Cacao (Theobroma cacao) is a small (4–8 m tall (15-26 ft)) evergreen tree in the family Sterculiaceae (alternatively Malvaceae), native to the deep tropical region of the Americas. There are two prominent competing theories about the origins of the original wild Theobroma cacao tree. One group of proponents believe wild examples were originally distributed from southeastern Mexico to the Amazon basin, with domestication taking place both in the Lacandon area of Mesoamerica and in lowland South America. Recent studies of Theobroma cacao genetics seem to show that the plant originated in the Amazon and was distributed by man throughout Central America and Mesoamerica. Its seeds are used to make cocoa and chocolate.
The bush is today found growing wild in the low foothills of the Andes at elevations of around 200–400 m (650-1300 ft) in the Amazon and Orinoco river basins. It requires a humid climate with regular rainfall and good soil. It is an understory tree, growing best with some overhead shade. The leaves are alternate, entire, unlobed, 10–40 cm (4-16 in) long and 5–20 cm (2-8 in) broad.
The flowers are produced in clusters directly on the trunk and older branches; they are small, 1–2 cm (1/2-1 in) diameter, with pink calyx. While many of the world's flowers are pollinated by bees (Hymenoptera) or butterflies/moths (Lepidoptera), cacao flowers are pollinated by tiny flies, midges in the order Diptera. The fruit, called a cacao pod, is ovoid, 15–30 cm (6-12 in) long and 8–10 cm (3-4 in) wide, ripening yellow to orange, and weighs about 500 g (1 lb) when ripe. The pod contains 20 to 60 seeds, usually called "beans", embedded in a white pulp. Each seed contains a significant amount of fat (40–50% as cocoa butter). Their most important active constituent is theobromine, a compound similar to caffeine.
The scientific name Theobroma means "food of the gods". The word cacao itself derives from the Nahuatl (Aztec language) word cacahuatl, learned at the time of the conquest when it was first encountered by the Spanish. Similar words for the plant and its by-products are attested in a number of other indigenous Mesoamerican languages.

History of cultivation
Cacao beans constituted both a ritual beverage and a major currency system in pre-Columbian Mesoamerican civilizations. At one point the Aztec empire received a yearly tribute of 980 loads (xiquipil in nahuatl) of cacao, in addition to other goods. Each load represented exactly 8000 beans.
In some areas, such as Yucatán, cacao beans were still used in place of small coins as late as the 1840s.

Pests