Confusion occasionally occurs between Yuca and Yucca.
Yuca: Spanish / American Indian name for Cassava (Manihot esculenta) a woody perennial shrub of the Euphorbiaceae with starchy edible tubers, albeit laced with cyanogenic glycosides which must be washed out before consumption. Much of the cyanide occurs in the skin and may be removed by peeling the tubers, prior to thorough cooking in boilng water. Cassava tubers have been used as food for thousands of years, over which time low-cyanogenic cultivars have been selected.
Yucca: a genus of succulent leafy rosetted plants within the Agavaceae, used as a source of food, fibre and building materials. However, the fleshy roots are not generally edible and may contain toxic soapy substances (saponins) which were used for washing clothes and hair.
It is thought that the genus Yucca was so named because of confusion with Cassava.