Page:Popular Science Monthly Volume 67.djvu/186

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180
POPULAR SCIENCE MONTHLY.

pressure from without. A little worm or insect, or even a very small fish, can pass within, but never back again. The sack acts like an ell trap or a catch-'em-alive mouse trap. These little sacks actually allure very small animals by displaying glandular hairs about the entrance. The small animals are imprisoned and soon perish and decay to nourish the wicked plant.

Fig. 2. Bladderwort, Ulricularia vulgaris, a Floating Aquatic, the Flowers, at least are protected from Crawling Insects. (Slightly reduced.)

It is not the purpose of these pages to go into details regarding the methods of insectivorous plants, but to tell how plants defend or protect themselves.

When scattered by Bursting Pods, the Seeds are seldom found by Animals.—When mature, the pistils of certain plants burst quickly and with considerable force, scattering the seeds in every direction. The small size and the inconspicuous colors of the seeds make it certain that few of them will ever be found and destroyed by insects or mice. Plants of this kind are euphorbias or spurges, violets, peas, beans, witch hazel, castor-oil plants, balsams and many more.

The bearded chaff enclosing the grains of porcupine grass and wild