perikarp

Pericarp is the part of a fruit formed from the wall of the ripened ovary after fertilization. It encloses the seed(s) and develops into the fruit's protective wall. In most flowering plants, the ovary wall differentiates into three tissue layers: an outer exocarp, a middle mesocarp, and an inner endocarp. The relative thickness and texture of these layers determine the fruit type. In fleshy fruits, the mesocarp is typically the edible part, and the endocarp may be soft or firm; in drupes the endocarp forms a hard stone surrounding the seed, while in some berries all three layers are soft. In pomes, edible tissue often arises largely from tissue outside the pericarp (the receptacle), while the pericarp forms the outer rind and the inner core around the seeds.

Pericarp development begins as the ovary enlarges after fertilization. Its adaptations contribute to seed protection and dispersal; for example, a thickened rind in citrus permits oil storage and protection; dry pericarps may split to release seeds in capsules and legumes. The pericarp is distinct from the seed coat (testa), though the two are carried together inside the mature fruit.

Understanding pericarp structure helps classify fruits and explain their anatomy and ecology. It is, however, important to note that in many cultivated fruits the edible portion consists of tissues derived partly from non-pericarp structures, such as the receptacle.