* Palisade mesophyll: This layer is located directly beneath the upper epidermis and is composed of tightly packed, elongated cells. These cells contain many chloroplasts, making them the primary site of photosynthesis in the leaf.

* Spongy mesophyll: This layer lies beneath the palisade mesophyll and is characterized by loosely arranged, irregularly shaped cells with large intercellular spaces. These spaces allow for gas exchange and facilitate the movement of carbon dioxide and oxygen within the leaf.

While these are the two main layers, there can be variations in the arrangement and structure of the mesophyll depending on the type of plant and its environment.