Emerald Nuts is the flagship brand of Diamond Foods, Inc., the leading walnut exporter in the United States. In fact, one of every two walnuts grown in the United States — roughly 325 million walnuts per year — is a Diamond Foods walnut. New York City is responsible for the largest consumption of walnuts by any American metropolitan area, with a yearly total of 1.8 million pounds. (That’s about a tenth of a pound per resident; I haven’t had a walnut in years, so someone must be picking up the slack.) And that, my friends, is where the good news ends. Brace yourselves: A walnut is not truly a nut, as its inner pericarp — its shell — is covered by a soft, fleshy outer layer. It is actually a drupe, though walnuts certainly sounds more delicious than waldrupes.For a school that has known nothing but Bowl Championship Series games the past seven seasons and always has its sights on playing for a national championship, this could be seen as a letdown.