CONTENTS. ix 



of light do not correspond with its intensity Effects of previous 

 illumination Time required for the action of light After-effects 

 of light Apogeotropism acts as soon as light fails Accuracy 

 with which plants bend to the light This dependent on the 

 illumination of one whole side of the part Localised sensitive- 

 ness to light and its transmitted effects Cotyledons of Phalaris, 

 manner of bending Results of the exclusion of light from their 

 tips Effects transmitted beneath the surface of the ground 

 Lateral illumination of the tip determines the direction of the 

 curvature of the base Cotyledons of A vena, curvature of basal 

 part due to the illumination of upper part Similar results with 

 the hypocotyls of Brassica and Beta Radicles of Sinapis aphelio- 

 tropic, due to the sensitiveness of their tips Concluding remarks 

 and summary of chapter Means by which circumnutation has 

 been converted into heliotropism or apheliotropisrn Page 449-492 



CHAPTER X. 



MODIFIED- CIRCUMNCTATION : MOVEMENTS EXCITED BY 

 GRAVITATION. 



Means of observation Apogeotropism Cytisus Verbena Beta 

 Gradual conversion of tlie movement of circumnutation into 

 apogeotropism in Rubus, Lilium, Phalaris, Avena, and Brassica 

 Apogeotropism retarded by heliotropism Effected by the aid 

 of joints or pulvini Movements of flower-peduncles of Oxalis 

 General remarks on apogeotropism Geotropism Movements of 

 radicles Burying of seed-capsules Use of process Trifolium 

 subterraneum Arachis Amphicarpasa Diageotropism 

 Conclusion 493-522 



CHAPTER XL 



LOCALISED SENSITIVENESS TO GRAVITATION, AND ITS TRANSMITTED 

 EFFECTS. 



General considerations Vicia faba, effects of amputating the tips of 

 the radicles Regeneration of the tips Effects of a short ex- 

 posure of the tips to geotropic action and their subsequent 

 amputation Effects of amputating the tips obliquely Effects 

 of cauterising the tips Effects of grease on the tips Pisum 



