Barbara Mayer, age 13, of Philadelphia, Penna., for her question:

Why does corn have silk?

 

 

An ear of golden corn is wrapped in a sheath of leaves called the husk. Between the husk and the neat rows of kernels we find a mass of silky fibers., On the ripe ear of corn the silk is no longer useful. Its work was done when the ear of corn was young and green. The silky threads played a part in fertilizing the corn kernels.

A corn plant, like most living things, grows from a germ or seed cell. The germ cell is formed from two different cells, one male and one female. In the animal world, the male cells are produced by one parent and the female cells_by the‑other parent, In the plant world, the male and female cells are often produced by the same plant, When this is so, the seed does not have to have two parents, It may be formed from a male and female cell produced by the same plant.

The growing corn plant, three to 20 feet tall, produces both female ovule cells and male sperm cells:. These cells are produced by two different flowers. One corn flower is the tassel which grows at the

The other flower is the trailing silk tip of the tall plant, the tassel is made up of hundreds of small flowers. At first it is usually pink, though it may be green, red, or purple, depending upon the variety of corn. Later the tassel will be dusted with golden pollen. There will be countless small grains of pollen, each grain containing two sperm cells.

Meantime the baby ears of corn are developing. The tall stem of the corn plant is jointed like bamboo and from the joints grow long narrow leaves. The base of each leaf is sheathed around the stem. The ear grows between the leaf and the stem. A single corn plant may grow one to eight ears,

Each ear is a pithy rod covered with neat rows of green seedlings which at this stage are called ovules. The ear is wrapped in the leafy husk. Each ovule grows a long green fiber which passes up through the husk and out at the tip. The tall corn plant now has a tassel on top and a number of silken skeins poking out from the husks down its stem. The ripened pollen is shaken loose by the breezes. Countless billions of pollen grains are now wafted throughout the corn field.

Some will be trapped by the threads of corn silk. When this happens, a pollen grain             grows a long tube down the center of a silken fiber, right down to the ovule at its                     base. The sperm seed then travels down the tube to fertilize the ovule so that it can                 develop into a seed. If there were no corn silk, the sperm cell could never reach the                 ovule.