97 



F<jrest Station, The soy-beans, short erect growers in the open, 

 and erect under the glass, but with rel .tively long stems, 

 becone runners in the forest. This effect on stem growth, 

 which obviously cannot be explained by the temperature in 

 the case of these cultures, is relatively very great, the 

 highest alue for the two-week stem elongation being over 4-1/2 

 times the seasonal averag-, and the highest value for the four- 

 week stem elongation being a little less than 4-12 times the 

 seasonal average. The four-week plants also show the same - 

 change in the relative position of the leaf area and dry weight 

 graphs that was shown by the covered plants. The leaf area 

 graph is above the dry weight graph for the entire season. The 

 forest cultures thus show a similarity to the covered cultvires 

 rather than to the exposed. This may be most reasonably ac- 

 counted for by assuming the similarity in the behavior of the 

 plants to be due to a similarity in the light conditions for 

 these two sets of cultiires. 



In the introduction to the discussion of the plant data, 

 it was stated th-^t the main purpose of this experiment was 

 to test the use of plants as instruments for me-^surlng climate. 

 5he feasibility of this method of measuring climatic condi- 

 tions has been urged by Livingston and McLean and by McLeam. " 



V McLean, F. T. , A preliminary study of climatic conditions 

 in Maryland, as related to plant growth. Physiol, Res, 2; 

 129-208, 191V, 



These authors state that the plant growth rates are a result 

 of the total of all the environmental conditions actins? on the 



