129 



The great variation iu composition of grasses becomes apparent on ex. 

 amining the one hundred and thirty-six analyses ; and by selecting the 

 Lighest and lowest determinations the following table of extremes lias 

 been prepared : 



Limits of composition of grasses. 



The highest ash is undoubtedly owing to the presence of adherent 

 soil, and the lowest carbo-hydrates are dependent relatively on the 

 same cause. The wide variations in fiber and albuminoids must be re- 

 garded, however, as being entirely due to physiological causes, which 

 are difficult to explain. Panicum sanyuinale, for instance, which in one 

 specimen contains the extreme amount of albuminoids and a small 

 amount of fiber has in another only half as much albumen and one and 

 three quarter times as much fiber. We learn, then, that species are not 

 in themselves at all fixed in their composition, there being as large vari- 

 ations among specimens of the same as between specimens of different 

 species. Examples may be found in several portions of the preceding 

 tables, and, for illustration, several analyses of Phleum pratense and of 

 Dactylis glomerata from widely separated localities are given iu the 

 following tables : 



Analyses of Phleum pratense (Timothy) from various localities. 

 FULL BLOOM. 



3594 



