Although it may sound weird at first, fruits are actually the ovaries of flowers. The fruit is a tasty vessel that holds the seed and carries it as the seed gets dispersed. Three types of fruit include simple fruits, aggregate fruits, and multiple fruits.
Simple fruits come from a single ovary and from flowers that have a single carpel (a carpel consists of an ovary, style, and stigma). Simple fruits can be fleshy (such as peaches) or dry (such as pea pods). Berries (such as the grapes shown in the picture) are a type of simple fruit that become almost completely fleshy at maturity. The seeds of berries are enclosed in the tissue of the carpel.
Aggregate fruits come from several ovaries of the same flower that are melded together, The types of flowers that produce aggregate fruits have multiple carpels and an equal amount of ovaries. These ovaries develop and eventually cluster together. Two categories of aggregate fruits include true fruits (such as raspberries) and accessory fruits (such as strawberries). Dissimilar to true fruits, accessory fruits have extra floral parts, such as the leaves on strawberries.
The third type of fruit is a multiple fruit. Multiple fruits form from separate flowers that are very close to one another. A good example of this is a pineapple: The mature ovaries that compose the pineapple have accessory parts (such as parts of the sepals and bracts. Sepals hold and protect the flower bud. Bracts are modified leaves, such as the green leaf-like structures that come out of the top of the pineapple). Each hexagonal structure on the surface of the pineapple is actually an individual fruit.
One of the main purpose of flowers developing fruits is for sexual reproduction. When fruits have a good taste, animals ingest the fruit and later disperse the seeds far away from the location of the parent. For flowers who dwell near the shore or in the water, their fruits may be able to float. This allows the fruit to float in the water until it reaches a new location farther away. Either way, the seeds of the flower is getting dispersed some distance away so that the genes of the flower will become more dispersed as well.