Zamia urarinorum

Zamia urarinorum is a cycad of the Peruvian Amazon, known from the department of Loreto, in the basins of the Chambira and Urituyacu rivers, tributaries of the Marañón, where it grows in swamp forests and peatlands, often standing in water. Described in February 2026, it is the most recently named species of the genus Zamia and the only cycad known to live in permanently waterlogged soils. Its name honours the Urarina people, who live on these floodplains. The IUCN has not yet assessed it; its authors recommend that it be rated Endangered.

Key facts about Zamia urarinorum

  • Accepted name: Zamia urarinorum Calonje, R. Zárate & M.Asa Jones (2026), accepted by The World List of Cycads (version 2026.08.15) and listed by GBIF; POWO could not be consulted directly
  • Former names and synonyms: none
  • Family: Zamiaceae, order Cycadales
  • Common names: none attested, in English or in any other language
  • Natural range: Peru, department of Loreto (Urarinas district: Tigrillo and Urituyacu rivers, Curuinsi), six known localities, at 115 to 180 m
  • IUCN status: Not Evaluated (NE); Endangered (EN) recommended by the authors of the description
  • CITES and other protection: CITES Appendix II (whole genus, since 1977; seeds exempt under annotation #4); Annex B in the European Union
  • Documented hardiness: no data (see Cold hardiness)
  • Light and soil: in the wild, from full sun in open peatlands to the shade of palm forests; acid peat or organic soils, permanently saturated; no growing advice published
  • Habit and adult size: slender above-ground stem 14 to 150 cm tall and 4.5 to 12 cm across; 2 to 6 leaves 68 cm to 3 m long
  • In the UK, US and Australia: no living plant recorded
  • Toxicity: no data specific to the species; treat it as poisonous, like all cycads (see Toxicity and precautions)

How to recognise Zamia urarinorum

Look for a slender above-ground stem, few leaves, a petiole bristling with prickles, and long, narrow leaflets, finely toothed only towards the tip and marked above by a raised lengthwise crease. The description below follows the original publication (Calonje and colleagues, 2026):

  • Stem: above ground, cylindrical, usually solitary, sometimes with two heads, 14 to 150 cm tall and 4.5 to 12 cm across; cataphylls triangular, 4.5 to 5.5 cm long, covered in grey-brown to yellow-brown felt.
  • Leaves: 2 to 6 per stem, upright to slightly spreading, 68 cm to 3 m long and 20 to 90 cm wide. The petiole, 28 to 136 cm long, is moderately to heavily armed with prickles 2 to 5 mm long, often pointing upwards; the rachis, 27 to 166 cm long, is unarmed or lightly armed. Petiole and rachis of young leaves are covered in white felt.
  • Leaflets: 10 to 52, papery to leathery, opposite or nearly so, narrowly elliptic to lanceolate, with a long drawn-out tip and a raised lengthwise crease above; the margin carries 10 to 41 fine teeth on the upper third or quarter. Median leaflets measure 10.7 to 45.6 cm by 2.5 to 7.8 cm, with 24 to 46 parallel veins. Young leaflets are pale yellowish green, turning mid-green in sun and dark brownish green in shade.
  • Male cones: 4 to 8 per head, conical-cylindrical, 5.1 to 5.2 cm long and 1.1 to 1.2 cm across at pollen release, covered in orange-pink to brown felt, on a peduncle 4.8 to 9 cm long; the cone axis is hairy.
  • Female cones: one per head, 13 to 19.5 cm long and 3.8 to 5.3 cm across when ripe, cylindrical, with a broad, blunt sterile tip, covered in grey-brown felt, on a peduncle 5.5 to 11.5 cm long.
  • Seeds: ovoid-pyramidal, 11.6 to 15.6 mm long and 7.8 to 9.3 mm wide, with a light red to orange-red fleshy coat.

Leaf shape varies with light. In open peatlands, in full sun, plants have shorter leaves and narrower, yellower leaflets that are often curved back; in the shade of closed forest, leaves are longer and leaflets broader and darker. The reproductive organs, on the other hand, are the same everywhere (Calonje and colleagues, 2026).

Hybrids

No hybrid is known.

