IQI4J 



FULLER— EVAPORATION AND SOIL MOISTURE 



223 



supply during the weeks of spring permits the growth of a meso- 

 phytic herbaceous spring flora. 



The open character of the forest on the oak dunes has brought no 

 increase of humus, as indicated by wilting coefficients of 1 . 1 per 



Fig. 20. 



dune 



the heavy line at 7 . 5 cm. and the light line at 25 cm. depth; wilting coefficients repre- 

 sented by broken lines. 



Fig. 21. — Graphs showing the range of soil moisture in the oak dune for 1912; the 

 heavy line at 7.5 cm. and the light line at 25 cm. depth; wilting coefficients repre- 

 sented by broken lines. 



cm 



5 



cm 



strata. 



moisture is irregul 



times 



5 



coefficients. The graphs indicate comparatively xerophytic 



