. A class-book of botany, designed for colleges, academies, and other seminaries ... Illustrated by a flora of the northern, middle, and western states; particularly of the United States north of the Capitol, lat. 38 3/4. Botany; Plants -- United States; Plants -- Canada. 78 THE STEM. 199. The PITH {medulla) occupies the central part of the stem. It consists of a light, spongy mass of ceUular tissue, is chiefly abundant in young plants, and appears to be sei-viceable only in the earher stages of growth. It is then pervaded by fluids; but as the plant advances in age, it becomes dry, being fill
. A class-book of botany, designed for colleges, academies, and other seminaries ... Illustrated by a flora of the northern, middle, and western states; particularly of the United States north of the Capitol, lat. 38 3/4. Botany; Plants -- United States; Plants -- Canada. 78 THE STEM. 199. The PITH {medulla) occupies the central part of the stem. It consists of a light, spongy mass of ceUular tissue, is chiefly abundant in young plants, and appears to be sei-viceable only in the earher stages of growth. It is then pervaded by fluids; but as the plant advances in age, it becomes dry, being filled with air only, and much diminished in FIG. 25. —Exogens, —oak, fir, &c.; Endogens, palm (American), Agave, &c. 200. Lnmediately around the pith is formed the medullary SHEATH, which is a thin, dehcate membrane of vascular tissue (33), sending off a portion of its spiral vessels to the stalk and veins of each leaf This, with the leaves, is the only part of exogenous stems which usually contains sphal vessels. 201. The WOOD is composed of concentric zones, or layers, pervaded and intersected by the medullary rays (204). The first, or inner layer, together with the pith and medullaiy sheath, is the product of the first year. One new layer is formed each successive year, during the life of the plant; hence the whole. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wood, Alphonso, 1810-1881. Claremont, N. H. , Manufacturing Co. , S. Ide, agent
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectbotany, bookyear1848
