Joannesia princeps, the arara nut-tree or andá-açu, is a species of moderate-sized tree in the family Euphorbiaceae, with a spreading canopy, large alternate and long petioled leaves, and coarse branches. Flowers are monoecious, and fruit is a large drupe. It is endemic to east Minas Gerais, north Espírito Santo to the south of Bahia, Brazil, and threatened by habitat loss.