6:j 



the four- week period including the last two we^ks of July and 

 the first two weeks of August, In the case of all stations, 

 this is one of the three four-week periods showing high tem- 

 perature values. The foiir-week climatic graphs, -^ill not be 

 taken up further here, ''^he method by which the four-week 

 data are derived from the two-week data amounts to the same 

 thing as smoothing the two-week graphs and only the more pro- 

 no'inced characteristics of the graphs remain after averaging. 

 The interest of the four-week climatic data thus lies mainly 

 in its relation to the plant growth rates. 



The four-week plant data . 



Relations between the olant measurements . 



Certain general relations were pointed out, in the case 

 of the two-week data, between the stem height and the leaf- 

 product, and mention was also made of the fact th .t the leaf- 

 product numbers showed only slight differences in value from 

 the leaf area and dry weight numbers when the actual growth 

 rates are expressed as in the present study, that is, using the 

 average of all of them as a unit to which to refer the Individual 

 rates. In the four week data, the rate of stem elongation may 

 be compared with the rate of leaf expansion as determined from 

 actual leaf area , instead of with the leaf-product which is 

 used in the discussion of the two-week data as an index of 

 area, '^he comparison between leaf area and stem height for 

 the four-week growth periods shov/s the same general relations 

 as appeared to exist betwe;~n stem-height and leaf-product for 

 the two-week growth periods. Owin? to the fact ihhat the plants 



