They are what we call fossils, and now I have no doubt you know all about it; if you do not you will some day,—that is, if you care to.
From what the rocks tell us, and for other reasons, we feel pretty sure that the earlier plants had only leaf and stem, but no flowers. And the very first leaves were not like the leaves we see in the woods and gardens about us, for they were probably large and mushy and had no veins to speak of. If you had picked one up it would have been flabby and squashy, and you would have been glad to put it down again. But nobody ever did pick one up, because nobody was there.
The earth was not ready for us yet. It was all soft and swampy or hard and cheerless, and we had to wait until these queer pioneer plants gradually changed into other plants and made the earth fit to live on.
But these flabby old friends of ours went to work with a will to get things in shape for us to come. Their green leaves and stems, where they had any, ate the gases in the air and stored them up as plant material. Then they died. They did us as much good by dying as by living, for only part of their substance went back as gases into the air; the rest went into the ground and began to make soil for other plants to grow in.
So Mr. Flabby Leaf was a very good life starter.
One thing we are quite sure of, and that is, these earlier plants did not have any seeds. When new plants came from the old ones, they merely sprouted out from the leaves or the roots, as a certain fern that grows in Fayal and other places does to-day. It is fun to raise this fern in a window box and watch the young ferns sprout out of the edge of the leaves of the old fern. After they get two or three tiny green leaves and the cunningest little curled-up frond, just like a big fern, off they tumble down to the ground, where they strike root and grow as calmly as though they had come the regular plant way and sprouted from a seed.
They do come the regular way the very early plants did, instead of coming the way modern plants do, for in some such way the earlier plants, no doubt, reproduced themselves.
They had no flowers and no seeds. Leaf and stem did it all. You see, these first plants were simple people, not complicated at all, and so each part of the plant was able to do all its own work. But after awhile the plant world became more complex; the earth grew drier, for one thing. The first plants lived in the water, no doubt, and so everything was much easier for them; at least they could always get plenty of water, which is a matter of great importance with plants.
No water, no plant. Then, too, the earth cooled more and more, and from being uniformly warm and moist, which was just the best conditions for plants to live without taking any trouble about it, the air was sometimes colder and contained less moisture.