How to determine whether a leaf is monocot or dicot and how does it affect transpiration?

Observe the leaf structure , the mono ct leaf shows parallel venation , whereas the dicot leaf shows reticulate venation.
The monocot leaf has isobilaterla symmetry, the symmetry in Dicot leaf is dorsiventral.
See the picture below to understand the difference.


Transpiration depends ipon positioning of stomata.
In monocot leaves the stomata are distributed equally on both the sides whereas in dicot leaves the stomata are mainly located on the lower side that is away from sun. Thus rate of transpiration is controlled in dicot leaves as stomata are not directly exposed to sunlight. The rate would be more in monocot plants.