TABLE OF CONTENTS XIX 



IV. Dorsiventrality, Polarity, and Anisotropy in Plant Organs, and 

 Phenomena of Correlation 



PAGE 



192. Dorsiventrality 503 



193. Polarity 505 



194. Anistropy 509 



195. General Considerations respecting the Eigidity of Plant Structures . 518 



196. The Arrangement of the Mechanical Tissues in Structures Resistant 



to Fluxion Tension and Pressure 523 



197. Correlation 525 



V. Movements of Variation 



198. Experiments with Acacia Lophanta 527 



199. Experiments with Phaseolus Multiflorus 528 



200. Experiments with the Lever Dynamometer 532 



201. Experiments with Mimosa Pudica and other Plants .... 534 



202. Movements of Variation in Mimosa Pudica evoked by Shock or 



Contact . . .'-'-' 536 



203. Further Movements of Variation evoked by Shock and Contact . 538 



204. Spontaneous Movements of Variation 539 



205. The Influence of External Conditions on some Movements of Varia- 



tion ,540 



