Phyllotaxy
Arrangement of leaves on stem and branches is called phyllotaxy. There kinds of leaf arrangements are found in plants.
(a) Alternate or spiral
When a single leaf arises at each node the phyllotaxy is alternate e.g. Sunflower, China rose, Mustard.
(b) Opposite
When two leaves arise at each node opposite to each other the phyllotaxy is opposite. When each pair at each node is placed at right angles to one another the condition is opposite decussate e.g. Calotropis, Guava etc. If all the pair occur in same line the phyllotaxy in opposite superposed e.g. Jaman.

(c) Whorled
When more than two leaves arise at each node in a whorl the phyllotaxy is whorled e.g. Oleander.