Phyllotaxy

It is the arrangement of leaves on stem or branch. The orientation and arrangement of leaves is such that they get appropriate amount of sunlight for photosynthesis.

It is of three types:

1. Alternate - A single leaf arising at each node. For example: china rose, mango

2. Opposite - Leaves occur in pairs at each node. This arrangement may be

• (a) Decussate - When the successive pairs of leaves at upper and lower nodes are at right angles. For example: Tulsi, Calotropis
• (b) Superposed - when the successive leaf pairs at upper and lower nodes are exactly in the same plane. For example: guava

3. Whorled - When there are more than two leaves at each node arranged in a circle or whorl. For example: Nerium