Zamia encephalartoides is a large, arborescent cycad of the family Zamiaceae, endemic to two isolated populations in the dry canyons of Santander Department, northeastern Colombia. It is one of the most remarkable and unusual species in the genus Zamia — a plant that breaks virtually every rule that defines a typical Zamia. Its robust trunk, recurving keeled leaves, spineless petioles, and above all its unique white seeds make it instantly recognizable. The species’ superficial resemblance to the African genus Encephalartos, reflected in its name, has fascinated botanists and collectors since its discovery, raising profound questions about convergent evolution among cycads.
The accepted name Zamia encephalartoides D.W.Stev. follows the nomenclatural authority of POWO (Plants of the World Online, Royal Botanic Gardens, Kew). The species was formally described by Dennis W. Stevenson in 2001 in the Flora de Colombia, more than two centuries after its first collection. The specific epithet encephalartoides means “resembling Encephalartos,” referring to the striking similarity of the leaves and cones to those of the African cycad genus. The local common name in Colombia is cacao de Indio.
Taxonomy and Phylogenetic Position
A 218-Year Wait for a Name
The taxonomic history of Zamia encephalartoides is extraordinary even by the standards of cycad botany. The species was first collected in 1783 during a Spanish botanical expedition to northeastern Colombia. Color illustrations were produced at the time, clearly depicting the distinctive female strobilus and the unique white seeds. Yet despite being documented in the eighteenth century, the species was not formally described until 2001 — a gap of 218 years. No collected herbarium specimen from the 1783 expedition has survived, though the original color plates remain as historical evidence.
Position in the South American Clade
Molecular phylogenetic analyses place Zamia encephalartoides in the South American “East of the Andes” clade. A 2019 DNA study by Calonje et al. positioned it in a clade with Zamia muricata (Venezuela, Colombia) and Zamia lecointei (Amazonia). A 2024 transcriptome study by Lindstrom et al. refined this placement, finding Zamia encephalartoides to be sister to a clade containing Zamia muricata, Zamia lecointei, and four other species within the East of the Andes group.
Stevenson originally placed Zamia encephalartoides in a “Río Magdalena Valley element” alongside Zamia muricata, Zamia lecointei, and Zamia poeppigiana, reflecting the geographic and ecological affinities of these South American species.
Convergent Evolution with Encephalartos
The resemblance of Zamia encephalartoides to the African genus Encephalartos is a textbook example of convergent evolution. Both genera independently evolved similar solutions to similar environmental challenges — aridity, seasonal drought, and exposed, rocky habitats — despite being separated by the Atlantic Ocean and tens of millions of years of divergent evolution. The stiff, keeled, recurving leaves, the robust trunk, and the general “xeromorphic cycad” gestalt are shared by many Encephalartos species from the dry regions of southern and eastern Africa. Yet Zamia encephalartoides is firmly placed in the New World genus Zamia by its reproductive morphology and molecular phylogeny.
Natural Habitat and Distribution
Zamia encephalartoides has one of the most restricted and ecologically unusual distributions in the genus. It is endemic to two populations in Santander Department, northeastern Colombia, near the Río Chicamocha and the Río Umpala — both tributaries of the upper Magdalena River system. The type specimen was collected near the Río Chicamocha at approximately 760 meters elevation.
What makes this species exceptional among trunking Zamia is its habitat. While virtually all other large, arborescent Zamia species grow in tropical rainforests with abundant rainfall, Zamia encephalartoides inhabits dry, semi-arid environments in the rainshadow canyons of the Colombian Andes:
The Río Chicamocha population grows in the understory of a mesic forest with a sparse canopy receiving approximately 1,000 mm of precipitation annually — less than half the rainfall typical of most Zamia habitats.
The Río Umpala population grows in xeric scrubland with no tree canopy — an astonishingly harsh environment for any cycad, and one that is more reminiscent of Encephalartos habitat in southern Africa than of a typical Zamia locality.
These dry, steep, rocky canyon slopes at moderate elevations experience significant seasonal temperature variation and low humidity — conditions that explain the species’ surprisingly good tolerance of drought and cold in cultivation.
Zamia encephalartoides is described as still locally common within its two known localities, but the total area of occupancy is extremely small and the populations are geographically isolated.
Morphological Description
General Habit and Stem
Zamia encephalartoides is a large, arborescent cycad with an erect, robust trunk reaching up to 2 meters in height and 25 cm in diameter. The trunk is smooth, lacking the prominent leaf-base scars of many other arborescent zamias. This palm-like silhouette, combined with the compact crown of keeled, recurving leaves, gives the species a distinctive appearance quite unlike any other New World cycad.
