7U 



were grown for a longer time, however, there are fewer cases 

 in the four week periods where the rate of stem elongation is 

 greater than the rate of leaf expansion. In most cases the 

 rate of stem elongration is well below the rate of leaf ex- 

 pansion* This relation again illustrates the teniency of the 

 soy-beans to show a low rate of height growth relative to the 

 rate of leaf expansion vrhen toth rates are large. A conside- 

 ration of the riant graphs with the purpose of bringing out 

 the relation between stem elongation rate and the rate of leaf 

 expansion follows below. 



For Oakland, the stem height g raph is above the leaf 

 area graph for the first three periods of the season and be- 

 low it for the other five neriods. For ^hewsville, the three 

 plant graphs follow each other very closely anci. the differences 

 in their relative positions are probably due, for the most part, 

 to individual variations in the plants of the separate cul- 

 tures. The Monrovia grap s also correspond closely with the 

 (e^fteep t i o n • - e-f- -tfe^—fao-^ that stem height shows a well-defined 

 tendency to remain below leaf area during the first part of 

 the season. For College, the stem height is ";ell below the 

 leaf area for the entire season e: cept for the two periods 

 beginning June 19 and September 25.' The Baltimore graphs 

 show stem height values higher than the corresponding leaf 

 area values in the periods beginning May 14, May 29, June 10, 

 and Aug. 20 dae to low light intensities as shown by the graph 

 of sxinshine intensity. The Darlington cultures show very 

 high values of the plant growth rates with stem height below 

 leaf area for the entire season. For Golsman, the stem height 

 graph remains below the leaf area graph for all the periods ex- 



