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Show X CONTENTS. t' Im tips of radicles cauterised transversely, and on their sa lVt 'd lower sides-Phaseolus, cauterisation and grease on uthpep ert.l pans -Go ssypm. m-Cucurbita' tips cauterised tra· nsvercse ly, and on their upper and lower sides-Zea, tips cautensed- on- 0 1 d' rr remarks and summary of chapter-Advantages of the u ~bn.?l.ty to geotropism being localised in the tips of the sens1 1 1 Page 23-545 radicles .. " " ·· " ·· CHAPTER XII. SuMMARY AND CoNOLUDING REMARKS. Nature of the circumnutating movement-Hi~tory of a gcrminati~g seed-'l'he radicle first protrudes and cucumnutates-I~s tip highly sensitive-Emergence of the hypocotyl or ?f the epiCo~yl from the ground under the form of an ar~h-Its cucumnutatwn d that of the cotyledons-The seedlmg throws up a leaf~~ aring stem-The circumnutation of all the parts or organsModified circumnutation-Epinasty and hyponasty-Movem:nts of climbing plants-N yctitropic moveme~t~-Movements exmted by light and gravitation-Localised sens1tiveness-Res~mblancc between the movements of plants and animals-The tip of the radicle acts h.k e a br am. 546-573 lNDEX •• 574-593 ERRATA. Page 3, foot-note, for Mr. Vine's read Mr. Vines': , 452, line 7 from bottom, for minntes read mmutes. THE MOVEMENTS OF PLANTS. INTRODUCTION. THE chief object of the present work is to describe and connect together several large classes of movement, common to almost all plants. The most widely prevalent movement is essentially of the same nature as that of the stem of a climbing plant, which bends successively to all points of the compass, so that the tip revolves. This movement has been called by Sachs "revolving nutation;" but we have found it much more convenient to use the terms circumnutation and circ,umnutate. As we shall have to say much about this movement, it will be useful here briefly to describe its nature. If we observe a circumnutating stem, which happens at the time to be bent, we will say towards the north, it will be found gradually to bend more and more easterly, until it faces the east; and so onwards to the south, then to the west, and back again to the north. If the movement had been quite regular, the apex would have described a circle, or rather, as the stem is always growing upwards, a circular spiral. But it generally describes irregular elliptical or oval figures; for the apex, after pointing in any one direction, commonly moves back to the opposite side, not, however, returning along the same line. Afterwards other irregular ellipses or ovals are successively described, with their longer B |
