The nucellus is diploid nutritive tissue present in ovule; it provides nutrition to developing embryo sac. In most ovules, nucellus is completely consumed during the development of embryo sac. In some ovules, where nucellus is abundant, it persists even after the development of embryo sac. These remains of nucellus are called perisperm. Perisperm is observed in seeds of beet, coffee, etc.
