An example of an endospermous seed is the maize grain. Endosperm is the tissue within the seed of a flowering plant that provides nutrients to the developing embryo. In endospermous seeds like maize, the endosperm is the primary source of food for the embryo. As the maize grain develops, the endosperm grows and stores starch and other nutrients, which are used by the embryo for growth and development when the seed germinates. So, the maize grain is a good example of an endospermous seed because it relies on the endosperm for its initial growth and development.