as a little spiral, like a green snail. It does not grow from an upright stem like the moss leaf. It is just as if nature said: "I cannot make a stem strong enough yet to stand up and bear many leaves. So I will just flatten and bury the stem, and make a broader crown. From that a stronger root can burrow into the ground, and many leaves rise into the air."
The stem of the little curled up snail-like leaf is soft and green, but it is quite thick. As the leaf uncurls, this stem seems to stretch, and grow more slender. Slowly it stiffens. The strings of cells that were simply water pipes and lungs, also become bones to hold it up. These bone tubes run right out to the tips of the leaves, growing smaller and smaller, as they have less to support. Then, from the sides, grow ribs, just as your ribs grow from your backbone. The stem of the fern leaf is a hint of a coming tree trunk; the veins in the leaf are hints of branches on the trunks. The fern leaf is really the far-away promise of a forest tree. Most fern-leaves are deeply parted between the ribs, clear down to the main stem, making branching leaflets. And on the very ends of the smallest leaflet veins, around the edges, the fern leaf bears its fruit, or spore discs, just as the most perfect rose tree bears its flowers and seed pods.
Find a fern leaf that is fully grown, in some shady spot in the woods. All around the edges of the underside, you will find little rusty spots. These are very regularly spaced, so you can easily guess there is some plan. If you look at them through a microscope you will see that they all grow from the ends of the veins, and are connected with the mid-ribs of the leaflet, and those mid-ribs with the main stem. (See Filicales, Volume II, page 661.) So all those little rusty spots are fed from the root in the ground. The rust spots are only tiny, pin-head grains, that look like a brown powder. But you will find them fastened tight. The microscope shows them to be little brown cases, filled with still smaller grains. These are spores, like those on the liver-wort and moss. Around each spore case is hung a necklace of crystal beads. These draw together, tighter and tighter, until they force the spore case to burst open, and shoot out the ripe spores.
