What is a Bulb?
A. A bulb is a flattened or compressed stem called a basal plate, usually growing underground, with a growing point on top and surrounded by enlarged, fleshy scales or layers that store food. The layers or scales are the bases of leaves. Roots grow downward from the basal plate. Root scars or dried roots may persist on the bottom of the basal plate. Bulbs may or may not be covered with papery structures called tunics. Tunics help to protect bulbs from drying out. The onion is a good example. Some bulbs do not have tunics. The Easter lily is a good example. Bulbs without tunics lack protection from drying out, so special care must be taken to keep them moist until they are planted.
