The wild olive, called in botanical books the variety _sylvestris_ or _oleaster_, is distinguished from the cultivated olive tree by a smaller fruit, of which the flesh is not so abundant. The best fruits are obtained by selecting the seeds, buds, or grafts from good varieties. The oleaster now exists over a wide area east and west of Syria, from the Punjab and Beluchistan[1389] as far as Portugal and even Madeira, the Canaries and even Marocco,[1390] and from the Atlas northwards as far as the south of France, the ancient Macedonia, the Crimea, and the Caucasus.[1391] If we compare the accounts of travellers and of the authors of floras, it will be seen that towards the limits of this area there is often a doubt as to the wild and indigenous (that is to say ancient in the country) nature of the species. Sometimes it offers itself as a shrub which fruits little or not at all; and sometimes, as in the Crimea, the plants are rare as though they had escaped, as an exception, the destructive effects of winters too severe to allow of a definite establishment. As regards Algeria and the south of France, these doubts have been the subject of a discussion among competent men in the Botanical Society.[1392] They repose upon the uncontestable fact that birds often transport the seed of the olive into uncultivated and sterile places, where the wild form, the oleaster, is produced and naturalized. The question is not clearly stated when we ask if such and such olive trees of a given locality are really wild. In a woody species which lives so long and shoots again from the same stock when cut off by accident, it is impossible to know the origin of the individuals observed. They may have been sown by man or birds at a very early epoch, for olive trees of more than a thousand years old are known. The effect of such sowing is a naturalization, which is equivalent to an extension of area. The point in question is, therefore, to discover what was the home of the species in very early prehistoric times, and how this area has grown larger by different modes of transport. It is not by the study of living olive trees that this question can be answered. We must seek in what countries the cultivation began, and how it was propagated. The more ancient it is in any region, the more probable it is that the species has existed wild there from the time of those geological events which took place before the coming of prehistoric man.