Though this colorful root vegetable was originally cultivated in the Andes of South America, it is also sometimes called the "New Zealand yam" due to its popularity there after being introduced in the mid-1800s. Oca can be difficult to find in North America, but in many parts of South America it is second only to the potato in area planted. It is an excellent source of vitamin C, potassium and iron.There are many different varieties of oca, so the flavors can vary. But in general, they are tangier and sweeter than potatoes, and can range from starchy to almost fruitlike. In fact, the "apricot" variety grown in New Zealand tastes much like its namesake fruit.