11/11/2023
As the ovules develop into seeds, the o***y begins to ripen and the o***y wall, the pericarp, may become fleshy (as in berries or drupes), or it may form a hard outer covering (as in nuts). In some multi-seeded fruits, the extent to which a fleshy structure develops is proportional to the number of fertilized ovules.[13] The pericarp typically is differentiated into two or three distinct layers; these are called the exocarp (outer layer, also called epicarp), mesocarp (middle layer), and endocarp (inner layer).