LIST OF TEXT ILLUSTRATIONS 



Frontispiece (wood cut portrait of the author and title pace of Lysenko's Theoreticai. 



Bases of Vernalization, 1935) "' 



Title page of Whyte and Hudson's account of Lysenko's vernalization method (1933/ . . . xv 



Title page of Lysenko's first article on "Effect of the Ther- 

 mal Factor on Length of Phases in Development of 

 Plants" 6 



Illustration from Gregory and Purvis' classic "Studies in the 

 Vernalization of Cereals," showing the relation between 



AGE of embryo AT BEGINNING OF VERNALIZATION IN THE EAR, 



and effectiveness of the treatment 34 



Spring rye. Relation between age of embryo at harvesting and 



TIME to antithesis IN RESULTING PLANTS 35 



Composite action spectrum curves showing the energy required 



AT various wave LENGTHS FOR THE SUPPRESSION OF FLORAL IN- 

 itiation in soybean and cocklebur 75 



Phenology of Marquis wheat at Moro, Oregon 130 



Phenology of Marquis wheat in a number of North American 



AREAS ^^^ 



Phenology of four varieties of flax in a number of North 



American areas ^34 



Phenology of Alaska peas at College Park, Maryland, 1925 



AND 1926 136 



Phenology of Alaska peas in a number of North American 



AREAS 13° 



Phenology of Black Beauty eggplants in a number of North 

 American areas 138 



Optimal temperatures of the development of tulip bulbs from 



the time of lifting from the ground to flowering 146 



Optimal temperatures during the development of hyacinth 



148 

 bulbs '■^° 



Actual development of the growing point in tulip and hya- 

 cinth, as a function of storage temperature 149 



Length of the growing point and flower cluster in the hya- 

 cinth, after they have been kept for various lengths of 



time at 11 DIFFERENT TEMPERATURES 150 



Relationship between stem growth rate and temperature of 



1 54 

 tomato plants '■-'^ 



Relations between (night) temperature and (1) total growth 

 of intact plants, (2) direct effect on stem elongation, (3) 

 growth of isolated roots, and (4) translocation 156 



Photoperiodische Reaktion finer Kurztagpflanze (Chrys- 

 anthemum) 1°' 



Photoperiodische Reaktion finer Langtagpflanze (Hyoscyamus 



niger) 1^8 



Regulierung finer endogenen Rhythmik und der Blattbewe- 



gung durch einen Lichtreiz bei Kurztagpflanzen 170 



Regulierung einer endogenen Rhythmik und der Blattbewe- 



gung durch einen Lichtreiz bei Langtagpflanzen 171 



WiRKUNG FINES WAHREND DER DUNKELPHASE GEBOTENEN ZuSATZ- 



lichtes auf die Blutenbildung der Kurztagpflanze Kalan- 



cho'e blossfeldiana 172 



Die Langtagpflanze Hyoscyamus niger bluht, wenn zum Kurz- 



