Page:Popular Science Monthly Volume 13.djvu/627

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THE ORIGIN OF FRUITS.

of animals than a cone like that of pines and fir-trees? Yet even this hard, scaly covering has been modified, in the course of ages, so as to form a fruit. In the cypress, with its soft young cones, we can see dimly the first step in the process; in the juniper, the cone has become quite succulent and berry-like; and finally, in the red fruit of the yew, all resemblance to the original type is entirely overlaid by its acquired traits.

Equally significant is the fact that closely-allied species often choose totally different means for attracting or escaping observation. Thus, within the limits of the rose tribe itself we get such remarkable variations as the strawberry, where the receptacle forms the fruit; the apple, which depends on the peduncle, or swollen stalk, for its allurement; the raspberry, where each seed-vessel of the compound group has a juicy coating of its own, and so forth: while, on the other hand, the potentilla has no fruit at all, in the popular sense of the word; and the almond actually diverges so far from the ordinary habits of the tribe as to adopt the protective tactics of a nut. Similarly, in the palm tribe, while most species fortify themselves against monkeys by shells of extravagant hardness, as we see in the vegetable ivory, and the solid coquilla-nuts from which door-handles are manufactured, a few kinds, like the date and the doom-palm, trust rather to the softness and sweetness of their pulp, as aids to dispersion. The truth which we learn from these diverse cases may be shortly summed up thus: Whatever peculiarities tend to preserve the life of a species, in whatever opposite ways, equally aid it in the struggle for life, and may be indifferently produced in the most closely-related types.

And now let us glance for a moment—less fully than the subject demands, for this long exposition has run away with our space—at the reactive effects of fruit upon the animal eye. We took it for granted above that birds and mammals could discriminate between the red or yellow berry and the green foliage in whose midst it grows. Indeed, were other proof wanting, we should be justified in concluding that animals generally are possessed of a sense for the discrimination of color, from the mere fact that all those fruits and flowers which depend for their dispersion or fertilization upon animal agency are brightly tinted, while all those which depend upon the wind, or other insentient energies, are green or dull-brown in hue. But many actual observations, too numerous to be detailed here, also show us, beyond the possibility of error, that the higher animals do, as a matter of fact, possess a sense of color, differing in no important particular from that of civilized man.

Whether this sense was developed, however, by the constant search for berries and insects, or whether it was derived from a still earlier ancestry, it would be very difficult to decide. It is possible that, as we saw reason to believe in the case of the flowers and the insect vision, the colors of fruits and the color-sense of birds and mammals may