Simple
fruits are the result of the ripening-to-fruit of a simple or compound ovary in a single flower with a single
pistil.[1][2][3][4] In contrast, a single flower with numerous pistils typically produces an
aggregate fruit; and the merging of several flowers, or a 'multiple' of flowers, results in a 'multiple' fruit. A simple fruit is further classified as either dry or fleshy.[5][6][7]
Types of simple fruits
Dry simple fruits
Achene – most commonly seen in aggregate fruits (e.g.,
strawberry).
Follicle – follicles are formed from a single carpel, and opens by one suture: (
milkweed); also commonly seen in aggregate fruits: (
magnolia,
peony).
Legume – (
bean,
pea,
peanut: botanically, the peanut is the seed of a legume, not a nut).
Fruits in which part or all of the
pericarp (fruit wall) is fleshy at maturity are termed fleshy simple fruits.
Fleshy simple fruits
Berry – the berry is the most common type of fleshy fruit. The entire outer layer of the ovary wall ripens into a potentially edible "pericarp", (see below).
Stone fruit or drupe – the definitive characteristic of a drupe is the hard, "lignified" stone (sometimes called the "pit"). It is derived from the ovary wall of the flower:
apricot,
cherry,
olive,
peach,
plum,
mango.
To distribute their seeds, dry fruits may split open and discharge their seeds to the winds, which is called
dehiscence. Or the distribution process may rely upon the decay and degradation of the fruit to expose the seeds; or it may rely upon the eating of fruit and excreting of seeds by
frugivores – both are called
indehiscence. Fleshy fruits do not split open, but they also are indehiscent and they may also rely on frugivores for distribution of their seeds. Typically, the entire outer layer of the ovary wall ripens into a potentially edible
pericarp.