The Seed

The ovules, after fertilisation, develop into seeds. A seed is therefore the fertilised, mature ovule. Structurally, a seed is made up of two main parts:

• a seed coat, which forms the protective outer covering, and
• an embryo, the young plant enclosed within.

The embryo is made up of an embryonal axis (also called the radicle-plumule axis) and one or two cotyledons. The cotyledons are the first leaves of the embryo and are usually simple in structure.

The number of cotyledons present in the seed is the basis of a fundamental distinction among flowering plants:

• seeds with a single cotyledon, as in wheat and maize, are monocotyledonous seeds, while
• seeds with two cotyledons, as in gram and pea, are dicotyledonous seeds. …