The Brazil nut tree is the only species in the monotypic genus Bertholletia. It is native to the Guianas, Venezuela, Brazil, eastern Colombia, eastern Peru, and eastern Bolivia. It occurs as scattered trees in large forests on the banks of the Amazon River, Rio Negro, Tapajós, and the Orinoco. The genus is named after the French chemist Claude Louis Berthollet.
The Brazil nut is a large tree, reaching 50 m (160 ft) tall and with a trunk 1 to 2 m (3.3 to 6.6 ft) in diameter, making it among the largest of trees in the Amazon rainforests. It may live for 500 years or more, and according to some authorities often reaches an age of 1,000 years. The stem is straight and commonly without branches for well over half the tree's height, with a large emergent crown of long branches above the surrounding canopy of other trees.
The bark is grayish and smooth. The leaves are dry-season deciduous, alternate, simple, entire or crenate, oblong, 20–35 cm (7.9–13.8 in) long and 10–15 cm (3.9–5.9 in) broad. The flowers are small, greenish-white, in panicles 5–10 cm (2.0–3.9 in) long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass.