[Boniato (Spanish), Nyami (Africa); Ñame (Panama);
D. rotundata, D. cayenensis]
True Yams are grown in Africa, Southeast Asia, the Caribbean and Latin America, but are only beginning to take root in North America. Unlike sweet potatoes they have a rough scaly skin, and can grow to as much as 150 pounds, though they are generally marketed at only a few pounds. Both White and Yellow varieties are native to Africa, but now grown in the Tropics worldwide. One variety, Kokoro, is used to make Yam Chips and for drying.
More on Yams.
True Yams are not interchangeable with North American "Yams", which are orange Sweet Potatoes (and now other colors as well). Flavor, texture and cooking properties are all different. Orange Sweet Potatoes are far too sweet to use in recipes for real Yams.