Stem, a plant organ that typically grows above ground and bears leaves, buds, and flowers. Stems conduct water and minerals from the roots to the leaves and also transport food made in the leaves to all other parts of the plant. In addition, stems give support to the plant and may also store food and water, act as reproductive structures, and may themselves manufacture food. .

StemsStems conduct water and minerals from the roots to the leaves.

Stems are found only in vascular plants; that is, plants that have specialized conducting tissues. Seed plants and ferns have stems; mosses do not. Stems provide many useful products, the most important of which is probably wood. (A tree trunk is a stem.) Stems are also the source of tannins, latex, and resins. Edible products that come from stems include sugar from sugarcane, maple syrup, and the white potato. (The potato is an underground stem.) Quinine comes from the bark of the cinchona tree and cinnamon from the bark of the cinnamon tree.

There are basically two different kinds of stemswoody stems and herbaceous stems. Woody stems, found in trees and shrubs, develop substantial amounts of woody tissue and are characteristic of plants that live for many years. Herbaceous stems develop little, if any, woody tissue and are characteristic of plants that live only for one season or plants whose stems die back at the end of a growing season.

Certain types of stems, called modified stems, do not fit the typical description of stems as to form and function. Some modified stems, such as tubers, bulbs, and corms, grow underground. Others, such as stolons and certain kinds of tendrils and thorns, grow aboveground. Woody and herbaceous stems are discussed in the following section, modified stems in the final section.