. College botany; structure, physiology and economics of plants. Botany. STEMS, BULBS AND BUDS 49 which connects the fascicular p^arts and gives rise to the medvl- lary rays (Fig. 23). The cambium is made up of very delicate, active parenchyma cells, which divide longitudinally and par- allel to the surface of the stem {, tangentially) with occa- sional longitudinal divisions at right angles to the surface of the stem {, radially) and witJi occasional cross-divisions. As a result of these tangential divisions new layers of cells are added to the fibro-vascular bundles, and the diameter
. College botany; structure, physiology and economics of plants. Botany. STEMS, BULBS AND BUDS 49 which connects the fascicular p^arts and gives rise to the medvl- lary rays (Fig. 23). The cambium is made up of very delicate, active parenchyma cells, which divide longitudinally and par- allel to the surface of the stem {, tangentially) with occa- sional longitudinal divisions at right angles to the surface of the stem {, radially) and witJi occasional cross-divisions. As a result of these tangential divisions new layers of cells are added to the fibro-vascular bundles, and the diameter of the stem gradually increases. Most of these layers are added to the xylem, which grows more rapidly than the phloem. However, in this latitude the xylem ceases to grow about the middle of August, but the phloem continues to grow until l^ovember. These new layers of cells are of the same charac- ter, but undergo differentia- tion to form the various tissues of the xylem and phloem which have been already de- scribed. We are unable to explain why some of tlieee cells 4'. —Diagrammatic drawing of dico- tyledonous stem showing relative location of the tissues and systems. The epidermal sys- tem composed of the cork (a, 6), the phel- logei^ or cork cambium (c), and the coUen- chyma (d); the cortex composed of paren- chyma (e, g) and the bast (/); the fibro- vascular system composed of the pUoetnC/i), the cambium (?) and the xylem {j)\ the medullary rays ik), and the pith {I).. 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 Cook, Melville Thurston, 1869-1952. Philadelphia and London, J. B. Lippincott Company
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1920
