. Botany of the living plant. Botany; Plants. THE CELLULAR CONSTRUCTION OF THE PLANT 19 schemes. Thus in the young state the axis, and, it may be said more generally, the plant-body throughout, is partitioned up into cells in somewhat the same way as a house is partitioned into rooms. And their arrangement is not at haphazard, but according to laws. // may be stated generally, as a fact of experience, that the whole of the plant-body, whether young or mature, is made up of such cells, or their derivatives. This generalisation used to be spoken of as the " cellular. Fig. 10. Diagram illust
. Botany of the living plant. Botany; Plants. THE CELLULAR CONSTRUCTION OF THE PLANT 19 schemes. Thus in the young state the axis, and, it may be said more generally, the plant-body throughout, is partitioned up into cells in somewhat the same way as a house is partitioned into rooms. And their arrangement is not at haphazard, but according to laws. // may be stated generally, as a fact of experience, that the whole of the plant-body, whether young or mature, is made up of such cells, or their derivatives. This generalisation used to be spoken of as the " cellular. Fig. 10. Diagram illustrating the plan of arrangement of cell-walls in the apex of the stem of an Angiosperm. XX = axis of construction. EE = external surface. PP=peri- clinal curves. AA =anticlinal curves. (After Sachs.) ; But it is now so fully demonstrated that the fact may be enunciated as a positive conclusion. It will be seen later what are the modifications which such cells undergo so as to produce the mature tissues of the plant, which often differ widely in form and structure from the young cells that give rise to them. From a comparison of cells in various states of division it is possible to construct a connected history of the process (Fig. 11). The nucleus takes the initiative (). By complex changes, which will be described in detail later, it divides into two exactly equivalent parts, which at first lie in the longer axis of the cell, embedded in the still undivided cytoplasm (). Then a delicate film of cell-wall is formed between them, inserted at right angles to the pre-existent walls, cutting the cell into two nearly equal parts, each containing a nucleus (). Such simple divisions are called somatic, belonging to the soma or plant-body, to distinguish them from certain divisions which involve further complications connected with the reproductive process. The number of somatic divisions is indefinite, and the numerous cells to which they give rise are
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