. The power of movement in plants . Plants; Botany. Chap. IV. DICOTYLEDONS. 229 was deflected, so that the filament projected almost horizontally, and its movements were traced during 48 h. on a vertical glass, as shown in the accompanying figure (Fig. 95). We here plainly see that the leaf was con- tinually circunmutating; _ ^u but the proper periodicity 6«je<«'v of its movements was dis- \ \ turbed by its being only dimly illuminated from above through a double skylight. We infer that this was the case, because two leaves on plants grow- ing out of doors, had their angles above the
. The power of movement in plants . Plants; Botany. Chap. IV. DICOTYLEDONS. 229 was deflected, so that the filament projected almost horizontally, and its movements were traced during 48 h. on a vertical glass, as shown in the accompanying figure (Fig. 95). We here plainly see that the leaf was con- tinually circunmutating; _ ^u but the proper periodicity 6«je<«'v of its movements was dis- \ \ turbed by its being only dimly illuminated from above through a double skylight. We infer that this was the case, because two leaves on plants grow- ing out of doors, had their angles above the horizon measured in the middle of the day and at 9 to about 10 on succes- sive nights, and they were found at this latter hour to have risen by an average angle of 9° above their mid-day position: on the following morning they fell to their former position. Now it may be observed in the diagram that the leaf rose during the second night, so that it stood at higher than at on the preceding night; and this may be attributed to the leaf adjusting itself to the dim light, coming exclu- sively from above. (4.) Brassica oleracfa (Cruciferse).—Hoftneister and Batalin " state that the leaves of the cabbage rise at night, and fall by day. We covered a young plant, bearing 8 leaves, under a large bell-glass, placing it in the same position with respect to the -•.S0';^. g:sitam,.8dm Crimhe maritima: circumnutation of leaf, disturbed by being insuffioiently illumi- nated from above, traced from June 23rd to 8 25th. Apex of leaf 151 inches from the vertical glass, so that the tracing was much magnified, but is here reduced to one-fourth of original scale. » ' Flora," 1873, p. 437. 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
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Keywords: ., bookcentury1800, booksubjectbotany, booksubjectplants, bookyear18
