Susanne Bowmann, age 13, of Watertown, N.Y., for her question:

WHAT IS COTYLEDON?

Cotyledon is the name given to the first leaves formed from a seed. These first leaves store and digest food for the new plant that is forming.

The cotyledons are really part of the seed. They are usually thick and blunt. When a seed begins to sprout, a tiny stem and roots develop from the different tissues in the embryo of the seed.

As the embryo grows, it uses up all the food stored in the seed. The cotyledons help in this process by digesting the stored food and moving it to the embryo.

In some plants, such as beans, the cotyledons or seed leaves cling to the stem and develop green coloring matter. Then they begin to manufacture food for the new plant through photosynthesis.

When the plant grows other leaves, the cotyledons dry up and fall off.

In other plants, as in peas, the cotyledons do not come above

ground.