Edible stem

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.

Plant stems have a variety of functions. Stems support the entire plant and have buds, leaves, flowers, and fruits. Stems are also a vital connection between leaves and roots. They conduct water and mineral nutrients through {xylem} tissue from roots upward, and organic compounds and some mineral nutrients through phloem tissue in any direction within the plant. Apical meristems, located at the shoot tip and axillary buds on the stem, allow plants to increase in length, surface, and mass. In some plants, such as cactus, stems are specialized for photosynthesis and water storage.

Typical stems are located above ground, but there are modified stems that can be found either above or below ground. Modified stems located above ground are crowns, [stolon]s, runners, or spurs. Modified stems located below ground are bulbs (which are actually primarily the enlarged base of the plant's leaves), corms, rhizomes, and tubers.

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Wikipedia