Zamia boliviana is a small, subterranean-stemmed cycad of the family Zamiaceae, native to the Cerrado savannas and transitional dry forests of northern Bolivia and adjacent western Brazil. While most Zamia species inhabit dense tropical rainforests, Zamia boliviana has adapted to one of the world’s great open ecosystems — the vast Cerrado biome, where it grows in well-drained, fire-prone grasslands and open woodlands. This ecological distinction, combined with its graceful, narrow-leafleted foliage and unarmed (spineless) petioles, makes it a species of considerable botanical interest and growing horticultural appeal.
The accepted name Zamia boliviana (Brongn.) A.DC. follows the nomenclatural authority of POWO (Plants of the World Online, Royal Botanic Gardens, Kew). The basionym is Ceratozamia boliviana Brongn. (1846), indicating that the species was initially placed in the genus Ceratozamia before being transferred to Zamia by Alphonse de Candolle in his Prodromus (1868). Key synonyms include Zamia brongniartii Wedd. (1849), a superfluous name, and Palmifolium bolivianum (Brongn.) Kuntze (1891). The native range according to POWO extends from Brazil (Mato Grosso) to northern Bolivia. The genus Zamia comprises over 80 recognized species distributed across the Americas.
Taxonomy and Phylogenetic Position
Within the Amazonian Clade
Molecular phylogenetic analyses by Calonje et al. (2019) and Lindstrom et al. (2024) place Zamia boliviana within the Amazonian Clade of the South American Zamia species. The 2019 DNA study defined this clade as containing Zamia boliviana, Zamia poeppigiana, Zamia macrochiera, Zamia hymenophyllidia, and Zamia amazonum. The 2024 transcriptome study refined this grouping, including Zamia urep and confirming the cohesion of the clade.
The Amazonian Clade is distinct from the Eastern Clade (which contains Zamia encephalartoides, Zamia muricata, and Zamia lecointei) and the Tolimensis Clade (Zamia huilensis, Zamia tolimensis). Together, these South American clades represent the southernmost radiation of the genus, reaching Bolivia — the southern limit of Zamia distribution worldwide.
Relationship with Zamia brasiliensis
Zamia boliviana is most closely related to Zamia brasiliensis Calonje & Segalla, a species described as recently as 2019 from Mato Grosso and Rondônia in Brazil. The two species share several traits that are rare among mainland Zamia: both have completely unarmed (prickleless) petioles, subterranean stems, and broadly similar reproductive cone morphology. However, they are readily distinguishable by leaflet width, cone details, and geographic distribution (see comparative section below).
The shared absence of petiolar prickles in Zamia boliviana and Zamia brasiliensis is a notable character. Outside the Caribbean/Florida clade (where unarmed petioles are the norm, as in Zamia integrifolia), prickleless petioles are extremely rare among mainland Zamia species, suggesting a derived trait in this South American lineage.
Natural Habitat and Distribution
Zamia boliviana has one of the broadest distributions of any South American Zamia species, with an extent of occurrence estimated at approximately 651,660 km² encompassing at least 19 known subpopulations. It occurs in the departments of Beni, Cochabamba, La Paz, and Santa Cruz in Bolivia, and in Mato Grosso state in western Brazil.
The species is found at elevations between 130 and 450 meters above sea level, primarily within the Cerrado ecoregion — the species-rich tropical savanna biome of central South America. The Cerrado is characterized by a strongly seasonal climate with distinct wet and dry periods, frequent fire, and well-drained, nutrient-poor, acidic soils (red-yellow latosols). Zamia boliviana grows in open woodlands, gallery forests, and savanna enclaves within transitional zones between the Cerrado and the Amazon Basin.
This open, fire-adapted habitat is highly unusual for a Zamia species. Most members of the genus are understory plants in closed-canopy tropical forests. The adaptation of Zamia boliviana to seasonal drought, fire, and full sun exposure represents a significant ecological departure from the ancestral condition, with implications for its cultivation requirements.
The species benefits from the presence of Noel Kempff Mercado National Park in Santa Cruz Department, Bolivia, one of the most biologically diverse protected areas in South America, where populations of Zamia boliviana are documented within the park boundaries.
Morphological Description
General Habit and Stem
Zamia boliviana is a small, dwarf cycad with a cylindrical, subterranean stem that branches with age. The stem remains entirely underground, with only the crown of leaves and the reproductive cones visible above the soil surface. The crown typically reaches about 80 cm in height. This subterranean growth habit provides excellent protection against the fires that regularly sweep through the Cerrado, allowing the plant to regenerate from its buried growing point after fire events.
Leaves and Leaflets
Each crown bears 1 to 3 pinnate compound leaves, up to 119 cm long. The foliage is sparse and open compared to the dense crowns of forest-dwelling zamias — a characteristic adaptation to the high-light, low-competition environment of the savanna.
