Chapter XXXIII: Part III: Plant Life (3)

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.

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.

LESSON CXXIX

THE HEDGE BINDWEED

_Leading thought_--There are some plants which have such weak stems that they are obliged to cling to objects for support. The bindweed is one of these, and the way that it takes hold of objects and grows upon them is an interesting story.

_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.

_Observations_--1. How does the bindweed get support, so that its leaves and its flowers may spread out in the sunshine? Why does its own stem not support it? What would happen to a plant with such a weak stem, if it did not twine upon other objects?

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.

THE DODDER

TEACHER’S STORY

Photo by Cyrus Crosby.]

If Sinbad’s “Old Man of the Sea” had been also a sneak thief, then we might well liken him to dodder. There is an opportunity for an excellent moral lesson connected with the study of dodder and its underhand ways. When a plant ceases to be self-supporting, when it gets its own living from the food made by other plants for their own sustenance, it loses its own power of food-making; and the dodder is an excellent example of the inevitable punishment for “sponging” a living. The dodder has no leaves of its own for it does not need to manufacture food nor to digest it. Its dull yellow stems reach out in long tendrils, swayed by every breeze, until they come in contact with some other plant to which they at once make fast. One of these tendrils seizes its victim plant as a serpent winds its prey, except that it always winds in the same direction--it passes under from the right side and over from the left. Who knows whether the serpents are always so methodical! After dodder gets its hold, little projections appear upon its coiled stems, which look like the prolegs of a caterpillar; but they are not legs, they are suckers, worse than those of the devil-fish; for the latter uses its suckers only to hold fast its prey; but the dodder uses its suckers to penetrate the bark of its victim, and reach down to the sap channels where they may, vampirelike, suck the blood from their victims, or rather the matured sap which is flowing from the leaves to the growing points of the host plant. Not having anything else to do, dodder devotes its energies to the producing of seeds, in order to do more mischief. The species which attack clover and other farm crops seem to manage to get their seeds harvested with the rest; and the farmer who does not know how to test his clover seed for impurities, sows with it the seeds of its enemy.

The dodder flowers are small, globular and crowded together. The calyx has five lobes; the corolla is globular, with five little lobes around its margin and a stamen set in each notch. A few of the species have a four-lobed calyx and corolla; but however many the lobes, the flowers are shiftless looking and are yellowish or greenish white; despite its shiftless appearance, however, each flower manages to mature four perfectly good, plump seeds.

There are, according to Gray, nine species of dodder more or less common in America. Some of the species, among which is the flax dodder, live only upon certain other species of plant life, while others take almost anything that comes within reach. Where it flourishes, it grows so abundantly that it makes large yellow patches in fields, completely choking out the leaves of its victims.

LESSON CXXX

THE DODDER

_Leading thought_--There are some plants which not only depend upon other plants to hold them up, but they suck the life-juice from these plants and thus they steal their living.

_Method_--Bring in dodder with the host plant for the pupils to study in the schoolroom, and ask them to observe afterwards the deadly work of this parasite in the field.

_Observations_--1. What is the color of the stem? In which direction does it wind?

2. How is the stem fastened to the host plant? Tear off these suckers and examine the place where they were attached with a lens, and note if they enter into the stem of the host plant.

3. How does the dodder get hold of its victim? Has the dodder any leaves of its own? How can it get along and grow without leaves?

4. How do the flowers look through a lens? Are there many flowers? Can you see the petal lobes and the stamens?

5. How many seeds does each flower develop? How do the seeds look? In what way are they a danger to our agriculture?

* * * * *

_I should also avoid the information method. It does a child
little good merely to tell him matters of fact. The facts
are not central to him and he must retain them by a process
of sheer memory; and in order that the teacher may know
whether he remembers, the recitation is employed,--re-cite,
to tell over again. The educational processes of my younger
days were mostly of this order,--the book or the teacher
told, I re-told, but the results were always modified by an
unpredictable coefficient of evaporation. Good teachers now
question the child to discover what he has found out or what
he feels, or to suggest what further steps may be taken, and
not to mark him on what he remembers. In other words, the
present-day process is to set the pupil independently at work,
whether he is young or old, and the information-leaflet or
lesson does not do this. Of course, it is necessary to give
some information, but chiefly for the purpose of putting
the pupil in the way of acquiring for himself and to answer
his natural inquiries; but information-giving about nature
subjects is not nature-study._--L. H. BAILEY in “The Outlook
to Nature.”

