After the pistil is fertilized, it differentiates and develops into multiple different layers of tissue from the ovary wall. The mature fruit peel can generally be divided into three layers: the outer peel, the middle peel, and the inner peel.
雌蕊受精后，由子房壁的组织分化、发育而成的多层不同的组织。成熟的果皮一般可分为外果皮、中果皮和内果皮三层

The pericarp of an immature fruit.
未成熟果的果皮。

The pericarp of a young fruit.
幼果的果皮。