cassava (kəsäˈvə) [key] or manioc mănˈēŏk, name for many species of the genus Manihot of the family Euphorbiaceae (spurge family). The roots, which resemble sweet potatoes and are eaten in much the same way, yield cassava starch, a staple food in the tropics. The cassava is native to Amazonia and has long been cultivated there by the indigenous population. It is now a major food source in many parts of the moist lowland tropics, particularly in Africa. Most cassava flour is made from M. esculenta, sometimes called bitter cassava because of the presence in the raw roots of prussic acid in sufficient quantities to be deadly. This poison is dispelled by long cooking or (for flour) pressing. Some cultivated varieties with a lesser acid content, called sweet cassava, are edible raw as well as boiled and can be used for fodder. It is important to process cassava as quickly as possible after harvesting; enzymes in the root will cause deterioration of the final product if processing is not completed within 48 hours. Cassava roots are also fermented to make an alcoholic beverage, are the source of tapioca, or Brazilian arrowroot, and are utilized in other ways, e.g., for cotton sizing and laundry starch. Cassava is classified in the division Magnoliophyta, class Magnoliopsida, order Euphorbiales, family Euphorbiaceae.