In tropical countries, where there is not too much moisture and shade, the trees are shaggy with lichens; and some of the most magnificent species, both as regards size and color, have been gathered in the Cinchona forests which clothe the lower slopes of the Andes, and in the warmer and more densely wooded parts of Australia and New Zealand. The thick impervious forests of Brazil, however, are said to be almost destitute of them. On the Alps of Switzerland the last lichens are to be found on the highest summits, attached to projecting rocks, exposed to the scorching heats of summer and the fierce blasts of winter; and from forty to forty-five kinds have been found in spots, surrounded by extensive masses of snow, between 10,000 and 14,780 feet above the level of the sea. It is interesting to know that the only plant found by Agassiz near the top of Mont Blanc was the Lecidea geographica, a very beautiful lichen, which covers the exposed rocks on the sides and summits of all the British hills, with its bright-green, map-like patches. This species was also gathered by Dr. Hooker at an elevation of 19,000 feet on the Himalayas, and occupied the last outpost of vegetation which gladdened the eyes of the illustrious Humboldt, when standing within a few hundred feet of the summit of Chimborazo, the highest peak of the Andes. The Lecidea geographica affords, I may mention, the most remarkable example of the almost universal diffusion of lichens, being the most Arctic, Antarctic, and Alpine lichen in the world--facing the savage cliffs of Melville Island in the extreme north, clinging to the volcanic rocks of Deception Island in the extreme south, and scaling the towering peak of Kinchin-junga, the most elevated spot on the surface of the earth.