| Phanerogamia, (Flowering plants) | I. Gymnosperms. (Naked seeds.) 1. Cycadaceae. (Palms, ferns, etc.) 2. Gnetaceae. (Joint firs.) 3. Conifers. Pines, firs, etc. II. Angiosperms. (Fruits.) 1. Monocotyledons. (One seed-leaf.) (Palms, bamboos, grasses, etc.) 2. Dicotyledons. (Two seed-leaves.) a. Herbs. b. Broad-leaved trees. |
Under the division of naked-seeded plants (gymnosperms), practically the only valuable timber-bearing plants are the needle-leaved trees or the conifers, including such trees as the pines, cedars, spruces, firs, etc. Their wood grows rapidly in concentric annual rings, like that of the broad-leaved trees; is easily worked, and is more widely used than the wood of any other class of trees.
Of fruit-bearing trees (angiosperms), there are two classes, those that have one seed-leaf as they germinate, and those that have two seed-leaves.
The one seed-leaf plants (monocotyledons) include the grasses, lilies, bananas, palms, etc. Of these there are only a few that reach the dimensions of trees. They are strikingly distinguished by the structure of their stems. They have no cambium layer and no distinct bark and pith; they have unbranched stems, which as a rule do not increase in diameter after the first stages of growth, but grow only terminally. Instead of having concentric annual rings and thus growing larger year by year, the woody tissue grows here and there thru the stem, but mostly crowded together toward the outer surfaces. Even where there is radial growth, as in yucca, the structure is not in annual rings, but irregular. These one seed-leaf trees (monocotyledons) are not of much economic value as lumber, being used chiefly "in the round," and to some extent for veneers and inlays; e. g., cocoanut-palm and porcupine wood are so used.
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. 203].