Simple fruit is a fruit that develops from a single pistil. When a single fruit develops from a single ovary of a single flower, it is called simple fruit. The ovary may be superior or inferior.
Depending upon the nature of pericarp (outer and edible layer of fruits), simple fruits can further be separated into two types
(1) SIMPLE FLESHY FRUITS:
Examples: Berry, Hesperidium, Pepo, Pome, etc.
In these fruits either the entire pericarp or part of the pericarp is succulent and juicy at maturity. The fruit wall of fleshy fruits may be distinguished into three layers – (1) the fruits outer coat (epicarp), (2) its middle mesocarp which is the middle layer or pith and (3) the inner endocarp surrounding the ovary or seeds.
Fleshy fruits are indehiscent, as the structures don't open.
Fleshy fruits are broadly divided into two types, (1) BACCATE and (2) DRUPACEOUS.
(2) SIMPLE DRY FRUITS:
Examples: Legume, Follicle, Siliqua, Capsule, Lomentum, Cremocarp, Achene, Caryopsis, Cypsela etc
Simple Dry Fruits are fruits whose mesocarp (middle layer as the flesh of a peach) is definitely dry at maturity. These fruits have dry pericarp, and are not distinguished into three layers as stated above.
The simple dry fruits are further divided into three types: (1) DEHISCENT DRY FRUITS, (2) SCHIZOCARPIC DRY FRUITS and, (3) INDEHISCENT DRY FRUITS.