1087. The science of the distribution of plants is comparatively of recent date. 'In the earliest days of botany,' says Schleiden, 'in every description of a plant was noted the place where it was found ; but no one anticipated that these notices enclosed the germ of a new science.' At last, Tournefort made a journey to the Levant, and when he ascended Mount Ararat, it struck him that in the gradual elevation of the mountain above the level of the sea, the vegetation assumed essentially different characters, and that these changes corresponded very closely with what he had observed in the vegetations of the mountains in his progress from Asia Minor to Lapland. This was a new idea started, which was eagerly caught at by the botanists of that day. Soon after Adanson discovered the fact, that umbelliferous plants seldom, if ever, occurred within the tropics. In 1807 appeared Humboldt's Essai sur la Geographic des Plantes, in which an attempt was first made 'to bring the observed peculiarities in the distribution of vegetables into connection with the specialities of the climate.' Ten years later, Humboldt made a farther advance, and 'comprehending the whole earth in one intelligent glance, he made the geography of plants part of a theory of the earth; and showed the dependence of the distribution of plants-on a great scale as well as on a small one-upon the physical qualities of the globe.' (Schleiden's Plant (1848), p. 239.)
