Edible plant stems are one part of plants that are eaten by humans. Most plants are made up of roots, stems, leaves, flowers, buds and produce fruits containing seeds. Humans most commonly eat the seeds (e.g. maize, wheat, coffee and various nuts), fruit (e.g. tomato), leaves (e.g. lettuce, spinach, and cabbage), or roots (e.g. carrots and beets), but humans also eat the stems of many plants (e.g. asparagus). There are also a few edible petioles (leaf stalks) such as celery, as well as some edible flowers.