The species is, therefore, a native of the region lying at the foot of the western mountains of the Indian Peninsula, and its cultivation in the neighbourhood is probably not earlier than the Christian era. It was introduced into Jamaica by Admiral Rodney in 1782, and thence into San Domingo.[1501] It has also been introduced into Brazil, Mauritius, the Seychelles, and Rodriguez Island.[1502] +Date-Palm+—_Phœnix dactylifera_, Linnæus. The date-palm has existed from prehistoric times in the warm dry zone, which extends from Senegal to the basin of the Indus, principally between parallels 15 and 30. It is seen here and there further to the north, by reason of exceptional circumstances and of the aim which is proposed in its cultivation. For beyond the limit within which the fruit ripens every year, there is a zone in which they ripen ill or seldom, and a further region within which the tree can live, but without fruiting or even flowering. These limits have been traced by de Martius, Carl Ritter, and myself.[1503] It is needless to reproduce them here, the aim of the present work being to study questions of origin. As regards the date-palm, we can hardly rely on the more or less proved existence of really wild indigenous individuals. Dates are easily transported; the stones germinate when sown in damp soil near the source of a river, and even in the fissures of rocks. The inhabitants of oases have planted or sown date-palms in favourable localities where the species perhaps existed before man, and when the traveller comes across isolated trees, at a distance from dwellings, he cannot know that they did not spring from stones thrown away by caravans. Botanists admit a variety, _sylvestris_, that is to say wild, with small and sour fruit; but it is perhaps the result of recent naturalization in an unfavourable soil. Historical and philological data are of more value here, though doubtless from the antiquity of cultivation they can only establish probabilities.