EUCALYPTUS, a genus of trees of the natural order Myrtaceoe, mostly, if not all, indigenous to Australia and Tasmania. In Australia the Eucalypti are commonly called “gum trees,” or “stringy·bark trees,” from their gummy or resinous products, or fibrous bark. The genus, from the evidence of leaf remains, appears to have been represented by several species in Eocene times (see Schimper, Traite de Paléontographie Végétale, 1874). The leaves arc-leathery in texture, hang obliquely or vertically, and arc studded with glands which contain a fragrant volatile oil. The flowers are apetalous, and resemble those of the myrtle, and the bud is closed by a lid, which is discarded when the flower expands. Within the hardened calyx, which constitutes the fruit, very numerous minute seeds are contained. The Eucalypti are rapid in growth, and many species are of great height, Ä. amygdalina attaining to even as much as 480 feet, or 150 feet more than the highest specimen of the Wellington™, {Sequoia) gigantea, with a diameter of 81 feet (see Joιιrn. of Forestry, March, 1878). The Blue Gum-tree, E. globulus, Labill., is so called from the rounded form of its operculated calyx, The leaves of trees from three to five years of age are large, sessile, and of a glaucous-white colour, and grow horizontally; those of older trees are ensiform, 6-12 inches long, and bluish-green in hue, and are directed downwards, lhe flowers are single or in clusters, and nearly sessile. This species is one of the largest trees in the world, and may attain a height of 375 feet. Since 1854 it has been successfully introduced into the south of Europe, Algeria, Egypt, Tahiti, New Caledonia, Natal, and India, and has been extensively planted in California, and, with the object of lessening liability ...