A fruit is formed after fertilisation as a result of cell division and differentiation in the ovary, i.e. a ripened ovary forms a fruit. The wall of the ovary develops into the fruit wall called pericarp, which may be fleshy or leathery or dry.
The fruit develop from the ovary of a flower not associated with any non-carpellary part is termed as true fruit (Mango). The other floral parts degenerate and fall-off. The fruit derived from ovary along with other accessory floral parts like Thalamus is called false fruit (Apple). Apple is called a false fruit because it develops from the thalamus instead of ovary (thalamus is the enlarged structure at the base of the flower).
