Rhizome is an underground STEM that grows horizontally and sends out roots and shoots from its nodes. It is a type of ROOTSTOCK, which is a modified STEM that stores food and nutrients for the plant. Rhizomes are different from roots, bulbs, tubers, and stolons in that they are not used for storing food or nutrients, but instead for vegetative reproduction. Stems are the main part of the plant that grows above ground, while stolons are stems that grow horizontally along the ground and produce new plants at their nodes.