arillate

Arillate is a botanical term used to describe seeds or fruits that bear an aril, a specialized outgrowth that partly or wholly covers the seed. An aril typically originates from the funiculus (the stalk attaching the seed to the ovary) or from the seed coat, and it is often fleshy and brightly colored to attract animals that disperse the seed. The presence of an aril distinguishes arillate seeds from exarillate seeds, which lack this structure.

Arils commonly function to aid seed dispersal by animals, providing a nutritious reward such as sugars or oils. Their appearance and edible quality vary widely among species. Arils may be conspicuously colored and fleshy, serving as a visual and olfactory lure for birds and mammals, or they may be less conspicuous and primarily structural or protective. Arillate seeds occur in various plant groups, including gymnosperms such as yew (Taxus) and angiosperms such as the nutmeg family (Myristicaceae), as well as fruits where the edible portion surrounds the seed.

Examples of arillate fruits and seeds include yew seeds encased in a red aril, and the edible coverings of lychee, longan, and rambutan around their seeds. In these cases, the aril is often a key factor in seed dispersal by animals. Etymologically, arillate derives from Latin arillus, meaning a small lump or a little kernel.