How do the pericarp, exocarp, mesocarp, and endocarp make up a fruit wall?

The pericarp is the technical term for the fruit wall, which develops from the ovary of a flower. It is composed of three distinct layers that serve to protect the seed and facilitate its dispersal.1

These three layers are organized as follows:

• Exocarp: This is the outermost layer of the pericarp. It forms the skin, rind, peel, or husk of the fruit. Its texture can vary significantly, ranging from soft and thin, as seen in tomatoes, to leathery or hard, as found in citrus fruits or pumpkins.12
• Mesocarp: This is the middle layer of the fruit wall. It is typically the fleshy or plump portion of the fruit. In some instances, such as in citrus, it includes the albedo, which is the spongy, white inner layer of the rind.12
• Endocarp: This is the innermost region of the pericarp. It surrounds and protects the seed directly. The endocarp can vary greatly in consistency; for example, it may form the stony pit of a cherry or the core of an apple.12