The açaí palm (, , from Nheengatu asai), Euterpe oleracea, is a species of palm tree (Arecaceae) cultivated for its fruit (açaí berries, or simply açaí), hearts of palm (a vegetable), fronds, and trunk wood. Global demand for the fruit has expanded rapidly in the 21st century, and the tree is cultivated for that purpose primarily. The species is native to eastern Amazonia, especially in Brazil, mainly in swamps and floodplains. Açaí palms are tall, slender trees growing to more than tall, with pinnate frons up to long. The fruit is small, round, and black-purple in color. The fruit became a staple food in floodplain areas around the 18th century, but its consumption in urban areas and promotion as a health food only began in the mid 1990s along with the popularization of other Amazonian fruits outside the region. Name The common name comes from the Portuguese adaptation of the Tupian word , meaning "[fruit that] cries or expels water". The importance of the fruit as a staple food in the Amazon River delta gives rise to the local legend of how the plant got its name. The folklore says that chief Itaqui ordered all newborns put to death owing to a period of famine. When his own daughter gave birth and the child was sacrificed, she cried and died beneath a newly sprouted tree. The tree fed the tribe and was called açaí because that was the daughter's name (Iaçá) spelled backwards. Its specific epithet oleracea means "vegetable" in Latin and is a form of (). Fruit The fruit, commonly known as açaí berry or açaí, is a small, round, black-purple drupe about in circumference, similar in appearance to a grape, but smaller and with less pulp and produced in branched panicles of 500 to 900 fruits. The exocarp of the ripe fruits is a deep purple color, or green, depending on the kind of açaí and its maturity. The mesocarp is pulpy and thin, with a consistent thickness of or less. It surrounds the voluminous and hard endocarp, which contains a single large seed about in diameter. The seed makes up about 60-80% of the fruit. The palm bears fruit year round but the berry cannot be harvested during the rainy season. Cultivation There are two harvests: one is normally between January and June, while the other is between August and December. The last harvest is the most