. Fossil plants : for students of botany and geology . Paleobotany. 314 CALAMITES. [CH. long and narrow parenchymatous cells ; as the section is tan- gential the characteristic scalariform character of the tracheids is not shown, the ladder-like bordered pits being confined to the radial walls of the tracheal elements. The much greater length than breadth of the cells which form the rays associated with the xylem tracheids, is a characteristic feature in Calamitean stems. The breadth of the principal ray, m, shows that the section has passed through the wood a short distance from the pith; in
. Fossil plants : for students of botany and geology . Paleobotany. 314 CALAMITES. [CH. long and narrow parenchymatous cells ; as the section is tan- gential the characteristic scalariform character of the tracheids is not shown, the ladder-like bordered pits being confined to the radial walls of the tracheal elements. The much greater length than breadth of the cells which form the rays associated with the xylem tracheids, is a characteristic feature in Calamitean stems. The breadth of the principal ray, m, shows that the section has passed through the wood a short distance from the pith; in a tangential section cut further into the wood the breadth of the principal rays would be considerably reduced. The large medullary-ray tissue consists of square-walled parenchymatous cells. The more highly magnified section, in. Fig. 76. Longitudinal tangential section of the same Calamite as that of figs. 74 and 75, showing a leaf-trace and curved tracheids at a node. From a section in the Binney Collection, x 100. fig. 76, shows a central group of parenchyma containing a few transversely cut tracheids, but the two kinds of elements are not clearly differentiated in the figure; this group of cells is. 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 Seward, A. C. (Albert Charles), 1863-1941. Cambridge : University Press
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishercambr, bookyear1898
