→ (i) The cotyledons: The cotyledons of the embryo are simple structures, generally thick and swollen due to storage of food reserves (as in legumes).
→ Mature seeds may be non-albuminous or ex- albuminous.
→ Non albuminous seeds: Non albuminous seeds have no residual endosperm as they are completely consumed during embryo development (e.g., pea, groundnut).
→ Albuminous seeds Albuminous seeds retain a part of endosperm as they are not completely used up during embryo development (e.g., wheat, maize, barley, castor).
→ Perisperm Occasionally, in some seeds such as black pepper and beet, remnants of nucellus are also persistent. This residual, persistent nucellus is the Perisperm.
→ (ii) Integuments: Integuments of ovules harden as tough protective seed coats.
→ (iii) Micropyle The micropyle remains as a small pore in the seed coat. This facilitates the entry of oxygen and water into the seed during germination.