This round burr (Fig. [44]) was one of the worst of my hangers-on. You know it quite well. It is the fruit of the burdock. Can some child tell me why I call this prickly burr a fruit?
Fig. 44
Now let us look carefully at this seed case or fruit of the burdock.
Instead of being smooth to the touch, like some other fruits we know, such as the apple and the pear, it is covered with stiff hooks. By these hooks it fastened itself so firmly to my clothes, that it was difficult to pull it off without making a tear.
Why does the burdock put its seeds into such a prickly case?
Please stop reading for a moment and try to answer this question.
Cudgel well your brains for the use of such a prickly seed case as that of the burdock plant.
Now I am hoping that one of you children will be able to think out some such answer as this:—
“Of course, the burdock plant doesn’t want its seeds to fall on the piece of ground that has been used up already by other burdocks, any more than the partridge vine wishes to drop its seeds in the same little hollow where other partridge vines have eaten all the good food. As this burdock plant cannot make its seed case so bright and pretty, and good to eat, that the birds will carry it off, it must manage in some other way to send its seeds on their travels. And this is what it does: it covers the seed case with little hooks. When the seeds inside are quite ripe, this case breaks off very easily. So when the children come hunting berries, it hooks itself to their clothes, or else it catches in the hair of their dogs, or takes hold of the wool of grazing sheep, and gets carried quite a way before it is picked or rubbed off. When that happens, it is far enough from its old home to set up for itself.”