The main difference between vegetables and greens is in the botany of the plants. That is, the parts that are classified as vegetables are the fruits, roots, stems and tubers. As examples, we have tomato, pumpkin and eggplant fruits; radish, cassava and carrots roots; hearts of palm and asparagus stems and potato tubers. Vegetables are the leaves and flowers of plants. Some leaves are lettuce, kale, cabbage, chard, spinach while the flowers are broccoli and cauliflower.