Some common tubers include potatoes, sweet potatoes, cassava, yams and Jerusalem artichokes. Though the names sweet potatoes and yams are used interchangeably, they are not the same thing.
The sweet potato is a vine related to the morning glory, and their flowers resemble each other. The tuber is long, tapered and can be many colors, though most people are familiar with the soft, orange-fleshed sweet potato.
Yams also come in many colors, but their skin is black and rough, and their flesh ranges from white to red. They are prepared much like sweet potato and are native to Africa.
Cassava looks very much like a yam, but it is native to South America and the Caribbean. Because it is prone to bruising, cassava is often sold with a wax covering. It is the source of tapioca and is poisonous when eaten raw; but cooking it removes any toxins.
Jerusalem artichokes are neither artichokes nor are they from Jerusalem. They are native to the Americas and were called girasole because of their sunflower-like blossoms. Girasole was then corrupted to Jerusalem. These tubers are highly nutritious, but the plant can be aggressive.
One of the most important crops in the world, the potato is prized for its versatility. It can be baked, sautéed, boiled, mashed, roasted and used in salads.