Structure of a simple leaf:

|
| Axillary bud: |
Clump of growth tissue from which the leaf sprouted; potential site of a new branch or leaf. |
| Lamina: |
Leaf blade, primary photosynthesis area. Contains chlorophyll; underside has
stomata for gas transfer. |
| Petiole: |
Stalk-like structure connecting lamina and stem. Can position the leaf for maximal light absorption.
Sessile leaves do not have petioles: their laminae are directly attached to the stem. |
| Veins: |
Nutrient transport system, containing xylem and phloem.
Xylem moves water and minerals from roots to leaves, phloem moves photosynthesis products (sugar) from leaves
to other parts of a plant. Usually, xylem is on the upper side of a leaf and phloem is on the underside. |