aril

Accessory seed cover other than a fruit; it may be fleshy and sometimes brightly coloured, woody, or hairy. In flowering plants (angiosperms) it is often derived from the stalk that originally attached the ovule to the ovary wall. Examples of arils include the bright-red, fleshy layer surrounding the yew seed (yews are gymnosperms so they lack true fruits), and the network of hard filaments that partially covers the nutmeg seed and yields the spice known as mace.

Another aril, the horny outgrowth found towards one end of the seed of the castor-oil plant Ricinus communis, is called a caruncle. It is formed from the integuments (protective layers enclosing the ovule) and develops after fertilization.