What is defined as a rootlike, underground stem capable of growing new roots and stems?

A rhizome is defined as a rootlike, underground stem that is capable of growing new roots and stems. This structure is specialized for vegetative reproduction and can spread horizontally beneath the soil surface. Rhizomes serve as storage organs, allowing the plant to survive adverse conditions and to propagate itself by sending up new shoots.

In contrast, a tuber, such as a potato, is an enlarged structure for storing nutrients but does not primarily function as a stem capable of producing new stems and roots in the way rhizomes do. Bulbs consist of a short stem surrounded by fleshy leaves, which store energy but are not structured like rhizomes. Rootstock refers to the part of a plant, or root, on which a graft is made and does not fit the definition of a stem capable of producing roots and stems like a rhizome does. Understanding these distinctions clarifies why rhizome is the best choice in this context.