Zamia roezlii is a large, arborescent cycad of the family Zamiaceae, native to the Pacific coastal lowlands of Colombia and Ecuador. With trunks reaching up to 7 meters in height, it is the tallest species in the genus Zamia — and arguably the most palm-like, often mistaken for a small palm when seen from a distance. Growing in swampy coastal forests just above the mangrove belt, sometimes in soils flooded by high tides, Zamia roezlii also produces the largest female cones and the largest plant sperm cells in the world — a single spermatozoid measuring approximately 0.4 mm, visible to the naked eye and propelled by some 40,000 cilia. Few cycads combine such imposing stature, such an extreme habitat, and such remarkable reproductive biology.
The accepted name Zamia roezlii Linden follows the nomenclatural authority of POWO (Plants of the World Online, Royal Botanic Gardens, Kew). The species was first published in 1873 in Linden’s Catalogue Général (no. 90), originally described from material cultivated in the garden of Jean Linden in Belgium. The specific epithet honors Benedikt Roezl (1824–1885), a Czech plant collector who traveled extensively through Mexico, Central America, and South America during the second half of the nineteenth century and who first collected this species. The synonym Aulacophyllum roezlii (Linden) Regel (1876) reflects the former segregation of plicate-leaved zamias into the genus Aulacophyllum. The local common name in Colombia is chigua (not to be confused with the distinct species Zamia chigua). The genus Zamia comprises over 80 recognized species distributed across the Americas.
Taxonomy and Phylogenetic Position
The Most “Primitive” Zamia?
Jones (1993) described Zamia roezlii as “the most primitive member of the genus,” an assessment based on its large overall size, massive reproductive structures, and several morphological characters considered ancestral within the Zamiaceae. While modern molecular phylogenies have refined our understanding of evolutionary relationships in the genus, Zamia roezlii remains exceptional in its combination of plesiomorphic (ancestral) features: enormous arborescent stature, massive cones, gigantic sperm, and variable chromosome numbers (2n = 22, 24, 25, and 26 have been reported).
The Chocó Plicate-Leaved Complex
Zamia roezlii belongs to a complex of plicate-leaved (corrugated-leaflet) species centered on the Chocó biogeographic province of northwestern South America. This complex, as outlined by Stevenson (2001), includes Zamia amplifolia, Zamia wallisii, Zamia gentryi, Zamia oligodonta, and Zamia montana on the Colombian side, forming a counterpart to the Panamanian plicate-leaved complex (Zamia skinneri, Zamia neurophyllidia, Zamia imperialis, Zamia hamannii, Zamia nesophila). All these species were formerly placed in the genus Aulacophyllum by Regel (1876) on the basis of their plicate leaflets and sequential (rather than simultaneous) leaf emergence.
Zamia roezlii is the largest member of this entire assemblage by a wide margin. Its closest relative is Zamia amplifolia, a slightly smaller species endemic to the southern Pacific coast of Colombia, which shares similar plicate leaflets and Chocó lowland forest habitat.
Natural Habitat and Distribution
Zamia roezlii is distributed along the Pacific coast of Colombia (departments of Chocó, Valle del Cauca, and Nariño) and the Pacific coast of northern Ecuador (provinces of Esmeraldas and Imbabura). The species may also extend into the Colombian Amazon (Amazonas Department), though the Pacific coastal populations are the core of its range.
The habitat of Zamia roezlii is extraordinary for a cycad. The species grows primarily in equatorial coastal forests and swampy lowlands just above the mangrove belt, at or near sea level. Many plants grow in brackish mud — soils that would be lethal to most cycads — and some individuals are periodically flooded by high tides. This tolerance of waterlogged, saline conditions is virtually unique among cycads and represents an extreme ecological adaptation within the order Cycadales.
The climate is equatorial: hot, wet, and humid year-round, with no discernible dry season and annual rainfall often exceeding 3,000 mm. Under these conditions, Zamia roezlii is non-cyclic in its reproduction, producing cones throughout the year rather than in a defined seasonal window.
The Sociedad Colombiana de Cícadas estimates more than 10,000 adult individuals across the species’ range. Zamia roezlii is locally abundant and produces large female cones with good seed output. The Afro-descendant communities of Chocó Department have integrated this species into their traditional resource management, and piles of harvested cones can sometimes be seen near settlements, where the starchy seeds are processed as food and considered a delicacy.