THE MILKWEED

_Teacher’s Story_

“_Little weavers of the summer, with sunbeam shuttle bright,
And loom unseen by mortals, you are busy day and night,
Weaving fairy threads as filmy, and soft as cloud swans,
seen
In broad blue sky-land rivers, above earth’s fields of
green._”
--RAY LAURANCE.

Is there any other young plant that shows off its baby-clothes as does the young milkweed! When it comes up through the soil, each leaf is folded lengthwise around the stem, flannel side out, and it is entirely soft and white and infantile. The most striking peculiarity of the milkweed plant is its white juice, which is a kind of rubber. Let a drop of it dry on the back of the hand, and when we try to remove it we find it quite elastic and possessed of all of the qualities of crude rubber. At the first trial it seems quite impossible to tell from which part of the stem this white juice comes, but by blotting the cut end once or twice, the hollow of the center of the stem is seen to have around it a dark green ring, and outside this is a light green ring. It is from the dark green ring encircling the stem cavity that the milk exudes. This milk is not the sap of the plant any more than resin is the sap of the pine; it is a special secretion, and is very acrid to the taste, rendering milkweed disgusting to grazing animals. If a milkweed stem be broken or gashed, this juice soon heals the wound and keeps out germs, and thus is of great use to the plant, since many insects feed upon it. If cut across, every vein in every leaf produces “milk”, and so does every small flower pedicel. When the “milk” is by chance smeared on cloth and allowed to dry, soap and water will not remove it, but it yields readily to chloroform, which is a solvent of rubber.

Photo by Verne Morton.]

The milkweed leaves are in stately conventional pairs; if one pair points east and west, the pair above and the pair below point north and south. The leaf is beautiful in every particular; it has a dark green upper surface, diversified with veins that join in scallops near the border; it is soft to the touch on the upper surface, and is velvety below. The lens reveals that the white under surface, or the nap of the velvet, is a cover of fine white hairs.

The flower of the milkweed is too complicated for little folks even to try to understand; but for the pupils of the seventh and eighth grades it will prove an interesting subject for investigation, if they study it with the help of a lens. In examining the globular bud, we see the five hairy sepals, which are later hidden by the five long, pinkish green petals which bend back around the stem. When we look into the flower, we see five little cornucopias--which are really horns of plenty, since they are filled with nectar; from the center of each is a little, fleshy tongue, with its curved point resting on the disk at the center of the flower. Between each two of these nectar-horns can be seen the white bordered opening of a long pocket--like a dress-pocket--at the upper end of the opening of which is a black dot. Slip a needle into the pocket opening until it pushes against the black dot, and out pops a pair of yellow saddle-bags, each attached to the black dot which joins them. These are the pollen-bags, and each was borne in a sac, shaped like a vest-pocket, one lying either side of the upper end of the long pocket. These pollen-bags are sticky, and they contract so as to close over the feet of the visiting bee.

1, _Milkweed flower, enlarged._ 2, _Same more enlarged. a,a,
nectar-horns; p, pocket; o,o, openings to the pocket; s,
pollen-bags in place; s′, pollen-bags removed._
]

Since the stem of the flower cluster droops and each flower pedicel droops, the bee is obliged to cling, hanging back down, while getting the nectar, and has to turn about as if on a pivot in order to thrust her tongue into the five cornucopias in succession; she is then certain to thrust her claws into a long pocket, and it proceeds to close upon them, its edges being like the jaws of a trap. The bee, in trying to extricate her feet, leaves whatever pollen-bags she had inadvertently gathered in this trap-pocket, which gives them passage to the stigma. But the milkweed flower, like some folks, is likely to overdo matters, and sometimes these pockets grasp too firmly the legs of the bee and hold her a prisoner. We often find insects thus caught and dead--a result as far from the plan of the flower as from that of the insect victim, had both been conscious. Sometimes bees become so covered with these pollen-bags, which they are unable to scrape off, that they die because of the clogging. But for one bee that suffers there are thousands that carry off the nectar triumphantly, just as thousands of people travel by water for one that is drowned.

