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In this chapter I am going to tell you how it is that flowers are able to make seeds which in their turn grow into flowers themselves.

First of all, look at a flower carefully. I do not know what flower you have before you, but it is sure to have all the things I am going to talk about. Look underneath the flower. What do you see there? Do you see some green leaf-like things? Do you remember that when the flower was in bud these green sepals, as we call them, folded over the flower and protected it from cold and rain? Have you a bud there? Look at it and see if the sepals are doing as I say.

What comes above the green sepals? Yes, you all know—the petals.

Now look inside the flower—what are those yellow-headed things standing round the middle of the flower? They are stamens, and most of you know that they hold pollen. Do you remember shaking the yellow pollen-powder out of the hazel catkins? It came out in a cloud. Touch the stamen heads with your finger. If they are ripe you will find that the tip of your finger is yellow. On page 21 is a picture of pollen grains showing what they look like under a microscope.

Now look right into the middle of the flower. You will see a green thing—the pistil. What is it like? Do you see its green tip? Touch it. Does it feel sticky? Has it a neck running down to the bigger part we call the seed-box? The tip is the stigma, the neck is the style, and the seed-box the ovary.

You might think that the most important parts of a flower were the protecting sepals, or the bright, showy petals, and that they could well do without the inner parts. But it is just the other way about—the stamens and the pistil are the most important parts, and sometimes a plant does without its sepals or petals—think of the flowers of grass, which are only stamens and pistil, and have no petals or sepals at all. But a plant cannot do without its stamens or pistil, for if it did it could never make seed.

That is why the stamens and the pistil are so important to the plant—they make seed; and without seeds to grow new plants what would happen? We should have a very bare world, shouldn’t we!

Now I will tell you how a seed is made. You know that the head of the stamen (the anther) holds pollen powder. This is in the form of very tiny grains, all of which want to go to a pistil of a flower—if possible a pistil of another flower, not their own flower. How can the pollen go where it wants to? It cannot fly off by itself, so it must get something to help it. Perhaps, if the flower blossoms early in the spring, before insects are about, it will ask the wind to help its stamens. If it flowers now, when many bees, butterflies and other insects are everywhere, it will ask some of those to carry its pollen from one place to another. Somehow or other the flower will see that its pollen is carried away to where it wants to go.

A HONEY-BEE GATHERING POLLEN FROM A FLOWER. ITS VISIT WILL HELP THE FLOWER TO MAKE SEEDS

We will suppose that a bee carries away the pollen. It comes looking for honey in the flower, and rubs against the ripe stamens. They spill their pollen-grains on to the bee’s back (have you seen a bee dusted with yellow pollen?), and when the bee flies off to another flower, taking the pollen on its back, those grains will be rubbed against the green pistil there, and will cling to it, because both grains and pistil-tip are sticky!

Now what happens? Something very strange indeed, something you could not see or guess yourself. Look at the picture opposite. No. 1 is a picture of the inside of a pistil. Do you see the fat part at the bottom and the long neck above, ending in the pistil-tip? At the tip is a pollen-grain. A bee brought it to the pistil from another flower a few days ago.

The pollen-grain knew that it had come to the right place. It began to put out a little white tube, and this made its way all down the neck of the pistil. Can you see it? It went right to the lower part where the ovules waited. Do you see the ovules? They look like seeds, and they will be seeds later on when each one has been reached by a pollen-tube. They are not seeds yet. They are only little half-seeds. They never will be seeds unless they are reached by a pollen-tube, because the pollen brings them what they need to become a whole seed.

The pollen-tube in the picture has travelled down to an ovule, and it has grown into it, right into the very middle. There was a little hole in the ovule’s two coats left ready for the pollen-tube to enter, and it easily found its way. Now it is joined to the ovule, and the little half-seed will soon be whole. It has got what it wanted, and now it can grow marvellously, can develop into a healthy seed, and in time go on a journey to find a new home, where it may grow into a vigorous new plant all by itself.

THE PARTS OF A FLOWER

1.

The inside of a pistil showing how the pollen-tube travels to an ovule.

2.

Many pollen-grains putting out tubes to ovules. The two tiny ovules have no pollen-tubes and so have not grown.

3.

A snapdragon flower. The bee alights on the lower part and its weight opens the “bunny-mouth.”

4.

The inside of a foxglove. Do you see the barricade of hairs at the entrance?

