''Lecythis ollaria'' (paradise nut) is a species of

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

found growing in forests in

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, Guyana, and

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

. The tree is known locally as coco de mono, and accumulates

selenium Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...

in its tissues.

Description

It is a large

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

tree growing to tall with spreading branches; it is in the same family (

Lecythidaceae The Lecythidaceae ( ) comprise a family of about 20 genera and 250–300 species of woody plants native to tropical South America, Africa (including Madagascar), Asia and Australia. Well known members of the family include the cannonball tree ...

) as the

Brazil nut The Brazil nut (''Bertholletia excelsa'') is a South American tree in the family Lecythidaceae, and it is also the name of the tree's commercially harvested edible seeds. It is one of the largest and longest-lived trees in the Amazon rainforest. ...

(''Bertholletia excelsa'') and has similar fruit. This is a large woody capsule up to diameter and very heavy, with a lid which bursts open when the seeds are ripe. Monkeys are said to put their hands inside the capsule in order to extract the seeds which have a fleshy interior rich in oil and a woody outer casing.

Toxicity

The nuts have a pleasant flavour and are eaten by humans. When two previously healthy women in South America developed unexplained nausea, vomiting and neurological symptoms, followed two weeks later by heavy hair loss, no cause could at first be found. It was later established that they were suffering from acute

toxicity brought on by eating paradise nuts. They still had elevated levels of selenium in their blood eight weeks after they had eaten the nuts. Further investigation of the tree found that the tissues of the bark, leaves, capsules and seeds all contained selenium but that the highest concentration was in the nuts which contained about five grams per kilogram, about half of which was soluble in water. The tree is considered to be a selenium accumulator and part of the element is bound to very selenium-rich

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

Status

The

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological spe ...

lists the paradise nut as being of

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

. This is because it has a widespread geographical distribution in the tropical rainforest.

References

{{Taxonbar, from=Q3285280 ollaria Trees of Brazil Trees of Venezuela Least concern plants Plants described in 1759 Taxonomy articles created by Polbot Taxa named by Carl Linnaeus