Morphological Description
General Habit and Stem
Zamia roezlii is the largest species in the genus. The stem is erect to decumbent, unbranched, reaching up to 7 meters in height (or 6.5 meters in length when decumbent) and 15 to 30 cm in diameter. The tall, slender trunk, crowned with a rosette of long, arching leaves, gives the plant a distinctly palm-like silhouette that is unmistakable in the field.
Leaves and Leaflets
The crown bears 5 to 16 leaves (exceptionally up to 45 in vigorous specimens). Each leaf is 1 to 3 meters long, with a petiole of 0.5 to 1 meter bearing scattered to densely distributed prickles. The rachis carries 10 to 20 pairs of leaflets, occasionally with a few prickles in the proximal third.
The leaflets are falcate (sickle-shaped), linear, 30 to 50 cm long and up to 12 to 15 cm wide, with entire (untoothed) margins. The surface bears the prominent parallel venation typical of the plicate-leaved complex, creating a grooved, corrugated texture. Newly emerging leaves may appear pale green to light red.
Reproductive Structures
Zamia roezlii is strictly dioecious and produces the largest cones of any Zamia species. Female cones (megastrobili) are massive and ovoid, substantially larger than those of any other member of the genus. Male cones are cylindrical, medium-sized relative to the plant’s overall dimensions. Cone production occurs year-round under the equatorial climate of the Chocó, rather than in seasonal pulses.
The species is pollinated by Pharaxonotha beetles, and herbivory by Eumaeus butterfly larvae has been documented.
The World’s Largest Plant Sperm
The most remarkable reproductive feature of Zamia roezlii is its gigantic spermatozoids. A single sperm cell measures approximately 0.4 mm in length — visible to the naked eye without magnification. Each spermatozoid is propelled by approximately 40,000 cilia, making it the largest and most complex plant sperm cell known to science. This superlative is a consequence of the ancestral gymnosperm reproductive biology retained by all cycads: unlike flowering plants, cycads still rely on motile sperm cells to swim through a liquid medium within the ovule to reach the egg cell.
Root System
Coralloid roots hosting nitrogen-fixing Nostoc cyanobacteria are present, as in all cycads.
Zamia roezlii vs. Zamia amplifolia: The Two Giants of the Chocó
Zamia amplifolia is the closest relative of Zamia roezlii and the second-largest member of the Chocó plicate-leaved complex. Both species share the same biogeographic region, similar habitat preferences, and the characteristic plicate leaflet morphology. However, they are readily distinguishable.
| Feature | Zamia roezlii | Zamia amplifolia |
|---|---|---|
| Distribution | Colombia (Chocó to Nariño) + Ecuador | Southern Pacific Colombia (endemic) |
| Maximum trunk height | Up to 7 m | Smaller, several feet |
| Trunk diameter | 15–30 cm | ~12 cm |
| Leaf length | Up to 3 m | Up to 2.5 m |
| Leaflet shape | Falcate, linear | Plicate, broader |
| Leaflet venation | Prominently grooved | Prominently grooved |
| Population | >10,000 adults | Restricted |
| IUCN status | Least Concern (LC) | Data Deficient / Endangered |
The fastest identification cue is overall size: Zamia roezlii is dramatically larger in all dimensions, with trunks reaching 7 meters versus the shorter stature of Zamia amplifolia. Zamia amplifolia is also much rarer and more geographically restricted.
Conservation Status
Zamia roezlii is classified as Least Concern (LC) on the IUCN Red List (per the World List of Cycads), reflecting its relatively large population (more than 10,000 adults), broad distribution across two countries, and locally abundant occurrence. However, the species’ arborescent habit makes mature individuals inherently vulnerable to habitat destruction: a 7-meter trunk takes decades to grow and cannot regenerate once felled.
Threats
Habitat destruction along the Pacific coast of Colombia and Ecuador for agriculture, logging, and infrastructure development.
Vulnerability of arborescent adults. While seedlings and juveniles may establish in disturbed areas, the loss of mature, cone-producing trees with their decades of growth represents an irreplaceable demographic blow. Stevenson (2001) noted this paradox: Zamia roezlii produces excellent seed crops, but the mature individuals needed to generate those crops are the most difficult to replace.
