to, though not identical with, those found in latitudes of corresponding mean temperature takes place; the lofty forests by degrees lose their splendour; stunted shrubs succeed; till at last the progress of the lichen is checked by perpetual snow. On the volcano of Teneriffe there are five successive zones, each producing distinct families of plants. The first is the region of vines, the next that of laurels; these are followed by the region of pines, of Ericas or heaths, of grass; the whole covering the declivity of the peak through an extent of 11,200 feet of perpendicular height. Near the equator oaks flourish at the height of 9200 feet above the sea; and, on the lofty range of the Himalaya, the primula, the convallaria, and the veronica flower, but not the primrose, the lily of the valley, or the veronica, which adorn our meadows; for, although the herbarium collected by Moorcroft, on his route from Neetee to Daba and Gartope in Chinese Tartary, at elevations as high or even higher than Mont Blanc, abound in Alpine and European genera, the species are universally different, with the single exception of the Rhodiola rosea, which is identical with the species that blooms in Scotland. It is not in this instance alone that similarity of climate obtains without identity of productions; throughout the whole globe a certain analogy both of structure and appearance is frequently discovered between plants under corresponding circumstances which are yet specifically different. It is even said that a difference of 25° of latitude occasions a total change, not only of vegetable productions, but of organised beings. Certain it is that each separate region both of land and water, from the frozen shores of the polar circles to the burning regions of the torrid zone, possesses a flora peculiarly its own. The whole globe has been divided by physical geographers into various botanical districts, differing almost entirely in their specific vegetable productions, the limits of which are most decided when they are separated by a wide expanse of ocean, mountain chains, sandy deserts, salt plains, or internal seas. A considerable number of plants are common to the northern regions of Asia, Europe, and America, where the continents almost unite; but, in approaching the south, the floras of these three great divisions of the globe differ more and more even in the same parallels of latitude, which shows that temperature alone is not the cause of the almost complete diversity of species that everywhere prevails. The floras of China, Siberia, Tartary, of the European district including central Europe and the coast of the Mediterranean, and the Oriental region comprising the countries round the Black and Caspian Seas, all differ in specific character. Only twenty-four species were found by MM. Humboldt and Bonpland in Equinoctial America identical with those of the Old World; and Dr. Robert Brown not only found that a peculiar vegetation exists in