A stem may be defined as that structure which develops from a bud to bear leaves -- either full-sized or rudimentary -- and buds. Stems have swellings at certain points called nodes. A node is the point on a stem where a leaf is or was attached. The area between nodes is termed the internode . Stems usually grow upward to the light, but may be subterranean.

The functions of stems are: to support and display leaves, fruit, and flowers; to carry water and nutrients from the roots to the leaves; and to carry food produced by the green parts back to the roots. In plants which lack leaves, such as cacti, all food is produced in the green stem. Stems may be annual, biennial, or perennial, although some plants with perennial roots have annual stems.

Stems may be adapted for food storage, such as tubers, corms, bulbs, or rhizomes. They may also be specialized as runners, tendrils, or thorns. The tendrils of Vitis spp. (grapes) and Parthenocissus quinquefolia (Virginia creeper) are modified stems. (Keep in mind that, in some species, tendrils may be modified leaves.)

• Crowns - short and inconspicuous stems. Such plants are said to be stemless or acaulescent, such as Gerbera spp. (gerbera daisy). Crown is also the name for the base of the stems where roots arise.
• Simple - stems without branches (side growths), such as in Carica papaya (papaya) and Zea mays (corn).
• Branched - stems with more than one terminal bud; with side growths or branches.
• Climbing - stems too weak to support themselves, which lean or twist about other plants or posts for support, such as in Bougainvillea spp. (bougainvillea) and Pyrostegia venusta (flame vine).
• Creeping - stems which rest on the surface of the ground, sending down roots at the nodes or joints, such as in the weed Complaya trilobata (wedelia) and Lantana montevidensis (trailing lantana).
• Rhizomes - prostrate, usually thickened, subterranean stems, with leaves coming from one side and roots from the other, such as Canna x generalis (canna) and some of the Begonia spp.
• Stolons - slender, modified stems growing along the surface of the ground and rooting at the nodes, as in Fragaria x ananassa (strawberry) and Stenotaphrum secundatum (St. Augustinegrass).

Source: Botany Handbook for Florida, Revised Edition, Kathleen C. Ruppert, January 1999 -- This document is copyrighted by the University of Florida, Institute of Food and Agricultural Sciences (UF/IFAS) for the people of the State of Florida. UF/IFAS retains all rights under all conventions, but permits free reproduction by all agents and offices of the Cooperative Extension Service and the people of the State of Florida. Permission is granted to others to use these materials in part or in full for educational purposes, provided that full credit is given to the UF/IFAS, citing the publication, its source, and date of publication.