"You will remember that I told you some plants could take the very necessary chemical nitrogen from the air; most of them, however, must get it from the soil. And so again this from the soil solution is worked over into available food.
"After all we must not fail to see that water is most important. It floats all the important food elements to the leaves for the work to be done there. The food carbon, of course, is an exception to this rule and I will say again in certain cases nitrogen is, also.
"Thus you boys and girls now understand how necessary it is that a soil should be of the right texture to hold water. If it is not, it must be helped to be so. Sand, you will remember, had to be doctored to hold water. Clay needed treatment in order to make it quit its bad habit of baking out.
"Here is a rather interesting experiment set up by Josephine and Ethel. Look at the first piece of apparatus—a tumbler partly full of water, a piece of cardboard over the top of the tumbler, and passing down through a hole in the cardboard a piece of plant just stem stripped of leaves, and finally a second tumbler clapped over the first. The second piece of apparatus is exactly like the first, only that the stem, one end of which is in the water, has leaves on the other end. Notice that the upper glass in the second case has moisture on it. The upper tumbler of the other set is perfectly dry. Whence, then, came the moisture? It must, of course, be the leaves which gave it off, since they represent the only difference in the two pieces of apparatus.
"I wish we might go on with whole sets of experiments, but for that we have not time.
"You understand a little of the mission of root, stem and leaf. The root does a good work in holding a plant in place. It is the foundation material of the plant. There is much, much more to be learned about all these subjects. This little is just to open your eyes to the wonders of the work each plant is performing all the time.
"I said I would show you some magic. Well, this magic has to do with plant improvement. It is not much of a trick to raise a plant, but it is a great one to be able to improve that plant.
"Let me tell you of a friend of mine whom we will call Rodney, because that is his real name. One day Rodney noticed the gardener doing something with a little flat knife to a pansy. Then he tied a little paper bag over the pansy, of course leaving the whole thing on the plant.
"'What are you doing?' asked the lad. 'I am fixing that pansy so that the seed from it shall be finer seed than they otherwise would be.'
"Then the old gardener explained this to Rodney: There are two parts to flowers which are very necessary, absolutely necessary to making seed. One part is the pistil, the other the stamen. Some flowers have both pistils and stamen, while others have just the pistil and one has to hunt for another plant having the stamen. You can tell the stamens in this way: they are the parts which have in their care the pollen. Most of you know pollen as a yellow powder or dust. Sometimes it is a sticky gummy mass. The pistil is that part of the flower which ends in the seed vessel. It very often takes a central position in the flower, standing up importantly as if it were the 'part' of the flower. And after all, it is. Now, when this pollen powder falls on the pistil it does not explode. The pistil merely opens up a bit and down travels the powder into the seed vessel to help form seed. There would be no real fertile seed without the pollen.