[Illustration: [Pollen]]
In the dark little dungeon cells of the anthers, the pollen grains lie.
Hundreds, and sometimes thousands of them, are packed in there as
closely as they can be. But they do not mind it, not in the least. They
grow and get ripe, and as soon as this happens, their prison door opens
and out they pour.
They are funny little things, not at all what they seem to be. For you
would think they were just little specks of dust of almost no shape at
all. But that is your fault, or rather the fault of your eyes.
You see your eyes were not meant to look at things so tiny as pollen
grains. You can see a common ball or even a small shot very well indeed;
but when it comes to pollen grains you are as blind as a mole. You will
have to put on your spectacles to see _that_, I can tell you, and very
powerful spectacles they will have to be, too. The best spectacles for
you to look through are the ones we call a microscope. Just put your eye
to that tube and you will see what you will see, for there are pollen
grains at the other end—pollen grains from several kinds of flowers;
there are some in the corner from our friend the morning-glory. And now
you know what I meant when I said you could not see a pollen grain; for
those little specks of dust have all at once become large and important
objects. Some are round and some are not, and all are creased or pitted
or ridged or covered with little points or marked in some other way. Now
you see why they stick so easily to the hairs on the bee or the
butterfly or whatever comes visiting the flowers for nectar. They are
not smooth, but all roughened over by these ridges and points.
And this is not the end of it. You have not yet seen a pollen grain. You
have only seen the outside of one.
For it has an inside. You think it is too small to have anything inside
of it?
I can tell you things _much_ smaller than that have something inside of
them. The truth is, these things seem so small because we are so large.
If we were as small as they, they would not seem small at all. They
would seem a very ordinary size indeed, and we would expect them to have
an outside and an inside.
The truth is, pollen grains are hollow. They are as hollow as the baby’s
rubber ball. But they are not _empty_. The baby’s rubber ball is not
empty; it is full of air. These pollen grains are not full of air. If
you were to see what is in them, you might not think it very important,
but that would be a great mistake, for they are full of—protoplasm!
The truth of the matter is, the pollen grain is a _cell_; it has a wall
outside and is made of protoplasm inside.
Protoplasm, you remember, is the material out of which every living
thing is made. You are made from protoplasm yourself; flowers are made
from it, too, and leaves and birds and _everything that lives_.
So you see if a pollen grain is filled with protoplasm, that is rather a
serious matter.
This pollen grain, small as it is, has a tough outer skin. It is not as
tough as leather, but it is tough for so small a grain, and is strong
enough to keep the protoplasm from running out.
The protoplasm in the pollen grain is what the ovule needs to nourish it
and make it able to grow. The ovule, too, is a cell filled with
protoplasm, and the protoplasm of the pollen and of the ovule must
somehow come together before the ovule can do any more growing.
You know how the bees and butterflies and all sorts of insects carry the
pollen from flower to flower and dust the stigmas with it. You may think
that when a pollen grain is safely landed on a stigma then the rest is
easy enough. But if you suppose the pollen grain can pass through the
style you are _very_ much mistaken. It cannot even pass through the
stigma. It is true, the tissues of both style and stigma are rather
loose, and that the style is sometimes hollow. But, as far as I know,
the pollen _never_ passes through. Small as it is, it is too large to
get through the tiny openings in the stigma, and then, you know, the
stigma is sticky and holds it fast.
Here is an interesting state of affairs! The ovule cell is waiting for
protoplasm, and the pollen cell is anchored safe and fast at the stigma.
But you may be sure there is a way out of this difficulty.
[Illustration: [Pollen]]
To begin, the pollen grain has two coats, a tough outer one and a
delicate inner one. There are openings, or at least weak places, in the
outer coat, and after the pollen has lodged on the moist stigma, the
protoplasm inside swells and comes bulging through these weak places.
The inner coat is forced out, as though some _extremely_ small fairy had
stuck her finger through the wall from the inside and pushed out a part
of the inner lining. Well, this finger-like part that comes through the
wall does not break open, but begins to grow. It grows longer and longer
until a tube is formed, a tube so small that only the microscope can
enable us to see it.
This tube pushes its way through the stigma into the style; there it
continues to grow like a long root, only it is _not_ a root, and it is
hollow; and the protoplasm from the inside of the pollen grain runs down
this tube.
[Illustration: [Pollen]]
You can guess what happens next. The tube grows and grows; it finds
plenty of nourishment in the tissue of the style, which is made of
material suitable to feed it. Of course, it grows down the style into
the ovary, because the style opens into the ovary.
When it reaches the ovary it finds its way to an ovule, and goes in at a
little door which the ovule keeps open for it.
Now, you see, there is an open path between the pollen grain and the
ovule, and the protoplasm from the pollen grain which has run down the
tube enters the ovule. Here it passes out of the tube by breaking
through the delicate wall, and unites with the protoplasm of the ovule.
Thus the ovule is fertilized. It is nourished and strengthened, and at
once begins to grow into a seed.
Meantime the shell of the pollen lies on the stigma, a little dried-up,
empty thing. Its work is done. Thanks to the bee or the butterfly or
some other flower-loving friend, it has been taken to the right place,
and all that was living in it, its protoplasm, goes on living in the
little ovule.
The pollen grains the bees carry home have a very different fate. They
are crushed and soaked and kneaded with honey and fed to baby bees.
But the flowers are willing the bees should have some to live on, and so
each flower makes thousands more than it needs. You see, if it did not
give the bees something to eat, they would not come and they could not
live on honey alone; they, too, need the protoplasm in the pollen to
nourish them.
Some kinds of flowers use their own pollen. They do not need the bees
and do not want them. So they keep their pollen shut up tightly and do
not make any honey to coax the bees to come. But nearly all flowers wish
to have other pollen than their own. And this they can only get by the
help of other people’s wings, as they have none of their own.
[Illustration: [Flower]]