All the little half-seeds in the ovary may be reached by pollen-tubes, and all may grow into whole seeds. The ovary is soon so full that it has to grow too! It swells and becomes larger. When the seeds are ripe it dries up and bursts, and the seeds are freed.

You have all shelled peas, I expect. But how many of you have seen the flowers that came before those long pods? How many have seen the young pea-pods, so small, so thin? You all know sweet-pea flowers, don’t you? Well, pea-flowers are the same shape but smaller. When the petals fell off, the pistil was left—a tiny pod. It grew and grew, and the seeds inside became fat and round. Before they were ripe their pod was picked, and perhaps you shelled the peas inside. Did you notice that at one end there were very small peas—perhaps one or two—that had never grown? They did not become pea-seeds—they remained little ovules, little half-seeds. Why? Who knows? Yes—because no pollen-tube reached them! Therefore they could not undergo the magic changes that made them into big fat seeds. They had to remain small and useless.

The pollen-grain and the ovule are partners. A pollen-grain by itself, or an ovule by itself, can never make a seed.

It is better for a plant to have pollen from another flower’s stamens for its seed-making, than from its own stamens. If a plant uses its own stamens’ pollen for its pistil the seeds will not be so healthy or so hardy as they would be if pollen from another plant were used. That is where the bees, butterflies and other insects come in—they take pollen from one flower to another, and so make sure that the seeds are the best that can be got! They do not know they are doing this, of course! No, they go to seek the honey that the flower provides to tempt them, or even to eat some of the pollen itself.

Left: WHAT POLLEN-POWDER LOOKS LIKE UNDER A MICROSCOPE. Right: A WONDERFUL PICTURE OF POLLEN-GRAINS SENDING THEIR TUBES DOWN THE STIGMA OF A FLOWER TO THE OVULES

An insect crawls into the flower for honey and becomes covered with pollen. Then it crawls into the next flower and the sticky pistil there takes some of the pollen from the insect’s back. All sorts of insects help the flowers. Those with open cups are visited by many kinds. Those with closed cups or with long honey-tubes (think of the snapdragon with its closed cup, or the nasturtium with its long honey-tube) attract more intelligent insects, such as the bee or the butterfly, which have long tongues to probe down the nasturtium spur, and in the case of the bee are wise enough to be able to open the closed “bunny-mouth” of the snapdragon to get at the honey inside.

Indeed, some of the bees are cleverer than they should be, and instead of opening the “bunny-mouth” of the snapdragon and crawling down inside the flower, past the stamens and pistil to reach the honey, they bite a hole at the bottom of the flower where the honey is kept, and so reach it by a short cut! When they do this it means that they do not brush against the pollen or the pistil, and so seeds are not made by that flower—unless it can use some of its own pollen, which it does not really want to do.

When the plant is going to use the wind to blow pollen on to its pistil, it does not bother about lovely petals, sweet scent or delicious honey. It produces simple flowers, plain and not easily seen.

But it is a different matter when living insects have to be used. Then flowers must have colour, brightness, scent or nectar—and the more particular they are about the kind of insect they want for visitor, the more complicated the flower becomes! Think of a simple wild-rose flower, with its open cup spread wide for any visiting insect. Then think of a snapdragon with its complicated “bunny-mouth,” or a white dead-nettle flower, a sweet-pea flower, or the long throat of a foxglove made specially for the big humble-bee. The foxglove has even grown a barricade of hairs at its entrance to stop tiny insects from crawling in! It prefers humble-bees, and means to get them. It does get them too, as you will soon find out if you watch a foxglove plant.

Now you know exactly how a seed is made. Use your eyes as you go about, and see how many different shapes of stamens and pistils you can find. You will be quite surprised at the discoveries you make!

THINGS TO DO

1.

Draw an open pea-pod from memory. Put in it some fat, ripening seeds, and one or two ovules that have never grown. Write down underneath why these ovules have not become seeds.

2.

Look at the stamens and pistils of as many flowers as you can this summer. Draw some of them on your Nature-chart.

3.

Try to find out whether plants grow in any other way than from seeds. (Bulbs, corms, runners, etc.)

4.

Watch snapdragons, foxgloves, and nasturtiums this summer to see the bees in them. Watch a butterfly closely. Try to see it uncoiling its long tongue to put into the heart of a flower. Look at the first picture in this book.

5.

Look at the green flowers of the stinging-nettle. Would you think that the wind or insects took the pollen from stamens to pistil?