some of the humblest lichens and mosses. Although these plants occupy but a very subsidiary and unimportant position among the vegetation which surrounds us in our daily walks, and are concealed in isolated patches in the woods and fields by the luxuriance of higher and more conspicuous plants, yet they constitute the sole vegetation of very extensive regions of the earth's surface. Every part of the globe, within a thousand feet of the line of perpetual snow, is redeemed from utter desolation by these plants alone. Above the valleys and the lower slopes which form the step of transition from plain to mountain—inhabited by prosperous and civilized nations—is the domain of mist and mystery, the region of storm—a world which is not of this world, where God and Nature are all in all, and man is nothing; and in this unknown region there are immense tracts familiar to the eye of wild bird, to the summer cloud, the stars and meteors of the night—strange to human faces and the sound of human voices, where the lichen and the moss alone luxuriate and carpet the sterile ground. The grandest and sublimest regions of the earth are adorned with garlands of the minutest and humblest plants; they are the tapestry, the highly-wrought carpeting laid down in the vestibules of Nature's palaces. If we look at a map of the world, we see that Europe and Asia are held together as it were by a huge ridge or backbone of mountain-elevation, which, although suffering partial interruption, may be roughly described as continuous from one ocean to another. It begins with the mountains of Biscay in Spain, passes on through the Pyrenees, with a slight interruption, into the Alps, which throw off the important spur or rib of the Apennines; thence it divides into the Balkan and Carpathians. We trace the chain next in the Caucasus and the mountains of Armenia—with the interruption of the Caspian Sea—passing into the Hindoo Coosh and the Himalaya Mountains, whence the chain forks and takes a direction north and south, enclosing like walls the whole delta of China, and thence dips into the eastern ocean. In Africa also, at its widest part, there is a similar backbone, beginning not far from Sierra Leone, and losing itself in the east in the mountains of Abyssinia; while in America the mountain-spine trends north and south from the Hudson's Bay territories, through the Rocky Mountains, uninterruptedly through the Isthmus of Panama, along the Andes to the Straits of Magellan. These vast mountain-systems, with their culminating regions in the Andes, Alps, and Himalayas, and their subsidiary branches or ribs in the Grampians, Dovrefields, Ural, and Atlantic ranges, are clothed on their sides, summits, and elevated plateaus, almost exclusively with cryptogamic vegetation, and enable us to form some conception of the immense altitudinal range of these plants. Then there are whole islands in the Arctic and Antarctic Oceans whose vegetation also is almost entirely cellular. The northern portion of Lapland, the continent of Greenland, the large islands of Spitzbergen, Nova Zembla, and Iceland, the extensive territories
