132 



With a few exceptions the specimens were personally collected in the 

 grounds of the Department, and are to be so understood when nothing 

 else is said in their description. They all grew in the summer of 1880 

 except the few series illustrative of the first year's growth of certain 

 species. The character of the soils has been designated as rich or gar- 

 den soil, good soil, poorer soil, and wayside soil. The first is that of the 

 experimental garden of the Department, and is above the average rich- 

 ness of cultivated soils ; the second is that of the lawns about the De- 

 pat tment building, the third, a light gravelly soil, occurring in a portion 

 of the grounds, and the last the gutters and paths. 



The specimens were cut close to the roots, weighed and dried rapidly 

 in a current of air at GO C. The methods of analysis were such as 

 have been described in previous reports. 



