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From Wikipedia, the free encyclopedia
The Brazil nut is a South American tree Bertholletia excelsa in the family Lecythidaceae, and also the name of the tree's commercially harvested edible seeds.
The Brazil nut tree is the only species in the 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, Rio Negro, and the Orinoco. The genus is named after the French chemist Claude Louis Berthollet.
It is a large tree, reaching 30–45 m (100–150 ft) tall and 1–2 m (3–6.5 ft) trunk diameter, 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 unbranched 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 long and 10–15 cm broad. The flowers are small, greenish-white, in panicles 5–10 cm long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass.
Brazil nuts only produce fruit in virgin forests (forests not previously disturbed by human activity), as forests that are not virgin usually lack an orchid that is indirectly responsible for the pollination of the flowers.[cite this quote] The Brazil nut tree's yellow flowers can only be pollinated by an insect strong enough to lift the coiled hood on the flower and with tongues long enough to negotiate the complex coiled flower. The orchids produce a scent that attracts small male long-tongued orchid bees (Euglossa spp), as the male bees need that scent to attract females. The large female long-tongued orchid bee pollinates the Brazil nut tree. Without the orchid, the bees cannot mate, and therefore the lack of bees means the fruit do not get pollinated.
If both the orchids and the bees are present, the fruit takes 14 months to mature after pollination of the flowers, and is a large capsule 10–15 cm diameter resembling a coconut endocarp in size and weighing up to 2 kg. It has a hard, woody shell 8–12 mm thick, and inside contains 8–24 triangular seeds 4–5 cm long (Brazil nuts) packed like the segments of an orange; it is not a true nut in the botanical sense.
The capsule contains a small hole at one end, which enables large rodents like the Agouti to gnaw open the capsule. They then eat some of the nuts inside while burying others for later use; some of these are able to germinate to produce new Brazil nut trees. Most of the seeds are "planted" by the Agoutis in shady places, and the young saplings may have to wait years, in a state of dormancy, for a tree to fall and sunlight to reach it. It is not until then that it starts growing again. Capuchin monkeys have been reported to open Brazil nuts using a stone as an anvil.