The maize grain is an endospermic seed.
2. The internal structure of seed or grain is like a monocotyledonous seed.
3. On the outside, there is a single covering representing fused pericarp or testa.
4. Inside, the grain is divided into two unequal portions : the endosperm and the embryo.
5. The endosperm is the upper half of the grain which is laden with starch, but its outer layer next to the grain coat, contains abundant protein. It is called aleurone layer.
6. The lower half of the grain is occupied by the embryo.
7. The embryo has single cotyledon attached to embryonal axis, called scutellum.
8. The portion of embryonal axis below the cotyledon is the radicle and the upper end of embryonal axis is the plumule, surrounded by a protective sheath called coleoptile.