212 MINNESOTA BOTANICAL STUDIES 



Two other common phenomena that aid in the depletion of the 

 water in the soil, are transpiration and evaporation. The study of 

 the indirect loss of water via vegetation has only been begun and no 

 significant data have as yet been secured for the sandhills of Ne- 

 braska. Because of the extensive reconnaissance of the whole 



1 2 30 4 5 



Open hilltop 



3 



Rim of blow-out 



3 



Bottom of blow-out 



Inner slope of blow-out 



Protected "pocket* 



Pine plantatlon^^^ ^ 



CZ=] night 



River thicket 



Fig. 7. Evaporation in c.c. from standardized evaporimeters. The graphs 

 ■I represent the average of 12-hour periods for 21 days. 



region necessary for the purpose of this report it has also been im- 

 possible to obtain a lengthy record of evaporation. During July, 

 1911, a record of evaporation for twenty-one days was obtained for 

 seven habitats of the region. These records were secured by the 

 use of the porous cup atmometer. The cups used were of the 



