TABLE V. BLOW-SAND. 



TABLE VI. BLOW-SAND. 



Cassia clianiiecrista 

 Ambrosia psilostachya 

 Euphorbia (Teyeri 

 roiiimelina virgiiiica 

 Oeiichrus tribuloides 

 C'roton glandulosus 

 Cristatella Jaiuesii 



g*f b o o 



e e d o o 



c d bo () 



a a o a o 



e a o o () 



a o o o () 



a o o () o 



TABLE VII. 



BLOW-SAND. 



( 'jcloloma atriplici folium 

 Cassia chania'crista 

 Ambrosia psilostachya 

 Ceiichrus triliuloides 



f*f g a f 



c e g g f 



f e e e c 



o o o o a 



THE BLOWOUT ASSOCIATION. 



When the excavation of the blowout has proceeded so far 

 that the maximum depth is reached, the blowout association 

 is developed at the bottom, in response to tlie ehanyed ecolog- 

 ical conditions. These are (\) a slight protection from the 

 wind, (2) a more stable substratum, and (3) a larger supply 

 of soil moisture. The result is an association essentially meso- 

 phytic in nature. Most of the members of the blow-sand asso- 

 ciation, excepting ('i/i'/dloiiKi and Crlstdfc/hi. persist for a time. 



See p. 159. 



