I wasn't going to mention the types of germination, but if I ignore it someone is bound to point it out. Whilst this has little or no effect upon growing techniques, it does give a more complete representation of the germination picture. As we shall see (hopefully), following the emergence and establishment of a new root system (radicle), the stem starts to develop and the plumule is thrust upwards. However, there are two types of germination, dependent upon what happens to the cotyledons: i.e. whether these grow ABOVE the ground (epigeal) or remain BELOW it (hypogeal).
'Hypogeal Germination of Monocot Corn (Maize)'; 'What Is A Seed?'; 'How To Germinate Seeds More Successfully'