John Pagg, age 11, of Winston‑Salem, N.C.,

Are sweet potatoes the same as yams?

A sweet potato looks very like a yam and tastes very like a yam, Cooked up with butter and brown sugar, Andy has never been able to tell which of these vegetables is the most delicious. In the southern part of the United States everybody calls a sweet potato a yam. A Scotsman is likely to call any potato a yam. Everyone knows there is a difference between a sweet potato and an ordinary potato. A botanist will tell you there is a difference between a sweet potato and a yam, Even though you cannot tell the difference when they get to the table.

Both yams and sweet potatoes are warm climate plants. Both grow their potatoes underground. Both grow leafy vines above ground. But, as plants, the two are not even related.

The yam belongs to a family of tropical vines that thrive in the West Indies and Polynesia. The sweet potato is a relative of the morning glory. The ordinary white potato is not related to either of them. It belongs to he same family as the tomato, petunia and the tobacco plant.