Collard greens and turnip greens are both members of the cabbage family. Collard greens taste somewhat more bitter than turnip greens which tend to be sweeter. Turnip greens are also smaller and more tender than their cousins, collards.
Both are widely considered to be very healthy foods. Collards are good sources of vitamin C and soluble fiber and contain multiple nutrients with potent anti-cancer properties. Turnip greens are a good source of vitamin A, foliate, vitamin C, vitamin K and clacium. Turnip greens are also high in lutein, an antioxidant. Neither green should be overcooked, as this results in much of the important vitamin and nutrient content being lost.