39§ 



BOTANICAL GAZETTE 



[NOVEMBER 



in coarse soil, being deep-rooted; some of them build temporary 

 dunes on the sand-hills and on the shores of the Great Lakes. 

 Each species occurs in places alone, but mixed growths of several of 

 these grasses, are about as frequent, and since they are very sim- 

 ilar in growth-form, in physiology, and in distribution, they are 

 for the present considered as members of one variable association. 

 Within the region these growths occur in scattered patches in 

 disturbed situations, frequently in railroad rights-of-way, and 

 usually in loose or sandy soil. Extremely local growths are found 

 on the higher mesas and foothill slopes. 





*-""-- -° v - 



— Gutierre 



this end of the mesa differs from the rest of it in that it is not at present pastured, 

 and in that Gutierrezia is scarce; Eriogonttm ejjusum is conspicuous, though not so 

 in the photograph; September 191 2. 



THE GUTIERREZIA- ARTEMISIA ASSOCIATION 



Gutierrezia -A rtemisia associatior 

 Undershrub formation. — Pound 



— Shantz 18, p. 60. 



Shantz 



Artemisia frigida society. - 

 Gutierrezia Sarothrae society. — Shantz 



371, in part 



format 



-Watson 



The Gutierrezia-Artemisia association, described by Shantz (18) , 

 is typically developed in the plains areas of the region studied. 

 Gutierrezia Sarothrae (Pursh) B. and R. is more abundant in the 



