how can we classify the lease based on their venation

Dear Student

Leaves can be categorised into two types of venation: Parallel and reticulate venation.
We can observe the venation on the leaves and can identify the type of root system it has. 
A plant that has leaves with parallel venation will have a fibrous root system.
Whereas, a plant which has leaves with reticulate venation will have tap root system.

Regards