An accessory fruit is a

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

that contains tissue derived from plant parts other than the

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

. In other words, the flesh of the fruit develops not from the floral ovary, but from some adjacent tissue exterior to the

carpel Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more ...

(for example, from receptacles or

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

). As a general rule, the accessory fruit is a combination of several floral organs, including the ovary. In contrast, true fruit forms exclusively from the ovary of the flower.Esau, K. 1977. ''Anatomy of seed plants''. John Wiley and Sons, New York. Accessory fruits are usually

indehiscent Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part. Structures that ...

, meaning that they do not split open to release seeds when they have reached maturity.

Incorporated organs

The following are examples of accessory fruits listed by the plant organ from which the accessory tissue is derived: Fruit with fleshy seeds, such as

pomegranate The pomegranate (''Punica granatum'') is a fruit-bearing deciduous shrub in the family Lythraceae, subfamily Punica, Punicoideae, that grows between tall. Rich in symbolic and mythological associations in many cultures, it is thought to have o ...

mamoncillo ''Melicoccus bijugatus'' is a fruit-bearing tree in the soapberry family Sapindaceae, native or naturalized across the New World tropics including South and Central America, and parts of the Caribbean. Its stone-bearing fruits, commonly called ...

, are not considered to be accessory fruits.

Examples

Apples and pears

The part of apples and pears that is consumed is, in fact, the

hypanthium In angiosperms, a hypanthium or floral cup is a structure where basal portions of the Sepal, calyx, the petal, corolla, and the stamens form a cup-shaped tube. It is sometimes called a floral tube, a term that is also used for corolla tube and cal ...

. The ovary is the papery core that surrounds the apple seeds. As the hypanthium ripens it forms the edible tissues.

Roses

For roses, the hypanthium is the tissue that composes the edible part of rosehips. Roses and apples are both members of the Rosaceae family; the fact that they have similar fruit morphology is a major consideration in placing them in the same taxonomic family.

Strawberries

The edible part of the

strawberry The garden strawberry (or simply strawberry; ''Fragaria × ananassa'') is a widely grown Hybrid (biology), hybrid plant cultivated worldwide for its fruit. The genus ''Fragaria'', the strawberries, is in the rose family, Rosaceae. The fruit ...

is formed, as part of the ripening process, from the receptacle of the strawberry flower. The true fruits (hence, containing the seeds) are the roughly 200 pips (which are, technically,

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...

s, a true fruit that contains a single seed from a single ovary). These pips dot the exterior of the strawberry.

Cashew apple

The

cashew apple Cashew is the common name of a tropical evergreen tree ''Anacardium occidentale'', in the family Anacardiaceae. It is native to South America and is the source of the cashew nut and the cashew apple, an accessory fruit. The tree can grow as tal ...

is an oval- or pear-shaped structure that develops from the

pedicel Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures ...

and the receptacle of the cashew flower and is technically called a

hypocarpium This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...

. It ripens into a yellow or red structure about long. The true fruit of the cashew tree is a kidney–shaped

drupe In botany, a drupe (or stone fruit) is a type of fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pip'' (UK), ''pit'' (US), ''stone'', or ''pyrena'') of hardened endocarp with a seed ...

that grows at the end of the cashew apple; the seed inside this drupe is the cashew nut of commerce.

Pineapple

The pineapple is formed when 50 to 200 unpollinated flowers coalesce in a spiral arrangement— the flowers form individually and then fuse as a single '

multiple fruit Multiple fruits, also called collective fruits, are fruiting bodies formed from a cluster of flowers, the ''inflorescence''. Each flower in the inflorescence produces a fruit, but these mature into a single mass. After flowering, the mass is call ...

'. The ovaries develop into berries and the fruit forms around an intercalary spike. The intercalary

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

(cluster of flowers) results when the terminal cluster of flowers are left behind by the growth of the main axis of the plant. Each polygonal area on the pineapple's surface is an individual flower.

Research

Current research has proposed that a single class of

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

s may be responsible for regulating accessory fruit formation and ripening. A study using strawberries concluded that hormone signaling pathways involving

gibberellic acid Gibberellic acid (also called gibberellin A3 or GA3) is a hormone found in plants and fungi. Its chemical formula is C19H22O6. When purified, it is a white to pale-yellow solid. Plants in their normal state produce large amounts of GA3. It is po ...

and

auxin Auxins (plural of auxin ) are a class of plant hormones (or plant-growth regulators) with some morphogen-like characteristics. Auxins play a cardinal role in coordination of many growth and behavioral processes in plant life cycles and are essent ...

affect gene expression, and contribute to the initiation of accessory fruit development. Metabolic modifications in different developing accessory fruit tissues are due to the varied distributions of compounds such as triterpenoids and

steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...

References

{{Fruits Fruit morphology