The milkweed pod has been the admiration of nature students from the beginning, and surely there is no plant structure that so interests the child as this house in which the milkweed carries its seeds. When we look at a green pod, we first admire its beautiful shape; on either side of the seam, which will sometime open, are three or four rows of projecting points rising from the felty surface of the pod in a way that suggests embossed embroidery. We open the pod by pulling it apart along the seam; and this is not a seam with a raw edge but is finished with a most perfect selvage. When we were children we were wont to dispossess these large green pods of their natural contents, and because they snapped shut so easily, we imprisoned therein bumblebees “to hear them sing,” but we always let them go again. We now know that there is nothing so interesting as to study the contents of the pod just as it is. Below the opening is a line of white velvet; at one end, and with their “heads all in one direction,” are the beautiful, pale-rimmed, brown, overlapping seeds; and at the other end we see the exquisite milkweed silk with the skein so polished that no human reel could give us a skein of such luster. If we remove the contents of the pod as a whole, we see that the velvety portion is really the seed-support and that it joins the pod at either end. It is like a hammock full of babies, except that the milkweed babies are fastened on the outside of the hammock.

No sooner is our treasure open to the air than the shining silk begins to separate into floss of fairy texture. But before one seed comes off, let us look at the beautiful pattern formed by the seeds overlapping--such patterns we may see in the mosaics of mosques.

Pull off a seed, and with it comes its own skein of floss, shining like a pearl; but if we hold the seed in the hand a moment the skein unwinds itself into a fluff of shining threads as fine as spiders’ silk, and each individual thread thrusts itself out and rests upon the air; and altogether there are enough of the threads to float the seed, a balloon of the safest sort. If we wreck the balloon by rubbing the floss through our fingers, we shall feel the very softest textile fiber spun by Mother Nature.

If we look closely at our seed we see a margin all around it. Well, what if the balloon should be driven over sea, and the seed dropped upon the water? It must then drown unless it has a life preserver; this margin that we have noted is of the safest cork, and is warranted to float; if you do not believe it, try it.

If we pull off all the seeds, we can see that the velvety support is flat and that all of the seeds are attached to it, but before we stop our admiring study we should look carefully again at the inside of the pod, for never was there a seed cradle with a lining more soft and satiny.

LESSON CXXXI

THE MILKWEED

_Leading thought_--The milkweed when wounded secretes a milky juice which is of a rubberlike composition; it flows out of the wounded plant and soon hardens, thus protecting the wound from germs. Milkweed flowers depend entirely upon insects for pollenation; the pollen is not a free, yellow powder, but it is contained in paired sacs, which are joined in V-shape. The seeds are carried by balloons, and they can float on water as well.

_Method_--Begin the study of the plant when it first appears above ground in April or May. Give the pupils the questions about the blossom for a vacation study, and ask that their observations be kept in their notebooks. The study of the pods and seeds may be made in September or October. When studying the milky juice, add a geography lesson on rubber trees and the way that rubber is made.

_Observations_--1. _The plant._ How does the milkweed look as it appears above ground in the spring? How are its leaves folded when it first puts its head up? Cut off a fully expanded plant a few inches above the ground. What flows out of the stem? Blot off the “milk” and study the cross-section of the stem. What is at the center? How many layers do you see around this center? Can you see from which the milkweed juice comes? How does the juice feel as it dries on your fingers? How does it look when dry? Place a few drops on a piece of paper and when it is dry pull it off and see if it is elastic. Break the edge of the leaf. Does the milky juice flow from it? Does it come from the veins? Do you think that this is the sap of the milkweed? Cut a gash in the milkweed stem and see how the “milk” fills the wound. How does this help the plant? Do cattle feed upon the milkweed when it grows in pastures? If not, why?

2. How are the leaves arranged on the stem? How do the upper and under sides of the leaves differ? Examine with a lens, and see what makes the nap of the velvet. What gives the light color to the under side? Sketch a leaf showing its shape and venation, noting especially the direction of the veins as they approach the edge of the leaf.

3. _The flower._ Where do the flower clusters come off the stems in relation to the leaves? Does the stem of the flower cluster stand stiff or droop? Take a good sized flower cluster and count the flowers in it. What would happen if all these flowers should develop into pods? How many flower clusters do you find on one plant? Which of these clusters open first? Last?

