BULB, the name applied to the structure formed by many plants from a bud, the outer leaves of which are thick and fleshy by reason of the reserve food-products with which they are crowded. This enables the plant to tide over an unfavourable period, such as a cold or dry spell, safely buried in the earth, and to be ready to come into flower as soon as good conditions return. Bulbs are very characteristic of arid regions such as the South African Karroo. Many of the best known spring flowers are bulbous, e.g., the daffodil, narcissus, hyacinth, etc. The crocus is not technically a bulb, the structure often referred to as such in this plant being a corm, which is the thickened base of a stem.