The outermost covering of a seed is the seed coat or Dicotyledonous Seed. The seed coat has two layers, the outer testa and the inner tegmen. The hilum is a scar on the seed coat through which the developing seeds were attached to the fruit. The hilum is a small pore called the micropyle. Within the seed coat is the embryo, consisting of an embryonal axis and two cotyledons. The cotyledons are often fleshy and full of reserve food materials. At the two ends of the embryonal axis are present the radicle and the plumule (Figure).
In some seeds such as castor, the endosperm formed as a result of double fertilization. is a food storing tissue? In plants such as bean, gram and pea, the endosperm is not present in mature seeds and such seeds are called non-endospermous.