Fig. 1.

Life cycle and architecture of tulip and lily bulbs. a Tulip and lily yearly growth cycle. Note that their growth cycle is very similar. Both require a period of cold, but for different purposes and blooming occurs in different seasons. b Bulbs can be regarded as modified plants where the stem has shorten into a basal plate, the leaves have been modified into bulb-scales. In the tulip bulb the axillary buds are located in the axils of the bulb-scales and the floral bud is located in the center on top of the basal plate