You know how thick and fleshy the roots of radishes, beets and turnips are.  Well, go into the garden and see if you can find a spring radish or an early turnip that has sent up a flower stalk, blossomed and produced seeds.  If you are successful, cut the root in two and notice that instead of being hard and fleshy like the young radish or turnip, it has become hollow, or soft and spongy (see Fig. 6).  Evidently the hard, fleshy young root was packed with food, which it afterwards gave up to produce flower stalk and seeds.

A fourth use of the root, then, is to store food for the future use of the plant.

=Experiment.=—­Plant a sweet potato or place it with the lower end in a tumbler of water and set it in a warm room.  Observe it from day to day as it puts out new shoots bearing leaves and roots (see Fig. 7).  Break these off and plant them in soil and you have a number of new plants.  If you can get the material, repeat this experiment with roots of horse-radish, raspberry, blackberry or dahlia.  From this we see that it is the work of some roots to produce new plants.  This function of roots is made use of in propagating or obtaining new plants of the sweet potato, horse-radish, blackberry, raspberry, dahlia and other plants.

[Illustration:  Fig. 4.  To show that plant-roots take water from the soil, the plants in A are suffering from thirst. B has sufficient water.]

[Illustration:  Fig. 5.  To show that plant roots take food from the soil.  Both boxes were planted at the same time.]

[Illustration:  Fig. 6.  A radish root, from which the stored food has been used to help produce a crop of seeds.  Notice the spindle shaded seed-vessels.]

[Illustration:  Fig. 7.  A sweet-potato root producing new plants.]

We have now learned five important things that roots do for plants, namely: 

Roots hold plants firmly in place.

They absorb water from the soil for the plants.

They absorb food from the soil for the plants.

Some roots store food for the future use of the plant.

Some roots produce new plants.

How do the roots do this work?  To answer this question it will be necessary to study the habit of growth of the roots of our plants.

HABIT OF GROWTH OF ROOTS

The proper place to begin this study is in the field or garden.  So we will make another excursion, and this time we will take with us a pick-axe or mattock, a shovel or two, a sharp stick, a quart or half-gallon pitcher, and several buckets of water.  Arrived in the field, we will select a well-developed plant, say, of corn, potato or cotton.  Then we will dig a hole about six feet long, three feet wide, and five or six feet deep, close to the plant, letting one side come about four or five inches from the base of the plant.  It will be well to have this hole