v FLUCTUATION 95 



height on July 4th, two months previously, there was a 

 marked negative correlation; r= 0'67, on 31 pairs: 

 plants which had been short in July possessed long leaves 

 in September. The height on September 12th at the 

 time of leaf measurement showed a small positive 

 correlation, while August 1st gave a transition stage 

 with no correlation at all. These data have obviously 

 some bearing on the -inter-play of root upon shoot, and 

 conversely. 



The correlation of height on July 4th with the data of 

 the first flower which varied in one series from June 19th 

 to July 28 is definitely curvilinear. Plants which were 

 stunted, and are therefore still short, flower proportionately 

 late, but this correlation vanishes after passing the mean 

 height, all the normal and super-normal plants flowering 

 at approximately the same time. Here we are probably 

 dealing with the data of initiation of the flowering-branch 

 buds. 



The correlation of early height with total flower- or boll- 

 production is also close, and becomes less distinct as we 

 pass to later height. This is effectively a statement that 

 stunted plants, even if they grow up later to normal 

 height, cannot produce a crop of normal size. This effect 

 of stunting acts partly through the delayed first-flower. 



The leaf. Fluctuation in absolute size of the leaf, as 

 expressed by measuring the length of the mid-rib, is 

 obviously complex. The correlation with stem-height, 

 previously mentioned, will serve to illustrate this. Still, even 

 leaf-length is tolerably definite, the P. E. ranging from 6 per 

 cent, to 3j per cent. The discussion of leaf- form, however, 

 introduces us to a new set of factors, of ontogenetic, or 

 even p.hylogenetic nature. The first leaf of the seedling 

 plant is entire, even when adult ; later leaves became 

 progressively more elaborate even when first unfolded, 

 until the five segmented typical leaf is reached. The 

 form assumed is nevertheless not independent of the 



