Tuber

This underground stem base can last for many years

A tuber, like a corm, is a swollen underground stem base. But it has no basal plate; roots grow both from its base and its sides. Multiple growth points are scattered over its upper surface.

An individual tuber can last for many years. Some (cyclamen, for example) continually enlarge but never produce offsets. Others, such as caladium, form protuberances that can be removed and planted separately.