In other trees which, struggling upwards to air and light, attain a prodigious altitude, or from their enormous girth and the colossal expansion of their branches require steadying from beneath, we find buttresses projecting like rays from all sides of the trunk. They are frequently from six to twelve inches thick, and project from five to fifteen feet, and, as they ascend, gradually sink into the bole and disappear at the height of from ten to twenty feet from the ground. By the firm resistance which they offer below, the trees are effectually protected from the leverage of the crown, by which they would otherwise be uprooted. Some of these buttresses are so smooth and flat as almost to resemble sawn planks; as, for instance, in the Bombax Ceiba, one of the most remarkable examples of this wonderful device of Nature. [Illustration: SNAKE-TREE.] In other cases we find the roots fantastically spreading and revelling in a variety of grotesque shapes, such as we nowhere find in the less exuberant vegetation of Europe. Thus, in the india-rubber tree (_Ficus elastica_), masses of the roots appear above ground, extending on all sides from the base, and writhing over the surface in serpentine undulations, so that the Indian villagers give it the name of the snake-tree. Sir Emerson Tennent mentions an avenue of these trees leading to the botanical garden of Peradenia, in Ceylon, the roots of which meet from either side of the road, and have so covered the surface as to form a wooden framework, the interstices of which retain the materials that form the roadway. These tangled roots sometimes trail to such an extent that they have been found upwards of 140 feet in length, whilst the tree itself was not thirty feet high. The roots of the Mangroves, which in the tropical zone are found fringing the shores of the sea, or the mouths of rivers, wherever the reflux of the tide exposes a broad belt of alluvial soil, are admirably adapted for securing a footing on the unstable brink of the ocean. [Illustration: MANGROVE.] The growth of these salt-water-loving trees (_Rhizophora gymnorrhiza_, _R. Mangle_) is equally peculiar and picturesque. The seeds germinate on the branches, and, increasing to a considerable length, finally fall down into the mud, where they stick, with their sharp point buried, and soon take root. As the young mangrove grows upwards, pendulous roots issue from the trunk and low branches, and ultimately strike into the muddy ground, where they increase to the thickness of a man’s leg; so that the whole has the appearance of a complicated series of loops and arches, from five to ten feet high, supporting the body of the tree like so many artificial stakes. It may easily be imagined what dense and inextricable thickets, what incomparable breakwaters, plants like these--through whose mazes even the light-footed Indian can only penetrate by stepping from root to root--are capable of forming.