Gateway to the Classics: Handbook of Nature Study: Cultivated Plants by Anna Botsford Comstock
 
Handbook of Nature Study: Cultivated Plants by  Anna Botsford Comstock

The Sunflower

Teacher's Story

Many of the most beautiful of the autumn flowers belong to the Compositæ,  a family of such complicated flower arrangement that it is very difficult for the child or the beginner in botany to comprehend it; and yet, when once understood, the composite scheme is very simple and beautiful, and is repeated over and over in flowers of very different appearance. It is a plan of flower cooperation; there are many flowers associated to form a single flower-head. Some of these, the "ray," or "banner," flowers, hold out bright pennants to attract the attention of insects; while the disk-flowers, which they surround, attend to the matter of the pollenation and production of seed.

The large garden sunflower is the teacher's ally to illustrate to the children the story of the composites. Its florets are so large that it is like a great wax model. And what could be more interesting than to watch its beautiful inflorescence—that orderly march toward the center in double lines of anther columns, with phalanxes bearing the stigmas surrounding them; and outside all, the ranks of ray-flowers flaunting their flags to herald to the world this peaceful conquest of the sleeping, tented buds at the center?

Ordinarily, in nature-study we do not pull the flowers apart, as is necessary in botany; in nature-study, all that we care to know of the flower is what it does, and we can see that without dissection. But with the compositæ the situation is quite different. Here we have an assemblage of flowers, each individual doing its own work for the community; and in order to make the pupils understand this fact it is necessary to study the individual florets.

We begin with the study of one of the buds at the center of the flower-head; this shows the white, immature seed below, and the closed, yellow corolla-tube above. Within the corolla may be seen the brown anther-tube, and on the upper part of the seed are two little, white, earlike scales, to which especial notice should be directed, since in other composites there are many of these scales and they form the pappus—the balloon to carry the seed. The bud shows best the protecting chaffy scale which enfolds the seed, its pointed, spine-edged tip being folded over the young bud, as may be seen by examining carefully the center of a freshly opened sunflower. In this tubular bud (see Fig. p. 632), there is a telescopic arrangement of the organs, and one after another is pushed out. First, the corolla-tube opens, starlike, with five pointed lobes, very pretty and graceful, with a bulblike base; from this corolla pushes out the dark-brown tube, made up of five anthers grown together. By opening the corolla, we see the filaments of the stamens below the joined anthers. This anther tube, if examined through a lens, shows rows of tiny points above and below, two to each anther, as if they had been opened like a book to join edges with their neighbors. The anther-tube is closed at the tip, making a five-sided cone; and at the seams, the yellow pollen bulges out, in starlike rays. The pollen bulges out for good reason, for behind it is the stigma, like a ramrod, pushing all before it in the tube for it is its turn next to greet the outer world. The two stigma-lobes are pressed together like the halves of a sharpened pencil, and they protrude through the anther-tube as soon as all the pollen is safely pushed out; then the stigma-lobes separate, each curling backwards so as to offer a receptive surface to welcome pollen grains from other florets, or even other sunflowers. In the process of curling back, they press the anther-tube down into the corolla, and thus make the floret shorter than when in the pollen stage. The banner-flower differs in many essentials from the perfect florets of the disk. If we remove one from the flower-head, we find at its base a seedlike portion, which is a mere pretense; it is shrunken, and never can be a seed because it has connected with it no stigma to bring to it the pollen. Nor does this flower have stamens nor a tubular corolla; instead it has one great, petallike banner, many times longer and wider than the corollas of the other flowers. All this flower has to do is to hold its banner aloft as a sign to the world, especially the insect world, that here is to be found pollen in plenty, and nectar for the probing.


[Illustration]

The flower of the sunflower-head enlarged.

1. A floret of the sunflower in the bud-stage as it appears at the center of the sunflower. Note the protecting bract at the right.

