I’LL BE STRAIGHT WITH YOU: We needed a Y to complete our alphabet! And since in this country the word yam is used completely interchangeably with sweet potato, I feel like I’m on safe ground. The food historian Jessica Harris points out that in fact, the true yam is an African tuber that is not grown in North America. The confusion, she says, came from early African slaves in the South, who when they arrived and saw the root of a morning glory–like vine, the sweet potato, called it by the name they knew at home. And the name stuck. Today both names are used by farmers and eaters alike. But even if it’s called a yam in your store, unless it was imported from Africa, what you’re eating is a sweet potato. See Warm Red Cabbage Salad with Sweet Potatoes (here).