Cocoyams are the starchy corms of two aroid plants: Xanthosoma sagittifolium (new cocoyams, also called tannia or yautia) and Colocasia esculenta (old cocoyams, better known as taro). They are staple foods across West and Central Africa, eaten roasted, boiled, or baked, and their flour serves as a food ingredient and as the base of fufu, the pounded dough eaten with soups. Like all aroids they contain irritating calcium oxalate crystals when raw, so thorough cooking is essential. Breeders select for yield, dry-matter content, and lower acridity.