4i6 



BOTANICAL GAZETTE 



[DECEMBER 



The leaf areas ranged from ii .32 sq. dm. in plant no. 6, which 

 gave the highest losses throughout (fig. 16), to 6.47 sq. dm. in 

 no. II, where the transpiration losses are among the lowest. A 

 good correlation existed between leaf area and the magnitude of 

 the losses. To avoid confusing a multiplicity of lines, data from 

 five of the maples have been omitted in this figure. The data of 

 these five trees are very similar to those shown. 



TABLE VII 

 Total losses (in gm.) from 12 maple trees from November 2 to May i 



* All leaves off. 



As in the case of the elms, a close correlation exists between 

 transpiration, evaporation, and temperature (fig. 15); in fact, the 

 general trend of the graphs is strikingly similar to those of the elms. 

 The same irregularity is shown during the period of defoliation. 

 On October 26 only the bare stems remained; these had a surface 

 area of o . 22-0 .48 sq. dm. 



Further losses from November 2 to May i are given in table 

 VII. The small losses are again evident, followed by a rapid rise 



