Plant Nature Study I by Various Plant Nature Study I by Various    

Lesson 30: Pests that are Beautiful (Animal Dispersal)

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June, the month of flowers, had passed and midsummer had come. The July heat made Peter lazy. It was much more comfortable to remain quiet through the day and do his running about in the cool of the evening and night. But most flowers are to be found only during the day, and so every once in a while Peter would slip out of the dear Old Briar-patch early in the morning and go in search of new flowers. You see, he was so interested that not even the hot weather could make him give up altogether. On some of these trips he found no new ones at all, and this was discouraging. But he knew that some plants do not bloom until midsummer, and so each time he would start out with renewed hope that he would find some of these.

He had gone up to the Old Pasture early one morning, and had hopped this way and that way without finding any flowers he had not seen before until he had become so discouraged that he had about made up his mind to go home. In fact, he had already started in that direction, when in an open place that was high and dry he came upon a plant a little more than a foot high which had a slender, stiff and somewhat rough stalk, which towards the top was much branched. The leaves were rather long, very narrow and pointed at the tips. They were shiny, and the upper ones were shorter and smaller than the lower ones. Each of the branches was in turn branched into many flower stems, and at the tops of these flower stems were white flowers that made Peter think at once of little Daisies. Together these flowers formed a loose cluster.

Of course, being like Daisies, each flower head was made up of two kinds of flowers, the outer ones snowy white just as in the Daisy, while the tiny flowers or florets crowded together in the center were a pale yellowish-green. Of the white ones each little flower head had from ten to twenty.

Peter knew it for an Aster right away. It was the Upland White Aster. There are many kinds of Asters, several of them white, but the Upland is the first of the white ones to bloom. The others bloom in August. It reminded Peter that summer was passing rapidly.

It was several days before Peter found another flower which was new to him. This time he happened to be hopping along the edge of Farmer Brown's wheat field. A spot of bright color in among the wheat plants caught his attention. He guessed right away that it must be a flower and of course he stopped to look.

"This is the last place I would have thought of looking for flowers," muttered Peter, as he made his way in through the wheat. "It is lucky I just happened to glance in here, and it is also lucky that this flower is of such a bright color; otherwise I wouldn't have seen it at all."

By this time he had reached the flower and was where he could have a good look at it. It was about two feet above the ground at the top of a straight, very hairy stalk, and these hairs were whitish. The leaves, which were long, pointed and narrow, were also hairy. The flower stem growing from the top of the stalk was quite long and rather stout.

The flower was large, purplish-red and very pretty. At least, Peter thought so. It was more than an inch across and the large, rounded, broad petals were opened out almost flat. Between the petals were narrow green sepals, almost like leaves, and these were longer than the petals. There were ten stamens and the pistil was divided into five parts. Together these so filled the heart of the flower that only insects with long, slender tongues could reach the nectar at the bottom of the tube.

Looking about, Peter soon found several more of the plants, one or two of which were slightly branched and bore one or two flowers at the end of each branch.

"I don't know what this flower is, but whatever it is, it is pretty. Yes, sir, it is pretty. I like to look at it. I hope I will see it often," said Peter, talking to himself as is his way.

Farmer Brown wouldn't have agreed with Peter at all. You see that flower was the Corn Cockle, sometimes called the Corn Rose, the Red Campion and Crown-of-the-field, a plant which is considered a great pest in grain fields, and one which is poisonous. It is not a native American, but long ago was brought from Europe and has liked this country so well that it has spread all over it. It is a member of the Pink family.

It happened that the very next flower Peter found was also one from Europe, which has liked this country so well that it has spread all over it. He didn't need to be told what this one was. He was acquainted with it. Yes, indeed, he was well acquainted with it. It was a plant for which he had no love at all, for more than once it had caused him no end of trouble. It was the Common Burdock, which is also called Beggar's-buttons. It was the plant which bears what are commonly known as burs, which really are the flower heads gone to seed. Many times had Peter patiently worked pulling them out of his fur.

The plant which Peter found was growing beside a fence. It was a big plant, branching so that it was quite bushy. The stalk was large, round and grooved. The lower leaves were large, broad and somewhat heart-shaped, and the stems of these leaves were hollow. The leaves were woolly on the underside.

At the ends of the branches were the flower heads growing in clusters. The florets were tiny tubes, purplish and white, and rather soft and silky looking as they peeped out from the midst of a thick covering of sharp, spreading bristles with long hooks. Now they were rather innocent-looking and pretty green balls, tipped with purple and white. But later they would turn brown and those tiny hooks would cling to whatever touched them, so that it would carry away the whole bur. This is the way in which the plant distributes its seeds.

