104 



Fig. 5. Normal successional relations between the Panicum pscndopubcsccns 

 (i), windward slope {2), basin (j), blowsand (4), deposit (5), Hudsonia (6), 

 and bunch-grass (7) associations. 



it becomes impossible to deciplier the entire past history of the veg- 

 etation, but any of the successions given in the diagram between the 

 basin, blowsand, and deposits may occur repeatedly, in any order, 

 and for any length of time, until finally the sand becomes static and 

 stabilization begins. The windward slope association alone is not 

 included in the blowsand complex. It can follow only the Panicum 

 pseudopuhcsccns or more rarely the bunch-grass association, and if 

 not succeeded bv the basin association reverts to bunch-srass. 



