Well, they go past just balancing in different kinds of oranges to adding in tangerines and sour oranges, which is kind of neat.

There are a lot fewer varieties of oranges grown in Florida now than, say, 30 years ago: it's now dominated by two varieties, each of which has around 40% of the market. This is troubling, of course, since they're all clones.

But then again, one could say the same thing about bananas, and I'm not sure I need to read books about bananas...