As you may have noticed, a seed merely lying loose on the ground is lifted up by its first little root in its effort to poke its nose into the soil. But Nature makes provisions for covering seeds up. They are covered by the castings of the earthworms, the dirt thrown out by burrowing animals and scratching birds. Some seeds fall into cracks where the ground is very dry and others are washed into them by the rains; while these as well as seeds lying on the surface are covered by the washings of the rain. Then come the roots that grip the soil.
Always growing just back of the tip, are thousands of root-hairs, as fine as down. These get food from the soil. They soon disappear from the older parts of the root, so that it stops gathering food itself and puts in all its time passing along to the stem and leaves the food gathered by the finer and younger roots. This is why plants are so apt to wilt if you aren't careful when transplanting them; the root-hairs get broken off. For the same reason, corn, after it grows tall, is not ploughed deeply. The fine roots reach out between the rows and the ploughshare would cut them off.
II. Mr. Root's Presence of Mind
All these things and more the roots do in their daily work—in the ordinary course of business. And it's wonderful enough. Don't you think so? But there are even stranger things to tell; things that would almost make us believe roots have what in human beings we call "presence of mind." That is to say, the faculty of thinking just what to do when something happens that one isn't looking for; when the house takes fire, for example, or the baby upsets the ink.
THREE SCHOOLS OF STRATEGY
A ROOT'S WAY OF CROSSING A ROAD
Take the case of tree roots crossing a country road for a drink of water. They do it just as you or I would, I'll be bound. Just suppose you and I were roots of a big tree that wanted to reach the moist bank of a stream, and there was a hard road-bed between. We can't go over the top, and the road-bed is so hard we can't go straight through on our natural level so we'll just stoop down and go under, won't we? That's exactly what the roots do. They dip down until they get under the hard-packed soil, and then up they come again on the other side and into the moist bank they started for.
The roots of each kind of plant or tree have their natural level; that's one reason, as we know, why so many different kinds of plants—grass, trees, bushes, and things—get on so well together in the fields and woods. The tree roots that we have just seen crossing the road only went down below their natural level because they had to, as if the tip said: