Wood must have supplied one of the earliest materials with which to erect buildings; the Grecian styles of architecture, beyond doubt, were derived from imitating in stone those structures first made of wood. All the largest members of the vegetable kingdom belong to this division; and indeed the same may be said of size which has been said of age, namely, that there is no limit except from accidental circumstances. [Illustration: FIG. 23.--WELLINGTONIA GIGANTEA.] In the Crystal Palace at Sydenham is a most wonderful and gigantic specimen of the Wellingtonia Gigantea (fig. 23), one of the class of trees called coniferous, and belonging to the exogens, the bark of which has been stripped off in portions at the place where it grew, each of which being numbered, has enabled them to be re-adjusted in their original places, the result of which is, the whole bark of this most magnificent tree appears as if growing on the timber. It measures 31 feet across at the base, and 93 feet in circumference; the original tree was 363 feet in height, its present height is 116 feet, and the bark is 18 inches thick. The Norfolk Island Pine (Araucaria excelsa) sometimes grows to 300 feet in height, and Humboldt, describing a specimen of the Pinus Trigona, says, "This gigantic fir was measured with great care; the girth of the stem at 6-1/4 feet above the ground was often 38 to 45 feet; one stem was 300 feet high, and without branches for the first 192 feet." As the exogens grow by the addition of woody matter to their circumference, of course the older the tree (other conditions being equal) the larger will be the trunk, but as the new wood is added to the outside, the centre loses its vitality and is liable to the attacks of both animal and vegetable parasites, and is therefore constantly found either decayed or totally destoyed; this is not, however, invariably the case, and many instances are found of wood of a great age remaining sound in the centre. At St. Nicholas in Lorraine is exhibited a plank of walnut wood made into a dining-table which is twenty-five feet wide. Besides timber for various useful purposes, this division of the vegetable kingdom furnishes us with both cotton and linen for clothing, and many of the dye-stuffs for ornamenting such clothing, also with many articles of food (although not so prolific in this respect as the Endogenæ), the potato, most green vegetables, as cabbages, lettuces, are exogenous, together with such roots as carrots, parsnips, &c.