. The power of movement in plants . Plants; Botany. Chap. VII. SLEEP OF LEAVES. 375 Tafftun^A- A filament had been fixed on the previous evei jng, longi- tudinally to the main petiole of a nearly fuU-growli, highly- sensitive leaf (four inches in length), the stem having been secured to a stick at its base; and a tracing was made on a vertical glass in the hot-house imder a high temperatiu-e. Id the flgu re given (Pig. 157), the first dot was made at ''^'k- ^57. August 2nd, and the last at 7 on the 3rd. During 12 h. on the first day the petiole moved thrice downwards and twice u
. The power of movement in plants . Plants; Botany. Chap. VII. SLEEP OF LEAVES. 375 Tafftun^A- A filament had been fixed on the previous evei jng, longi- tudinally to the main petiole of a nearly fuU-growli, highly- sensitive leaf (four inches in length), the stem having been secured to a stick at its base; and a tracing was made on a vertical glass in the hot-house imder a high temperatiu-e. Id the flgu re given (Pig. 157), the first dot was made at ''^'k- ^57. August 2nd, and the last at 7 on the 3rd. During 12 h. on the first day the petiole moved thrice downwards and twice upwards. Within the same length of time on the second ^'^o'^-^- day, it moved five times down- wards and four times upwards. As the ascending and descend- ing lines do not coincide, the petiole manifestly circumnu- tates; the great evening fall and nocturnal rise being an exaggeration of one of the cir- cumnutations. It should, how- ever, be observed that the pe- tiole fell much lower down in the evenings than could be seen on the vertical glass or is represented in the diagram. After 7 on the 3rd (when the last dot in Fig. 157 was made) the pot was carried into a bed-room, and the petiole was found at ( after midnight) standing almost up- right, and much more highly inclined than it was at 4 it had begun to fall, and continued falling till , after which hour it zigzagged and again circumnutated. Similar observations were made on another petiole, with nearly the same result. On two other occasions the movement of the main petiole 25. „/>,.«.3«' e° When observed again at -^^^osi pmKca: ani nyctitropio movement or main pe- tiole, traced during 34 h. 30 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,
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Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
