The Maize, or Indian Corn
"Hail! Ha-wen-ni-yu! Listen with open ears to the words of thy people. Continue to listen. We thank our mother earth which sustains us. We thank the winds which have banished disease. We thank He-no for rain. We thank the moon and stars which give us light when the sun has gone to rest. We thank the sun for warmth and light by day.
Keep us from evil ways that the sun may never hide his face from us for shame and leave us in darkness. We thank thee that thou hast made our corn to grow. Thou art our creator and our good ruler, thou canst do no evil. Everything thou doest is for our happiness."
HUS prayed the Iroquois Indians when the corn had ripened on the hills and valleys of New York State long before it was a state, and even before Columbus had turned his ambitious prows westward in quest of the Indies. Had he found the Indies with their wealth of fabrics and spices, he would have found there nothing so valuable to the world as has proved this golden treasure of ripened corn.
The origin of Indian corn, or maize, is shrouded in mystery. There is a plant which grows on the table-lands of Mexico, which is possibly the original species; but so long had maize been cultivated by the American Indians that it was thoroughly domesticated when America was first discovered. In those early days of American colonization, it is doubtful, says Professor John Fiske, if our forefathers could have remained here had it not been for Indian corn. No plowing, nor even clearing, was necessary for the successful raising of this grain. The trees were girdled, thus killing their tops to let in the sunlight, the rich earth was scratched a little with a primitive tool, and the seed put in and covered; and the plants that grew therefrom took care of themselves. If the pioneers had been obliged to depend alone upon the wheat and rye of Europe, which only grows under good tillage, they might have starved before they gained a foothold on our forest-covered shores.
The Corn Plant
In studying the maize it is well to keep in mind that a heavy wind is its worst enemy; such a wind will lay it low, and from such an injury it is difficult for the corn to recover and perfect its seed. Thus, the mechanism of the corn-stalk and leaf is adapted for prevention of this disaster. The corn-stalk is, practically, a strong cylinder with a pithy center; the fibres of the stalks are very strong, and at short intervals the stalk is strengthened by hard nodes, or joints.
If the whole stalk were as hard as the nodes, it would be inelastic and break instead of bend; as it is, the stalk is very elastic and will bend far over before it breaks. The nodes are nearer each other at the bottom, thus giving strength to the base; they are farther apart at the top, where the wind strikes, and where the bending and bowing of the stalk is necessary.
The leaf comes off at a node and clasps the stalk for a considerable distance, thus making it stronger, especially toward the base. Just where the leaf starts away from the stem there is a little growth called a rain-guard; if water should seep between the stalk and the clasping leaf, it would afford harbor for destructive fungi. The structure of the corn leaf is especially adapted to escape injury from the wind; the strong veins are parallel with a strong but flexible midrib at the center; often, after the wind has whipped the leaves severely, only the tips are split and injured. The edges of the corn leaf are ruffled and, where the leaf leaves the stalk, there is a wide fold in the edge at either side; this arrangement gives play for a sidewise movement without breaking the leaf margins. The leaf is thus protected from the wind, whether it is struck from above or horizontally. The true roots of the corn plant go quite deep into the soil, but are hardly adequate to the holding of such a tall, slender stalk upright in a wind storm; therefore, all about the base of the plant are brace-roots, which serve to hold the stalk erect—like the stay-ropes about a flagpole.