The burs cling to the tails of cattle and become so entangled that it is hard work to get them out. They cling to the clothing of people who brush against them. Boys and girls love to make balls, baskets, nests and other things of the green burs, for when pressed together they cling closely by means of those little hooks. The roots and fresh leaves are sometimes used for medicine. Peter had once tasted one of those leaves, and once was enough; it was bitter and sour.

    Plant Nature Study I by Various Plant Nature Study I by Various    

Lesson 30: Pests that are Beautiful (Animal Dispersal)

Directions

Study the lesson for one week.

Over the week:

  • Read the story.
  • Review the synopsis.
  • Recite aloud the vocabulary words and their definitions.
  • Learn the concepts.
  • Complete the enrichment activities.
  • Study the review questions.

Synopsis

Peter studies a Daisy-like composite flower called the Upland White Aster. The Aster is made of two types of florets - the outer snowy white ray floret and the inner yellow-green disk floret. He next finds the poisonous Corn Cockle, a beautiful purplish-red flower considered a weed or a pest by farmers, as it grows in grain fields. The Corn Cockle has a hairy stem and spiky, hairy green leaves. Peter also examines the Common Burdock, which grow prickly seed burs that hitch rides on the fur of animals and the clothing of people. Children can make balls, baskets, and nests out of the burs, which cling together due to their hooks.

Vocabulary

Composite: Made up of multiple components.
Bur: A rough, prickly husk around the seeds or fruit of some plants.
Disperse: To scatter in different directions.

Concepts

Animal Dispersal:

  1. The burs of the Common Burdock hitch a ride on fur and clothing, enabling the plant to disperse or spread its seeds.
  2. Plants are very limited in how far they can move, so some rely on help from other organisms, such as animals and people.
  3. Burs dispersed by animals and people have special hooks that enable them to cling to fur and clothing.
  4. Other mechanisms of seed dispersal includes gravity (seeds fall to the ground), ballistic (a pod bursts open and throws out its seeds), wind, and water.

Enrichment

Activity 1: Narrate the Story

  • After reading or listening to the story, narrate the story events aloud using your own words.

Activity 2: Review Seed Dispersal Mechanisms

Look at the following images of seeds and guess how they are optimized for dispersal.

Activity 3: Take a Nature Walk, Visit a Flower Shop, or Research Online - Animal Seed Dispersal

  • Embark upon a nature walk.
  • See if you can locate a specimen of a plant that uses animals for seed dispersal.
  • Make observations of the plant and its habitat and gather data.
  • Use the gathered information to create the field book entry.

Activity 4: Complete a Field Book Entry   

After your nature walk, complete page 35 in 'Science Field Book for Third Grade.'

Review

Question 1

Why don't farmers like the Corn Cockle?
1 / 3

Answer 1

Farmers consider the Corn Cockle a weed or a pest, since it grows in grain fields and competes with crops for nutrients and water.
1 / 3

Question 2

Why is the Common Burdock able to spread quickly across relatively long distances?
2 / 3

Answer 2

The Common Burdock spreads quickly over long distances because animals carry its seeds to far-off places.
2 / 3

Question 3

What are some other mechanisms of seed dispersal in addition to animals?
3 / 3

Answer 3

Additional mechanisms of seed dispersal include gravity, water, wind, and ballistic.
3 / 3

  1. Why don't farmers like the Corn Cockle? Farmers consider the Corn Cockle a weed or a pest, since it grows in grain fields and competes with crops for nutrients and water.
  2. Why is the Common Burdock able to spread quickly across relatively long distances? The Common Burdock spreads quickly over long distances because animals carry its seeds to far-off places.
  3. What are some other mechanisms of seed dispersal in addition to animals? Additional mechanisms of seed dispersal include gravity, water, wind, and ballistic.

References

  1. 'Burdock Hooks Diagram by Prosthetic Head. (CC BY-SA 3.0)' Wikimedia Commons. commons.wikimedia.org/wiki/File:Burdock_Hooks.jpg. n.p.
  2. Burgess, Thornton. Burgess Flower Book for Children. Ithaca, Boston, Massachusetts. Little, Brown, and Company, 1923.
  3. Comstock, Anna Botsford and Gordon, Eva L., Handbook of nature-study (Twenty-fourth edition). Ithaca, New York Comstock Publishing Company, Inc, 1911.