This section is from the "The New Student's Reference Work Volume 5: How And Why Stories" by Elinor Atkinson.
Next above the liver-wort, is a plant that will tell you how to find your way home if you ever get lost in the woods. One of the very first lessons a little Indian boy learned, when he went hunting, was that moss grows mostly on the north side of trees. It does that because the north side is damp and shady. If liver-wort is the child of the algae, or seaweed, moss is the grandchild and the fern the great-grandchild. They all like plenty of water, each one needing a little less water, and able to bear a little stronger sunlight. Each next higher plant learned new things. The liver-wort learned to grow leaves, to send down little sucker hairs and to fill spore cases. Let us see what moss learned to do.
Moss grows from a spore like the liver-wort. It nestles in any damp, shady spot it can find ; on a porous rock or the bark of a tree, or on a soft bit of ground. At first it grows little strings of green cells, very much like its grandmother, the seaweed. These lie flat. They seem to be food cells for little brown rootlets that burrow into the soil, and for buds that rise in the air.
It doesn't matter at all which side of the moss-spore lies on the ground. The strings of food cells spread around it; the rootlets go down from the underside, and the buds rise from the upper. Neither the root nor the stem are in the spore at all, only cell material, whose business it is to get food from the earth and the air. The cells on the ground burrow for food, and the upper cells reach for it. The interesting part about moss is that the upper growth does not flatten into a leaf, that sprouts another leaf, like the liver-wort. It grows upward into a little stem, and leaves sprout from the stem. It grows upward, oh, quite a little bit of an inch, budding leaves all around the stem, and finally bears a little seed case on the tip.
Bravo! Don't you feel like clapping your hands? Think how long and hard those little yeast cells full of protoplasm had to work, before they could make the moss plant with a true root, a stem, a leaf and a seed case. But when it has done it moss is still such a tiny fairy plant, and so slender and delicate that it cannot stand alone. You always find the mosses crowded so closely together that they make green plush cushions. This is partly so that the little plants can hold each other up, and partly too, perhaps, so the spongy matted mass can hold plenty of water. One little moss plant, standing alone, would soon become very dry. If you want to separate one plant from a cushion of moss you will have to melt the earth out in water, until the little rootlets can be pulled apart.
There it is, at last, a pigmy pine tree, with a sort of cone-shaped pod on the tip. This is often called the moss fruit, but it isn't a fruit as seeds of higher plants are. It is a spore case, very much like those of the liver-wort. But here is a funny thing. Moss makes seed first, and then a spore case. The seed is borne on the tip of the stem. It doesn't burst or fall off, or go anywhere. It just begins to grow right where it was formed. It sends a little anchor root down into the mother stem, and a bud upward in the form of a little leafless stalk. (See picture in Volume II, page 1282, Musci.) On the tip of the stalk is set a pointed and fringed fool's cap. That is a spore case. Mosses, like liver-worts, grow from spores. The spores make true plants with root, stem, leaves and seed. But the next plants do not grow from these seed. The seed stay on the parent plant, and make spores to grow new plants.
All the strength and cleverness of the moss plant goes into making these spore cases on the tip. (See Moss Capsule, page 1283.) The fool's cap is really only a husk, like the chaff of wheat. Underneath it is a cup, with a curly hair-fringed rim, and a cone rising from the middle. The cone is pitted in regular ray-like rows, something like the tip of a baby ear of corn before the grains come. In these cups are the same little balls as in the liver-wort. On other plants nearby and mosses, you know, so closely crowded together that they seem like one plant, there are other cups in which those double lashed whips thrash around in a bath. You can easily guess what they do, for it is the story of the liverwort all over again. The whip cells find the ball cells, and the two unite to form spores. When the spores are ripe the cases pop open. The spores are carried away by the little hairs set around the rim of the cone.
Having made a leaf, a root, a stem and a seed, what was the next thing to be done? You remember the stem of the moss is very slender and soft. It couldn't grow very high, nor stand alone, nor keep itself from dying. Just as the green cells of algae live in colonies, and so form fronds or feathery hints of leaves, so moss plants live in colonies to protect each other. The next step for these baby plants is to learn to stand alone. See Moss, Musci.