Iriartea deltoidea

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Iriartea deltoidea
Iriartea deltoidea 049.jpg

Iriartea deltoidea

Systematics
Monocots
Commelinids
Order : Palm- like arecales
Family : Palm family (Arecaceae)
Genre : Iriartea
Type : Iriartea deltoidea
Scientific name of the  genus
Iriartea
Ruiz & Pav.
Scientific name of the  species
Iriartea deltoidea
Ruiz & Pav.

Iriartea deltoidea is a South American palm tree . It is the only species of the genus Iriartea and named after the Spanish diplomat Bernardo de Iriarte (1735–1814).

features

Iriartea deltoidea is an often very large, single-stemmed and monocular palm. The trunk is upright, often bulbous and covered with conspicuous, ring-shaped leaf scars. It reaches a height of up to 25 m with a diameter of 10 to 30 cm. Up to 100 slender stilt roots form a dense cone that covers the base of the trunk. The stilt roots are up to 2 m long and 3.5 cm thick and are studded with spines.

The chromosome number is 2n = 32.

leaves

The palm has very few leaves , mostly 4 to 7. These are pinnate and fall off with a smooth scar. The leaf sheaths form a clearly pronounced, 60 to 150 cm long crown shaft. The petiole is rather short, has a groove on the top and is rounded on the underside. The rhachis is angular on the top and rounded on the underside, and 2 to 4.3 m long. The leaflets are large, asymmetrically rhombic (deltoid, hence the name) to elliptical. The (proximal) leaf margin closer to the petiole has entire margins in the lower third, then toothed out. The distal edge of the leaf is shorter and completely toothed and then torn out. The whole leaflet itself is irregularly split into linear segments that are in different levels and give the leaf a feathery appearance.

Inflorescences

The inflorescences are single and under the leaves (infrafoliar). They hang, are up to 2 m long and are strongly curved in the bud stage. They are branched one to two times, the male flowers open first ( proterandry ). The peduncle is thick and round in cross section. The cover sheet is short, tubular, two-keeled and open at the tip. There are 8 to 12 bracts on the peduncle. They are spiral, tubular, surround the inflorescence and leave conspicuous, almost ring-shaped scars after falling off. The inflorescence axis is the same length as or slightly longer than the stem, it bears small, collar-like bracts in a spiral. The side axes of the first order are finger-shaped in the distal area of ​​the inflorescence, unbranched at the tip of the inflorescence. They are very long and have triads of flowers in a spiral arrangement. At the top of the axes these are reduced to single or paired male flowers.

blossoms

The male flowers are approximately symmetrical. The three sepals are not fused, rounded, imbricat . The three petals are three to four times as long as the calyx, valvate , boat-shaped and curved. There are 9 to 20 stamens with very short stamens and serpentine, long anthers . The rudiment of the stamp is very small or missing entirely. The pollen is ellipsoidal and rather bisymmetrical. The germ opening is a distal sulcus . The longest axis measures 31 to 35 microns.

The female flowers are smaller than the male. The three sepals are free and overlap widely. The three petals are also free, broad, rounded, imbricated with the exception of the triangular valvate tips. The up to 12 staminodes are very small and tooth-shaped. The gynoeceum is spherical, triple with three ovules and three scars . Usually only one ovule matures to seed.

The pollination is done by bees.

Fruits and seeds

The fruit is usually spherical, yellow when ripe and 2 to 2.8 cm in diameter. The remnant of the scar is at the top. The exocarp is smooth, the mesocarp grainy and fibrous, and the endocarp very thin. The seed is spherical, sits basal. The scar (hilum) is circular, the endosperm is homogeneous.

Distribution and locations

Iriartea deltoidea occurs from Costa Rica and Nicaragua south to Colombia, Ecuador, Peru, Bolivia, Venezuela and Brazil. To the east, their distribution is limited to the western Amazon basin.

It grows in tropical lowland rainforest and in low areas of the mountain rainforest. It is seldom to be found above 1300 m above sea level. It grows on slopes and hilltops, in the lowlands also on flat terrain. It does not make any special demands on the floor. In the east of its range it is bound to the edge of rivers. The annual precipitation is mostly between 2000 and 3000 mm, the focus of their distribution is likely to be in areas with more than 2500 mm.

The focus of their geographical distribution are the eastern slopes of the Andes at altitudes between 300 and 1200 m. It is much rarer at lower altitudes.

Systematics

The genus Iriartea is placed within the family Arecaceae in the subfamily Arecoideae , tribe Iriarteeae . The relationships within the tribe have not been clarified. Three studies came to contradicting results.

In the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew, only the species Iriartea deltoidea is recognized.

use

The outer part of the trunk is very hard. It is used for building houses and for making spears. According to Alfred Russel Wallace (1853) the bulbous parts of the trunks are used for canoes. In the Choco region of Colombia, coffins are made from the trunks.

supporting documents

  • John Dransfield, Natalie W. Uhl, Conny B. Asmussen, William J. Baker, Madeline M. Harley, Carl E. Lewis: Genera Palmarum. The Evolution and Classification of Palms . Second edition, Royal Botanic Gardens, Kew 2008, ISBN 978-1-84246-182-2 , pp. 362-364.

Individual evidence

  1. a b c d e f g h i j Andrew Henderson: Arecaceae. Part I. Introduction and the Iriarteinae . Flora Neotropica, Vol. 53, 1990, pp. 1-100. ISBN 0-89327-353-8
  2. Rafaël Govaerts (ed.): Iriartea. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 21, 2009.

Web links

Commons : Iriartea deltoidea  - collection of images, videos and audio files