. Plants and their uses; an introduction to botany. Botany; Botany, Economic. 254 INDUSTRIAL PLANTS. connected as to form a sort extend radially the plates of pitl Fic. 'J'.i'S. — Diagram of niaple stem showing the development of wood and bark through first and second years. At the tip is a mass of living formative material (shown unshaded) from the sides of which arise protrusions that finally In- come leaves. Also arising from the formative region, just above the base of the very young leaves, are protrusions which develop into formative regions like that of the main tip, and, as growing-poi
. Plants and their uses; an introduction to botany. Botany; Botany, Economic. 254 INDUSTRIAL PLANTS. connected as to form a sort extend radially the plates of pitl Fic. 'J'.i'S. — Diagram of niaple stem showing the development of wood and bark through first and second years. At the tip is a mass of living formative material (shown unshaded) from the sides of which arise protrusions that finally In- come leaves. Also arising from the formative region, just above the base of the very young leaves, are protrusions which develop into formative regions like that of the main tip, and, as growing-points, produce leaf-bearing branches of the main stem. In the center, around the axis, the formative n:ia- terial as it grows older becomes 7^'i^h. (shown as dotted), and this pith is continuous with that of the branches. The surface becomes changed into a skin or epidermis (shown by coarse shading), cover- ing both stem and leaves. Parts of the formative material between the epidermis and the pith become variously hardened into bundles of fibrous materia!: around the central pith arise strands of wood (shown by fine shading); near the epidermis arise corresponding strands of bark (shown by black), surrounded by more or less pith-like material which may become green, corky, or otherwise peculiar (shown dotted like the pith); and between the rings of wood and bark is a layer of formative material which is con- tinuous with that of the tip and* is called the cambium. From this cambium in successive years new W'ood is added to that within and new bark to that on its outer side, and thus both wood and bark in- crease in thickness by annual lay- ers. But on the outside the epi- dermis, and then the older bark, is pushed off or worn away so that the total thickness of the bark is limited. Both wood and bark are continued into the leaves, but not the cambium. The strands of wood and those of bark are so )f network through the meshes of which called jtith-rays. (Original.) a layer of c
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
