Tulip bulbs are tunicated. Bulbs which lack the papery outer covering, such as lily bulbs are described as non-tunicated. This graphic was taken from The Physiology of Flower Bulbs, 1993. These organs also may be tunicated or non-tunicated, and they have nodes from which meristems originate. Gladiolus, freesia, crocus, and ixia are some examples.
Caladium is the most common floricultural tuber.
This graphic was taken from The Physiology of Flower Bulbs, 1993. Rhizomes A rhizome is a modified stem, and the stem tissue itself is the primary storage tissue. The rhizome, however, is unique in that it grows horizontally through soil. This graphic was taken from The Physiology of Flower Bulbs, 1993. A tuberous root consists of enlarged fleshy root tissue.