It is the ascending part (generally above ground but some underground) of the axis bearing branches, leaves, flowers and fruits.
It develops from the plumule of the embryo of a germinating seed.
A stem is one of two main structural axes of a vascular plant, the other being the root.
The stem bears nodes and internodes.
The region of the stem where leaves are born are called nodes while internodes are the portions between two nodes.
The stem bears buds, which may be terminal or axillary.
Stem is generally green when young and later often become woody and dark brown.
Some common types are:
Herbaceous Stem: Soft and green stems found in non-woody plants like grasses and flowers.
Woody Stem: Hard and rigid stems that contain wood, typical of trees and shrubs.
Aerial Stem: Stems that grow above the ground, like the stolons of strawberries.
Underground Stem: Stems that grow below the ground, such as rhizomes (e.g., ginger) or tubers (e.g., potatoes).
Bulb: A short vertical underground stem with fleshy storage leaves attached, e.g. onion, daffodil, and tulip. Bulbs often function in reproduction by splitting to form new bulbs or producing small new bulbs termed bulblets. Bulbs are a combination of stem and leaves so may better be considered as leaves because the leaves make up the greater part.
Creeping or Runner Stem: Stems that run horizontally along the ground, producing new plants at nodes (e.g., strawberries).
Trunk: The main stem of a tree, usually thick and upright.
Rhizome: A horizontal, underground stem that can give rise to new shoots and roots.
Stolon: A horizontal stem that runs above the ground and produces new plants at its nodes.
The main function of the stem is spreading out branches bearing leaves, flowers and fruits.
It conducts water, minerals and photosynthates.
Some stems perform the function of storage of food, support, protection and of vegetative propagation.
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