The Ear of Corn
The ears of corn are borne at the joints or nodes; and the stalk, where the ear presses against it, is hollowed out so as to hold it snugly; this is very suggestive of a mother holding a baby in her arms. In the following ways, the husks show plainly that they are modified leaves: The husk has the same structure as the leaf, having parallel veins; it comes off the stem like a leaf; it is often green, and therefore does the work of a leaf; it changes to leaf shape at the tip of the ear, thus showing that the husk is really that part of the leaf which usually clasps the stem. If a husk tipped with a leaf is examined, the rain-guard will be found at the place where the two join. As a matter of fact, the ear of corn is on a branch stalk which has been very much shortened, so that the nodes are very close together, and therefore the leaves come off close together. By stripping the husks back one by one, the change from the outside, stiff, green leaf structure to the inner delicate, papery wrapping for the seed, may be seen in all its stages. This is a beautiful lesson in showing how the maize protects its seed, and the husk may well be compared to the clothing of a baby. The pistillate flowers of the corn, which finally develop into the kernels, grow in pairs along the sides of the end portion of the shortened stalk, which is what we call the "cob." Therefore, the ear will show an even number of rows, and the cob shows distinctly that the rows are paired. The corn-silk is the style of the pistillate flowers; and therefore, in order to secure pollen, it must extend from the ovule, which later develops into a kernel, to the tip of the ear, where it protrudes from the end of the husk. A computation of the number of kernels in a row and on the ear makes a very good arithmetic lesson for the primary pupils, especially as the kernels occur in pairs.
The Growth of the Corn
If we cut a kernel of corn crosswise we can see, near the point where it joins the cob, the little plant and the root. Corn should be germinated between wet blotters, in a seed-testing experiment, before observations are made on the growing corn of the fields. When the corn first appears, the corn leaves are in a pointed roll which pierces the soil. Soon they spread apart, but it may be some time before the corn-stalk proper appears. Then it stretches up rapidly, and very soon will be tipped with beautiful pale brown tassels. These tassels merit careful study for they are the staminate flowers. Each floret has two anthers hanging down from it, and each half of each anther is a little bag of pollen-grains; and in order that they shall be shaken down upon the waiting corn-silk below, the bottom of each bag opens wide when the pollen is ripe. The corn-silk, at this stage, is branched at the tip and clothed with fine hairs, so that it may catch a grain of the precious pollen. Then occurs one of the most wonderful pollen stories in all nature, for the pollen-tube must push down through the center of the corn-silk for its whole length, in order to reach the waiting ovule and thus enable it to become a kernel of corn. These young, unfertilized kernels are pretty objects, looking like seed-pearls, each wrapped in furry bracts. If the silk from one of these young flowers does not receive its grain of pollen, then the kernel will not develop and the ear will be imperfect. On the other hand if the pollen from another variety of corn falls upon the waiting stigmas of the silk, we shall find the ear will have upon it a mixture of the two varieties. This is best exemplified when we have the black and white varieties of sweet corn growing near each other.
One reason why corn is such a valuable plant to us is that its growth is so rapid. It is usually not planted until late spring, yet, with some varieties, by September the stalks are twenty feet high. The secret of this is that the corn, unlike many other plants, has many points of growth. While young, the lower part of the stalk lying between every two nodes is a growing center and the tip of the stalk also grows; in most plants, the tip of the stems is the only center of growth. The first two experiments suggested will demonstrate this. When blown down by the wind, the corn has a wonderful way of lifting itself, by inserting growing wedges in the lower sides of the nodes. A corn-stalk blown down by the wind will often show this wedge-shape at every joint, and the result will be an upward curve of the whole stalk. Of course, this cannot be seen unless the stalk is cut lengthwise through the center. Experiment 3 is suggested to demonstrate this.
During drought the corn leaves check the transpiration of water by rolling together lengthwise in tubes, thus offering less surface to the sun and air. The farmer calls this the curling of the corn, and it is always a sign of lack of moisture. If a corn plant with leaves thus curled, be given plenty of water, the leaves will soon straighten out again into their normal shape.
References: Corn Plants, Sargent; Cornell Nature-Study Leaflets, Vol. I; Elements of Agriculture, Warren; The First Book of Farming, Goodrich; Agriculture, Jackson and Dougherty; Rural School Agriculture, Hays; Columbia's Emblem, Houghton, Mifflin and Co.
Leading thought—The Indian corn, or maize, is a plant of much beauty and dignity. It has wonderful adaptations for the development of its seed and for resisting its arch-enemy, the wind.
Method—The study may begin in spring when the corn is planted, giving the pupils the outline for observations to be filled out in their note-books during the summer, when they have opportunities for observing the plant; or it may be studied in the autumn as a matured plant. It may be studied in the school room or in the field, or both.
