. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. ;u8 SECOXDARV CHAXGES. develope into the bundles arranged round the leaf-traces. One, and perhaps some few closely grouped cells of the canibial ring divide tangentially; from the internal cell or cells an initial strand is formed by longitudinal divisons facing in different directions, \vhile the outer cells continue the centrifugal tangential division. Those products of the latter, which adjoin the initial strand externall)', assume at once the properties of relatively wide parench
. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. ;u8 SECOXDARV CHAXGES. develope into the bundles arranged round the leaf-traces. One, and perhaps some few closely grouped cells of the canibial ring divide tangentially; from the internal cell or cells an initial strand is formed by longitudinal divisons facing in different directions, \vhile the outer cells continue the centrifugal tangential division. Those products of the latter, which adjoin the initial strand externall)', assume at once the properties of relatively wide parenchymatous cells, the initial strand is therefore separated by paren- chyma from the canibial ring, which successively retreats outwards. Simultaneously with the first formation of the initial strands, a ccntrifugally successive development of parenchyma on the part of the cambium takes place between them. Since this development continues slowly, the cambial ring, which retreats slowly outwards, forms a number of new initial strands in the manner above described, at successively alternating points at its periphery ; this centrifugally progressive activity accordingly produces those irregular circles of vascular bundles, separated by delicate and wide-celled parenchyma, which surround the ring of the leaf-traces. The number of these bundles varies greatly according to the strength of the internodcs; in weak seed- lings it is often hardly 8-10 (Fig. 236), in strong flowering shoots 2-3 times that number. During the process described, the growth in the direc- tion of the transverse diameter continues in the middle of the transverse section of the internode. The vascular bundles increase the number and size of their elements in the usual way — especially the united bundles of the trace (:-) are usually to be distinguished at an early stage by their considerable size; "the cells of the whole interfascicular parenchyma in- crease throughout in width. The cells derived directly fr
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
