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.