  “These,” said Uncle George, “are what we grow our snowdrops and crocuses from.” As he spoke he handed each of the boys a few hard, round objects. Some of these were small, white, and almost pear-shaped. The others were larger, rounder, and brown in colour. “The small white ones are snowdrop bulbs,” he continued. “The others are crocus corms. There is a great difference between a bulb and a corm, as we shall see when we examine and compare them.” “The corm is covered with brown, papery skins, and has white buds on the top of it,” said Frank. “These brown skins are leaves,” remarked Uncle George. “Leaves?” said Tom. “I thought all leaves were green.” “Oh no, Tom, there are other leaves besides green leaves, called scale-leaves. Green leaves, as you know, give off the moisture which the roots take up from the soil. They also take in plant-food from the air. Scale-leaves protect buds, flowers, and tender stems from cold and from insects. These thin brown leaves of the crocus corm are scale-leaves formed underground. Please remove the brown scale-leaves from one of the corms, Frank.”
When Frank had done so, it was seen that these leaves were attached in layers all round the corm. The corm was now a white, rounded lump. The removal of the scale-leaves had left thin rings of leaf-marks; and on these leaf-marks, here and there a tiny bud was seen. “Now,” said Uncle George, “we can see that a corm is a stout, swollen, underground stem. If you could imagine a horse-chestnut stem to be squeezed up into a lump, you would have something like a corm. These rings of leaf-marks are the nodes, where leaves and buds are found on all stems. The large buds on the top of the corm correspond to the large buds at the end of your horse-chestnut stem. Now, let us take off one of these large top buds. Notice that it is covered with many tough, protective scale-leaves.” Crocus Bud Dissected.
Removing these scales, Uncle George came to a round object in the centre. “This,” he said, “is a long sack or bag. It contains the flower of the crocus.” Taking a needle, he carefully opened this up. “Now, boys,” he said, “take your magnifiers and look carefully.” Frank and Tom looked, and saw a curious little “Let us now,” he said, “examine the snowdrop bulb. “Here we have thick, fleshy scale-leaves. If we remove them one by one, we find that they are all attached to a flat, button-shaped stem. Between the thick scale-leaves we see, here and there, a small side bud, and on the top the baby snowdrop flower snugly wrapped up in their sack. This protective sack is called a spathe.” Uncle George then took from his pocket a very large bulb. “This,” he said, “is the bulb of the narcissus or ‘white lily.’ It is almost exactly like the snowdrop bulb, but it is larger, so that we can see things much more distinctly.” He then split the large bulb down the centre with his knife. With a pin he pointed out the baby flower wrapped up in its spathe. All the parts of the flower were seen, even the little seed-vessel containing the tiny eggs, which become seeds after the flower has grown up. “If you remember,” said Uncle George, “in our lesson on seeds we learned that a seed contained a baby plant and a large supply of plant-food. I am now going to show you that both the corm and the bulb contain a large food supply. We have seen that the protective bud-scales in the corm are tough and thin, while the stem is swollen and hard. In the bulb, on the other hand, the bud-scales are thick and fleshy, while the stem is flat and very small. If we place some of our crocus corms “That, like the seeds which we grew in water, bulbs and corms contain a store of food,” said Frank.
“That is correct, Frank. Let us put a corm and a bulb in water. Let us also plant one of each in a pot of soil. We will watch them growing and compare them from week to week. “Now I am going to show you a simple experiment. You know that the food we eat is drawn largely from plants. This food which we take from the plant world “I have here in this bottle a substance, called iodine, dissolved in water. Anything containing starch turns blue when touched with iodine. Now observe what happens here.” Uncle George poured some of the iodine into a saucer. He then dipped into the iodine a piece of crocus corm, a thick scale of the snowdrop bulb, soaked seeds of maize and wheat, a slice of raw potato, and a piece of bread. Each at once turned dark blue on being dipped into the liquid. “Now, boys,” he said, “what do you learn from this?” “The food store in bulbs and corms is the same as that in seeds,” said Tom. “The food supply of the bulb is contained in the thick, fleshy scale-leaves, while in the corm it is in the stem,” said Frank. “Very good,” said Uncle George. “It also shows us, I think, that we ourselves owe a great deal to the plant world.” Exercises on Lesson II.
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