Harvesting for food. The traditional use of cone seeds as food by Afro-descendant communities in Chocó, while part of a culturally important practice, could become unsustainable if harvest rates exceed natural regeneration.
Conservation Measures
Zamia roezlii is listed under CITES Appendix II. The species’ integration into community-based sustainable use programs in Chocó offers a promising model for conservation that aligns the interests of local communities with the protection of cycad populations.
Growing Zamia roezlii: Complete Care Guide
Light and Exposure
Filtered light to partial shade. The species grows in the forest understory and along forest edges in habitat. Whitelock notes that it “looks best when given some protection from the sun.” However, in the equatorial lowlands, “shade” is relative — ambient light levels are high even in the understory.
Soil and Drainage
This is where Zamia roezlii defies the rules. In habitat, the species grows in swampy, brackish mud — conditions that would kill most cycads. However, Whitelock warns that it “will not adjust to heavy soil in cultivation as it does in habitat.” In practice, a rich, organic, well-drained mix is recommended for container and garden culture. The species’ native tolerance of waterlogging and salinity may reflect a specific microbial or mycorrhizal symbiosis that is not replicated in cultivation.
Watering and Humidity
Water abundantly and maintain high humidity (80% or above). The species comes from one of the wettest climates on Earth, with no dry season. Do not allow the substrate to dry out.
Temperature
Strictly tropical. Zamia roezlii is described as “very sensitive to frost and drought” (Jones 1993). No frost tolerance should be assumed. USDA zones 11 and above for outdoor cultivation. In all other climates, a heated tropical greenhouse is required.
Container Culture
The species’ ultimate size (trunk to 7 m, leaves to 3 m) makes it a challenging but spectacular specimen for large tropical greenhouses and botanical gardens. Growth is slow, and container culture is feasible for many years before the plant outgrows its space. Use a large container with rich, organic, well-drained mix.
Toxicity
All parts of Zamia roezlii are toxic due to the presence of cycasin and related compounds. The traditional food use involves extensive processing (washing, soaking, fermentation) to remove toxins before consumption. Keep away from pets and children.
Frequently Asked Questions
Is Zamia roezlii really the tallest Zamia? Yes. With trunks reaching 7 meters, Zamia roezlii is the tallest species in the genus. Jungle Music (a specialist cycad nursery) notes that “Zamia roezlii has possibly the tallest trunk of any Zamia.” Only a handful of non-Zamia cycad species (notably Lepidozamia hopei and Dioon mejiae) produce taller trunks.
What is special about its sperm cells? Zamia roezlii produces the largest known plant sperm cells — approximately 0.4 mm long, visible to the naked eye, and propelled by about 40,000 cilia. This is a consequence of the ancestral motile-sperm reproductive system retained by all cycads.
Can Zamia roezlii really grow in saltwater swamps? In habitat, yes. Some populations grow in brackish mud just above the mangrove belt, with periodic tidal flooding. However, this tolerance does not easily translate to cultivation, where well-drained substrates are recommended.
Is Zamia roezlii used as food? Yes. The Afro-descendant communities of Chocó, Colombia, harvest the large seed cones and process the starchy seeds for food through extensive detoxification. The cones are considered a delicacy.
Sources and Further Reading
IUCN Red List of Threatened Species. Zamia roezlii. https://www.iucnredlist.org/
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.
Jones, D.L. (1993). Cycads of the World. Smithsonian Institution Press, Washington, D.C.
Linden, J. (1873). Zamia roezlii. Catalogue Général, no. 90: 10.
Stevenson, D.W. (2001). Cycadales. Flora de Colombia, 21: 1–92.
Stevenson, D.W. (2004). Cycads of Colombia. The Botanical Review, 70: 194–234.
Sociedad Colombiana de Cícadas (SCC). Zamias de Colombia. https://www.cycadascolombia.org/
Whitelock, L.M. (2002). The Cycads. Timber Press, Portland, Oregon.
POWO (2026). Zamia roezlii Linden. Plants of the World Online. Royal Botanic Gardens, Kew. https://powo.science.kew.org/