. Botany of the living plant. Botany; Plants. 46 BOTANY OF THE LIVING PLANT are the sieve-plates which are perforated, while the cytoplasm that lines the tubes is collected in a mass above each plate. The tubes are embedded in long prismatic cells of the phloem-parenchyma, and in this stem no bast-fibres are present. The cambium consists of long, very narrow cells, with thin walls and dense protoplasm. In each radial row of them the cells are as a rule of the same length, showing that they are the result of division of a single parent cell. capita endod epid pith xylera phloem -H M ^. Fig. 24.
. Botany of the living plant. Botany; Plants. 46 BOTANY OF THE LIVING PLANT are the sieve-plates which are perforated, while the cytoplasm that lines the tubes is collected in a mass above each plate. The tubes are embedded in long prismatic cells of the phloem-parenchyma, and in this stem no bast-fibres are present. The cambium consists of long, very narrow cells, with thin walls and dense protoplasm. In each radial row of them the cells are as a rule of the same length, showing that they are the result of division of a single parent cell. capita endod epid pith xylera phloem -H M ^. Fig. 24. Median longitudinal section through a vascular strand of Scrophularia nodosa, similar to that shown in Fig. 23. The arrow indicates the pore of a stoma, and points towards the centre of the stem. ( x 150 ) The xylem is more varied in structure, and if the section happened to have followed one of those radial series of vessels seen in the trans- verse section, its appearance would be as shown in Fig. 24. Starting inwards from the cambium, a series of fibrous tracheides would be met. They are elongated and pointed, with thick lignified walls bearing small pits. They surround and embed a larger pitted vessel, which appears as a wide tube without any protoplasmic contents, and is limited by a thick, pitted, woody wall. About half-way down the section it is marked by a ring ; this indicates where an oblique septum divided two of those cells from the fusion of which the vessel. 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 Bower, F. O. (Frederick Orpen), 1855-1948; Wardlaw, C. W. (Claude Wilson), 1901-. London, Macmillan and Co. , ltd.
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