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

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Discussion

Diagnosis

Biology And Ecology

Uses

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. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)

Anatomy

Fossil record

  • Pinnate leaf fragments from the Miocene of Peru are described as Iriartites tumbezensis (Berry 1919b), although the author comments that this is, “…a convenient form-genus for the remains of fossil palms that appear to belong to tribe Iriarteeae, but whose exact generic identity is uncertain.” Furthermore, material described as Sabalites from the Tertiary of Venezuela (Berry 1921b) resembles a leaf of Iriartea, but these fossils need to be restudied. Gardner (1882) recovered an abundance of pinnate palm leaves from the Middle Eocene Bournemouth Freshwater Beds, which he considered to resemble Iriartea more than any other genus (Chandler 1963). A ‘palm nut’ from the Miocene of the Panama Canal Zone (Gatun) is described as being, “very close to the endocarp of Iriartea” (Berry 1921a) and a seed (Iriartea collazoënsis) recorded from the Middle Oligocene of Puerto Rico is considered to resemble closely those of Arenga and Iriartea (Hollick 1928). The anatomy of a large specimen ofstem wood, Palmoxylon iriarteum, from the West Indies(Antigua), in the collection of the Naturhistoriska Riksmuseet,Stockholm, was described in detail by Stenzel (1897) whoconsidered it ancestral to Iriartea; no age is given. Comparisonsof palm stem wood or root to generic level should always beviewed with caution. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)

Use Record

Uses

Bibliography

A. J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008
B. World Checklist of Arecaceae