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

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

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 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 ...

(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 (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s, such as the mace of the nutmeg 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 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 (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 ...

-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 (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit ...

taxa. The edible false fruit of the longan, lychee 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 ( ; ) are a group of woody, perennial Seed plant, seed-producing plants, typically lacking the protective outer covering which surrounds the seeds in flowering plants, that include Pinophyta, conifers, cycads, Ginkgo, and gnetoph ...

s, notably the yews and related conifers such as the lleuque and the

kahikatea ''Dacrycarpus dacrydioides'', commonly known as kahikatea (from Māori language, Māori) and white pine, is a Pinophyta, coniferous tree endemism, endemic to New Zealand. A Podocarpaceae, podocarp, it is New Zealand's tallest tree, gaining hei ...

. Instead of the

wood Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin t ...

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 (botany), family Taxaceae, native to Western Europe, Central Europe and Southern Europe, as well as Northwest Africa, and parts of Southwest Asia.Rushforth, K. (1999). ''Trees of Bri ...

''), 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 (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

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.

In ''Dacrycarpus dacrydioides''

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

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. In pre-European times the aril of the kahikatea was a food source for Māori. The washed arils were called and were eaten raw.

References

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Development in ''Taxus''

In ''Dacrycarpus dacrydioides''

See also

References

Further reading