Page:Popular Science Monthly Volume 52.djvu/84

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POPULAR SCIENCE MONTHLY.

The fruit is the vehicle of the seed, and in each seed lies hidden the germ of a new plant. To spread itself as far and wide over the earth as its environing conditions will allow is the aim of every plant. In some the fruit has developed into an edible berry, and the hard-coated seeds pass uninjured through the bodies of animals, and are scattered long distances away from the parent plants. In many forms it is fashioned for sailing in air currents; in some, like the cocoanut, with its tough, buoyant husk, to be floated on the waves and washed by the tides and ocean currents to distant shores. Every plant tends to hold back this dispersive effort until its seeds have matured. As this is accomplished PSM V52 D084 Cocklebur.png the ovary ripens into the fruit, of a form and fashion after its kind. The green color, that served to protect it when ripening amid the mass of foliage, changes to the conspicuous reds and yellows that catch the eye of a wandering animal—and so its part is played. Among these burs and "stickers" of our autumn woodlands we see but another means for securing this end. The wandering deer or bear, the hunter following its trail through the undergrowth, the fox, skunk, raccoon, and such lesser wood folk, each serves a turn in bearing away these bristly fruits. How well it has been accomplished is seen in the wide dispersal of these plants. A striking fact in evidence of this is the relatively large number that have come from the shores of Europe as uninvited guests. Circæa, the burdock, cocklebur, several species of cleavers, and a species of comfrey have thus become naturalized in our country, and it is not improbable that several of our native species have found their way to the Old World by catching fast to some passing vagrant, who later took ship and landed with the burs still clinging to his clothes.

Reproduction and dispersal are the two great aims in the life of every plant and animal. All else is but the means, the mere contrivances to gain the best advantage in the accomplishment of these