If you break off at the ground one of your bean plants, and place the slip in a glass of water, you will see for yourselves how readily it sends out new roots.
I have read of a village tree the roots of which had made their way into a water pipe. Here they grew so abundantly that soon the pipe was entirely choked. This rapid, luxuriant growth was supposed to have been caused by the water within the pipe.
So you see there are underground roots and above-ground roots and water roots. Usually, as you know, the underground roots get their food from the earth; but sometimes, as with the Indian pipe, they feed on dead plants, and sometimes, as with the yellow false foxglove, on other living roots.
WHAT FEW CHILDREN KNOW
To-day we must take another look at the plants in the schoolroom garden.
By this time some of them have grown quite tall. Others are just appearing above the earth.
Here is a young morning-glory (Fig. [120]). We see that its stem, like that of the bean, was the first thing to come out of the seed. This stem has turned downward into the earth. From its lower end grows the root, which buries itself deeper and deeper.
An older plant shows us that the upper part of the stem straightens itself out and grows upward, bearing with it a pair of leaves (Fig. [121]).
