bulb - Bulbil

A highly modified shoot forming an underground storage organ. It is composed of overlapping leaves or leaf bases, swollen with food reserves which nourish early growth. The bulbs usually persist from year to year, the reserves being replenished before the plant dies back.

A bulb is an underground vertical shoot that has modified leaves (or thickened leaf bases) that are used as food storage organs by a dormant plant.

A bulb's leaf bases generally do not support leaves, but contain food reserves to enable the plant to survive adverse conditions. The leaf bases may overlap and surround the center of the bulb as with lilies, or may completely surround the inner regions of the bulb, as with the onion. A modified stem forms the base of the bulb, and plant growth occurs from this basal plate. The correct term for plants that form underground storage organs, including bulbs as well as tubers and corms, is geophyte. Some epiphytic orchids (family Orchidaceae) form above-ground storage organs called pseudobulbs, that superficially resemble bulbs.

Plants that form true bulbs are all monocotyledons, and include:

Onion, garlic, and other alliums, family Alliaceae.

Bulbil

Some lilies form small bulbs called bulbils in their leaf axils. Several members of the onion family, Alliaceae, including Allium sativum (garlic), form bulbils in their flower heads, sometimes as the flowers fade, or even instead of the flowers.