Charles Darwin's Works: The power of movement in plantsD. Appleton, 1896 - Science |
Common terms and phrases
apex apheliotropic apogeotropism arched basal bean became bend beneath the horizon blade bowed Brassica oleracea Cassia cause caustic cauterised circum circumnutating movement close coty cotyl course curvature curved damp darkness deflected described dicotyledonous direction diurnal position ellipses epicotyl exposed figure following morning geotropism glass filament ground growing growth heliotropic horizontal glass hypocotyl hypogean illuminated inch in height inch in length inclined lateral leaflets lateral light leaf leaves ledons Leguminosa magnified main petiole manner ment Mimosa pudica move nearly nocturnal nutation nyctitropic movements observed original scale Oxalis peduncle perpendicular petiole Phalaris plumule position pulvinus radicles right angles rise rose Sachs seed seed-coats seedlings sensitive shellac shown side sink sleep slightly species squares of card stem stolon stood straight summit temperature terminal leaflet tips traced Trifolium tropism upper surfaces upright upwards vertical glass Vicia faba whilst Würzburg young leaf zigzag zigzag line
Popular passages
Page 474 - We must therefore conclude that when seedlings are freely exposed to a lateral light some influence is transmitted from the upper to the lower part, causing the latter to bend.
Page 573 - It is hardly an exaggeration to say that the tip of the radicle thus endowed, and having the power of directing the movements of the adjoining parts, acts like the brain of one of the lower animals...
Page 573 - Echinoeystis, or excited by gravitation the same part bends towards the centre of gravity. In almost every case we can clearly perceive the final purpose or advantage of the several movements.
Page 572 - We believe that there is no structure in plants more wonderful, as far as its functions are concerned, than the tip of the radicle. If the tip be lightly pressed or burnt or cut, it transmits an influence to the upper adjoining part, causing it to bend away from the affected side; and, what is more surprising, the tip can distinguish between a slightly harder and softer object, by which it is simultaneously pressed on opposite sides. If, however, the...
Page 224 - Ortegesii behaved differently from that of 0. sensitiva, for it stood at a less angle above the horizon in the middle of the day, than in the morning or evening. By 10.20 PM it had risen greatly. During the middle of the day it oscillated much up and down.
Page 558 - The flowerpeduncles are likewise continually circumnutating. If we could look beneath the ground, and our eyes had the power of a microscope, we should see the tip of each rootlet endeavoring to sweep small ellipses or circles as far as the pressure of the sur1 p.
Page 572 - Finally, it is impossible not to be struck with the resemblance between the foregoing movements of plants and many of the actions performed unconsciously by the lower animals. With plants an astonishingly small stimulus suffices ; and even with allied plants one may be highly sensitive to the slightest continued pressure, and another highly sensitive to a slight momentary touch. The habit of moving at certain periods is inherited both by plants and animals ; and several other points of similitude...
Page 266 - These are usually inclined at about 45° above the horizon, but they stiffen and straighten themselves so as to stand upright in a part of their circular course ; namely, when they approach and have to pass over the summit of the shoot from which they arise. If they had not possessed and exercised this curious power, they would infallibly have struck against the summit of the shoot and been arrested in their course. As soon as one of these tendrils with its three branches begins to stiffen itself...
Page 572 - But the most striking resemblance is the localisation of their sensitiveness, and the transmission of an influence from the excited part to another which consequently moves. Yet plants do not of course possess nerves or a central nervous system ; and we may infer that with animals such structures serve only for the more perfect transmission of impressions, and for the more complete intercommunication of the several parts.
Page 573 - ... in accordance with its importance for the life of the plant. The course pursued by the radicle in penetrating the ground must be determined by the tip ; hence it has acquired such diverse kinds of sensitiveness. It is hardly an exaggeration to say that the tip of the radicle thus endowed, and having the power...