What is the difference between a bulb, a corm, and a tuber?

Bulbs, corms, and tubers are all parts of a plant that grow underground. They are each a storage unit for food that gives the plant the energy it needs to grow, bloom, and complete its life cycle each year. A bulb is an underground stem and leaf. It grows in protective layers, much like an onion. At the very center of the bulb is a small version of the flower itself. The bulb’s basil plate—a round and flat hairy mass (the beginnings of roots) on the bottom of the bulb—helps the bulb stay together. Examples of bulbs include tulips, daffodils, lilies, narcissus, and amaryllis. A corm is an underground stem. It has the same type of protective covering and basal plate as the bulb, but it does not grow in layers. Instead, the corm is the base for the flower stem and has a solid texture. Crocuses and gladiolus are both corms. The tuber is an underground stem or root. Just like a potato, it has leathery skin, lots of “eyes,” and no basal plate. The eyes are the growing points where the plants eventually emerge. Dahlias, begonias, and anemones are all tubers.

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