4. Take off a single bud with its stem, or pedicel. Does the milky juice come at the break? Is the bud stem stiff or drooping? What is its color and how does it feel? What is the shape of the bud? How many sepals has it? Look at the stem, sepals and bud with a lens and describe their covering. Look for a flower just opening where the petals stand out around it like a five-pointed star. What is their color? What happens to the petals when the flower is fully expanded? Can you see the sepals then? Look straight into the flower. Do you see the five nectar-horns? Look at them with a lens and describe them. What do you suppose is the use of the little curved tongue coming out of each? Where does the tip of the tongue rest? With a lens, look between two of the nectar horns; can you see a little slit or pocket, with white protruding edges? Note just above the pocket a black dot; thrust a needle into this pocket near its base and lift it toward the crown of the flower, touching the black dot. What happens?

5. Describe the little branched object that came out when you touched it with a needle. These are the pollen saddle-bags and each bag comes from a pocket at one side of, and above the long pocket. Do these saddle-bags cling to the needle? Look with a lens at some of the older flowers, and see if you can find the pollen-bags protruding from the long pocket. See if you can find how the long pocket is a passageway to the stigma. To see how the little saddle-bags were transported, watch a bee gathering nectar. Describe what happens.

6. Since the flowers bend over, how must the bee hold on to the flower while she gathers nectar from the horns? As she turns around, would she naturally pull out some of the saddle-bags? Catch a bee in a collecting tube and see if her feet have upon them these pollen-sacs. After gathering these pollen-sacs upon her feet, what happens to them when she visits the next flower? Is the opening of the long pocket like a trap to scrape the sacs off? Can you find on milkweed flowers any bees or other insects that have been entangled in these little traps and have thus perished? Try the experiment of drawing a thread into one of these traps and with your lens see if the opening closes over it.

7. How many kinds of insects do you find visiting the milkweed flowers? Can you detect the strong odor of the flowers? Why must the milkweed develop so many flowers and offer such an abundance of nectar?

THE WHITE WATER LILY

_Teacher’s Story_

“_Whence O fragrant form of light,
Hast thou drifted through the night
Swanlike, to a leafy nest,
On the restless waves at rest._”

Thus asks Father Tabb, and if the lily could answer it would have to say: “Through ages untold have the waves upheld me until my leaves and my flowers have changed into boats, my root to an anchor, and my stems to anchor-ropes.”

There is no better example for teaching the relation between geography and plant life than the water lily. Here is a plant that has dwelt so long in a certain situation that it cannot live elsewhere. The conditions which it demands are quiet water, not too deep, and with silt bottom. Every part of the plant relies upon these conditions. The rootstock has but few root hairs; and it lies buried in the silt, not only because this gives it food, but because it can there act as an anchor. Rising from the rootstock is a stem as pliable as if made of rubber, and yet it is strong; its strength and flexibility are gained by having at its center four hollow tubular channels, and smaller channels near the outside. These tubes extend the whole length of the stem, making it light so that it will float, and at the same time giving it strength as well as flexibility. At the upper end of the stem is a leaf or flower, which is fashioned as a boat. The circular leaf is leathery and often bronze-red below, with prominent veins, making an excellent bottom to the boat; above, it is green with a polished surface, and here are situated its breathing-pores, although the leaves of most plants have these stomata in the lower surface. But how could the water lily leaf breathe, if its stomata opened in the water? The leaf is large, circular and quite heavy; it would require a very strong, stiff stem to hold it aloft, but by its form and structure it is fitted to float upon the water, a little green dory, varnished inside, and waterproof outside.

The bud is a little, egg-shaped buoy protected by its four pinkish brown, leathery sepals; as it opens, we can see four rows of petals, each overlapping the space between the next inner ones; at the center there is a fine display of brilliant yellow anthers. Those hanging over the greenish yellow pit, which has the stigma at its center, are merely golden hooks. When the flower is quite open, the four sepals, each a canoe in form, lie under the lily and float it; although the sepals are brownish outside, they are soft white on the inside next the flower. Between each two sepals stands a large petal, also canoe-shaped, and perhaps pinkish on the outside; these help the sepals in floating the flower. Inside of these there is a row of large creamy white petals which stand upright; the succeeding rows of petals are smaller toward the center and grade into the outer rows of stamens, which are petallike at the base and pointed at the tip. The inner rows of stamens make a fine golden fringe around the cup-shaped pistil. This flower is of great use in teaching that sepals, petals and stamens have the same origin and grade into each other, showing the intermediate stages.

