. Plant life, considered with special references to form and function. Plant physiology. Fig. 13.—Nostoc. A^ a pelatinuus cnlnny, irre^'ularly liibed. Natural size. />, a portion of a serpentine filament witli five heterucysts (one at each end by which it was separated from the rest of the cells composing the filament, and three inter- mediate ones) and the jelly belonging to it. Magnified about 400 diam.—After Thuret and Janczcwski. ' broken up into any number of pieces and each piece will retain all its powers. Here and there in the chain there occur cells unlike the rest {h, fig. 14), ca
. Plant life, considered with special references to form and function. Plant physiology. Fig. 13.—Nostoc. A^ a pelatinuus cnlnny, irre^'ularly liibed. Natural size. />, a portion of a serpentine filament witli five heterucysts (one at each end by which it was separated from the rest of the cells composing the filament, and three inter- mediate ones) and the jelly belonging to it. Magnified about 400 diam.—After Thuret and Janczcwski. ' broken up into any number of pieces and each piece will retain all its powers. Here and there in the chain there occur cells unlike the rest {h, fig. 14), called heterocysts, whose function seems to be to break the chain into pieces, from the growth of which independent colonies may arise. The association of considerable numbers of these plants in colonies gives rise to masses of jelly which vary from the size of a pin-head to 2—5 centimeters in diameter. They may be found adhering to water-weeds as clear- or dirty-green masses, or sometimes floating free (A, fig. 13). 14. Filaments of loose organization.—Of very near kin to these plants are the oscillarias, which have received this name from the pendulum-like swinging of tlieir tips (fig. 15). In them the cells remain connected more extensively and more firmly, so that each is disk-shaped, and the filament is much less easily separated into its component cells. More-. 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 Barnes, Charles Reid, 1858-1910. New York, H. Holt & company
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