Bergman notes it “will tolerate partial or perhaps full sun along the coast and a few hours of sun far inland.”
Soil: Well-drained, mineral-rich. The quartzite and sandstone substrates of the natural habitat produce thin, gravelly, well-drained soils. In cultivation, a free-draining mix of coarse sand, pumice, loam, and minimal organic matter replicates these conditions. Good drainage is essential — the pronounced dry season in the natural habitat means the species is adapted to periodic drought, not persistent moisture.
Watering: Regular during the growing season, reduced during winter. The natural habitat receives 600–1000 mm annually, concentrated in two rainy seasons, with a long, dry winter period. In cultivation, water generously from spring through autumn and reduce to minimal watering in winter. Avoid overhead irrigation — LLIFLE notes that “irrigation systems can be detrimental to cycads, damaging the leaves and stems from the pressure of the water as well as over-watering.”
Feeding: Responds well to regular balanced fertilisation. A balanced NPK with trace elements applied monthly during the growing season promotes vigorous leaf production and the development of the species’ characteristically dense, multi-leaved crown.
Growth rate: Fast by Encephalartos standards. LLIFLE notes it will reach coning size in 8–10 years — a remarkably short time for an Encephalartos, where 15–20 years to first cone is more typical. The vigorous suckering habit means that established plants quickly develop into impressive multi-stemmed clumps.
Container culture: Well-suited to container cultivation for many years. The moderate eventual size (trunk to 2 m, fronds to 1.7 m) and relatively compact habit make this one of the better Encephalartos species for long-term container growth. In temperate climates, a large container in a greenhouse or conservatory, brought outdoors in summer, provides an excellent growing environment.
Landscape use: In frost-free gardens (USDA zones 10–12), Encephalartos bubalinus makes a striking specimen or group planting. The multi-stemmed habit, dense crown of dark green leaves, and buff-coloured new growth create a plant of considerable textural interest. LLIFLE describes it as making “a choice feature plant.” The disproportionately large cones — particularly the greenish, sessile male cones produced in clusters — add a dramatic reproductive display. The species is well represented in botanical gardens and specialist collections where tropical cycads can be grown.
Comparison with related East African species
| Character | E. bubalinus | E. kisambo | E. hildebrandtii | E. tegulaneus |
|---|---|---|---|---|
| Distribution | N. Tanzania / S. Kenya (Nguruman, Lake Natron) | S. Kenya / N. Tanzania (hills) | Coastal Kenya / Tanzania | Kenya (Matthews Range) |
| Altitude | 1300–2150 m | 800–1800 m | Sea level to 350 m | 1200–2300 m |
| Trunk | Erect → procumbent, 1.4–2 m × 33–45 cm, suckering | Erect, barrel-shaped, to 4 m × 40 cm | Erect, 6–12 m × 35–50 cm | Erect, 7–10 m × 35–50 cm |
| Leaf length | 60–165 cm | 2–3 m | 2–3 m | 2–3 m |
| Leaflet character | Closely spaced, rounded tip with sharp point, cupped | Longest in complex (24–37 cm), 4–6 spines upper margin | Broad, entire or with few teeth | Tile-like microsporophylls (diagnostic) |
| Male cones | Sessile, erect, 27.5–55 cm (diagnostic) | Stalked, 25–35 cm | Stalked, 25–40 cm | Stalked, 20–30 cm |
| Female cones | Stalked, 32–45 cm × 20–25 cm | Stalked, 35–45 cm | Stalked, 30–50 cm | Stalked, 25–35 cm |
| Suckering | Vigorous (6+ stems) | Occasional | Rarely | Rarely |
| Growth rate | Fast (coning in 8–10 years) | Fast | Fast | Fast |
| Cold hardiness | Zone 9b–10a (montane, some cool tolerance) | Zone 10a | Zone 10a–10b (coastal tropical) | Zone 10a (montane, some cool tolerance) |
| IUCN status | NT (stable but narrow range) | EN (~5000 plants) | NT (widespread coastal) | LC/CR (by subspecies) |
| Key diagnostic | Sessile male cones; buff tomentum | Longest leaflets in complex | Largest trunk in E. Africa | Tile-like microsporophylls; tallest E. African |
Propagation
Seed: The species produces ovoid seeds, 30–40 mm long, with a red-orange sarcotesta. Seed set appears to be occurring in the wild. A characteristic shared with all Encephalartos — and worth noting — is that full-sized seeds are produced even from unpollinated cones, in which case the seeds are not viable but appear normal externally. This is an important consideration when purchasing seed: apparent seed quality does not guarantee viability. When viable seed is available, standard germination protocols apply: clean the sarcotesta (gloves — toxic), sow on free-draining medium at 27–28 °C. Germination is reportedly reliable.
Offsets: The species’ vigorous suckering habit makes offset propagation the most practical vegetative method. Well-developed offsets with established root systems can be separated from the parent clump and potted individually. Given the species’ relatively fast growth rate, offset-derived plants can reach an impressive size within a few years.
A cycad at the crossroads of fire and grassland
Encephalartos bubalinus occupies an ecological niche that is both ancient and dynamic. The quartzite ridges and montane grasslands of the Nguruman Hills are fire-maintained landscapes — the open, treeless character of the habitat is sustained by periodic burning, whether natural (lightning) or anthropogenic (pastoral management by Maasai herders). Cycads are among the few woody plants that can survive repeated burning: their thick, insulating trunks and underground root systems protect the meristem from fire damage, and their tough, leathery foliage regrows rapidly after defoliation. In this sense, Encephalartos bubalinus is not merely tolerating fire but may actually benefit from it: fire suppresses competing woody vegetation, maintains the open grassland habitat the cycad prefers, and releases nutrients into the shallow soils.
This fire-adapted ecology connects Encephalartos bubalinus to the South African montane species — Encephalartos ghellinckii, Encephalartos cycadifolius, Encephalartos friderici-guilielmi — that also thrive in fire-maintained grasslands at comparable altitudes. The convergence is ecological rather than phylogenetic: the East African and South African montane cycads are not each other’s closest relatives, but they have independently adapted to the same suite of environmental pressures — thin soils, strong sun, periodic drought, cool nights, and regular fire.
For the collector, Encephalartos bubalinus offers something that few Encephalartos species provide: fast growth, vigorous suckering, impressive cones, moderate size, and a constitution tough enough to handle real-world garden conditions. It deserves to be far better known than it is.
Authority websites
POWO — Plants of the World Online: https://powo.science.kew.org/…
IUCN Red List: https://www.iucnredlist.org/species/41941/10606598
World List of Cycads: https://cycadlist.org
Bibliography
Melville, R. (1957). Encephalartos in Central Africa. Kew Bulletin 12(2): 237–257. [Original description, p. 252, fig. 4]
Melville, R. (1958). Flora of Tropical East Africa: Gymnospermae. Crown Agents, London.
Faden, R.B. & Beentje, H.J. (1989). Encephalartos kisambo (Zamiaceae). Bulletin du Jardin Botanique National de Belgique 59: 189–196. [Comparison with bubalinus]
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.
Bösenberg, J.D. (2010). Encephalartos bubalinus. The IUCN Red List of Threatened Species 2010: e.T41941A10606598.
Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa 550(1): 1–31.