ROOTS.
When we are about to do a thing thoroughly and systematically we often say we will "begin at the root of the matter." That is because the root of a plant is supposed to be the first thing in its life. It is indeed the foundation, the substructure of a plant, but not strictly the first thing that starts to grow. The little stem feels the first quiver of life, and the root follows. You can see the little stem, or caulicle in fat seeds like squash and melon, beans and pease. Split a squash seed, and between the two fat sides the caulicle lies cozily tucked, like a tiny tail or handle. Plant a squash seed in the earth. The caulicle, fed by the two fat sides, pushes its way upward into the air, making a stem with leaves, and finally a big vine, while from its lower end the root develops and pushes itself as fast as possible into the earth.
The roots of some plants are small. I think most weeds make pretty large and strong roots, which are hard to pull up. But when a tree has grown to its full size its roots are almost as large as its branches. I once saw a fine old maple-tree cut down, and its roots dug up to make room for a cellar. I was surprised to see what a big hole the roots made. Two men dug for several days before they had the roots all up.
The work for the roots to do is to drink water. The upper half of the plant is very thirsty, and calls constantly for water. The roots push and dig into the moist soil, drink in water, and pass it up by a sort of pumping process. Only think, drinking and pumping! That is what roots do. And so if the earth is dry, and the roots can find nothing to drink, the plant will die. But after a shower see how glad the leaves seem, and how stiff and straight they stand, because the roots are sucking up great draughts of water.
To protect roots in their hard burrowing work a little cap of hard cells is fitted over their tips. Little hairs grow all over them, whose purpose is to help absorb moisture.
Some thick and fleshy roots are good to eat. They form many of our best vegetables. Beets, turnips, parsnips, and carrots are such roots. They belong to biennial or two-year plants. The first year they store up food in their roots; the second year draw upon this food, and produce flowers and fruit. They are named from their shapes. Fusiform, like radishes, when thicker in the middle, tapering at both ends. Carrots are conical, thicker at the top. Turnips bulge out in the middle, and are napiform. When clustered like a dahlia the roots are fascicled. All are taproots, or main roots. Besides these primary roots there are secondary. You may have noticed secondary roots springing from the joints of a corn-stalk above ground. The wonderful banyan-tree sends down roots from its branches, making new trees, until one tree is the mother of a colony.
There are plants which take their nourishment from the air alone, and not from the soil. They need roots as hold-fasts, not as drinking-cups. Some lovely orchids grow in that way. Those leathery patches which you have seen on old fence-rails and rocks are lichens. They have roots for attachment only, and such are called aerial roots.
Then there are climbing rootlets. Look at the poison-ivy, but do not touch it, and you will see it climbing over tree-trunks and fence-posts by means of rootlets. The trumpet-creeper will show you the same thing. These rootlets are very strong, as you will find if you try to pull, as I did once, a trumpet-creeper out of a grape-vine.
A large class of plants are beggars and thieves. This is a hard thing to say of them, but, what would you call them when they press their roots into the bark of other plants and suck their sap, which is the same to the plant as life-blood? Why can't they dig in the soil for themselves? Some of these plants wear fine clothes, and look innocent enough. There is the beautiful yellow fox-glove. Many times I have seen it, tall and showy on hill-sides and in woods. But they were root-parasites, that is, fastened by their roots on the roots of other plants, sucking juices dishonestly. The delicate purple gerardia sometimes does the same thing. So, you see, appearances are deceptive, and in plants, as well as people, you cannot always tell character from the outside.