The Hedge Bindweed

Teacher's Story

I once saw by the roadside a beautiful pyramid, covered completely with green leaves and beset with pink flowers. I stopped to examine this bit of landscape gardening, and for the first time in my life I felt sorry for a burdock; for this burdock had met its match and more in standing up against a weakling plant which it must have scorned at first, had it been capable of this sensation. Its mighty leaves had withered, its flower-stems showed no burs, for the bindweed had caught it in its hundred embraces and had squeezed the life out of it. Once in Northern Florida our eyes were delighted with the most beautiful garden we had ever seen and which resolved itself later into a field of corn, in which every plant had been made a trellis for the bindweed; there it flaunted its pink and white flowers in the sunshine with a grace and charm that suggested nothing of the oppressor.

Sometimes the bindweed fails to find support to lift it into the air. Then it quite as cheerfully mats itself over the grass, making a carpet of exquisite pattern. This vine has quite an efficient way of taking hold. It lifts its growing tips into the air, swaying them joyously with every breeze; and the way each extreme tip is bent into a hook seems just a matter of grace and beauty, as do the two or three loose quirls below it; when during its graceful swaying the hook catches to some object, it makes fast with amazing rapidity; later the young arrow-shaped leaves manage to get an ear over the support, and in a very short time the vine makes its first loop, and the deed is done. It is very particular to twine and wind in one way, following the direction of the hands of the clock—from the right, under, and from the left, over the object to which it clings. If the support is firm, it only makes enough turns around it to hold itself firmly; but if it catches to something as unstable as its own tendrils, they twist until so hard-twisted that they form a support in themselves.

Hedge bindweed.

It is rather difficult to perceive the alternate arrangement of the leaves on the bindweed stem, so skillful are they in twisting under or over in order to spread their whole graceful length and breadth to the sun; to the careless observer they seem only to grow on the upper or outer side of the vine. The leaves are arrow-shaped, with two long, backward, and outward projecting points, or "ears," which are often gracefully lobed. Early in the year the leaves are glossy and perfect; but many insects love to nibble them, so that by September, they are usually riddled with holes.

The flower bud is twisted as if the bindweed were so in the habit of twisting that it carried the matter farther than necessary. Enveloping the base of the flower bud are two large sepal-like bracts, each keeled like a duck's breast down the center; if these are pulled back, it is seen that they are not part of the flower, because they join the stem below it. There are five pale green sepals of unequal sizes, so that some look like fragments of sepals. The corolla is long, bell-shaped, opening with five, starlike lobes; each lobe has a thickened white center; and while its margins are usually pink, they are sometimes a vivid pink-purple and sometimes entirely white. Looking down into this flower-bell, and following the way pointed out by the white star-points which hold out the lobes, we find five little nectar-wells; and each two of these wells are separated by a stamen which is joined to the corolla at its base and at its anther-end presses close about the style of the pistil. When the flower first opens, it shows the spoon-shaped stigmas close together, pushing up through the anther cluster; later, the style elongates, bringing the stigmas far beyond the anthers. The pollen is white, and through the lens looks like tiny pearls.

When we study the maturing seed-capsule, we can understand the uneven size of the sepals better; for after the corolla with the attached stamens falls, the sepals close up around the pistil; the smallest sepal wraps it first, and the larger ones in order of size, enfolding the precious parcel; and outside of all, the great, leafy bracts with their strong keels provide protection. The pod has two cells and two seeds in each cell. But it is not by seeds alone that the bindweed spreads; it is the running rootstock which, when the plant once gets a start, helps it to cover a large area. The bindweed is a relative of the morning-glory and it will prove an interesting study to compare the two in methods of twining, in the time of day of the opening of the flowers, the shape of the leaves, etc. So far as my own observations go, the bindweed flowers seem to remain open only during the middle of the day, but Müller says the flowers stay open on moonlight nights to invite the hawk-moths. This is an interesting question for investigation, and it may be settled by a child old enough to make and record truthful observations.

There are several species of bindweed, but all agree in general habits. The field bindweed lacks the bracts at the base of the flower.

Method—It is better to study this plant where it grows; but if this is not practical, the vine with its support should be brought into the schoolroom, the two being carefully kept in their natural relative positions. Several of the questions should be given to the pupils for their personal observation upon this vine in the field. It is an excellent study for pencil or water-color drawing.

2. How does it climb upon other plants? Does its stem always wind or twist in the same direction? How does it first catch hold of the other plant? If the supporting object is firm, does it wind as often for a given space as when it has a frail support? Can you see the reason for this?

3. Look at the leaves. Sketch one, to be sure that you see its beautiful form and veins. Note if the leaves are arranged alternately on the stem, and then observe how and why they seem to come from one side of the stem. Why do they do this?

4. What is there peculiar about the flower bud? Look at its stem carefully and describe it. Cut it across and look at the end with a lens and describe it. Turn back two sepal-like bracts at the base of the flower or bud. Are they a part of the flower, or are they below it? Find the true sepals. How many are there? Are they all the same size?

5. Examine the flower in blossom. What is its shape? Describe its colors. Look down into it. How many stamens are there, and how are they set in the flower? How does the pistil look when the flower first opens? Later? Can you see the color of the pollen? Can you find where the nectar is borne? How many nectar-wells are there?

6. What insects do you find visiting bindweed flowers? Do the flowers remain open at night or on dark days?

7. Study the seed-capsule. How is it protected on the outside? What next enfolds it? Can you see now the uses of the sepals of several sizes? Cut a seed-capsule across with all its coverings, and see how it is protected. How many seeds are there in the capsule?

8. Has the bindweed other methods of spreading than by seeds? Look at the roots and tell what you observe about them.

9. Make a study of the plant on which the bindweed is climbing, and tell what has happened to it.

10. Compare the bindweed with the morning-glory, and notice the differences and resemblances.

Supplementary reading:  "Morning-Glory Stories," in Flowers and Their Friends, Morley; Botany Reader, Newell, Chap. 10; Golden Numbers, page 74.