Though native to South America, the majority of cassava now comes from Africa, where it's an important staple. Also called manioc and yuca, the cassava is a root that ranges from 6 to 12 inches in length and from 2 to 3 inches in diameter. It has a tough brown skin which, when peeled, reveals a crisp, white flesh. There are many varieties of cassava but only two main categories, sweet and bitter. The bitter cassava is poisonous unless cooked. Cassava is available year-round in Caribbean and Latin American markets. It should be stored in the refrigerator for no more than 4 days. Grated, sun-dried cassava is called cassava meal. Cassava is also used to make cassareep and tapioca.