1917] Ayres: Nutrient Solution on Plantu Grown in Sand Cultures 355 



.1.2,3N5|l,2h|4|.5|l,2.3|4l5|l,2|5|4|3 



45 1 



34 



25 



45 



1 ?3 4l.5lll2l3l4l5lll2l5|4|5 



Group \ 



B C 



Series I 



D 



A 



B C 



Series II 



D 



B c 



Series III 



D 



Fig. 4. — Diagraniinatic representation of the number of flowers produced 

 by each plant in series I, II, and III. 



Flower Production in Series I 



The nitrogen supply is seen to have a very definite influence 

 upon flower production. In series I no flowers were produced 

 by plants 1 and 2 of any group and in only two groups were 

 any flowers produced by plant 3, showing definitely that unless 

 nitrogen is present in excess of 0.05 per cent as NaNO., the under- 

 nourished tobacco plant will not flower. Flower production in 



