Aril - Seed Appendages
It is an outgrowth that arises from the funicle or the testa near the raphe and covers the seed partially or completely. It is often referred to as the third integument. It is often fleshy or brightly colored. The edible part of litchi fruit is aril, which envelops the hard brown seed coat. In Myristica fragrans the hard seed (nutmeg of commerce) is covered by a thin, irregular and bright-orange aril (that gives us the precious spice mace). Seeds of Pithecellobium dulce, a leguminous tree, have a fleshy red aril that partially surrounds the seed. In Crossosoma californicum a fimbriate aril covers the seed on the sides.
Cells of the aril contain oils, starch, sugars, pigments and aroma containing compounds. The appendage is mostly an attraction for birds, which consume the aril and scatter the seeds. Seeds of white water lily, Nymphaea Alba have a spongy aril that provides buoyancy for dispersal of seed by water.