Diversity is important for the resilience of food systems, as well as for its own sake. Just how diverse are the systems that produce our food? I explore this question with a focus on wheat and bread and North America, and even more specifically in baking, milling and farming. Although the opacity of food and agricultural systems makes definitive answers difficult, these segments appear to be increasingly uniform with respect to ownership, geography, varieties and genes. There are also important countertrends, (...) and while efforts to resist uniformity are currently small, they are making some progress in maintaining or even increasing diversity in some areas. (shrink)