One of the things I’ve learned from eating out of a CSA box (if you don’t know what CSA is, look here) is that there are parts of many plants which are edible and useful, but which we never see because they will not stand up to the long trip to the packers and to your grocery aisle. If they survive the trip, they would probably not make it home and in a pan in an edible state. So they become waste instead of a source of variety and thrift. Other plants fall by the wayside due to the mysteries of marketing. Who knows if the plant ever really would catch on and be appreciated- if the focus groups say nay, the rest of us will never see them.
There’s so much abundance, variety and good order in natural things, and people have been thrifty throughout the ages in taking advantage. Necessity probably drove things then, but a kind of voluntary thrift benefits us. Roots like the “red meat daikon” (picture below from my own CSA) can be topped and put in a cellar to sustain people over the winter, but long before you get to that, you can cook up a pot of their peppery leaves. These days, unless you buy your food from a farmers’ market or CSA or grow your own, you may never taste a radish green. They wilt quickly after the plant is pulled.

…another good reason to befriend a farmer, preferably one who really likes to eat.