Stem (node, bud, leaf axil, leaf scar, lenticel)

A stem grows above the ground – a column from which new parts grow. It may be woody, herbaceous, or both.

Drawing by Jen at Experimentnumberone.wordpress.com

New parts, such as branches, leaves or flowers, grow from nodes, spaced along the stem. These are areas where cell division and specialization creates new growth. New growth starts as a bud. Further growth pushes the early cells further out, where they continue to mature. Other new cells create water and food pathways to the rest of the plant.

Once a bud has developed into a leaf, more buds may form in the leaf axil, just above the base of the first connection. These auxiliary buds may develop into a flower or another leaf. A mature flower may turn into a fruit, connecting to the node using the structures set up for the flower.

A terminal bud generates new growth at the end of the stem.

When a leaf falls off at the end of the growing season, it leaves a leaf scar showing a distinctive pattern.

Photo AnRo0002, Wikimedia Commons

Woody stems have bark that generally seals in moisture and gas. Some plants create porous lenticels in their bark to allow the transfer of oxygen, carbon dioxide and water vapor between plant cells and the atmosphere. The size, shape, and orientation of these lenticels are useful in identifying plant families and species.

Water Birch – photo by Zoya Akulova-Barlow

Want more? See Wikipedia.

Corrections/Comments: bruce@PlantID.net