. Botany for high schools and colleges. Botany. 444 BOTANY bundles are more numerous. In such a stem it is evident that there can be no considerable increase in thickness after it is once formed, and we consequently find that palms take a longtime for the formation of a broad bud or growing- point {liunctuin vegetationis), and afterward push up a cylin- drical stem in which little change subsequently takes j^lace. In the Dragon trees {Draccena, sp.) and some other Monoco- tyledons, there is a thick layer of paren- chymatous cortex be- tween the column of fibro-vascular bundles and the ejoiderm
. Botany for high schools and colleges. Botany. 444 BOTANY bundles are more numerous. In such a stem it is evident that there can be no considerable increase in thickness after it is once formed, and we consequently find that palms take a longtime for the formation of a broad bud or growing- point {liunctuin vegetationis), and afterward push up a cylin- drical stem in which little change subsequently takes j^lace. In the Dragon trees {Draccena, sp.) and some other Monoco- tyledons, there is a thick layer of paren- chymatous cortex be- tween the column of fibro-vascular bundles and the ejoidermis (Fig. 322, r), and in the deeper layers of this a persistent meri- stem tissue is found (Fig. 322, x). In this meristem there are formed fibro-vascular bundles,which lie par- allel to those already formed, and in this way the stem slowly increases in thickness. 545.—In those Di- cotyledons whose stems increase in thickness there always develops soon a layer of meristem tissue, of one fibro-vascular. Fig. 322 —Cross-section of Ftem of Draccena. e, epidermis; k. cork ; r, cortex ; 6, a fibro vascular bundle bending out to a leaf ; m, parei chyma of the fundamental system ; g, gr, fibro-vascular iiuudles ; a?, meristem zone of the fundamental system in which new bundles and tissues are forming,—After Sachs. which connects the cambium layer bundle with that of the other (Fig. 323). This is made easier from the fact that in most (but not all) Dicotyle- dons the bundles lie at nearly the same depth beneath the epidermis on all sides of the stem, thus forming a cylinder, or in cross-section, a ring, as in Fig. 323. Both the fascicu'. 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 Bessey, Charles Edwin, 1845- [from old catalog]. New York, H. Holt and company
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