160 



Bulletin 80 



The prevalence of small amounts of copper in vegetation 

 throughout this locality is shown by the figures in table VI. 

 Samples of corn and alfalfa contained comparable quantities of 

 copper, which, however, were exceeded by the amount found in a 

 sample of mistletoe growing on a willow fully twenty-five feet 

 above the ground. This is due chiefly to the perennial character 

 of mistletoe which, therefore, has more time to accumulate cop- 

 per. It is interesting to note also that seeds of alfalfa and 

 corn contain less copper than corresponding foliage. Corn leaves 

 were observed to contain 6.1 parts of copper per million parts of 

 air-dry substance, while grain from the same locality contained 

 from 0.73 to 0.43 parts. Alfalfa seed contained about one-half 

 as much copper as the stalks and leaves, while wheat hay carry- 

 ing a large proportion of grain shoived a low proportion of cop- 

 per. These facts are probably connected with transpiration, 