Possible confusion

The closest species is Zamia multidentata, described in 2023 from the Serra do Divisor (Acre, Brazil) and reported from Peru in the same 2026 paper. Both have a slender above-ground stem and toothed leaflets. According to Calonje and colleagues (2026), Zamia urarinorum differs in having:

  • fewer leaves (2 to 6 per stem, against 8 to 14);
  • narrowly elliptic to lanceolate leaflets, up to 45.6 cm long (against ovate to elliptic leaflets no longer than 21.7 cm), finely toothed only on the upper third or quarter;
  • much smaller male cones (5.1 to 5.2 cm against 8.2 to 8.3 cm), with a hairy axis (hairless in Zamia multidentata);
  • female cones on shorter peduncles (5.5 to 11.5 cm against 12 to 17.5 cm in the 2026 comparative table; the 2023 description of Zamia multidentata gives 15 to 19 cm) and smaller seeds;
  • a permanently flooded habitat, whereas the 2026 authors describe Zamia multidentata as a species of well-drained terra firme forest.

Two other Amazonian species come close: Zamia hymenophyllidia, with membranous leaflets whose veins are raised above, and Zamia urep, from Huánuco, with an underground stem and strongly veined leaflets. Zamia poeppigiana, the other trunk-forming Amazonian Zamia, is far more massive: up to 3 m tall and 25 cm across.

Taxonomy

Zamia urarinorum is accepted by The World List of Cycads and listed as accepted by GBIF; POWO could not be consulted directly. The species has no synonyms. It was described by Michael Calonje (Montgomery Botanical Center, Florida), Ricardo Zárate-Gómez (Research Institute of the Peruvian Amazon, IIAP) and Malcolm A. Jones, with Rosane Segalla, Manuel Martín Brañas, Carlos Gabriel Hidalgo Pizango and Fernando Roca Alcázar, in the journal Phytotaxa (volume 741, pages 1 to 17), published on 12 February 2026.

With it, the Amazon basin has eleven species of Zamia, four of them with an above-ground stem: Zamia poeppigiana, Zamia multidentata, Zamia hymenophyllidia and Zamia urarinorum. Above-ground stems were long thought to be rare in the region, where only Zamia poeppigiana was recognised in the early 2000s. For its authors, the discovery confirms that the diversity of Amazonian cycads is still underestimated (Calonje and colleagues, 2026). Being so recent, the species was not sampled in the transcriptome phylogeny of the genus published by Lindstrom and colleagues in 2024.

Etymology and history

The epithet urarinorum, “of the Urarina”, honours the indigenous Urarina people, in recognition of their long presence in, and stewardship of, the flooded lowlands of the Peruvian Amazon where the species grows. The Urarina, about 5,812 people at the 2017 census, live on the Pastaza alluvial fan, between the Chambira and Corrientes basins (Calonje and colleagues, 2026).

The species was spotted during a biodiversity survey along the Tigrillo river, in the district of Urarinas, by an IIAP expedition devoted to the biodiversity and social dimensions of Urarina territory, in March and April 2025. The plants were studied at the communities of Raya Yacu, Nuevo Horizonte and Puerto Rico. The holotype was collected on 12 April 2025 at Raya Yacu, at 135 m, by Ricardo Zárate, Michael Calonje and Malcolm Jones (number 24417); it is kept at the herbarium of San Marcos University in Lima (USM), with duplicates in the HH and FTG herbaria. Two older collections, made in August 2003 at Juan Velasco Alvarado and Reforma, also belong to the species (Calonje and colleagues, 2026).

Common names

No common name is attested for this species, in English, Spanish or Urarina.

In the wild

Zamia urarinorum is known from six localities in the department of Loreto: three along the Tigrillo river, which flows into the Chambira shortly before the latter joins the Marañón, two along the Urituyacu, a direct tributary of the Marañón, and one near the community of Curuinsi. These sites, at 115 to 180 m, lie on the southern edge of the Pastaza alluvial fan, the largest humid tropical alluvial fan in the world, which holds the largest known peatland complex in Amazonia (Calonje and colleagues, 2026).

The species occupies three types of humid forest, all on soils saturated with water and flooded periodically or permanently:

  • peat forests with slender trees (“varillales hidromórficos”), on deep peat (89 to 251 cm on average depending on the site, up to 3.80 m), acid (pH close to 4) and poor, where the water table stays near the surface; the species is most abundant in their open, fully lit form;
  • “shebonal” forests, flooded for part of the year and dominated by the palm Attalea phalerata, without peat accumulation, where it is fairly common;
  • aguaje palm swamps (“aguajal”, dominated by Mauritia flexuosa), where it is rare.

