Читать книгу Enid Blyton's Nature Lessons - Enid blyton - Страница 5
ОглавлениеSOME SEEDS AND FRUITS
“In every hedge and every lane
Hips and haws are seen again,
Keys of ash and sycamore
Flutter to the woodland floor,
Dandelion clocks set out
And thistle seeds are blown about.”
The plants that were brilliant with flowers in the summer, all the trees whose leaves shook and whispered in the wind, and all the bushes that decked themselves with gay blossoms, have one great plan—and that is to make seeds which will grow into plants, bushes, and trees like their parent.
Now that the autumn is beginning, we can see how their plan has been worked out. Look where you please, you will see fruits and seeds ready for their journey to a new home.
Why do all these plant-babies have to find new homes? How do they get there? Does anyone help them, or do they go all by themselves?
The reason they need new homes, as far away from their parents as possible, is that, if all seeds fell by their parent plant, they would suffer from overcrowding when they grew, and would not have enough light or air. So the parent plant sends them away.
SEED DISPERSAL
(1) Sycamore, (2) Ash, (3) Elm, (4) Dandelion, (5) Willow-herb, (6) Clematis, (7) Poppy, (8) Geum, (9) Cleavers, (10) Haws, (11) Pansy, (12) Acorn, (13) Sweet Pea.
They are taken to their new homes in many ways. The wind helps some. Animals and birds help others. The parent plant itself helps many, and water, too, plays a part in taking some seed-babies to another home.
The Wind
We will talk about the wind’s help first, because many fruits and seeds are scattered far and wide by him. Some seed-cases grow wings and fly away with their seeds when the wind blows.
Perhaps you will think, in this connection, of the sycamore seeds, or “keys,” as we call them. They are very like the keys with which we wind up our clocks. They have two little wings, and they are pretty to watch as they fly from the tree through the air, circling and twisting like fairy propellers. If you stand on a chair and throw them up in the air you will see them go twirling round and round as they slowly fall.
The ash keys, or spinners, grow wings too. I expect you have seen bunches of them hanging down from the tree. They have just one wing each, but with that they can fly a long distance in the wind, especially when it blows strongly. I have found ash keys lying in a road a long, long way from the trees.
The elm has little bunches of fruits, each fruit with a wing all round it, not just at one end as in the ash and sycamore.
Some plants provide their seed-babies with feathery plumes to help them to go sailing off in the wind. The willow-herb, whose pink flowers you are sure to have seen growing in waste places, has a very clever way of making sure its babies will have a good journey. The seed-case is long and thin. When the seeds inside are ripe, it splits downwards into four pieces, which twist themselves back. And inside, beautifully arranged one above another, are the tiny seeds, each with a plume of very fine hairs. Directly the wind puffs along, out fly the little seeds, and float far away in the air.
Of course you have seen the dandelion clocks, and blown them to tell the time. Next time you find a clock pull one of the little fruits out and have a good look at it. It has a little parachute of hairs to carry it up into the air. It only waits for the wind to help it, and off it goes.
Near by, on the hedge, you may see the grey plumes of the clematis, or traveller’s joy. Most people call it Old Man’s Beard when its little fruits are all ready to fly, for it looks just like grey fluffy hair. If you look at it you will see that each wee fruit has grown a long silky feather, very delicate and soft. They are the prettiest, daintiest things.
One of the most fascinating seed-boxes is that of the poppy. Poppy seeds have no wings to spread in the wind, but they get him to help them in another way. Look at a dry poppy head. At the top, just beneath the “lid,” you will see lots of little holes. Turn the head upside down and shake it. If there are still seeds inside they will come tumbling out, just like pepper out of a pot! When the wind blows, and rocks the poppy head from side to side, or shakes it roughly, it scatters out the seeds and they blow here, there, and everywhere.
When Animals Help
Now we will talk about a few plants which get animals to help them in sending their children out into the world.
They do this in two ways—either by making the fruit attractive to animals to eat, hoping then that the seeds will be scattered; or by giving their fruits hooks or bristles, so that they catch on to the legs and coats of animals brushing by, and then are carried to other parts of the field.
The one you will probably know the best is goose-grass, or cleavers. Cleavers is a good name for this plant, because not only do the fruits cling or cleave to anyone brushing against them, but also the stems and leaves. The little fruits are covered with short-hooked prickles, and sheep and dogs often carry scores of the tiny burrs with them, shedding them here and there, as they rub through grass or bushes.
The geum, too, has its fruits armed with tiny, wiry button-hooks that catch on to the coats of animals as firmly as do the bristles of goose-grass.
The scarlet, juicy hip of the wild rose attracts birds, who, in pecking at it, peck out also the little fruits inside and so scatter them. The birds do the same for the haws, often swallowing the stone inside as well as the red case. They cannot digest the stone, and, after it has passed through the bird’s body, it falls to the ground perhaps a mile away from the parent tree.
Fruits that Explode
Some plants help their seeds into the world by exploding the seed-case suddenly, and sending out the seeds with a jerk. The gorse, for example, bursts its pods with a pop, and scatters the seeds all about.
The pansy case bursts into three parts, each like a little boat, and when these dry they shrink up, and so force out the little hard seeds. If you pick a pansy seed-case, you will be astonished to see how high the seeds jump. The violet, too, sends out its seeds in the same way, often as far as 10 feet, which is a great distance for such a tiny plant.
Floating Seeds
Plants that grow in the water get its help in sending their seeds away. The water-lily seeds are often sent long distances from one side of a lake to another. There are air-spaces between the seed and its coat, and so it floats about gaily until the time comes when it sinks to the mud, and there grows into a little water-lily plant.
The coconut, too, often sends its big babies on the water, and they bob about on the sea until one day, perhaps, they are cast up on a little island, and there sprout up into trees.
You will find it is exciting work to wander about fields and lanes, poking into hedges and grass, to discover seed-cases of all kinds. You will be surprised at the enormous number you will come across.
QUESTIONS TO ANSWER AND THINGS TO DO
(1)
How do the seeds get to their new homes? What helps them?
(2)
Put down the names of all the seeds you know that have wings, parachutes or plumes.
(3)
How do plants get animals to help them in carrying away their seeds?
(4)
How does the pansy send its seeds away?
(5)
Draw as many fruits and seeds as you can.
(6)
See how many you can find next time you are out for a walk.