2. A floret in earliest stage of blossoming.

3. A floret in the latest stage of bloom with the parts named.

4. A ray or banner-flower.

But more wonderful than the perfection of each floret is their arrangement in the flower-head. Around the edge of the disk the banner-flowers, in double or treble rank, flare wide their long petals like the rays of the sun, making the sunflower a most striking object in the landscape. If the sunflower has been open for several days, next to the ray-flowers will be seen a circle of star-mouthed corollas from which both ripened pollen and stigmas have disappeared, and the fertilized seeds below them are attaining their growth. Next comes a two or three-ranked circle, where the split, coiled-back stigma-lobes protrude from the anther-tubes; within this circle may be two or three rows of florets, where pollen is being pushed out in starry radiance; and within this ring there may be a circle where the anther-tubes are still closed; while at the center lie the buds, arranged in exquisite pattern of circling radii, cut by radii circling in the opposite direction; and at the very center the buds are covered with the green spear-points of their bracts. I never look at the buds in the sunflower without wondering if the study of their arrangement is not the basis of much of the most exquisite decoration in Moorish architecture. To appreciate fully this procession of the bloom of the sunflower from its rim to its center, we need to watch it day by day—then only can its beauty become a part of us.

The great, green bracts, with their long pointed tips, which "shingle" the house of every sunflower family, should be noted with care, because these bracts have manifold forms in the great Compositæ  family; and the pupil should learn to recognize this part of the flower-head, merely from its position. In the burdocks, these bracts form the hooks which fasten to the passer-by; in the thistle, they form the prickly vase about the blossom; while in the pearly everlasting, they make the beautiful, white, shell-like mass of the flower which we treasure as immortal. In the sunflower, these bracts are very ornamental, being feltlike outside and very smooth inside, bordered with fringes of pretty hairs, which may be seen best through a lens. They overlap each other regularly in circular rows, and each bract is bent so as to fit around the disk.

In looking at a mass of garden sunflowers, we are convinced that the heavy heads bend the stems, and this is probably true, in a measure. But the stems are very solid and firm, and the bend is as stiff as the elbow of a stovepipe; and after examining it, we are sure that this bend is made with the connivance of the stem, rather than despite it. Probably most people, the world over, believe that sunflowers twist their stems so that their blossoms face the sun all day. This belief shows the utter contentment of most people with a pretty theory. If you believe it, you had best ask the first sunflower you see if it is true, and she will answer you if you will ask the question morning, noon and night. My own observations make me believe that the sunflower, during the later weeks of its bloom, is like the Mohammedan, keeping its face toward the east. True, I have found many exceptions to this rule, although I have seen whole fields of sunflowers facing eastward, when the setting sun was gilding the backs of their great heads. If they do turn with the sun, it must be in the period of earliest blossoming before they become heavy with ripening seeds.

The sunflower seed is eagerly sought by many birds, and it is raised extensively for chicken-feed. The inadequate little pappus falls off, and the seeds are set, large end up, in the very ornamental diamond-shaped sockets. They finally become loosened, and now we see a reason for the bending flower-head; for, as the great stem is assaulted by the winds of autumn, the bended heads shake out their seed and scatter them far afield.

Lesson CLX

The Sunflower

Leading thought—The sunflower is not a single flower, but is a large family of flowers living together; and each little flower, or floret, as it is called, has its own work to do for the family welfare.


Method—Early in September, when school first opens, is the time for this lesson. If sunflowers are growing near by, they should be studied where they stand; and their story may thus be more completely told. Otherwise, a sunflower should be brought to the schoolroom and placed in water. If one is selected which has just begun to blossom, it will show, day by day, the advance of the blossoming ranks. I have kept such a flower fourteen days, and it blossomed cheerfully from its rim to its very center. A large sunflower that has only partially blossomed is also needed for taking apart to show the arrangement of this big flower-family. Take a bud from the center, a floret showing anther-tube and another showing the curled pair of stigmas, and a ray or banner-flower. (See Fig. p. 632). Each pupil should be furnished with these four florets; and after they have studied them, show them the other half of the sunflower, with each floret in place. After this preliminary study, let them observe the blossoming sunflower for several consecutive days.


