Elements of Structural and Systematic Botany

numerous cavities or chambers separated by delicate partitions. Often these cavities are of sufficient size to be visible to the naked eye, and examined with a hand lens the section a

en of the common spiderwort (Tradescantia), ×

cell (Fig. 1) is an oblong sac, with a delicate colorless wall which chemical tests show to be composed of cellulose, a substance closely resembling starch. Within this sac, and forming a lining to it, is a thin layer of colorless matter containing many fine granules. Bands and threads of the same substance traverse the cavity of the cell, which is filled with a deep purple homogeneous fluid.

own as the cell wall, and in young plan

part of the cell. If sufficiently magnified, the granules within the protoplasm will be seen to be in active streaming motio

without a cell wall. n, n

the bodies of the highest plants and animals are composed. We shall find that the cells may become very much modified for vari

d C, hairs consisting of a row of cells. The terminal rounded cell secretes a pec

cavities (vacuoles, v) filled with cell sap, but no cell wall. The protoplasm is in constant movement, and by extensions of a portion of the mass and contraction of other parts, the whole creeps slowly along

ts cellular structure. Ep. epidermis. h, a hair, × 50. C, a cell from the prothallium (young pl

m receding from the wall (Fig. 4, C), showing that it is normally in a state of tension due to pressure from within of the cell sap. The cell wall shows the same thing though in a less degree, owin

rgans of the higher plants. The simplest tissues are rows of cells, such as form the hairs covering the surface of the organs of many flowering plants (Fig. 3), and are due to a di