It has been pointed out that the principal characteristic of the vegetation of the Arctic Regions is the predominance of perennial and cryptogamous plants; but further southward, where night begins to alternate with day, or in what may be called the sub-arctic zone, a difference of species appears which greatly enhances the beauty of the landscape. A rich and vividly-coloured flora adorns these latitudes in Europe as well as in Asia during their brief but ardent summer, with its intense radiance and intense warmth,--consisting of potentillas, gentians, starry chick-weeds, spreading saxifrages and sedums, spiræas, drabas, artemisias, and the like. The power of the sun is so great, and the consequent rapidity of growth so extraordinary, that these plants spring up, and blossom, and germinate, and perish in six weeks. In a lower latitude many ligneous plants are found,--as berry-bearing shrubs, the glaucous kalmia, the trailing azalea, the full-blossomed rhododendron. The Siberian flora differs from the European in the same latitudes by the inclusion of the North American genera, phlox, mitella, and claytonia, and by the luxuriance of its asters, spiræas, milk-vetches, and the saline plants goosefoot and saltwort. * * * * * In Novaia Zemlaia and other northern regions the vegetation is so stunted that it barely covers the ground, but a much greater variety of minute plants of considerable beauty are aggregated there in a limited space than in the Alpine climes of Europe where the same genera occur. This is due to the feebleness of the vegetation; for in the Swiss Alps the same plant frequently usurps a large area, and drives out every other,--as the dark blue gentian, the violet-tinted pansy, and the yellow and pink stone-crops. But in the far north, where vitality is weak and the seeds do not ripen, thirty different species, it has been observed, may be seen “crowded together in a brilliant mass,” no one being powerful enough to overcome its companions. In these frozen climates plants may be said to live between the air and the earth, for they scarcely raise their heads above the soil, and their roots, unable to penetrate it, creep along the surface. All the woody plants--as the betula nava, the reticulated willow, andromeda tetragona, with a few bacciferous shrubs--trail upon the ground, and never rise more than an inch or two above it. The _Salix lanata_, the giant of the Arctic forests, is about five inches in height; while its stem, ten or twelve feet long, lies hidden among the moss, and owes shelter, almost life, to its humble neighbour. * * * * *