It has been stated that pond lilies, in the state of nature, have an interesting way of opening in the early morning, closing at noon and opening again toward evening. If we knew better the habits of the insects which pollenate these flowers, we should possibly have the key to this action. In our ponds in parks and grounds we find that each species of pond lily opens and closes at its own particular time each day. Each flower opens usually for several consecutive days, and the first day of its blooming it opens about an hour later and closes an hour earlier than on the days following. After the lilies have blossomed, the flower stem coils in a spiral and brings the ripening seeds below the surface of the water. The reason for this has not yet been discovered. After about two months the pod bursts letting the seeds out in the water. Each seed is in a little bag, which the botanists call an aril, and which serves as a life preserver floating the seed off for some distance from the parent plant. The aril finally decays and the seed falls to the bottom where, if the conditions are favorable, it develops into a new plant.

To emphasize the fact that the water lily is dependent upon certain geographical conditions, ask the pupils to imagine a water lily planted upon a hillside. How could its roots, furnished with such insufficient rootlets, get nourishment there? How could its soft, flexible stems hold aloft the heavy leaves and blossoms to the sunlight? In such a situation it would be a mere drooping mass. Moreover, if the pupils understand the conditions in which the water lilies grow in their own neighborhood, they can understand the conditions under which the plant grows in other countries. Thus, when they read about the great _Victoria regia_ of the Amazon,--that water lily whose leaves are large enough to support a man,--they would have visions of broad stretches of still water and they should realize that the bottom must be silt. If they read about the lotus of Egypt, then they should see the Nile as a river with borders of still water and with bottom of silt. Thus, from the conditions near at hand, we may cultivate in the child an intelligent geographical imagination.

LESSON CXXXII

THE WATER LILY

_Leading thought_--The water lily has become dependent upon certain conditions in pond or stream, and has become unfitted in form to live elsewhere. It must have quiet waters, not too deep, and with silt bottom.

_Method_--The study should be made first with the water lilies in a stream or pond, to discover just how they grow. For the special structure, the leaves and flowers may be brought to the schoolroom and floated in a pan of water. The lesson may easily be modified to fit the yellow water lily, which is in many ways even more interesting, since in shallow water it holds its leaves erect while in deeper water its leaves float.

_Observations_--1. Where is the water lily found? If in a pond, how deep is the water? If in a stream, is it in the current? What kind of bottom is there to the stream or pond? Do you find lilies in the water of a limestone region? Why?

2. What is the shape of the leaf? What is the color above and below? What is the texture? How is it especially fitted to float? How does it look when very young?

3. Examine the petiole. How long is it? Is it stiff enough to hold up the leaf? Why does it not need to hold up the leaf? How does it serve as an anchor? Cut a stem across and describe its inside structure. How does this structure help it float?

4. Examine the open flower. How many sepals? How many rows of petals? How do the stamens resemble the petals? Can you see in the water lily how the sepals, petals and stamens may all be different forms of the same thing? How are the sepals fitted to keep the flower afloat? At what times of the day does the lily open? At what hours does it close?

5. Describe the pistil. When the lily first opens, how are the stamens placed around the pistil? What happens to the seed-box after the blossoms have faded? Does the seed-pod float upon the water as did the flower? What sort of stem has the flower? How does this stem hold the seed-pod below the water?

6. What sort of seed has the water lily? Sketch the seed-pod. How does the seed escape from it? How is it scattered and planted?

7. What sort of a root has the water lily? Are there many fine rootlets upon it? Why? How does this rootstock serve the plant aside from getting food?

8. Imagine a water lily set on a dry hillside. Could the stems uphold the flowers or leaves? Is the petiole large enough to hold out such a thick, heavy leaf? Could the root get food from a dry location? Why?

9. Judging from what you know of the places where water lilies grow and the condition of the water there, describe the Nile where the lotus grows. Describe the Amazon where the _Victoria regia_ grows.

PONDWEED

_Teacher’s Story_

The study of any plant which has obvious limitations as to where it may grow should be made a help in the study of geography. Pondweed is an excellent subject to illustrate this principle; it grows only in quiet beds of sluggish streams or in ponds, or in the shallow protected portions of lakes. It has tremendous powers of stretching up, which render it able to grow at greater depth than one would suppose possible, often flourishing where the water is from ten to twenty feet deep. Often, when the sun is shining, it may be seen like a bed of seaweed on the bottom. Its roots, like those of most water plants, have less to do with the matter of absorbing water and nourishment than do the roots of land plants, one of their chief functions being to anchor the plant fast; they have a firm grip on the bottom; and if pondweed is cut loose, it at once comes to the surface, floats helplessly on its side, and soon dies.

