85- 



the relative value of the leaf-product is 138. l^'or Easton 

 the leaf-product is lower than would be expected for the peridd 

 beginning Aug. 17 and for Princess Anne, the nlant values for 

 the period beginning Aug. 8 are much lower than for the oeriod 

 beginning July 7 which had approximately the ssme climatic 

 conditions as the frTst inentioned oeriod. 



A third peculiarity of the graphs that cannot be corre- 

 lated with the climatic data is that the stem height reaches 

 its highest value for the season before the leaf-product for 

 all station except Sarlington and loleman. "^or "Darlington, 

 the highest value for stem height and leaf-product both come 

 in the period beginning July 10 and for Coleman the maximum 

 value for stem height comes in the period beginning July 22 

 while the leaf-prodcut reaches its highest value for the 

 season at this station in the preceeding period. At the re- 

 maining sta-^ions, the highest value of stem height occurs two 

 weeks or a month earlier than the highest value of leaf-pro- 

 duct. 



The foregoing discussion of the two-week data empha- 

 sizes the obvious fact that the problem of corjslating the plant 

 and climatic measurements is an exceedingly complicated one. 

 Assuming that the conditions of the experiment give approxi- 

 mately constant root environment, the plant growth rates are 

 a function not only of the climatic factors, three of which 

 are measured for these studies, but of the conditions within 

 the plant as well, TJ'e do not a^^ present know how to measure 

 these internal conditions. The g^rowth rate is thus a function 

 of a number of variables some of which are known and some un- 

 known. The object of the preceeding discussion has been sim- 



