An aril (pronounced ), also called an arillus, is a specialized outgrowth from a

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

that partly or completely covers the seed. An arillode or false aril is sometimes distinguished: whereas an aril grows from the attachment point of the seed to the

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

(from the funiculus or '' hilum''), an arillode forms from a different point on the seed coat. The term "aril" is sometimes applied to any fleshy appendage of the seed in

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s, such as the mace of the

nutmeg Nutmeg is the seed or ground spice of several species of the genus ''Myristica''. ''Myristica fragrans'' (fragrant nutmeg or true nutmeg) is a dark-leaved evergreen tree cultivated for two spices derived from its fruit: nutmeg, from its seed, an ...

seed. Arils and arillodes are often edible enticements that encourage animals to transport the seed, thereby assisting in seed dispersal. Pseudarils are aril-like structures commonly found on the pyrenes of

Burseraceae The Burseraceae are a moderate-sized family of 17-19 genera and about 540 species of flowering plants. The actual numbers differ according to the time period in which a given source is written describing this family. The Burseraceae are also k ...

species that develop from the mesocarp of the ovary. The fleshy, edible pericarp splits neatly in two halves, then falling away or being eaten to reveal a brightly coloured pseudaril around the black seed. The aril may create a

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

-like structure, called (among other names) a '' false fruit''. False fruit are found in numerous

Angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants ...

taxa. The edible false fruit of the

longan ''Dimocarpus longan'', commonly known as the longan () and dragon's eye, is a tropical tree species that produces edible fruit. It is one of the better-known tropical members of the soapberry family Sapindaceae, to which the lychee and rambu ...

lychee Lychee (US: ; UK: ; ''Litchi chinensis''; ) is a Monotypic taxon, monotypic taxon and the sole member in the genus ''Litchi'' in the Sapindus, soapberry family, ''Sapindaceae''. It is a tropical tree native to Southeast and Southwest China (t ...

and ackee fruits are highly developed arils surrounding the seed rather than a pericarp layer. Such arils are also found in a few species of

gymnosperm The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, '' Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμν ...

s, notably the yews and related conifers such as the lleuque and the kahikatea. Instead of the

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...

y cone typical of most gymnosperms, the reproductive structure of the yew consists of a single seed that becomes surrounded by a fleshy, cup-like covering. This covering is derived from a highly modified cone scale.

Development in ''Taxus''

In European yew plants (''

Taxus baccata ''Taxus baccata'' is a species of evergreen tree in the family Taxaceae, native to western, central and southern Europe (including Britain and Ireland), northwest Africa, northern Iran, and southwest Asia.Rushforth, K. (1999). ''Trees of Britain ...

''), the aril starts out as a small, green band at the base of the seed, then turns brown to red as it enlarges and surrounds the seed, eventually becoming fleshy and scarlet in color at maturity. The aril is attractive to fruit-eating

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s and is non-toxic. All other parts of the yew are toxic, including the seed housed inside the aril. If the seed is crushed, breaks or splits in the stomach of a human, bird or another animal, it will result in poisoning. Birds digest the fleshy aril as a food source, and pass the seeds out in their droppings, promoting dispersal of the seeds. Taxus baccata MHNT

In ''Dacrycarpus dacrydioides''

The kahikatea tree, '' Dacrycarpus dacrydioides'', is native to

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...

. In pre-European times the aril of the kahikatea was a food source for

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the Co ...

. The washed arils were called and were eaten raw.{{cite web , url=http://web.auckland.ac.nz/uoa/science/about/departments/sbs/newzealandplants/maoriuses/food/conifers/kahikatea-dacrycarpus.cfm , title=Kahikatea, Dacrycarpus , work=web.auckland.ac.nz , year=2011 , quote=The juicy, swollen, red stalk which holds the seed is known as {{lang, mi, koroi. , access-date=10 September 2011 , url-status=dead , archive-url=https://web.archive.org/web/20120112114227/http://web.auckland.ac.nz/uoa/science/about/departments/sbs/newzealandplants/maoriuses/food/conifers/kahikatea-dacrycarpus.cfm , archive-date=12 January 2012

Development in ''Taxus''

In ''Dacrycarpus dacrydioides''

See also

References

Further reading