The petioles are smooth, completely lacking prickles — a diagnostic trait shared only with Zamia brasiliensis among mainland South American zamias.
Each leaf carries 16 to 40 leaflets. The leaflets are linear-lanceolate, 19 to 29 cm long and 1.1 to 2.0 cm wide, tapering to a pointed apex. The texture is chartaceous (papery) rather than coriaceous, and the margins are smooth along most of their length with a few small teeth near the tip. The overall impression is of an elegant, grass-like or fern-like foliage, quite distinct from the broad, leathery leaflets of species like Zamia furfuracea or Zamia neurophyllidia.
Reproductive Structures
Zamia boliviana is strictly dioecious. Male plants produce up to five cylindrical pollen cones per crown, on short peduncles. The cones are covered in solid yellow-cream tomentum (pubescence). Female plants produce a single seed cone (megastrobilus) per crown, cream-tan with green undertones to cream-yellow or tan.
The seeds have a sclerotesta (hard inner seed coat) measuring 11 to 15 mm long and 7 to 10 mm wide, enclosed in a fleshy sarcotesta that is red-orange at maturity.
Research on the reproductive biology of Zamia boliviana in the Cerrado has revealed intimate plant-pollinator interactions involving Pharaxonotha beetles, consistent with the obligate insect pollination syndrome observed across the genus. However, studies have documented a male-biased effective sex ratio in wild populations, with only about 71% of females reproducing over a given monitoring period. This low reproductive output, combined with slow growth, makes populations vulnerable to disruption even when overall numbers appear stable.
Root System
Coralloid roots hosting nitrogen-fixing Nostoc cyanobacteria are present, as in all cycads. The symbiosis is particularly important in the nutrient-poor, acidic latosol soils of the Cerrado, where available nitrogen is limited.
Zamia boliviana vs. Zamia brasiliensis: A Comparative Guide
Zamia brasiliensis, described by Calonje and Segalla in 2019 from Mato Grosso and Rondônia (Brazil), is the closest relative of Zamia boliviana. The two species have adjacent but non-overlapping distributions: Zamia brasiliensis occurs to the east of Zamia boliviana, at the interface between the Cerrado and the Amazonian forest. Their separation into distinct species was supported by consistent morphological differences and geographic isolation. A third related species, Zamia ulei, is an Amazonian species readily distinguished by its prickly petioles.
| Feature | Zamia boliviana | Zamia brasiliensis |
|---|---|---|
| Distribution | N. Bolivia, W. Brazil (Mato Grosso) | E. Brazil (Mato Grosso, Rondônia) |
| Habitat | Cerrado savanna, open woodland | Transitional forest, semi-deciduous |
| Stem | Subterranean, cylindrical | Subterranean |
| Petiole | Unarmed (no prickles) | Unarmed (no prickles) |
| Leaflet width | 1.1–2.0 cm (narrow) | Significantly broader |
| Leaflet shape | Linear-lanceolate | Elliptic to oblong |
| Pollen cone tomentum | Solid yellow-cream | Orange-brown on sterile apex |
| Megastrobilus peduncle | Short | Long (15+ cm) |
| IUCN status | Least Concern (LC) | To be assessed |
The single fastest identification cue is leaflet width: narrow, grass-like leaflets (1–2 cm) indicate Zamia boliviana; significantly broader leaflets indicate Zamia brasiliensis. The tomentum color on male cones provides a secondary confirmation.
Growing Zamia boliviana: Complete Care Guide
Light and Exposure
Unlike most Zamia species, Zamia boliviana grows in open, sun-exposed environments in the wild. In cultivation, it thrives in full sun to partial shade. This sun tolerance makes it better suited to outdoor conditions in subtropical gardens than the shade-demanding forest zamias.
Soil and Drainage
This is the most critical cultural factor. Zamia boliviana is adapted to the extremely well-drained, acidic, mineral-rich latosol soils of the Cerrado. In cultivation, use a predominantly inorganic, very well-drained mix with at least 80% mineral components (coarse sand, pumice, perlite, laterite) and minimal organic matter. A slightly acidic to neutral pH (5.5 to 6.5) is preferable. Waterlogging is rapidly fatal.
Watering
The species experiences a pronounced dry season in its native habitat (Cerrado climate: approximately 5 to 6 dry months per year). In cultivation, water moderately during the warm growing season and reduce watering sharply during the cool or dormant period. The subterranean caudex stores water reserves but is highly susceptible to rot in wet, cool conditions.
Temperature and Cold Hardiness
Zamia boliviana is adapted to warm tropical conditions with daytime temperatures of 25 to 32 °C and nighttime minima of 19 to 22 °C during the growing season. However, the Cerrado climate includes a cooler dry season, and the species’ subterranean caudex provides inherent frost protection.
