Part 8

People plant large fields of sweet potatoes, particularly in the South. So next time you eat a sweet potato, remember it is one kind of morning-glory which has given it to you.

The sweet potatoes are no relation whatever to our common potatoes; they do not belong to the same family.

The sweet potato is not the only useful morning-glory. There is the jalap, though if you have ever made its acquaintance you may differ from me as to its value; for however useful it may be from the doctor’s point of view, it certainly possesses properties which are quite the reverse of agreeable.

It, too, forms large tubers, which it stores full of plant food, but it so happens that this particular plant food is not fit for human food. We put it to quite another use. In fact, jalap is used as a medicine. It grows very luxuriantly at Jalapa, or, as the Mexicans spell it, Xalapa, in Mexico, and that is the way it gets its name of jalap.

In spite of its very disagreeable taste and beneficial effect upon sick people, the jalap is a lovely vine with beautiful deep pink flowers.

If you saw it growing along the eastern slopes of the Mexican mountains you would never suspect it of being a medicine plant, and you might not suspect it of being a convolvulus, since its flowers are flat instead of tubular in form.

Several members of the Convolvulus Family have the same medicinal properties as jalap, and one in particular, whose name is scammony, is very highly esteemed.

It has an uncommonly bad taste, and its swollen roots are brought all the way from Syria and Asia Minor, not because of their bad taste, but because of their power as a medicine. The scammony, like the jalap, is a pretty plant in spite of its bad-tasting, medicinal roots.

Most of the Convolvulaceæ have a milky, bitter juice,—even our pretty, harmless morning-glories,—and in the jalap and scammony this seems to be exaggerated in quality and quantity.

A few of the Convolvulaceæ manage to make woody stems and become shrubs instead of vines.

Two of these live on the Canary Islands, and their sap, instead of being nauseous and bad-smelling, has a delicate and delicious fragrance. People take the wood from root and stems and press out the oil to be used in making perfumery.

Perhaps you know the odor of oil of rhodium. Whenever you smell it you are inhaling the fragrance from a Canary convolvulus.

It is a little surprising to find our convolvulus so widespread and so really useful in different parts of the world; but there is another side to the history of this highly respectable family. Every family, probably, has its black sheep, and not even the Convolvulaceæ can hope to have all their relatives honest and useful or beautiful.

Still, one hates to speak of the dodders. They are in the world, however, and they belong to the Convolvulus Family; there is no denying that, however much one might like to. None of the Convolvulus Family ever speak of them—at least I have never heard of their doing so.

As a rule, the members of the Convolvulus Family are aristocrats. They have descended from a long line of plants that have gone on improving. That is what makes an aristocrat in plant land,—to be descended from a long line of plants that have kept on improving. Simply to belong to an old family does not count for much in the plant world, unless that old family has kept on doing something to improve itself.

We know the Convolvulaceæ are aristocrats for one thing by their tubular corollas; it took good, wide-awake ancestors to make corollas without separate petals anyway, and particularly tubular ones. Then their color tells their history. They are often blue or purple, which is a very aristocratic color among flowers. Instead of being blue-blooded, they are blue-colored.

The moonflower is not blue, but think what a tube it has and what a large fine corolla; and then think, too, that it has learned to bloom at night so as to get fertilized by the moths, and that is a very aristocratic thing to do, I assure you.

If a flower blooms at night it is as great an honor as to wear a blue corolla. For you see it has taken as much growth in the direction of progress to acquire the night-blooming habit as to acquire a blue corolla.

The cypress vine has a red corolla, which is a good color, but not quite as advanced as blue. You see, in the beginning of the world flowers were yellow; then some became white, then pink. Probably red was the next step, then came purple, and last of all blue.

But the cypress vine has very finely divided leaves, as you remember, and in that it is ahead of the morning-glories. For in the beginning of the world, we are told, leaves were not divided, and only after a long time did some plants learn to divide them, and so increase their usefulness as leaves.

But when we come to the dodders, they have no leaves at all. The reason for this is, they do no work for themselves. The green leaves, as you know, prepare the food for the plant and work very hard to do it. If the dodders have no leaves, where do they get their food? That is just the trouble. They make other plants give it to them. They are very much like tramps, going about and living on other people. Only they are worse than tramps, for they do not say, “Please give me something to eat. I am hungry and want some starch and nitrogen compounds.” They do nothing of the sort. They catch hold of another plant and take away its juices without leave or license. So you see they are really thieves and robbers, these rascally dodders. No wonder the morning-glories are not proud of them. Not that the dodders care. It is a question whether they even know they are related to the morning-glories.

They think of little but how to get something to eat out of other people.

They begin their shameful career from the very seed. Instead of sprouting in the spring with the other seeds, they lie still until all the other plants have gone out of their seeds and are at work making green leaves and storing their stems with plant juices.

Then Dodder the Robber comes out. But instead of sending down a root and up a stem like other seeds, he just pushes out a little thread-like body, which fastens into the ground. You might think this an honest little root going down into the ground if you did not know friend Dodder. But it is no root; it does not suck up juices from the earth: it simply anchors the little robber so he cannot be blown away. Now the thread-like body grows larger and sticks up out of the ground, carrying the seed-coat with it. The seed-coat is packed with food which the parent plant stored away there. The young dodder nourishes itself with this food until it is all gone; then it casts off the empty seed-coat, and behold young Dodder ready for the fray. What he very much wants at this time is a fresh young twig to cling to and suck the juice out of. If nothing of the sort is handy he is in a bad way, for he is too helpless to do anything for himself. He has no green leaves, and does not know how to make any, and without green leaves he cannot get a thing to eat. Poor Dodder! after all, it is not wholly his fault he is such a good-for-nothing specimen of planthood. You see he came from bad stock. His parents were like this before him, and no one has ever taught him any better. Well, there he lies, as helpless a plant as you can imagine. But just let a green shoot come within reach! Then you will see! He twists around it without stopping to say “by your leave.” He pierces it with little suckers that draw out its juices. Now Dodder is all right. He has plenty of food without the trouble of making a bit of it himself.

And then how he grows! Up the poor weed he twines, a slender yellow stem that looks as much like yellow yarn as anything else. Around and around he turns; he has no leaves to make, only useless little scales that show where long ago his ancestors once had honest leaves.

You will sometimes find the weeds in a damp place a perfect tangle of dodder vines, so that nothing else is to be seen. They cover the weeds, sucking out their juices and smothering them. And when the time comes the dodder breaks out into innumerable bunches of flowers, which grow at short distances along the yellow stems. These flowers are small and generally white, and clustered so close together that they form a sort of knot or rosette on the stem.

You would never imagine to look at them that they belonged to our Morning-Glory Family.

Their corollas are more or less cleft, being grown together only at the base.