usually it is catapillars feeding off of the leaf
What is the hod of the small opening on the underside of leaves
lenticels or may be spores....
stomata
Stomata
They are called stomata, openings or pores in the epidermis of leaves.
stomata stomata
Stomata
Leaves have small openings called stomata on the underside of the blade. Stomata function in gas exchange.
Spiracles
They are called stomata, tiny holes that regulate the intake/output of gas, such as carbon dioxide and oxygen.
The stomata.
Transpiration is the process by which plants lose water from their leaves through small openings called stomata.