. Botany for high schools and colleges. Botany. 142 BOTANY. the basal growth of the bud is resumed, and shortly after- ward, or simultaneously, the apical growth also. The thick scales separate by the slight elongation of the stem, and being of no further use to the plant they soon fall off. The inter- calary growth of the scale-bearing portion of the stem is gen- erally much less than of that which bears leaves, hence the first internodes which appear in the spring of the year are quite short. The punctum vegetationis of such a winter bud, after resuming its activity, goes on developing leave
. Botany for high schools and colleges. Botany. 142 BOTANY. the basal growth of the bud is resumed, and shortly after- ward, or simultaneously, the apical growth also. The thick scales separate by the slight elongation of the stem, and being of no further use to the plant they soon fall off. The inter- calary growth of the scale-bearing portion of the stem is gen- erally much less than of that which bears leaves, hence the first internodes which appear in the spring of the year are quite short. The punctum vegetationis of such a winter bud, after resuming its activity, goes on developing leaves as lateral members exactly as if there had been no interruption in its activity. Upon the approach of autumn again the. Fig. 122.—Longitudinal section of the apex of the stem of a moss (Fontinalis anti- pyretica). v, apical cell ; «, outer part of one of the segments cut off from apical cell; «, apical cell of a lateral leaf-bearing shoot arising below a leaf; c, first cell of a leaf; b, b, cells forming cortex. —After Leitgeb. same process of bud-formation takes place by the decrease in the rapidity of extension, and its final cessation ; this is fol- lowed again by the resumption of growth upon the advent of spring. Thus the stem exhibits a periodicity in its growth, and one of its phases is the so-called winter bud. 182.—Branches of stems (lateral stems) normally originate in the punctum vegetationis . as lateral outgrowths (Fig. 122, z); each develops first into a conical mass, w^hich then becomes the punctum vegetationis of a new stem, and upon it lateral members arise, as in the case of the principal stem. The new stem may elongate at once into a leafy shoot, as. 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
Size: 1649px × 1516px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisher, booksubjectbotany
