Timber is produced only by the Spermatophyta, or seed-bearing plants, which are subdivided into the Gymnosperms (conifers), and Angiosperms (broad-leaved). The conifer or cone-bearing tree, to which belong the pines, larches, and firs, is one of the three natural orders of Gymnosperms. These are generally classed as "softwoods," and are more extensively scattered and more generally used than any other class of timber, and are simple and regular in structure. The so-called "hardwoods" are "Dicotyledons" or broad-leaved trees, a subdivision of the Angiosperms. They are generally of slower growth, and produce harder timber than the conifers, but not necessarily so. Basswood, poplar, sycamore, and some of the gums, though classed with the hardwoods, are not nearly as hard as some of the pines. SECTION II CONIFEROUS TREES WOOD OF THE CONIFEROUS TREES Examining a smooth cross-section or end face of a well-grown log of Georgia pine, we distinguish an envelope of reddish, scaly bark, a small, whitish pith at the center, and between these the wood in a great number of concentric rings. Bark and Pith The bark of a pine stem is thickest and roughest near the base, decreases rapidly in thickness from one to one-half inches at the stump to one-tenth inch near the top of the tree, and forms in general about ten to fifteen per cent of the entire trunk. The pith is quite thick, usually one-eighth to one-fifth inch in southern species, though much less so in white pine, and is very thin, one-fifteenth to one twenty-fifth inch in cypress, cedar, and larch. In woods with a thick pith, the pith is finest at the stump, grows rapidly thicker toward the top, and becomes thinner again in the crown and limbs, the first one to five rings adjoining it behaving similarly. What is called the pith was once the seedling tree, and in many of the pines and firs, especially after they have been seasoning for a good while, this is distinctly noticeable in the center of the log, and detaches itself from the surrounding wood. Sap and Heartwood