Observations—

1. A little flower which is part of a big flower-family is called a floret. You have before you three florets of a sunflower and a banner-flower. Study first the bud. Of how many parts is it composed? What will the lower, white part develop into? Can you see two little white points standing up from it on each side of the bud? Note the shape and color of the unopened floret. Note that there is a narrow, stiff, leaf-like bract, which at its base clasps the young seed, while its pointed tip bends protectingly over the top of the bud.

2. Take an open floret with the long, dark brown tube projecting from it. Note that the young seed is somewhat larger than in the bud, and that it still has its earlike projections at the top. Describe the shape of the open corolla. Look at the brown tube with a lens. How many sides has it? How many little points projecting at the top and bottom on each side of the tube? How does the tube look at the tip, through a lens? Can you see the pollen bursting out? If so, how does it look? Do you think that there is just one tubular anther, or do you think several anthers are joined together to make this tube? Open the corolla-tube carefully, and see if you can answer this last question. Open the anther-tube, and see if you can find the pistil with its stigmas.

3. Take a floret with the two yellow horns of the stigma projecting. Where is the brown anther-tube now? Is it as long as in the floret you have just studied? What has happened to it? What did the stigmas do to the pollen in the anther-tube? How do the two parts or lobes of the stigma look when they first project? How later?

4. Make a banner-flower. How many parts are there to it? How does the seedlike portion of the blossom look? Do you think it will ever be a good seed? Describe the corolla of this flower. How much larger is it than the corolla of the florets? Has the banner-flower any pistil or stamens? Of what use is the banner-flower to the sunflower family? Do you think that we would plant sunflowers in our gardens for their beauty if they had no banner-flowers?

5. After studying the separate flowers, study a sunflower in blossom, and note the following: Where are the banner-flowers placed? How many rows are there? How are they set so that their banners make the sunflower look like the sun? Do you see why the central portion of the sunflower is called the disk, and the banner-flowers are called the rays—in imitation of the sun?

6. Next to the banner-flowers, what sort of florets appear? How many rows are there? What kind form the next circle, and in how many rows? What stages of the florets do you find forming the inner circle, and how many rows? What do you find at the center of the flower-head? Note the beautiful pattern in which the buds are arranged. Can you see the separate buds at the very center of the sunflower? If not, why?

7. Make notes on a sunflower that has just opened, describing the stages of the florets that are in blossom; continue these notes every day for a week, describing, each day, what has happened. If the sunflower you are observing is in garden or field, note how many days elapse between the opening of the outer row of flowers and the opening of the central buds.

8. Look below or behind the sunflower, and note the way it is attached to the stem. What covers the disk? These green, overlapping, leaflike structures are called bracts. What is the shape of one of these bracts? What is its texture, outside and inside? Look at it, with a lens, along the edges, and note what you see. How are the bracts arranged? Do they not "shingle" the house in which the sunflower-family lives? This covering of the disk, or the house where the sunflower-family lives, is called the involucre.

9. Does the stem of the sunflower hold it upright? Some people declare that it twists its stem so as to face the sun all day. Do you think this is true?

10. Study a sunflower-head after the seeds are ripe. Do the little ears which you saw at the top of the seeds still remain? How does the sunflower scatter the seeds? Note how the disk looks after the seeds are all gone. What birds are especially fond of sunflower seeds? Of what use are the seeds commercially?


"Flowers have an expression of countenance as much as men or animals. Some seem to smile; some have a sad expression; some are pensive and diffident; others again are plain, honest, and upright, like the broad-faced Sunflower, and the hollyhock."

Henry Ward Beecher.



"Eagle of flowers! I see thee stand,

And on the sun's noon-glory gaze;

With eye like his thy lids expand

And fringe their disk with golden rays;

Though fixed on earth, in darkness rooted there,

Light is thy element, thy dwelling air,

Thy prospect heaven."

—"The Sunflower," Montgomery.


 Table of Contents  |  Index  |  Home  | Previous: The Blue Flag, or Iris  |  Next: The Bachelor's Button
Copyright (c) 2005 - 2019   Yesterday's Classics, LLC. All Rights Reserved.