Cassava

Cassava (Manihot esculenta), also called yuca or manioc, a woody shrub of the Euphorbiaceae (spurge family) native to South America, is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates. Nigeria is the world's largest producer of cassava. Note: mind 2 different plants that just change 1 letter: Yucca and Yuca.

Cassava is the third-largest source of carbohydrates for meals in the world.[1][2] It is classified as sweet or bitter, depending on the level of toxic cyanogenic glucosides. (However, bitter taste is not always a reliable measure.[3]) Improper preparation of cassava can leave enough residual cyanide to cause acute cyanide intoxication and goiters, and has been linked to ataxia or partial paralysis.[4] Nevertheless, farmers often prefer the bitter varieties because they deter pests, animals, and thieves.[5] In some locations the more toxic varieties serve as a fall-back resource (a "food security crop") in times of famine.[6]
source: http://en.wikipedia.org/wiki/Cassava