138 THE AGRICULTURAL GRASSES OF THE UNITED STATES. 



The preceding analyses furnish the data from which is derived the 

 general conclusion that as a grass grows older its content of water de- 

 creases, ash decreases, fat decreases, albuminoids decrease, carbo-hy- 

 drates increase, crude fiber increases, non-albuminnoids decrease till 

 bloom or slightly after, when it is at its lowest, and then increases again 

 during the formation of the seed. 



There are exceptions to these rules, but for the large majority of spe- 

 cies under ordinary conditions of environment they hold good. 



There are almost no exceptions to the fact that the water decreases in 

 the maturer specimens that is to say, the plant gradually dries up and 

 becomes less succulent. The ash is very dependent on locality and 

 surroundings, and as in the analyses which are here published it in- 

 cludes whatever soil there may be mechanically adherent to the blade 

 or stalk as collected, it sometimes shows irregularities from one period 

 to another. 



The albuminoids decrease in amount with great regularity, the few 

 cases where an increase appears being owing to the fact that the speci- 

 mens were probably grown under varying conditions. 



The fiber sometimes decreases, as in Bromus erectus^ but the change 

 in that direction is never large. 



The non-albuminoid constituents, however, are often quite the reverse 

 of constant in their manner of appearance and disappearance, and show 

 themselves to be largely or more affected by environment than any other 

 constituent. In Agrostis vulgaris they continue to decrease after bloom, 

 and in Anthoxanthum odoratum and Festuca ovina they increase steadily 

 from early growth to maturity. The relative amount present in the 

 same species from different localities is extremely variable, as may be 

 seen in the analyses of Phleum pratense, where specimens from Indiana 

 contain almost no non-albuminoid nitrogen, while those from the Dis- 

 trict of Columbia and elsewhere are well supplied. The specimens from 

 poorer soil having the smallest amount in some cases and the largest in 

 others, the fact can hardly be due directly and entirely to the lack of cul- 

 tivation, but as the averages show that the best grasses contain the least 

 non-albuminoids it is plain that it is dependent on the sources of nitro- 

 gen and the supply furnished the plant. The usual changes in the non- 

 albuminoids seem to point to the possibility that they increase at the 

 time of the formation of the seed in the act of transferring to the seed, 

 as amides, the nitrogen of the plant. 



THE BEST PERIOD OF GROWTH AT WHICH TO CUT FOR HAY. 



Although largely a matter of opinion, it would seem from the forego- 

 ing results that the time of bloom or very little later is the fittest for 

 cutting grasses to be cured as hay. The amount of water has dimin- 

 ished relatively, and there is a proportionately larger amount of nutri- 

 ment in the material cut, and the weight of the latter will be at its 

 highest point economically considered. Later on, the amount of fiber 

 becomes too prominent, the stalk grows hard, arid, indigestible, and the 



