Pistils, stamens, calyx, fade and die

The Story-book of Science by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. POLLEN

CHAPTER LXI. POLLEN

“IN a few days, even in a few hours, a flower withers. Pistils, stamens, calyx, fade and die. Only one thing survives: the ovary, which will become fruit.

“Now, in order to outlive the other parts of the flower and remain on its stem when all the rest dries up and falls, the ovary, at the moment when blossoming is at its greatest vigor, receives a supplement of strength, I should almost say a new life. The magnificence of the corolla, its sumptuous colorings, its perfumes, serve to celebrate the solemn moment when this new vitality comes to the ovary. This great act accomplished, the flower has had its day.

Grains of Pollen

“Well, it is the pollen, the yellow dust of the stamens, that gives this increase of energy without which the nascent seeds would perish in the ovary, itself withered. It falls from the stamens on to the stigma, always coated with a stickiness apt to hold it; and from the stigma, it makes its mysterious action felt in the depths of the ovary. Animated with new life, the nascent seeds develop rapidly, while the ovary swells so as to give them necessary room. The final result of this incomprehensible travail is the fruit, with its contents of seeds ready to germinate and produce new plants. Do not question me further about these wonderful things concerning which even the keenest observer ceases to see clearly. God only, the wisest of beings, knows how a grain of pollen can give birth to something that was not before, and can cause the ovary to feel the stirring of the vital principle.

“I will tell you now how we know that the falling of the pollen on to the stigma is indispensable to the development of the ovary into fruit.

“Most flowers have both stamens and pistils. All those we have just looked at are in that class. But there are plants that have some flowers with stamens and others with pistils. Sometimes the flowers with stamens only and those with pistils only are found on the same plant; sometimes they are found on separate plants.

“Did I not fear to overcharge your memory, I would tell you that plants having flowers with stamens only and flowers with pistils only on the same plant are called monœcious plants. This expression means ‘living in one house.’ In a word, the flowers with stamens and those with pistils live together in the same house, since they are found on the same plant. The pumpkin, cucumber, melon, are monœcious plants.

“Vegetables whose flowers with stamens and flowers with pistils are found on different plants are termed diœcious; that is to say, plants with a double house. By this is meant that the ovary and pollen are not found in the same plant. The locust, date, and hemp are diœcious.

Flowering branch of Locust Tree

“The locust is a tree of extreme southern France. Its fruit grows in pods similar to those of the pea, but brown, very long, and plump. This fruit, in addition to seeds, has a sugary flesh. Supposing we took a notion, if the climate permitted, to grow locust seeds in our garden. What locust tree must we plant? Evidently the tree with pistils, because it alone possesses the ovaries which become fruit. But that is not enough. Planted by itself, the locust tree with pistils will be able to blossom abundantly every year, without ever producing any fruit; for its flowers would fall without leaving a single ovary on the branches. What is wanting? The action of the pollen. Close to the locust with pistils let us plant one with stamens. Now fructification proceeds as we wish. Wind and insects carry the pollen from the stamens to the stigmas; the torpid ovaries spring to life, and in time the locust pods grow and ripen perfectly. With pollen, fruit; without pollen, no fruit. Are you convinced, Jules?”

“Without doubt, Uncle; only, unfortunately, we do not know the locust. I should prefer a plant of our own region.”

Date-palm

“I will tell you of one that will permit you to prove what I have told you; but first of all let me mention a second example.

“The date-tree, like the locust, is diœcious. Arabs cultivate it for its fruit,—dates, their chief food.”

“Dates are those long fruits of a very sweet taste, preserved dry in boxes,” said Jules. “A Turk was selling some at the last fair. The kernel is long and split all along one side from one end to the other.”

“That is it. In the country of the date-tree, a sandy country burnt by the sun, spots of watered and fertile earth are rare. These spots are called oases. It is necessary to utilize them as much as possible. So the Arabs plant only date-trees with pistils, the only ones that will produce dates. But when they are in flower, the Arabs go long distances to seek bunches of flowers with stamens on wild date-trees, to shake the dust on the trees they have planted. Without this precaution there is no harvest.”

“Uncle will tell us so much,” Emile interposed, “that I shall have as much regard for the pollen as I have for the ovary. Without it, I should not have tasted the dates of the Turk who smoked such a long pipe; without it, no apricots and no cherries.”

“In the garden there is a long pumpkin-vine that will soon blossom. I will give it to you for the following experiment.

“The pumpkin is monœcious; flowers with stamens and flowers with pistils inhabit the same house, the same plant. Before they are full-blown they can easily be distinguished from each other. The flowers with pistils have under the corolla a swelling almost as large as a nut. This swelling is the ovary, the future pumpkin. The blossoms with stamens have not this swelling.

“Cut off all the blossoms with stamens before they are full-blown, and leave those with pistils. For greater surety, wrap each one of these in a piece of gauze before it is in full-bloom. The covering must be large enough to permit the flower to open. Do you know what will happen? Not being able to receive the pollen, since the flowers with stamens are cut off, and since, also, the gauze wrapping keeps out the insects from the neighboring gardens, the pistillate flowers will wither after languishing a while, and the plant will not produce any pumpkins.

“Would you, on the contrary, like such and such blossoms, at your choice, to produce pumpkins in spite of their gauze prison and the suppression of the staminate blossoms? With the tip of your finger take a little pollen from one of the blossoms you have cut off, and put the yellow dust on the stigma of a pistillate flower. Then replace the gauze wrapping. That is enough, the pumpkin will come.”

“You will let us try that delightful experiment?” asked Jules.

“I will, I give the pumpkin-vine over to you.”

“I have some gauze,” volunteered Claire.

“And I some string to tie it with,” added Emile.

“Come along,” cried Jules.

And, gay as larks, the three children ran to the garden to get everything ready for the experiment.

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