Iriartea Ruiz & Pav.
  • Fl. Peruv. Prodr.: 149 (1794) 

Notes: Distribution: C. & S. Trop. America

General Description

Solitary, robust, often very tall, unarmed, pleonanthic, monoecious tree palm. Stem erect, ± bellied, conspicuously ringed with leaf scars, bearing slender stilt roots forming a dense cone obscuring the stem base. Leaves rather few in number, pinnate, neatly abcising; sheaths forming a well-defined crownshaft; petiole rather short, adaxially channelled, abaxially rounded; rachis adaxially angled, abaxially rounded; leaflets large, asymmetrically deltoid to elliptic, the proximal margin entire for ca. 1/3 its length then praemorsely toothed, the distal margin entire for a shorter distance, then praemorsely toothed, ribs conspicuous sometimes with scaly margins, the main ribs diverging from the base to the margin, the whole leaflet usually irregularly split into linear segments displayed in different planes giving the leaf a plumose appearance, transverse veinlets not evident. Inflorescences solitary, infrafoliar, pendulous, strongly curved in bud, branching to 1 order distally to 2 orders proximally, protandrous; peduncle massive, ± circular in cross-section; prophyll short, tubular, 2-keeled, apically open; peduncular bracts 8–12, spirally arranged, tubular, the proximal several short, soon splitting, the distal very long, tubular, enclosing the inflorescence, all bracts variously hairy, eventually deciduous, leaving conspicuous, close annular scars; rachis equalling or slightly longer than the peduncle, bearing spirally arranged, minute, collar-like bracts; first-order branches digitately branched proximally, unbranched distally, bases of branches swollen; rachillae very long, moderately robust, bearing spirally arranged, slightly sunken, close triads throughout their length except at tips where bearing solitary or paired staminate flowers; rachilla bracts and floral bracteoles not evident. Staminate flowers ± symmetrical; sepals 3, distinct, gibbous, rounded, imbricate, bearing deciduous, bristle-like hairs; petals 3, 3–4 times longer than the sepals, valvate, ± boat-shaped and curved, the tips rounded to acute; stamens 9–20, filaments very short, slender, anthers elongate, acute to mucronate apically, latrorse; pistillode minute or lacking. Pollen ellipsoidal, ± bi-symmetric; aperture a distal sulcus; ectexine intectate, closely to densely gemmate, gemmae often coalesced into larger units, sometimes with large well-defined gemmae, surrounded by smaller gemmae, aperture margin similar; longest axis 31–35 µm [1/1]. Pistillate flowers smaller than the staminate; sepals 3, distinct, broadly imbricate; petals 3, distinct, broad, rounded, imbricate except at the triangular valvate tips; staminodes to 12, very small, tooth-like; gynoecium globose, trilocular, triovulate, stigmas 3, low, only 1 ovule normally maturing, basally attached, form unknown. Fruit mostly globose, yellow when ripe, stigmatic remains apical; epicarp smooth, mesocarp granular and fibrous, endocarp very thin. Seed globose, basally attached, hilum circular, raphe branches coarse anastomosing, endosperm homogeneous; embryo lateral. Germination adjacent-ligular; eophyll praemorse, undivided. Cytology: 2n = 32.

Diagnostic Description

Robust solitary pinnate-leaved palm of humid rain forest in Central and South America, the stems with a dense cone of stilt roots and sometimes ventricose; leaflets are rhomboid, praemorse, longitudinally divided to give the whole leaf an ostrich-feather appearance; fruit has apical stigma remains and a lateral embryo.


Leaf (Tomlinson 1961, Roth 1990), root (Seubert 1998a, 1998b, Avalos 2004), stamen development (Uhl and Moore 1980), gynoecium (Uhl and Moore 1971), seed (Roth 1990).


Frequently gregarious in lowland tropical rain forest but reaching 1200 m, often as a distinct component of the forest canopy. Pollination is by bees (Henderson 1985).


A single species, distributed from Costa Rica and Nicaragua southwards to Colombia, Ecuador, Peru, Bolivia, Venezuela and Brazil.


The outer part of the trunk is extremely hard and durable and is used in the construction of dwellings and in making spears. Wallace (1853) records the use of swollen sections of the trunk as canoes (see also Johnson [1998]). Henderson et al. (1995) recorded the use of stems for coffins in the Choco region of Colombia. For medicinal uses, see Plotkin and Balick (1984).

Common Names

Stilt palm, horn palm.

Distribution Map

  • Native distribution
Found in
  • Southern America Brazil Brazil North
  • Brazil West-Central
  • Central America Costa Rica
  • Nicaragua
  • Panamá
  • Northern South America Venezuela
  • Western South America Bolivia
  • Colombia
  • Ecuador
  • Peru


  • 1 J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008
  • 2 Govaerts, R. & Dransfield, J. (2005). World Checklist of Palms: 1-223. The Board of Trustees of the Royal Botanic Gardens, Kew.

 Information From

Palmweb - Palms of the World Online
Palmweb 2011. Palmweb: Palms of the World Online. Published on the internet Accessed on 21/04/2013
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Global Biodiversity Information Facility
  • C All Rights Reserved
eMonocot. (2010, 1st November). Retrieved Wednesday, 8th February, 2012, from
  • D Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
World Checklist of Selected Plant Families
WCSP 2014. 'World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; Retrieved 2011 onwards
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