CONTENTS XV 



Section V Growth Factors and Flowering 



The Influence of Gibberellin and Auxin on Photoperiodic 



Induction, by Anton Lang 329 



Some Aspects of Photothermal and Chemical Control of 



Growth and Flowering, by Faust o Lona 351 



Influence of Gibberellic Acid on the Flowering of Xanthium 

 in Relation to Number of Induction Periods, by Victor A . 

 Greulach and John G. Haesloop 359 



Effects of Gibbereflin and Amo-1 61 8 on Growth and Flower- 

 ing of Chrysanthemum morifolium on Short Photoperiods, 

 by Henry M. Cathey 365 



Effects of Gibberellin on the Photoperiodic Responses of 

 Some Higher Plants, by S. H. Wittwer and M. J. Bukovac 373 



Influence of Certain Growth Regulators on Flowering of the 



Cocklebur, by Frank B. Salisbury 381 



Some Interrelations of Compensatory Growth, Flowering, 

 Auxin, and Day Length in Coleus blumei Benth, by 

 W. P. Jacobs, Robert V. Davis, Jr., and Bob Bulhvinkel 393 



Section VI Analysis of Plant Photoperiodism 



Chemical Nature of the Inductive Processes, by James 



Bonner 411 



The Photoreaction and Associated Changes of Plant Photo- 

 morphogenesis, by Sterling B. Hendricks 423 



A Kinetic Analysis of Photoperiodism, by R. B. Withrow 439 



Section VII The Relation of Light to Rhythmic 

 Phenomena in Plants and Animals 



Daily Rhythms as Coupled Oscillator Systems and Their Re- 

 lation to Thermoperiodism and Photoperiodism, by Calvin 

 S. Pittendrigh and Victor G. Bruce 475 



Physiological Mechanism and Biological Importance of the 

 Endogenous Diurnal Periodicity in Plants and Animals, 

 by Erwin Biinning 507 



