CONTENTS. IS 



of light do not correspond with its intensity — Etticts of previonii 

 illumination — Time required for the action of light — After-offects 

 of light — Apogeotropism acts as soon as light fails — Accuracy 

 with which plants benft to the light — This dependent on th<3 

 ijlumination of one whole side of the pait — 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 s>irface 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 — Eadicles of Sinapis aiihelio- 

 tropic, due to the sensitiveness of their tips — Concluding remarks 

 and summary of chapter — Means by which circumnuiatidu has 

 been converted into hel iotropism or apheliotropism Page 44 9-i3'A 



CHAPTEE X. 



Modified Cibcumndtation : Movements excited by 

 Gravitatios. 



Means of observation — Apogeotropism — Cytisns — Verbena — Beta 

 - — Gradual conversion of tlie movement of ciicummitation into 

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

 — Apogeotropism retarded by heliotropism — Effected by the aid 

 of joints or pulvini — Movements of flowt-r-peduncles of Oxalis — 

 General remarks on apogeotropism — Geotropism — Movements of 

 radicles — Burying of seed-capsules — Use of process — Trifolium 

 subterraneum — Arachis — Amphicarpaja — Diageotropism — 

 Conclusion 493-522 



CHAPTEE XL 



Localised Sensitiveness to Gravitation, and its TBANSMiTTBft 

 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 geotro]'io action and their subsequent 

 amputation — Kflects of amputating the tips obliquely — Kff'ects 

 of cauterising the tips — Effects of grease on the tips — Pisum 



