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We saw in the last two lessons that a plant has a root, stem, leaves, flowers, and seed-boxes. To-day I want to tell you how these grow.
If your teacher will let you make a little experiment, you can watch a plant yourself as it grows out of the seed. Get a saucer and a small piece of flannel. Put the flannel in the saucer, and pour water over it till it is quite wet. Then get someone to give you a pinch of mustard seed, and scatter it on the flannel. Put this on the windowsill, or on the table, and take care to keep the flannel wet. Then watch what happens.
The second day after you have sown the seeds, you will find that they are swollen and soft. They have sucked up some water, and are using it to grow. On the third day many of the seeds will have sent out a tiny white root, which will cling to the flannel.
The tip of the root will now suck in more water, and if you will open a seed you will find that it is splitting in half. Each of the two halves is going to be a leaf. But they are not green, they are still quite white, and you would not think that they were leaves.
When you go to school on the fourth morning you may find these two halves out of their coat. Some of them are white, but some are turning green above and purple below, and everyone would now call them leaves. They grow up on a stem, and the empty coat of the seed still hangs on the place where the stem and the root meet. Look well at the shape of these leaves, they are made of two rounds with a dent in the middle. They are the seed-leaves of the mustard plant. They have come out of the seed, and have used the food that was in it, to spread themselves out, and rise up into the sunlight. Now as the light pours down on them, they turn green, and can make their own food out of the water and gases, which the roots suck in. For the root has now many rootlets and root-hairs on it, as you will see if you will pull one out of the flannel.
In a few days a green tip shows between the two seed-leaves, and grows up, opening out into two more leaves. These again have a little bud growing between them, which spreads out into other leaves, and so the plant goes on getting larger.
But the new leaves are quite different in shape from the seed-leaves. They are long, and are cut up into five leaflets, one large one at the tip, and two small ones on each side.
What you have seen happen to the mustard seed on the flannel is just what happens to every seed you sow in the ground. First it swells, when the warm rain reaches it. Then it puts out a tiny root. The seed-leaves stretch themselves out, their stem grows, and they creep out of their coat, and find their way above ground.
There they turn green in the sunlight, and begin to work up nourishing food. With this food they make fresh stems and leaves, till they grow into big plants, or even trees.
Another pretty experiment you can make is to soak a haricot bean in warm water, and put it on the top of some earth in a pot. Keep the earth moist and watch the bean, as you did the mustard seed. It will take longer to grow. It may be nearly a week before the root finds its way into the earth, and another week before the big green seed-leaves break out of the seed-coat.
It is very curious to watch the root. First it sends out only one rootlet. Then several more grow out, till the bean looks like a big spider with long legs. The heavy bean still lies on the earth, while the stem goes on growing. So the stem forms an arch, with the seed at one end, and the root at the other. At last the seed-leaves grow thinner as the plant uses the food in them, and the stem is strong enough to lift them, so that they stand up in the air. They do not leave the seed-coat down below, as the mustard seed did. They carry it up with them, and it dries and falls off at the top. Then you can see the new bud, between the seed-leaves, which soon opens out into real leaves.
Grow mustard seed on damp flannel. Soak a haricot bean in warm water for one night, and then keep it on very damp earth in a flower-pot.