. The power of movement in plants. Plants; Botany. Ghap. VII. SLEEP OP LEAVES. 379 altlLOUgh. the proper order of their movements in relation to the day and night was wholly lost. Thus, one leaf descended during the iirst two nights ( between 10 and 7 next morn- ing) instead of ascending, and on the third night it moved chiefly in a lateral direction. The second leaf behaved in an equally abnormal manner, moving laterally during the first night, descending greatly during the second, and ascending to an unusual height during the third night. With plants kept at a high temperature
. The power of movement in plants. Plants; Botany. Ghap. VII. SLEEP OP LEAVES. 379 altlLOUgh. the proper order of their movements in relation to the day and night was wholly lost. Thus, one leaf descended during the iirst two nights ( between 10 and 7 next morn- ing) instead of ascending, and on the third night it moved chiefly in a lateral direction. The second leaf behaved in an equally abnormal manner, moving laterally during the first night, descending greatly during the second, and ascending to an unusual height during the third night. With plants kept at a high temperature and exposed to the light, the most rapid circumnutating movement of the apex of a leaf which was observed, amounted to -g^ of an inch in one second; and this would have equalled ^ of an inch in a minute, had not the leaf occasionally stood still. The actual distance travelled by the apex (as ascertained by a measure placed close to the leaf) was on one occasion nearly | of an inch in a vertical direction in 15 m.; and on another occasion |- of an inch in 60 m.; but there was also some lateral movement. Mimosa albida*—The leaves of this plant, one of which is here figured (Fig. 159) reduced to f of the natural size, present soma Fig. Mimosa albida ; leaf seen from vertioally above. interesting peculiarities. It consists of a long petiole bearing only two pinnae (here represented as rather more divergent than is usual), each with' two pairs of leaflets. But the inner * Mr. Thistleton Dyer informs us that this Peruvian plant (whii'h was sent to us from Kew) is con- sidered by Mr. Bentham (' Trims. Linn. Soo.,' vol. xxx. p. 390) to be " the species or variety whicli most commonly represents the M seiisitiva of our ;. 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
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Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
