Ovary (botany)

Simple fruits are derived from one ovary of a single flower, while aggregate fruits are derived from many ovaries of one flower. Differently, a multiple fruit is derived from multiple ovaries each from their own individual flowers.

After double fertilization and ripening, the ovary becomes the fruit, the ovules inside the ovary become the seeds of that fruit, and the egg within the ovule becomes the zygote.[1][2] Double fertilization of the central cell in the ovule produces the nutritious endosperm tissue that surrounds the developing zygote within the seed.[2] Angiosperm ovaries do not always produce a fruit after the ovary has been fertilized. Problems that can arise during the developmental process of the fruit include genetic issues, harsh environmental conditions, and insufficient energy which may be caused by competition for resources between ovaries; any of these situations may prevent maturation of the ovary.[3][4][5][6]

The orange is a simple fruit called a hesperidium. It is the mature ovary of a single orange blossom. Though it seems to have sections when cut open, all of these sections together come from a single ovary that develops into different layers.[7]

Fruits are important in the dispersal and protection of seeds, and variation in fruit shape or size results from an evolutionary response that aids in the dispersal of seeds in different environments.[8][9] For example, the seeds of large fleshy fruits are often dispersed through endozoochory; this means that animals consume the fleshy fruit and as a result disperse its seeds with their movement.[10] The seeds of fruits can be dispersed by endozoochory, gravity, wind, or other means.

There are some complications to the definition of a fruit, as not all botanical fruits can be identified as culinary fruits. A ripened ovary may be a fleshy fruit such as a grapefruit or a dry fruit such as a nut. Further complicating this, culinary nuts are not always botanical nuts; some culinary nuts such as the coconut and almond are another type of fruit called a drupe.[11][12]

In this same way, not all "fruits" are true fruits. A true fruit only consists of the ripened ovary and its contents. Fruits can be separated into three major categories: simple fruits, aggregate fruits, and multiple fruits. Simple fruits like oranges are formed from a single ovary which may or may not consist of multiple parts, while aggregate and multiple fruits are formed from several ovaries together.[13] Aggregate fruits like raspberries are the ripened ovaries of one flower that form a single fruit, and multiple fruits like pineapples are formed from the ovaries of separate flowers that are close together.[13][14][15]

Because aggregate and multiple fruits are formed from many ripened ovaries together, they are actually infructescences or groups of fruits that are arranged together in a structure.[13] Some fruits, like the apple, are accessory fruits which can include other parts of the flower such as the receptacle, hypanthium, perianth, or calyx in addition to the mature and ripened ovary.[16]

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  The raspberry is an aggregate fruit. Each raspberry develops from one flower, but its flower has many ovaries that become the small circular drupes making up the raspberry. There is a seed in each drupe.
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  Section of a raspberry flower
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  The pineapple is a multiple fruit. Each of the purple spikes in this picture are a separate flower, so the whole structure is an inflorescence. This means that the small sections of a pineapple are each a fruit that develop from a separate ovary, and together they make up a multiple fruit.

A superior ovary is an ovary attached to the receptacle above the attachment of other floral parts. A superior ovary is found in types of fleshy fruits such as true berries, drupes, etc. A flower with this arrangement is described as hypogynous. Examples of this ovary type include the legumes (beans and peas and their relatives).

A half-inferior ovary (also known as “half-superior”, “subinferior,” or “partially inferior,”) is embedded or surrounded by the receptacle.[19] This occurs in flowers of the family Lythraceae, which includes the crape myrtles. Such flowers are termed perigynous or half-epigynous. In some classifications, half-inferior ovaries are not recognized and are instead grouped with either the superior or inferior ovaries.

More specifically, a half-inferior ovary has nearly equal portions of ovary above and below the insertion point. Other varying degrees of inferiority can be described by other fractions. For instance, a "one-fifth inferior ovary" has approximately one fifth of its length under the insertion point. Likewise, only one quarter portion of a "three-quarters inferior ovary" is above the insertion.

An inferior ovary lies below the attachment of other floral parts. A pome is a type of fleshy fruit that is often cited as an example, but close inspection of some pomes (such as Pyracantha) will show that it is really a half-inferior ovary. Flowers with inferior ovaries are termed epigynous. Some examples of flowers with an inferior ovary are orchids (inferior capsule), Fuchsia (inferior berry), banana (inferior berry), Asteraceae (inferior achene-like fruit, called a cypsela) and the pepo of the squash, melon and gourd family, Cucurbitaceae.