CONTENTS vii 



XL v.— ON THERMO-GEOTROPISM. 



PAGE. 



Necessary conditions for geotropic curvature — Modify iuj;; 

 influence of temperature on geotropic curvature — 

 Magnetic analogue — Tropic equilibrium under varying 

 intensities of stimulus — EfEect of variation of tempera- 

 ture on geotropic torsion — Variation of apo-geotropic 

 curvature under thermal change — EfEect of variation 

 of temperature on dia-geotropic equilibrium . . 509 



PART IV. 

 NIGHT AND DAY MOVEMENTS IN PLANTS. 



XLVL— DIURNAL MOVEMENTS IN PLANTS. 



Complexity of tiie problem — The difiEerent factors in- 

 volved — Autonomous movements — Epinasty and hypo- 

 nasty — L'csitive and negative thermouasty — Thermo- 

 geotropism — Classification of diurnal movements — 

 Discriminating tests for classification — Diurnal variation 

 of light and of temperature ..... 523 



XLVIL— DIURNAL MOVEMENT DUE TO ALTERNATION OF 

 LIGHT AND DARKNESS. 



Experimental arrangements — The Quadruples Nyctitropic 

 Recorder — Diurnal movement of the leaflet of Cassia 

 alata — Effect of variation of temperature — Effect of 

 variation of light — Diurnal movement of the terminal 

 leaflet of Desmodium gyrans — The 'midday sleep' . 535 



XL VIII.— DIURNAL MOVEMENT DUE TO VARIATION OF 

 TEMPERATURE AFFECTING GROWTH. 



Tropic and nastic movements — Distinction between thermo- 

 nastic and therrao-geotropic action — Diurnal movement 

 of Nymphcea — Action of light — Efl:ect of variation of 

 temperature 546 



