Page:Popular Science Monthly Volume 28.djvu/90

82 even here, the calyx has extremely long, narrow teeth, thickly covered with smooth hairs, which serve to keep its beans safe. The analogy of a prickly pear or a rose-hip will show how very unpleasant such hairs feel in the mouth. The beautiful, small barefoot clover derives its expressive name from a further development of the same principle. The long teeth of the calyx project beyond the flowers, and are enveloped in soft, downy hair, which gives the whole head a very dainty, feathery appearance. As soon as the flowers are faded, the head looks like a mere mass of soft fluff, unenticing to herbivorous animals, and effectually concealing the seeds from birds or insects. The starry clover of Southern Europe, naturalized in England at Shoreham and a few other spots, starts from much the same point, but has specialized itself both against large and small depredators. On the one hand, its smooth, woolly calyx, much like that of crimson clover during the flowering stage, spreads out after blossoming into a star-shaped pattern, and forms with its neighbors a dry, bristly, interlacing head, thickly studded with sharp hairs; and this suffices to protect it from cattle and goats. On the other hand, the mouth of the calyx, being thus exposed by the spreading of the teeth, is closed by a perfect chevalde-frise of convergent tufted hairs, all meeting in the center of the throat; and this barrier answers the same purpose as that of the sea clover, though in a different manner, by forming a false bottom to exclude insects. I notice on the dry Mediterranean hills that these bristly heads are rejected by the goats and sheep, like those of Boccone's clover, and even donkeys refuse to eat them.

Turning to a somewhat different class, there are some clovers which protect their seeds in a quite distinct manner, by merely turning them out of sight. Common Dutch clover does this in a simple yet very noticeable fashion. It bears its pretty white flowers in tall globular heads on a lengthened footstalk, which renders them extremely conspicuous objects to the fertilizing bees. But each flower is stalked within the head, and, as soon as it has been fertilized, it turns downward, and fades brown against the common footstalk. Every head of Dutch clover thus habitually consists of two parts—an upper part, containing erect open flowers or flower-buds, not yet fertilized; and a lower part, containing overblown flowers, already fertilized, and now engaged in setting their seed. This plan combines two distinct advantages at once. In the first place, the bees lose no time in discriminating between the mature honey-bearing blossoms and those already rifled, which insures more frequent visits and a larger general average of seed-setting. In the second place, the fruiting pedicels and pods, being turned down and concealed, are less likely to be visited by small animal foes, such as flying insects, which might lay their eggs within, and let the grub feed (as often happens) on the growing seed. Dutch clover is a fodder-plant, and therefore, probably, in its native state does not grow much in places exposed to the ravages of large