Swollen underground stems or roots which are organs of perennation
and vegetative propagation and contain stored food material. The potato
is a stem tuber. It swells at the tip of a slender underground stem (or
stolon) and gives rise to a new plant the following year. In stem tubers new plants develop from the buds, or eyes, growing in the axils of the scale leaves. Tubers are propagated by sections containing at least one eye. Dahlia tubers
are swollen roots. In the wild, tubers enable the plant to survive an adverse season(winter or dry season). See also food
storage in plants.