Explain : Structure of dicotyle-donous seed.

$\rightarrow$ The outermost covering of a seed is the seed coat.

$\rightarrow$ The seed coat has two layers, the outer testa and the inner tegmen.

$\rightarrow$ The hilum is a scar on the seed coat through which the developing seeds were attached to the fruit.

$\rightarrow$ Above the hilum is a small pore called the micropyle.

$\rightarrow$ 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.

$\rightarrow$ At the two ends of the embryonal axis are present the radicle and the plumule.

$\rightarrow$ In some seeds such as castor the endosperm formed as a result of double fertilisation, is a food storing tissue.

$\rightarrow$ In plants such as bean, gram and pea, the endosperm is not present in mature seeds and such seeds are called non-endospermous.