stænglen

Stænglen is the above-ground axis of a vascular plant that supports leaves, flowers, and fruits while acting as a conduit for water, minerals, and organic nutrients between roots and shoots. It consists of nodes and internodes; at nodes are buds and potential lateral shoots. The stem typically has an outer protective layer (epidermis or periderm), a cortex, and a central vascular system formed by xylem and phloem.

Anatomy and growth differ among plant groups. In dicots, vascular bundles are arranged in a ring, while in monocots they are scattered throughout the stem. Growth occurs in two main ways: primary growth from apical meristems lengthens the stem, and secondary growth in many woody plants increases girth through the activity of the vascular cambium and cork cambium, producing wood (secondary xylem) and outer protective tissues.

Functions include support for the plant, transport of water and minerals from roots via xylem, and distribution of sugars and other metabolic products via phloem. Stems may also store nutrients and, when green, participate in photosynthesis. They can be adapted in various ways to suit environments, such as becoming woody or herbaceous, developing thickened or succulent tissues, or forming specialized structures.

Types and adaptations include herbaceous stems (soft and flexible) and woody stems (trees and shrubs). Modifications include stolons or runners that spread vegetatively, rhizomes underground stems, tubers for storage, thorns or spines for defense, and climbing stems with tendrils or hooks. Stænglen thus plays a central role in plant architecture, physiology, and reproduction.