The stem is very soft and pliable and the plant relies entirely on the water to keep it upright. A cross-section of the stem shows that its substance is spongy, with the larger open cells near the outer edge, thus helping it to float. The leaves are two or three inches long, their broad bases encircling the stem, their tips tapering to slender points. They have parallel veins and ruffled edges. They are dull olive green in color, much darker than the stems; in texture they are very thin, papery, and so shining as to give the impression of being varnished. No land plants have such leaves; they remind us at once of kelp or other seaweeds. The leaves are scattered along the stems, by no means thickly, for water plants do not seem to need profuse foliage.

In blossom time the pondweed shows its real beauty. The stems grow and grow, like Jack’s bean stalk, and what was a bed of leaves on the pond bottom suddenly changes into a forest of high plants, each one standing tall and straight and with every leaf extended, as if its stems were as strong and stiff as ironwood; but if a wave disturbs the water the graceful undulations of the plant tell the true story of the pliant stems. There is something that arouses our admiration when we see one of these pondweeds grown so straight and tall, often three or four yards high, in order to place its little, greenish-brown flower-head above the water’s surface. We have spent hours looking down into such a submerged forest, dreaming and wondering about the real meaning of such adaptations.

1, _Flower of a pondweed enlarged, early stage_, 2, _same at later stage_. ]

Although the stem is flexible, the somewhat curved, enlarged portion of it just below the flower-head is rigid; it is also more spongy than the lower part of the stem and is thus fitted to float the flower. The flower itself is one of the prettiest sights that nature has to show us through a lens. It is a Maltese cross, the four reddish stigmas arranged in a solid square at the center; at each side of this central square is a double-barrelled anther, and outside of each anther is a queer, little, dipper-shaped, green sepal. When the anthers open, they push away from the stigmas and throw their pollen toward the outside. There may be thirty or more of these tiny, cross-shaped flowers in one flower-head. In the bud, the cup-shaped sepals shut down closely, exposing the stigmas first, which would indicate that they ripen before the pollen is shed. The pollen is white, and is floated from plant to plant on the surface of the water; often the water for yards will be covered with this living dust.

LESSON CXXXIII

PONDWEED

_Leading thought_--The pondweed lives entirely below the water; at blossom time, however, it sends up its flower stems to the surface of the water, and there sheds its pollen, thus securing cross-pollenation.

_Method_--As this is primarily a lesson that relates to geography, the pondweed should be studied where it is growing. It may be studied in the spring or fall, and the pupils asked to observe the blossoming which occurs in late July. After the pupils have seen where it grows, the plants themselves may be studied in an aquarium, or by placing them in a pail or basin of water. There are confusing numbers of pondweeds but any of them will do for this lesson. The one described in the Teacher’s Story is probably _P. perfoliatus_.

_Observations_--1. Where is the pondweed found? Does it ever grow out of water? Does it ever grow in very deep water? Does it ever grow in swiftly flowing water?

2. Has the pondweed a root? Does the pondweed need to have water carried to its leaves, as it would if it were living in the air? What is one of the chief uses of the roots to the pondweed? Break off a plant, does it float? Do you think it would float off and die, if it was not anchored by its root?

3. Compare the stem of pondweed with that of any land plant standing straight. What is the chief difference? Why does the pondweed not need a stiff stem to hold it up? Cut the stem across, and see if you can observe why it floats?

4. Examine the leaves. Are all of them below the surface of the water? If some float, how do they differ in texture and form from those submerged? How are they arranged on the stem? Are they set close together? What is the difference in texture between its leaves and those of the jewelweed, dock or any other land plant? If any leaves project out of the water are they different in form and texture from those submerged? Sketch the leaf, showing its shape, its edges, and the way it joins the stem.

5. How far below the surface of the water does the pondweed usually lie? Does it ever rise up to the water’s surface? When? Have you ever noticed the pondweed in blossom? How does the blossom look on the water? Can you see the white pollen floating on the surface of the water? Look down into the water and see the way the pondweed stands in order to float its blossoms.

6. Study the blossom. Note the stem that bears it. Is the part that bears the flower enlarged and stiffer than the stem below? Do you think that this enlarged part of the stem acts like the bob on a fish-line? Examine a flower cluster with a lens. How many flowers upon it? Study one flower carefully. Describe the four stigmas at the center. Describe the anthers arranged around them. Describe the sepal which protects each anther. When the anthers open do they discharge the pollen toward or away from the stigmas?

