134 WILLIAM H. BROWN 



It is certain that the problem of wilting here dealt with will 

 require a great deal of very carefully planned study before any 

 satisfactory general conclusion may be reached. For the present, 

 it seems advisable to regard the definite conclusions of Briggs 

 and Shantz as probably applicable only to a special complex 

 of aerial conditions. 



SUMMARY 



The percentage of soil moisture at the time of wilting for simi- 

 lar plants of Martynia louisiana, Physalis angulata var. linkiana, 

 Tropaeolum majus, and Vicia faba, grown under the same con- 

 ditions and in the same soil, has been found to vary with the 

 rate of evaporation at the time of wilting, providing however 

 that, in the case of altered conditions, the plant is not allowed 

 time enough under the new evaporation rate to become physio- 

 logically altered. 



This residual moisture content of the soil at the time of wilting 

 varies according to the atmospheric conditions under which the 

 plant has been grown and appears to be increased by excessive 

 soil temperatures. 



