16 



BULLETIN 191, U. S. DEPARTMENT OF AGRICULTURE. 



low brush, as well as of other plants, especially 

 indicates, therefore, a retrogressive succession 

 t^^pe. 



cleep-rooted species, 

 in the wheat-grass 



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Section B of figure 6, in addition to showing 

 healthy specimen of yellow brush may feed at a 

 3^ feet, emphasizes the interesting fact that 



that the roots of a 



depth in excess of 



small wheat grass 