The species is the only larger, trunking Zamia that is not from a rainforest environment — a distinction that underpins its special appeal to collectors and its unusual cultivation requirements.
Leaves and Leaflets
The crown bears 10 to 15 compound leaves, each 50 to 100 cm long. The leaves are distinctly keeled (V-shaped in cross-section) and gently recurving, creating an elegant, arching crown silhouette. The foliage is light green to lime-green, giving the plant a fresh, luminous appearance.
The petiole is 15 to 25 cm long and — critically — completely unarmed (no prickles). This is unusual for Zamia and contributes to the “user-friendly” reputation of the species among collectors. The rachis is likewise spineless.
Each leaf bears 15 to 24 pairs of leaflets. The leaflets are lanceolate to oblong, with somewhat revolute (rolled-under) margins. Leaflet morphology changes with age: juvenile plants produce broader leaflets that become proportionally longer and narrower as the plant matures.
Reproductive Structures
Zamia encephalartoides is strictly dioecious. Both male and female strobili are produced at the crown. The female cones (megastrobili) are robust and distinctive.
The most remarkable reproductive feature of this species is its white sarcotesta. Zamia encephalartoides is the only Zamia in the world whose mature seeds are enclosed in a white (rather than red or orange) fleshy covering. The closely related Zamia pseudoparasitica from Panama produces yellow seeds, and an undescribed species from Ecuador also has yellow sarcotesta, but white seeds are unique to Zamia encephalartoides. The ecological significance of white seed color — which presumably affects seed dispersal by animal vectors — is not fully understood.
Root System
Coralloid roots housing nitrogen-fixing Nostoc cyanobacteria are present, as in all cycads.
Cold Hardiness and Drought Tolerance
Zamia encephalartoides has earned a reputation among experienced cycad growers for surprisingly good cold and drought tolerance — traits that make it one of the most interesting South American Zamia species for cultivation in marginal subtropical climates.
Evidence from Specialist Sources
Dave’s Garden rates the species as hardy to USDA zone 9b (−3.8 °C / 25 °F).
Jungle Music (specialist cycad nursery, Southern California) reports cold tolerance “down to about 26 °F (−3.5 °C)” and notes that “it has successfully been grown outdoors in Southern California.”
A Dave’s Garden user describes it as “surprisingly hardy considering it’s from tropical Colombia” and attributes this tolerance to its origin “from the higher mountain deserts of Colombia.” The user also notes good sun tolerance and highly attractive, lime-green, spineless foliage.
Cycadales.eu, a European specialist source, groups Zamia encephalartoides with species from seasonally dry Colombian habitats that “pose no problem in a frost-free greenhouse in South France,” describing it as “easy to grow.”
Why Is It Cold-Hardy?
The cold and drought tolerance of Zamia encephalartoides is a direct consequence of its unique habitat. The dry canyons of the Chicamocha and Umpala rivers experience far greater temperature variation than the equatorial lowland rainforests where most South American Zamia species occur. Nighttime temperatures at 760 meters in the Colombian Andean canyons can drop significantly, and the pronounced dry season imposes the kind of seasonal stress that pre-adapts a species to withstand drought and cool conditions in cultivation.
Practical Cold Hardiness Guidelines
USDA 10a to 11: Reliable outdoors year-round in well-drained soil with full sun to partial shade.
USDA 9b (−3.8 °C): Feasible in sheltered positions with excellent drainage. Established plants with well-developed trunks have the best chance of surviving brief frost events. Winter protection (mulch, fleece) advisable.
Below USDA 9b: Container culture or frost-free greenhouse recommended. The species’ drought tolerance makes it well-suited to cool, dry winter storage under glass.
Drought tolerance: Significantly higher than most Zamia species. The xeric scrubland habitat of the Umpala population demonstrates that this species is adapted to survive extended dry periods. In cultivation, established plants can be treated more like a succulent or a xeric Encephalartos than a typical moisture-loving Zamia.
Conservation Status
Zamia encephalartoides is classified as Endangered (EN) on the IUCN Red List, under criteria B1ab(iii,v)+2ab(iii,v), reflecting its extremely restricted extent of occurrence, limited area of occupancy, and ongoing decline in habitat quality and population size.
Threats
Habitat destruction is the principal threat. Both known populations are located in areas where forest and scrubland are being cleared for farming. The steep, dry canyon slopes of the Chicamocha and Umpala rivers, though seemingly inhospitable, are increasingly targeted for agricultural expansion.
Extremely restricted range. With only two known populations in a single Colombian department, the species is highly vulnerable to localized catastrophes and has virtually no demographic resilience.
Illegal collection is a concern given the species’ high desirability among cycad collectors. Its rarity, unusual appearance, and Colombian origin (which makes legal seed acquisition logistically difficult) combine to create market conditions favorable to illicit trade.
