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 

 tima 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 19 th 

 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 nornial 

 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 PE. ranging from 6 per 

 cent, to S-g- per cent. The discussion of leaf-form, however, 

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

 even phylogenetic 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 



