. The elements of botany embracing organography, histology, vegetable physiology, systematic botany and economic botany ... together with a complete glossary of botanical terms. Botany. divide into two cells, which, in turn, divide, and so on in- definitely (Fig, 218). 124. In the higher plants, the punctum vegetationis has no apical cell. Here the pri- mary meristem consists of cells which are very small and numerous. The outer- most layer of cells is continu- ous, with the epidermis of the older portion further back. In fact, it produces it. Hence it is called the primordial epidermis (Fig.
. The elements of botany embracing organography, histology, vegetable physiology, systematic botany and economic botany ... together with a complete glossary of botanical terms. Botany. divide into two cells, which, in turn, divide, and so on in- definitely (Fig, 218). 124. In the higher plants, the punctum vegetationis has no apical cell. Here the pri- mary meristem consists of cells which are very small and numerous. The outer- most layer of cells is continu- ous, with the epidermis of the older portion further back. In fact, it produces it. Hence it is called the primordial epidermis (Fig. 219, D), or dermatogen (Gr. derma, skin; genein, to be produced). Beneath the dermatogen are generally found several continuous layers out of which the cortex originates. These are called the primordial cor- tex (Fig. 219, Per), or periblem (Gr. p&rihlema, cloak). The nucleus of tissue, enclosed by the periblem, and out of which the fibro-vascular bundles and pith are produced (Fig. 219, Pier), is called the plerome {Gr. pleroma, a fill- ing up). A short distance back from the apex of the punetum vegetationis the leaves (and buds) take their origin as exogenous structures, that is, from the external cell-layer, or dermatogen, 125. The root, like the stem, is furnished with a ^itnciitm wjre- 220 Fig. 219. The growing point, or punctum vegetationis, in longitudinal section; D, dermatogen; Per, periblem; Pier, plerome. Fig. 220. Diagram of longi- tudinal section through the root-tipj showing the apical cells {Ap) and the root-cap ().. 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 Kellerman, William Ashbrook, 1850-1908. Philadelphia, J. E. Potter and Company
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1883
