. Nature-study; a manual for teachers and students. Nature study. LESSONS WITH PLANTS 339 ditches, may be shown with the compound miscroscope. These httle uniceHular plants ha\-e the power of locomotion. On moist earth in ditches there is often a coating of bluish- green alg;ie, the Oscillatoria, which also have some power of movement. There arc spore-cells set free by man}- plants that swim acti\elv about, and are reproductive devices. Though the larger plants may not move about, yet they can move their various parts. A few observations on growing plants will show them to be thoroughly alive
. Nature-study; a manual for teachers and students. Nature study. LESSONS WITH PLANTS 339 ditches, may be shown with the compound miscroscope. These httle uniceHular plants ha\-e the power of locomotion. On moist earth in ditches there is often a coating of bluish- green alg;ie, the Oscillatoria, which also have some power of movement. There arc spore-cells set free by man}- plants that swim acti\elv about, and are reproductive devices. Though the larger plants may not move about, yet they can move their various parts. A few observations on growing plants will show them to be thoroughly alive and active. In a glass germinator ("see p. 300) notice how the roots of seedlings crrow do\A'n. Invert the o germinator. Note that in a day or so the roots have turned and now grow downward again. They seem to know enough to grow down. Note also how a rootlet bends away from and around an obstruction, such as a pebble placed in its course. The root is sensitive to touch and responds by a curvature. Plant a sunflower or other seedling in the drain hole of a small flowerpot full of earth and hang it up somewhere. Note that soon the stem curves upward. The same may be shown. Fig. 136. Squash Seedling Laid on its Side has Straightened up 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 Holtz, Frederick Leopold, 1870-. New York, C. Scribner's Sons
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