. A manual of structural botany; an introductory textbook for students of science and pharmacy. Plant morphology. ETIOLATED LEAVES 193 sition. Upon the outer portion of the pitcher a line of glandular tissue stretches downward. The insect feeds upward along this line of secre- tion, which so changes its nature toward the top of the pitcher, that by the time the insect reaches that point he is more or less intoxi- cated, and on crossing the margin, or quickly thereafter, falls into the liquid and is drowned, digestion promptly occurring by means of enzymes excreted into the liquid by special gl
. A manual of structural botany; an introductory textbook for students of science and pharmacy. Plant morphology. ETIOLATED LEAVES 193 sition. Upon the outer portion of the pitcher a line of glandular tissue stretches downward. The insect feeds upward along this line of secre- tion, which so changes its nature toward the top of the pitcher, that by the time the insect reaches that point he is more or less intoxi- cated, and on crossing the margin, or quickly thereafter, falls into the liquid and is drowned, digestion promptly occurring by means of enzymes excreted into the liquid by special glands located upon the inner face of the Fig. 560. Modified (pitcher) leaf of Nepenthes. 561. Modified leaf of Dionaea The Venus's Fly-trap.—Another form is the well-known Venus's fly-trap (Fig. 561), which secretes a nectar by certain glands which surround its margin. The insect, alighting upon this point, is instantly seized through the spasmodic coming together of the two lateral halves of the leaf, which act precisely like the jaws of a trap. Digestive fluids are then immediately poured forth from special glandular tissues on the leaf-surface and digestion and absorption take place. That the nutrients thus absorbed are of service to the plant has been proved by elaborate experiments, in which the effects of such feeding have been estimated by comparing their reproduction with that of other similar plants, similarly treated in all respects except that they were deprived of this form of food. Etiolated Leaves.—In other cases, the plant being nourished by means of fully prepared nutrients absorbed from other leafy plants (host-plants) upon which they are parasitic, the leaves lose the chloro- phyll tissue upon which their ordinary functions depend, and are known as Etiolated leaves. They become reduced in size and scale-like in form. 13. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - col
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