. A manual of botany. Botany. 328 MANUAL OP BOTANY Fig. 702. being known as the piliferoics layer. In the roots of Mono- cotyledons and Cryptogams the true epidermis only persists at the apex, forming as before a many-layered root-cap. The rest of the root bears a piliferous layer, but it is in these cases the external layer of the periblem. The external layer of roots is consequently not a true epi- dermis ; it is generally termed the epiblema. The cells of the dermatogen are somewhat oblong when seen in section, and are usually rich in protoplasm. As they grow older the walls become thickene
. A manual of botany. Botany. 328 MANUAL OP BOTANY Fig. 702. being known as the piliferoics layer. In the roots of Mono- cotyledons and Cryptogams the true epidermis only persists at the apex, forming as before a many-layered root-cap. The rest of the root bears a piliferous layer, but it is in these cases the external layer of the periblem. The external layer of roots is consequently not a true epi- dermis ; it is generally termed the epiblema. The cells of the dermatogen are somewhat oblong when seen in section, and are usually rich in protoplasm. As they grow older the walls become thickened, especially on the outer siu:- faoe [fig. 702). Viewed from the surface Fig. 702. TransTerse section of ^j^g present a great variety of outhne. the petiole of a species of "^ ^ ^ •' Begonia, e. Epidermis with The thickened walls become outicu- variable extent, par- ticularly their outer layers. In very thick-walled cells these outer cuticu- Generai parenchyma, beioV larised layers can often be stripped off liypoderma. After Sjichs. •^ „ ^ , , , , , formmg a sort of detachable structure- less membrane, termed the cuticle (fig. 706). When the cells become adult they lose a great deal of their protoplasmic contents. Fie. 703. Fig. 704. r°g°=°^^^©r. cuticle above and hypoderma i • j . below, the latter formed of iansea 10 a collerichymatous cells cl, c7, with thickened angles v, v. chl. Chlorophyll granules, p. "^P^^^S^^m^^^ Ol^. 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 Green, J. Reynolds (Joseph Reynolds), 1848-1914. London, J. & A. Churchill
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