Arillus

An aril, also called arillus, is a specialized outgrowth from a seed 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, 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 plants, 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.