In April 2025 most plants had their stems partly or wholly under water. They root directly in the water, not only on hummocks or at the foot of trees, without any sign of root or stem rot, even after long submersion. One adult plant, on a flooded bank, even had its growing tip fully submerged, and remained healthy. Other Zamia live under very heavy rainfall, such as Zamia chigua and Zamia roezlii of the Chocó, but the latter, which grows near mangroves, keeps to hummocks that do not flood. Zamia urarinorum is the only cycad known to thrive in permanently saturated, oxygen-poor soils (Calonje and colleagues, 2026).

The climate is humid tropical: 2,040 to 2,830 mm of rain a year (2,380 mm on average), with a marked rainy season from March to May, and mean maximum temperatures of 34 °C (93.2 °F) almost constant all year. The pollinator is not known, but the authors suspect a beetle of the genus Pharaxonotha, which pollinates other South American Zamia. They observed extensive leaf damage, including a caterpillar of the butterfly Eumaeus toxana, a regular feeder on American cycads. A male cone was shedding pollen on 13 March 2025; in April the plants carried new leaves, nearly ripe female cones and young male cones (Calonje and colleagues, 2026).

Conservation status and regulation

Zamia urarinorum has not yet been assessed by the IUCN (Not Evaluated in The World List of Cycads, version 2026.08.15). Its authors recommend that it be rated Endangered (EN) under criteria B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v): its extent of occurrence is 2,280 km² and its area of occupancy 24 km² (22 km² in another passage of the paper), and several plausible threats could affect all the subpopulations. This preliminary assessment has no official standing (Calonje and colleagues, 2026).

The three localities on the Tigrillo river are very isolated, without roads and little affected by people: low population density, the absence of roads and Urarina traditions that favour the forest limit deforestation there. The authors nevertheless list emerging threats: pollution from oil pipeline leaks, road and power-line projects, commercial agriculture, unsustainable harvesting of forest products and the erosion of traditional knowledge. Above all, the species depends on a permanent water regime: any change in drainage, rainfall or climate could be fatal to it in the wild.

Like all Zamia except Zamia restrepoi, which is in Appendix I, Zamia urarinorum falls under CITES Appendix II, where the genus has been listed since 4 February 1977. The listing carries annotation #4 (version adopted at CoP20, in force on 5 March 2026): seeds, pollen, seedlings and tissue cultures obtained in vitro and transported in sterile containers, and cut flowers of artificially propagated plants, are not covered by CITES. International trade in the plants themselves, on the other hand, requires an export permit. In the European Union the species is listed in Annex B of Regulation (EC) No 338/97, whose annexes are now set by Regulation (EU) 2026/1383, applicable since 29 June 2026. Species+ does not yet name the species, but the listing covers the whole genus (“Zamia spp.”) and therefore includes it (checked on 3 October 2026).

This general information does not replace the official texts: check the regulations in force before buying or exchanging plants, ask the seller for proof of origin, and prefer plants raised from cultivated seed.

Growing Zamia urarinorum

No growing advice has been published, and no grower’s report is documented: described in 2026, the species does not seem to be in cultivation yet, in Europe or elsewhere.

It raises an unusual question for a cycad. Zamia, like most cycads, dislike sodden soil, and overwatering is the leading cause of rot in cultivation. Zamia urarinorum is the exception in the wild, but nothing shows how it would behave in a pot, away from its habitat: constant heat, moving water, acid peat and the root associations of these swamps. The authors see in it new physiological adaptations that remain to be studied. Any attempt at cultivation would belong in a heated glasshouse and would remain experimental.

In cultivation in the UK, US and Australia

No living plant is recorded. BGCI has no entry for the species, the online catalogue of Montgomery Botanical Center (Coral Gables, Florida) has none either, and the British nursery Trebrown does not list it (all queried on 25 October 2026). Duplicates of the type are kept in the herbarium of Fairchild Tropical Botanic Garden (FTG), in Miami, but these are dried specimens, not living plants.

Propagation

No data specific to the species. Like all Zamia, it has separate male and female plants and would be propagated from fresh seed. No germination data have been published.

Pests and diseases

In the wild, the authors noted extensive herbivore damage to the leaves, including caterpillars of Eumaeus toxana. No disease is documented, and submerged plants showed no rot (Calonje and colleagues, 2026).

Cold hardiness

There are no cold-tolerance data for Zamia urarinorum. It lives in the Amazonian lowlands, under mean maximum temperatures of 34 °C (93.2 °F) that hardly vary through the year; nothing suggests that it can withstand frost.

