This is a singular kind of root. It is spread out like a hand. Each of these fingers can be separated from the rest, and will grow by itself. The roots of the dahlias are of this kind.
Bulbs.
Some roots are bulbs, as they are called. The onion is a bulbous root. Below is one cut open. You see that it is all made up of coats, one inside of another, which you can peel off. The roots of hyacinths, lilies, blue-bells, and crocuses, are bulbs. These lie in the earth very still through all the winter. The life in them is asleep, just as it is in the buds. But it wakes up in the spring, and down go the roots from the bottom of the bulbs, and up come the plants from their tops. It is sometimes said that a bulb is really a bud, only it is in the ground, instead of being in the air as most buds are. Thus the onion is a bud, and the real roots of the plant are what you see branching down from the bottom of the bulb.
Slips of plants.
You have heard people talk about setting out slips. A slip is a branch of a plant. Some plants will grow from slips. Geraniums will. If you put a slip of geranium into the ground and keep it well watered, a root will shoot down into the earth from the end of the stem. And so the branch cut off becomes a growing plant. Before it was cut off it got its food with the other branches from the root of the plant to which it belonged. After it was cut off it could not live unless it could get a root of its own to suck up its food from the ground.
Duck-meat.
Most plants get their food from the ground. But some do not. Some get their food from water. This is the case with a plant called duck-meat, that is found in ponds and ditches where the water is still. You see little leaves on the surface of the water, and the roots hang like threads from the leaves. This is represented in this figure. Now there is something in the water in these places which is sucked up by these roots and makes the leaves grow. Sea-weed has no roots extending down into the ground, but it gets its nourishment from the water.
Hanging moss.