[THE THIRSTY FLOWERS.]
BY MRS. SOPHIE B. HERRICK.
Fill a glass with water, and let a piece of common tape or a strip of muslin hang so that its lower end shall dip into the water, and then notice it: the liquid creeps slowly but surely up the strip. If the end which you have in your hand is dropped on the table beside the glass, the goblet may be entirely emptied, the water running up over the edge of the glass before it runs down again. This behavior of water would seem very queer if we had not noticed something of the kind all our lives. It is caused by what is called capillary attraction. Whenever one part of a material full of fine openings which lead through it is dipped into a liquid, the fluid runs through the whole stuff, even if it has to run upward. Try a lump of sugar: put one corner into your cup of tea or hot milk, and watch it soak the lump through. The burning of a lamp is upon the same principle. The wick serves to carry the oil from the globe of the lamp to feed the flame. As soon as the oil gives out, the light fades and dies away.
Fig. 1.—Cells. A, Leaf of Geranium Flower; B, Leaf of Sorrel.
Every part of a plant needs water: it must be close around every little cell. These cells are the tiny queer-shaped bags full of liquid that are packed close together, and make up the leaves, stems, and flowers of plants. In Fig. 1 you see the cells of a leaf of geranium flower, and one of sorrel or sour grass, which, if you are like the children I know, you have many a time eaten to get the pleasant sour taste. Well, every one of these tiny cells must be kept wet all the time, or the plant will die. The only way we can think of that water could get up into the leaves and flowers from the earth is by capillary attraction, as it runs up the slip of muslin. And if it were not for this singular behavior of water, the only plants in the world would be those that grow in the seas and rivers and lakes. The land would be as barren as the desert of Sahara.
Now try to think of some plant with all the earth away—a tree, for instance—and you will see that it is a sort of double growth; that there is an upside-down tree in the ground, with its trunk and branches and twigs, as well as one above the ground. The under-ground twigs do not bear leaves, but each one of them wears on its head a little cap or helmet to protect the tender growing part from being injured as it pushes its way through the hard earth. The most important parts of a tree are those that seem of least consequence, the rootlets and the leaves. These are to the tree what our mouths and stomachs and our lungs are to us: the roots are the feeders and the leaves the breathing apparatus of plants.
Fig. 2.—Corn Stalk cut across.
As the under-ground tree grows, the tender little roots push their way down into the darkness and cold of the deep soil; they find their way around stones and through great clods of earth, anywhere and everywhere, until they get their little noses into water or damp earth, and then they begin to suck. Sometimes it is only pure water that they take up from the earth, but generally it is a sort of broth—water with plant food dissolved in it.