7. What happens after the flowers are pollenated? Do they still float? What sort of seed-capsule has the pondweed? Do the seeds break away and float?

* * * * *

“_Again the wild cow-lily floats
Her golden-freighted, tented boats,
In thy cool caves of softened gloom,
O’ershadowed by the whispering reed,
And purple plumes of pickerel weed,
And meadow-sweet in tangled bloom._

“_The startled minnows dart in flocks,
Beneath thy glimmering amber rocks,
If but a zephyr stirs the brake;
The silent swallow swoops, a flash
Of light, and leaves with dainty plash,
A ring of ripples in her wake._”
--“Birch Stream”, ANNA BOYNTON AVERILL.

The staminate flowers are massed at the tip, and the pistillate flowers which form the “cat-tail” are massed lower down on the stalk.

Photo by Verne Morton.]

THE CAT-TAIL

_Teacher’s Story_

In June and early July, if the cat-tail be closely observed, it will be seen to have the upper half of the cat’s tail much narrower and different in shape from the lower half--as if it were covered with a quite different fur. It seems to be clothed with a fine drooping fringe of olive-yellow. With the aid of a lens, we can see that this fringe is a mass of crowded anthers, two or three of them being attached to the same stalk by a short filament. These anthers are packed full of pollen, which is sifted down upon the pistillate flowers below by every breeze; and with every puff of stronger wind, the pollen is showered over all neighboring flowers to the leeward. There is not much use in trying to find the pistillate flowers in the plush of the cat-tail. They have no sepals nor petals, and are so imbedded in the thick pappus which forms the plush that the search is hardly worth while for nature-study, unless a microscope is used. The ovary is rather long, the style slender, and the stigma reaches out to the cut-plush surface of the cat-tail. The pupils can find what these flowers are by studying the seed; in fact, the seed does not differ very much from the flower, except that it is mature and is browner in color.

It is an interesting process to take apart a cat-tail plant; the lower, shorter leaves surround the base of the plant, giving it size and strength. All the leaves have the same general shape, but vary in length. Each leaf consists of the free portion, which is long and narrow and flat towards its tapering tip but is bent into a trough as it nears the plant, and the lower portion of the leaf, which clasps the plant entirely or partially, depending upon whether it is an outer or inner leaf, and thus adds to its strength. We almost feel as if these alternate leaves were consciously doing their best to protect the slender, flower stem. The free part of the leaves is strengthened by lengthwise veins, and they form edges that never tear nor break. They are very flexible, and therefore yield to the wind rather than defy it. If we look at a leaf in cross-section, we can see the two thick walls strengthened by the framework of stiff veins which divide the interior into long cells. If we cut the leaf lengthwise we can see that these long cells are supported by stiff, coarse partitions.

Where the leaf clasps the stem, it is very stiff and will break rather than bend. The texture of the leaf is soft and smooth, and its shade of green is attractive. The length of the leaves is often greater than that of the blossom stalk, and their graceful curves contrast pleasantly with its ramrod-like stiffness. It is no wonder that artists and the decorators have used the cat-tail lavishly as a model. It is interesting to note that the only portion of the leaves injured by the wind is the extreme tip.

The cat-tail is adapted for living in swamps where the soil is wet but not under water all the time. When the land is drained, or when it is flooded for a considerable time, the cat-tails die out and disappear. They usually occur in marshy zones along lakes or streams; and such a zone is always sharply defined by dry land on one side and water on the other. The cat-tail roots are fine and fibrous and are especially fitted, like the roots of the tamarack, to thread the mud of marshy ground and thus gain a foothold. The cat-tails form one of the cohorts in the phalanx of encroaching plants, like the reeds and rushes, which surround and, by a slow march of years, finally conquer and dry up ponds. But in this they overdo the matter, since after a time the soil becomes too dry for them and they disappear, giving place to other plants which find there a congenial environment. The place where I studied the cat-tails as a child is now a garden of joe pye weed and wild sunflowers.

_Reference_--Plant Life, Coulter.

LESSON CXXXIV

THE CAT-TAIL

_Leading thought_--The cat-tail is adapted to places where the soil is wet but not under water; its pollen is scattered by the wind, and its seeds are scattered by wind and water. Its leaves and stalks are not injured nor broken by the wind.