Mediterranean and European experience

No cultivation result has been published in France or Italy, outdoors or in a pot, and no dated frost episode concerns this species. The Jardin zoologique tropical in La Londe-les-Maures, in the Var (southern France), has no observation of it; its only pointer for the genus, a Zamia integrifolia from Florida that survived −7 °C (19.4 °F) in February 2012 with foliage damage, says nothing about an Amazonian swamp species. Only heated glasshouse culture is conceivable.

United Kingdom, United States and Australia

No cold record exists, and no hardiness zone has been given by any source. In the UK it would need a heated glasshouse all year; even in southern Florida or tropical northern Australia, its saturated, peaty habitat would be hard to reproduce outdoors. This is a deduction from the habitat, not a tested result.

Toxicity and precautions

No toxicity study specific to Zamia urarinorum has been published. The risk is, however, documented in the genus and in other cycads: Zamia contain toxic glycosides (cycasin, macrozamin), from which methylazoxymethanol is derived, and the ASPCA cites for Zamia furfuracea cycasin and BMAA, a neurotoxic amino acid, with vomiting, bloody diarrhoea and liver damage in dogs, cats and horses; the seeds are the most dangerous part. In the absence of evidence to the contrary, treat the plant as poisonous: keep seeds and leaves out of reach of children and animals, and wear gloves to clean seeds. If any part is swallowed, contact a poison centre, a doctor or a vet straight away.

Traditional uses

The description of the species documents no use of the plant by the Urarina or other local people.

Frequently asked questions

What does the name urarinorum mean?

“Of the Urarina”. The epithet honours the Urarina people, who live on the floodplains of Loreto, in Peru, where the species grows.

When was it discovered?

In 2025, and it was described in February 2026. It was spotted during a biodiversity survey along the Tigrillo river; two collections from 2003 were later referred to it. It is the most recently described Zamia.

Can a cycad really live in water?

This one can. Its roots, and sometimes its stem, grow under water in permanently saturated peatlands without rotting. It is the only cycad known to be adapted to such a habitat; the others are harmed by excess water.

So should it be watered heavily in cultivation?

Nobody knows. No cultivation has been documented, and the conditions of its swamp (heat, moving water, acid peat) are hard to reproduce. For other Zamia, excess water remains dangerous.

How does it differ from Zamia multidentata?

By its fewer leaves (2 to 6 instead of 8 to 14), its longer, narrower leaflets toothed only near the tip, its much smaller male cones and its flooded habitat.

Is it endangered?

Probably. The IUCN has not yet assessed it, but its authors recommend an Endangered rating: six known localities and a strong dependence on a water regime that could change.

Is it hardy?

Almost certainly not. It lives in the Amazonian lowlands, in a climate that is hot all year; it would need a heated glasshouse.

Is it poisonous?

It must be assumed so. No analysis concerns the species, but the cycads studied contain serious toxins, especially in the seeds.

Further reading on Succulentes

Sources

Reference sites

Bibliography

  • Calonje, M., Zárate-Gómez, R., Jones, M.A., Segalla, R., Martín Brañas, M., Hidalgo Pizango, C.G. & Roca Alcázar, F. (2026). Zamia urarinorum (Cycadales, Zamiaceae), a new cycad species from wetland forests of Loreto, Peru. Phytotaxa 741(1): 1–17. https://doi.org/10.11646/phytotaxa.741.1.1 [Original description; full text read.]
  • Segalla, R., Soares-Pimenta, R. & Calonje, M. (2023). Zamia multidentata (Cycadales, Zamiaceae), a new arborescent species of Zamia from Acre, Brazil. Phytotaxa 598(1): 21–31. https://doi.org/10.11646/phytotaxa.598.1.2 [Closest species; original description read.]
  • Lindstrom, A., Habib, S., Dong, S., Gong, Y., Liu, J., Calonje, M., Stevenson, D. & Zhang, S. (2024). Transcriptome sequencing data provide a solid base to understand the phylogenetic relationships, biogeography and reticulated evolution of the genus Zamia L. (Cycadales: Zamiaceae). Annals of Botany 134(5): 747–768. https://doi.org/10.1093/aob/mcae065 [Published before the description; the species is not sampled.]
  • Calonje, M., Stevenson, D.W. & Osborne, R. (2026). The World List of Cycads, version 2026.08.15. Montgomery Botanical Center, Coral Gables. https://doi.org/10.5281/zenodo.21958524 [Reference checklist; consulted directly.]