Observations on the corn plant—
1. Describe the central stem. How many joints, or nodes, has it? Of what use to the plant are these nodes? Are the joints nearer each other at the bottom or the top of the plant?
2. Where do the leaves come off the stem? Describe the relation of the bases of the leaves to the stem. Of what use is this to the plant?
3. Note the little growth on the leaf where it leaves the stalk. Describe how this prevents the rain from seeping down between the stalk and the clasping leaf. What danger would there be to the plant if the water could get into this narrow space?
4. What is the shape of the leaf? Describe the veins. Does the leaf tear easily across? Does it tear easily lengthwise? Of what use to the leaf is this condition?
5. Are the edges of the corn leaf straight or ruffled? How does this ruffled edge permit the leaf to turn without breaking? Describe at length the benefit the corn plant derives from having leaves which cannot be broken across and that can bend readily sidewise as well as up and down.
6. Describe the roots of the corn plant. Describe the brace-roots. Explain their use.
7. Describe all the ways in which the corn plant is strengthened against its enemy, the wind.
Observations on the ear of corn—
8. Where on the corn plant are the ears borne? Are two ears borne on the same side of the stalk? Remove an ear, and see how the stalk is changed to give it room.
9. Where do the ears come off the stalk in relation to the leaves?
10. Examine the outside husks, and compare them with the green leaves. What is there to suggest that the corn-husk is a leaf changed to protect the seed? Do you think that the husk represents that portion of the leaf which clasps the stalk? Why? Describe how the inner husk differs from the outer in color and texture. Describe how this is a special protection to the growing kernels.
11. After carefully removing the husk, examine the silk and see if there is a thread for every kernel. Is there an equal amount of silk lying between every two rows? Do you know what part of the corn flower is the cornsilk? What part is the kernel?
12. How many rows of kernels are there on an ear? How many kernels in a row? How many on the whole ear? Do any of the rows disappear toward the tip of the ear? If so, do they disappear in pairs? Do you know why? Are the kernels on the tip of the ear and near the base as perfect as those along the middle? Do you know whether they will germinate as quickly and vigorously as the middle ones?
13. Study a cob with no corn on it and note if the rows of kernel-sockets are in distinct pairs. This will, perhaps, show best if you break the cob across.
14. Break an ear of corn in two, and sketch the broken end showing the relation of the cob to the kernels.
15. Are there any places on the ear you are studying, where the kernels did not grow or are blasted? What happened to cause this?
16. Describe the requisites for a perfect ear of seed-corn. Why should the plant from which the seed-ear is taken be vigorous and perfect?
Observations on the growth of corn—Work for the Summer Vacation—
17. How does the corn look when it first comes up? How many leaves are there in the pointed roll which first appears above the ground? How long before the central stalk appears?
18. When do the tassels first appear? What kind of flowers are the corn tassels? Describe the anthers. How many on each flower? Where do the anthers open to discharge their pollen?
19. How large are the ears when the pollen is being shed? Study an ear of corn at this period. Note that the kernel is the ovule, the silk is attached to it and is the long style extending out beyond the husks. Note that the tip, or stigma, is branched.
20. What carries the pollen for the corn plant? If you have rows of popcorn and sweet corn or of sweet corn and field corn next to each other, why is it that the ears will show a mixture of both kinds?
Compare the growth of the corn plant with that of the pigweed. When the corn-stalk first appears above ground, tie two strings upon it, one just above a joint and one below it. Tie two strings the same distance apart on the stem of a pigweed. Measure carefully the distance between these two strings on the two plants. Two weeks later measure the distance between the strings again. What is the result?
Measure the distance between two of the nodes or joints near the tip of a certain corn-stalk. Two weeks later measure this distance again and compare the two.
When a stalk of corn is still green in August, bend it down and place a stick across it at about half its length. Describe how it tries to lift itself to an erect attitude after two or three weeks. Cut lengthwise across one of the nodes, beyond the point held down by the stick, and see the wedge-shaped growth within the joint which helps to raise the stalk to an upright position.
During the August drought, note that the corn leaves are rolled. Give a corn plant with rolled leaves plenty of water and note what happens. Why?