Conservation Measures
Zamia encephalartoides is listed under CITES Appendix II and is protected under Colombian law (Resolution 213 of 1977, governing protected plant species). It is included in the Conservation Action Plan for the Zamias of Colombia, which has made its conservation needs visible to stakeholders.
The species is represented in the cycad collections of the Bogotá and Medellín Botanical Gardens in Colombia, and in several international collections. Ex situ cultivation provides genetic insurance, but in situ protection of the two remaining wild populations is the critical priority.
Growing Zamia encephalartoides: Complete Care Guide
Light and Exposure
Unlike most Zamia species, Zamia encephalartoides tolerates full sun to partial shade. The Umpala population grows in completely exposed xeric scrubland with no tree canopy. In cultivation, a sunny to lightly shaded position is ideal. The species is notably more sun-tolerant than its rainforest-dwelling congeners.
Soil and Drainage
Excellent drainage is critical. This species grows on steep, rocky slopes in the wild and will not tolerate waterlogged conditions. Use a mineral-rich, very well-drained mix: coarse sand, pumice or perlite, and a small proportion of organic matter. A slightly calcareous substrate may be beneficial, reflecting the limestone-derived soils of the Chicamocha canyon.
Watering
Significantly more drought-tolerant than most Zamia species. Water moderately during the growing season, allowing the substrate to dry substantially between irrigations. Reduce watering sharply in winter. In regions with cool, wet winters, keeping the plant dry during dormancy is essential to prevent rot.
Fertilization
A light feeding regime with slow-release palm or cycad fertilizer during the growing season. The species grows slowly and does not require heavy feeding.
Container Culture
An outstanding container subject for collectors. The combination of drought tolerance, sun tolerance, spineless foliage, and architectural growth habit makes Zamia encephalartoides one of the most rewarding Zamia species for pot culture. Use a heavy, well-drained container (terracotta is ideal) and a mineral-heavy mix. The species’ tolerance of dry conditions makes winter storage under glass straightforward.
Toxicity
All parts of Zamia encephalartoides are toxic due to the presence of cycasin and related compounds. Keep away from pets and children.
Frequently Asked Questions
Why does Zamia encephalartoides look like an African Encephalartos? The resemblance is a classic example of convergent evolution. Both genera independently evolved similar leaf and trunk morphology in response to similar environmental pressures — aridity, seasonal drought, and exposed rocky habitats — despite being separated by the Atlantic Ocean and tens of millions of years of evolutionary divergence.
Why are the seeds white? Zamia encephalartoides is the only Zamia species with white mature seeds (sarcotesta). All other zamias produce red or orange seeds, with the exception of Zamia pseudoparasitica (yellow) and an undescribed Ecuadorian species (yellow). The ecological significance of white seed color is unknown.
Is Zamia encephalartoides drought-tolerant? Yes — significantly more so than most Zamia species. One of its two known populations grows in xeric scrubland with no tree canopy and only about 1,000 mm of annual rainfall. In cultivation, it can be treated more like a xeric cycad than a typical moisture-loving Zamia.
How cold-hardy is Zamia encephalartoides? Specialist sources rate it as hardy to USDA zone 9b (−3.8 °C / 25 °F). Its origin in dry Andean canyons at moderate elevation, where temperatures drop significantly at night, pre-adapts it to tolerate cool conditions that would damage lowland rainforest zamias.
Sources and Further Reading
- Calonje, M., Meerow, A.W., Griffith, M.P., Salas-Leiva, D., Vovides, A.P., Coiro, M. & Francisco-Ortega, J. (2019). A Time-Calibrated Species Tree Phylogeny of the New World Cycad Genus Zamia L. (Zamiaceae, Cycadales). International Journal of Plant Sciences, 180(4): 286–314.
- Haynes, J.L. (2022). Etymological compendium of cycad names. Phytotaxa, 550(1): 1–31.
- Lindstrom, A. et al. (2024). Transcriptome sequencing data provide a solid base to understand phylogenetic relationships, biogeography and reticulated evolution of the genus Zamia L. Annals of Botany, XX: 10.
- Stevenson, D.W. (2001). Zamia encephalartoides. In: Flora de Colombia, 21: 40–42, fig. 5.
- Sociedad Colombiana de Cícadas (SCC). Zamias de Colombia. https://www.cycadascolombia.org/
- POWO (2026). Zamia encephalartoides D.W.Stev. Plants of the World Online. Royal Botanic Gardens, Kew. https://powo.science.kew.org/
- IUCN Red List of Threatened Species. Zamia encephalartoides. https://www.iucnredlist.org/