What is Phyllotaxy? Explain.

$\rightarrow$ Phyllotaxy is the pattern of arrangement of leaves on the stem or branch.
$\rightarrow$ This is usually of three types: alternate,opposite,and whorled.
$\rightarrow$ Alternate: In this type of phyllotaxy,a single leaf arises at each node in an alternate manner,e.g.,China rose,mustard,and sunflower.
$\rightarrow$ Opposite: In this type,a pair of leaves arise at each node and lie opposite to each other,e.g.,Calotropis and guava.
$\rightarrow$ Whorled: If more than two leaves arise at a node and form a whorl,it is called whorled phyllotaxy,e.g.,Alstonia.