. The power of movement in plants . Plants; Botany. (Jhap. Vm, HELIOTROPISM. 42£ manner over nearly the same space, and a figure formerly given is here reproduced (Fig. 172). If the hypocotyl is exposed to a moderately strong lateral light it moves quickly towards this side, travelling in a straight, or nearly straight, line. But when the lateral light is very dim its course is extremely tortuous, and evidently consists of modified circunmutation. Seedlings were placed before a north-east window, protected by a linen and muslin blind and by a towel. The sky was cloudy, and when- ever the cloud
. The power of movement in plants . Plants; Botany. (Jhap. Vm, HELIOTROPISM. 42£ manner over nearly the same space, and a figure formerly given is here reproduced (Fig. 172). If the hypocotyl is exposed to a moderately strong lateral light it moves quickly towards this side, travelling in a straight, or nearly straight, line. But when the lateral light is very dim its course is extremely tortuous, and evidently consists of modified circunmutation. Seedlings were placed before a north-east window, protected by a linen and muslin blind and by a towel. The sky was cloudy, and when- ever the clouds grew a little lighter an additional muslin blind was temporarily suspended. The light from the window was Fig. Brassica oleracea ordinary circumnutating mcvement of the hypoeotyl of a seedling plant. thus so much obscured that, judging by the unassisted eye, the seedlings appeared to receive more light from the interior of the room than from the window; but this was not really the case, as was shown by a very faint shadow cast by a pencil on a card. Nevertheless, this extremely small excess of light on one side caused the hypocotyls, which in the morning had stood upright, to bend at right angles towards the window, so that in the evening (after 423 ) their course had to be traced on a vertical glass parallel to the window. It should be stated that at , by which time the sky had become darker, the towel was removed and replaced by an additional muslin blind, which itself was removed at 4 , the other two. 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 : D. Appleton
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Keywords: ., bookcentury1800, booksubjectbotany, booksubjectplants, bookyear18
