THE AGRICULTURAL GRASSES OF THE UNITED STATES. 12^ 



The great variation in composition of grasses becomes apparent on 

 examining the one hundred and thirty-six analyses and by selecting 

 the highest and lowest determinations the following table of extremes 

 has been prepared : 



Limits of composition of grasses. 



Dry substance. 



Highest. 



Lowest. 



19. 24 



3. 57 



5. 77 



1. 48 



66. 01 



34. 01 



37. 72 



17. 68 



23. 13 



2. 80 



3. 70 



.45 



1.64 



.00 



60.7 



.00 



76. 50 



60. 00 



Ash 



Fat 



Nitrogen free extract 



Cnide fiber 



Albuminoids 



Xitrogen 



Xon-albuminoid nitrogen 



Per cent, of nitrogen as non-albuminoid 

 Water in fresh grass 



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 regarded, 

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

 difficult to explain. Digitaria sangulnale, 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 Fhelum pratense and of 

 Bactylis glomerata from widely separated localities are given in the fol- 

 lowing tables : 



Analyses of Phleuni pratense (timothi/) from various localities. 

 FULL BLOOM. 



















1^ 

















■© . 



« c ^ 



Locality. 







act. 



© 



05 



1 

 o 



•S a 



b. of 

 on as 

 inoid 







p 









%^ 



» S s 









1 















<\ 









< 





•A 





Department garden, 1881 



7. 16 



4. 47 



50. 03 



27. 35 



10. 99 



L 75 



.51 



29.1 



Department garden, 1880 



5. 66 



3. 58 



58. 93 



21. 93 



9. 90 



1. 58 



.38 



24.0 





4. 93 



4. 22 



52. 83 



30. 43 



7. 69 



1. 23 



.15 



12. 2 



!N"ew Hampshire 



4. 57 



4. 20 



57. 16 



28. 28 



5. 79 



.93 



. 10 



lois 



Indiana 



7. 05 



2. 18 



52. 99 



32. 26 



5. 52 



. 88 



.00 



.0 



2218 GR— 9 



