Greens--collard, turnip, mustard, and more--are a defining staple of southern food culture. Seemingly always a part of the southern plate, these cruciferous vegetables have been crucial in the nourishing of generations of southerners. Having already been celebrated in operatic terms--composer Price Walden's "Leaves of Green" includes this lyrical note: "From age to age the South has hollered / The praises of the toothsome collard--greens now get their leafy culinary due in Thomas Head's Savor the South cookbook. Head provides a fascinating culinary and natural history of greens in the...