Text-book of botany, morphological and physiological . icker-walled, while their walls assume a deeper red colour; the outermost layeroften produces numerous long root-hairs (Fig. 69). In the Bog-mosses (Sphagnum), on the G Sz MORPHOLOGY OF TISSUES. other hand, one outermost layer of cells of the stem, or 2-4 such, assume an entirelydifferent character. These cells (Fig. 70, e) have thin coloured walls, they are muchbroader than those of the inner tissue ; the walls sometimes show thin thickening-bandsrunning in a spiral manner, and open externally by large orifices, being also in com-municati
Text-book of botany, morphological and physiological . icker-walled, while their walls assume a deeper red colour; the outermost layeroften produces numerous long root-hairs (Fig. 69). In the Bog-mosses (Sphagnum), on the G Sz MORPHOLOGY OF TISSUES. other hand, one outermost layer of cells of the stem, or 2-4 such, assume an entirelydifferent character. These cells (Fig. 70, e) have thin coloured walls, they are muchbroader than those of the inner tissue ; the walls sometimes show thin thickening-bandsrunning in a spiral manner, and open externally by large orifices, being also in com-munication with one another by similar orifices (/), In the fully developed conditionthey contain only air or water, which rises in them as in an actual capillary this epidermal tissue the stem is similar to that of Mosses; the cells becometowards the surface gradually narrower, thicker-walled, and of a darker colour. Asimilar epidermal layer, and with similar hygroscopic properties, occurs in the aerial rootsof Orchids and of some FIG. 70.—Transverse section of the stem of Sj>hagnu77icymbifoliunt (X900); x inner cells with colourless soft wallsj/ cortical cells, becoming gradually narrower and thicker-walled towards the surface ; e e the epidermal layer; / orificesthrough which the opposite cells communicate with oneanother. Fig. 71.—Piece of a radial transverse section through the sporangium oiFitnaria hygrotnetrica (X300); e epidermis; the thickblack streak at its circumference is the cuticle. (For further explanation of the fig. see Book II.)
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