No precise cold hardiness data from specialist growers are widely available for this species. Based on its Cerrado origin (where occasional night temperatures in the cooler months can approach 10 °C or lower at higher-elevation sites) and its subterranean habit, a cautious estimate of USDA zone 10a to 10b (minimum −1 to 1.7 °C) for established plants seems reasonable, with zone 9b marginal at best and only with dry winter conditions. Container culture with frost-free winter storage is the safest approach in any climate cooler than USDA 10a.
Humidity
The species tolerates moderate humidity (70 to 90% during the wet season in habitat) but also withstands lower humidity during the dry season. In cultivation, average indoor humidity is generally adequate.
Fertilization
A light, low-nitrogen fertilizer regime is appropriate. In the Cerrado, soils are nutrient-poor, and the species is adapted to oligotrophic (low-nutrient) conditions. Avoid heavy organic feeds.
Container Culture
An interesting collector’s plant for heated greenhouses and bright conservatories. The subterranean growth habit, narrow leaflets, and manageable size make it well-suited to pot culture. Use a heavy, mineral-rich, fast-draining substrate in a terracotta pot. The species’ tolerance of a dry dormancy period simplifies winter management under glass.
Propagation
Seed is the primary propagation method. Seeds must be cross-pollinated between male and female plants. In the native range, pollination is carried out by Pharaxonotha beetles; in cultivation, hand pollination is necessary. Clean seeds of their sarcotesta and sow in warm (25 to 30 °C), moist, well-drained mineral medium. Germination is slow.
Toxicity
All parts of Zamia boliviana are toxic due to the presence of cycasin and related compounds. Keep away from pets and children.
Conservation Status
Zamia boliviana is classified as Least Concern (LC) on the IUCN Red List (assessed 2020, published 2022), the lowest threat category. This is notable within a genus where many species are Endangered or Critically Endangered.
The Least Concern status reflects the species’ large extent of occurrence (over 651,000 km²), stable population trend, presence within protected areas (including Noel Kempff Mercado National Park), and at least 19 known subpopulations. However, the species was previously classified as Rare (1997) and Near Threatened / Vulnerable (2019 regional review), and ongoing threats should not be underestimated.
Threats
Habitat loss in the Cerrado is the overarching concern. The Cerrado is one of the most threatened biomes on Earth, losing vast areas to soybean agriculture, cattle ranching, and charcoal production every year. Many Zamia boliviana populations lie outside formal protected areas and are vulnerable to land conversion.
Fire regime changes — While Zamia boliviana is adapted to natural fire, altered fire regimes (more frequent or more intense fires driven by agricultural management) can reduce population viability, particularly affecting seedlings and juveniles.
Illegal collection for the ornamental trade is a potential risk, though no major population declines from this source have been documented.
Pollinator decline — The use of insecticides and herbicides in agricultural areas adjacent to Zamia boliviana populations could reduce the specialized Pharaxonotha beetle pollinators, impairing reproduction in fragmented populations.
Frequently Asked Questions
Is Zamia boliviana a rainforest plant? No — this is one of the key distinguishing features of the species. Unlike most Zamia, Zamia boliviana grows in the open savannas and dry woodlands of the Cerrado biome. It is adapted to full sun, seasonal drought, fire, and nutrient-poor soils.
How does Zamia boliviana differ from Zamia brasiliensis? The two species are close relatives sharing unarmed petioles and subterranean stems, but Zamia boliviana has narrow, linear-lanceolate leaflets (1–2 cm wide) while Zamia brasiliensis has significantly broader leaflets. Male cone tomentum also differs: solid yellow-cream in Zamia boliviana vs. orange-brown-tipped in Zamia brasiliensis.
Is Zamia boliviana endangered? No — it is currently classified as Least Concern by the IUCN, with a stable population trend and a large extent of occurrence. However, the Cerrado biome itself is heavily threatened by agricultural expansion, and long-term monitoring is essential.
Is Zamia boliviana easy to grow? It requires very specific conditions: excellent drainage (mineral-rich substrate), full sun to partial shade, warm temperatures, and a dry dormancy period. It does not tolerate waterlogging or heavy organic soils. For growers willing to replicate Cerrado-like conditions, it is a manageable and rewarding species.
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.
- Calonje, M. & Segalla, R. (2019). Zamia brasiliensis, a new species of Zamia (Zamiaceae, Cycadales) from Mato Grosso and Rondônia, Brazil. Phytotaxa, 404(1): 1–12.
- Glos, R.A.E. et al. (2022). Leaflet Anatomical Diversity in Zamia (Cycadales: Zamiaceae). The Botanical Review.
- 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.
- Osborne, R., Calonje, M.A., Hill, K.D., Stanberg, L. & Stevenson, D.W. (2012). The world list of Cycads. Memoirs of the New York Botanical Garden, 106: 480–510.
- POWO (2026). Zamia boliviana (Brongn.) A.DC. Plants of the World Online. Royal Botanic Gardens, Kew. https://powo.science.kew.org/
- IUCN Red List of Threatened Species. Zamia boliviana. https://www.iucnredlist.org/