The most useful of the monocotyledons, or endogens, ("inside growers," as they are sometimes called,) are the bamboos, which are giant members of the group of grasses, Fig. 1. They grow in dense forests, some varieties often 70 feet high and 6 inches in diameter, shooting up their entire height in a single season. Bamboo is very highly valued in the Orient, where it is used for masts, for house rafters, and other building purposes, for gutters and water-pipes and in countless other ways. It is twice as strong as any of our woods. Under the fruit-bearing trees (angiosperms), timber trees are chiefly found among those that have two seed-leaves (the dicotyledons) and include the great mass of broad-leaved or deciduous trees such as chestnut, oak, ash and maple. It is to these and to the conifers that our principal attention will be given, since they constitute the bulk of the wood in common use. The timber-bearing trees, then, are the: (1) Conifers, the needle-leaved, naked-seeded trees, such as pine, cedar, etc. Fig. 45, p. 199. (2) Endogens, which have one seed-leaf, such as bamboos, Fig. 1. (3) Broad-leaved trees, having two seed-leaves, such as oak, beech, and elm. Fig. 48, p. 202. The common classifications of trees are quite inaccurate. Many of the so-called deciduous (Latin, _deciduus_, falling off) trees are evergreen, such as holly, and, in the south, live oak, magnolia and cherry. So, too, some of the alleged "evergreens," like bald cypress and tamarack, shed their leaves annually. [Illustration: Fig. 1. A Bamboo Grove, Kioto, Japan.] Not all of the "conifers" bear cones. For example, the juniper bears a berry. The ginko, Fig. 2, tho classed among the "conifers," the "evergreens," and the "needle-leaf" trees, bears no cones, has broad leaves and is deciduous. It has an especial interest as being the sole survivor of many species which grew abundantly in the carboniferous age. [Illustration: Fig. 2. Ginko Leaf.] Also, the terms used by lumbermen, "hard woods" for broad-leaved trees and "soft woods" for conifers, are still less exact, for the wood of some broad-leaved trees, as bass and poplar, is much softer than that of some conifers, as Georgia pine and lignum vitae. Another classification commonly made is that of "endogens" (inside growers) including bamboos, palms, etc., and exogens (outside growers) which would include both conifers and broad-leaved trees. One reason why so many classifications have come into use is that none of them is quite accurate. A better one will be explained later. See p. 23. As in the study of all woods three sections are made, it is well at the outset to understand clearly what these are. The sections of a tree made for its study are (Fig. 3): (1) Transverse, a plane at right angles to the organic axis. (2) Radial, a longitudinal plane, including the organic axis. [Illustration: Fig. 3. A. A, B, C, D, Transverse Section. B, D, E, F, Radial Section. G, H, I, J, Tangential Section.