Achenes are the fruit embedded in a fleshy receptacle. Multiple - fruits derived from many closely clustered flowers, such as in Morus spp. Seeds - consist of an outer coat or wall, which is usually very tough, hard, or woody, within which are cotyledons and the embryo. Seeds normally have just one embryo, but sometimes have more than one, as Citrus spp. Seeds are developed as a result of the fertilization of the egg in the ovule of the ovary of a flower.
Seeds vary greatly in color, texture, longevity, and methods of dispersal.
Some of the modifications of seeds which aid in dispersal are coverings of spines, hooks, bristles, cotton, or plumes, or having wings and arils. They also vary in the types and abundance of food they contain. In monocots, such as grasses, the single cotyledon remains inside the seed and acts as a digestive organ for the embryo. Cotyledons of dicots are often pushed up out of the seed at germination and reach above ground where they develop green color and act as true leaves. All Rights Reserved.