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Page:Popular Science Monthly Volume 65.djvu/425

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421
SOME PLANTS WHICH ENTRAP INSECTS.

jection shaped like the tail of a fish. The hood is marked opposite the mouth by a number of translucent spots which some botanist has imagined are false windows, against which entrapped flies bump their heads in a wild effort to escape, being thus diverted from the real opening!

In the swamps and along the streams of the rich tropical forests of Borneo, Java and Ceylon are found the East Indian pitcher-plants (Nepenthes), a group in many ways more highly developed than their American relatives, for there are forty species of them, all plants growing to a considerable size and several of them forming important constituents of the vegetation. PSM V65 D425 Drummond pitcher plant of the south.pngFig. 4. Drummond's Pitcher-plant of the South, with its Covering Lid and Showy Marking. The stem is erect or half-climbing, with long narrow leaves tapering to slender ends, which will twine like a tendril about any supporting twig or stick and then give rise to a single pitcher, or failing to find a support, will fail too to produce the pitcher. In variety of design, brilliance of color and showy contrast of spots and stripes the East Indian pitchers far outdo those of the American plants. They are provided too with elaborate lids and covers which here have a double meaning, for the pitcher is not filled with rain-water, but with a secreted water of its own, which must not be diluted by the rain, as it contains precious substances given out with the water from glands in the bottom of the pitcher. The most important of these substances is a digestive principle much resembling the pancreatic juice of the human stomach; and scarcely less important is a faint trace of hydrochloric acid, without the presence of which the digestive juice can not work, for it is not here for any idle purpose, but for the business of digesting quickly the abundant prey which tropical insect life affords. A fly which falls into a glass of water is often able to escape because the close-set hairs covering its body do not permit it to become thoroughly wet. In the liquid of the pitchers is another substance known as azerin, the property of which is to cause any hairy surface to become quickly wet, which means for the fly sure drowning.