What is the protective waxy layer on the outer surface of a leaf called?

The protective waxy layer on the outer surface of a leaf is known as the cuticle. This layer serves several important functions. Firstly, it acts as a barrier to reduce water loss through evaporation, helping to maintain moisture levels within the leaf and overall health of the plant. Additionally, the cuticle protects the leaf from environmental stressors, such as UV radiation, pathogens, and physical damage.

While epicuticular wax is indeed a component of the cuticle, it refers specifically to the waxy substances found on the surface of the cuticle itself. Stomata are pores on the leaf surface that regulate gas exchange, while chloroplasts are the cellular structures responsible for photosynthesis. These other terms describe different aspects of leaf structure and function but do not represent the outer protective layer.