Acai, (Euterpe oleracea), also spelled assai or assaÃ, species of palm (family Arecaceae) cultivated for both its fruit and edible hearts of palm. Native to tropical South and Central America, acai palms are common along the Amazon River estuary and are cultivated on floodplains, especially in the state of Pará in Brazil. The plant has long been valued commercially for its high-quality hearts of palm, and its fruits, touted as a superfood, grew in popularity worldwide in the early 21st century.