_Method_--As this is primarily a geography lesson, it should be given in the field if possible; otherwise the pupils must explore for themselves to discover the facts. The plant itself can be brought into the schoolroom for study. When studying the seeds, it is well to be careful, or the schoolroom and the pupils will be clothed with the pappus for weeks.

_Observations_--1. Where are the cat-tails found? Is the land on which they grow under water all the year? At any part of the year? Is it dry land all the year? What happens to the cat-tails, if the land on which they grow is flooded for a season? What happens to them, if the land is drained?

2. How wide a strip do the cat-tails cover, where you have found them? Are they near a pond or brook or stream? Do they grow out in the stream? Why do they not extend further inland? What is the character of the soil on which they grow?

Photo by Verne Morton.]

3. What sort of a root has the cat-tail? Why is this root especially adapted to the soil where cat-tails grow? Describe the rootstock.

4. _The cat-tail plant._ Are the leaves arranged opposite or alternate? Tear off a few of the leaves and describe the difference between the lower and the upper end of a leaf as follows: How do they differ in shape? Texture? Pliability? Color? Width? Does each leaf completely encircle the stalk at its base? Of what use is this to the plant? Of what use is it to have the plant stiffer where the leaves clasp the stalk? What would happen in a wind storm if this top-heavy, slender seed stalk was bare and not supported by the leaves? What is the special enemy of long, tall, slender-leafed plants?

5. Take a single leaf, cut it across near where it joins the main stalk and also near its tip. Look at the cross-section and see how the leaf is veined. What do its long veins or ribs do for the leaf? Split the leaf lengthwise and see what other supports it has. Does the cat-tail leaf break or tear along its edges easily? Does the wind injure any part of the leaf?

6. Study the cat-tail flowers the last half of June. Note the part that will develop into the cat’s tail. Describe the part above it. Can you see where the pollen comes from? The pistillate flowers which are in the plush of the cat-tail have no sepals, petals, odor nor nectar. Do you think that their pollen is carried to them by the bees? How is it carried?

7. Examine the cat-tail in fall or winter. What has happened to that part of the stalk above the cat-tail where the anthers grew? Study two or three of the seeds, and see how they are provided for traveling. What scatters them? Will the cat-tail seed balloons float? Would the wind or the water be more likely to carry the cat-tail seeds to a place where they would grow? Describe the difference between the cat-tail balloon and the thistle balloon.

8. How crowded do the cat-tail plants grow? How are they arranged to keep from shading each other? In how many ways is the wind a friend of the cat-tails?

9. How do the cat-tails help to build up land and make narrower ponds and streams?

LESSON CXXXV

A TYPE LESSON FOR A COMPOSITE FLOWER

_Leading thought_--Many plants have their flowers set close together to make a mass of color, like the geraniums or the clovers. But there are other plants where the flowers of one flower-head act like the members of a family, those at the center doing a certain kind of work for the production of seed, and those around the edges doing another kind of work. The sunflower, goldenrod, asters, daisies, cone-flower, thistle, dandelion, burdock, everlasting, and many other common flowers have their blossoms arranged in this way. Before any of the wild-flower members of this family are studied, the lesson on the garden sunflower should be given. (See Lesson CLXII).

_Method_--These flowers may be studied in the schoolroom with suggestions for field observations. A lens is almost necessary for the study of most of these flowers.

_Observations_--1. Can you see that what you call the flower consists of many flowers set together like a beautiful mosaic? Those at the center are called disk-flowers; those around the edges banner or ray-flowers.

2. Note that the flowers around the edges have differently shaped corollas than those at the center. How do they differ? Why should these be called the banner flowers? Why should they be called the ray-flowers? How many banner-flowers are there in the flower family you are studying? How are the banners arranged to make the flower-head more attractive? Cut off or pull out all the banner-flowers and see how the flower-head looks. What do the banner-flowers hold out their banners for? Is it to attract us or the insects? Has the banner-flower any stigma or stamens?

3. Study the flowers at the center. Are they open, or are they unfolded, buds? Can you make a sketch of how they are arranged? Are any of the florets open? What is the shape and the color of the corolla? Can you see the stamen-tubes pushing out from some? What color are the stamen-tubes? Can you see the two-parted stigmas in others? What color is the pollen. Do the florets at the center or at the outside of the disk open first? When they first open, do you see the stamen-tube or the stigma?