. The power of movement in plants. Plants; Botany. Chap. Vll. SLEEP OF LEAVES. 38£ derable angle bbneath the horizon at 10 In the case of fonr youngish leaves, which were from 2 to 2 J inches in length, these angles were found to be 50°, 56°, 60°, and 65°. At the end of August, when the plants had grown to a height of 10 to 11 inches, the younger leaves were so much curved downwards at night that they might truly be said to be asleep. This is one Fig. Nicotiana glanca; shoots with leaves expanded during the day, and asleep at night. Figures copied from photographs, and reduced. of t
. The power of movement in plants. Plants; Botany. Chap. Vll. SLEEP OF LEAVES. 38£ derable angle bbneath the horizon at 10 In the case of fonr youngish leaves, which were from 2 to 2 J inches in length, these angles were found to be 50°, 56°, 60°, and 65°. At the end of August, when the plants had grown to a height of 10 to 11 inches, the younger leaves were so much curved downwards at night that they might truly be said to be asleep. This is one Fig. Nicotiana glanca; shoots with leaves expanded during the day, and asleep at night. Figures copied from photographs, and reduced. of the species which must be well illuminated during the day in order to sleep, for on two occasions when plants were kept all day in a room with north-east windows, the leaves did not sleep at night. The same cause probably accounts for the leaves on our seedlings raised in the dead of the winter not Bleeping. Professor Pfeffer informs us that the leaves oi another species (<S. JoruUensis ?) hang vertically down at 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 Darwin, Charles, 1809-1882; Darwin, Francis, Sir, 1848-1925. New York, Appleton
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Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
