SWEET-CLOVER SEED. 



25 



of the ones labeled when the flowers at their bases were just ready to 

 open was largely due to the dropping of the flowers on the older 

 racemes before the experiment was begun. 



It will be seen that the production of mature pods on the plant 

 not watered was much greater on the racemes that were labeled 

 before the flowers opened than on the older racemes. This difference 

 is undoubtedly due to the precipitation which fell on the sixth and 

 tenth days of the experiment. It is believed that the yield of 15.23 

 pods to the raceme on the ones labeled when the pods were 9 to 12 

 days old is representative of the production of pods per raceme pre- 

 vious to the precipitation and that the other racemes on this plant 

 would have yielded proportionately if conditions had remained the 

 same. 



In the early spring of 1916, Melilotus alba was planted in several 

 large pots in the greenhouse of the Department of Agriculture at 

 Washington, D. C. These pots were placed outside the greenhouse 

 in the late spring, where they remained until the following January, 

 when they were taken into the greenhouse. The plants grew rapidly 

 and began to flower during the latter part of April, 1917. At this 

 time two pots were placed in a large cage made of screen having 20 

 meshes to the linear inch. One pot was submerged in a tub of water, 

 so that the soil was saturated at all times, while the plant in the other 

 pot was given only sufficient water to keep it from wilting. The 

 pods on a few racemes were self-pollinated and the results obtained 

 are given in Table IX. 



Table IX. — Effect of moisture on the seed production of Melilotus alba at Washington, 



D. C, in 1917. 



Soil treatment. 



Total number of — 



Flowers that ma- 

 tured (per cent). 



Racemes. 



Flowers. 



Pods 

 formed. 



Total. 



Increase. 



Soil given only a limited quantity of water 



12 

 17 



227 

 425 



65 

 234 



28.63 

 55.05 





Soil saturated 



26.22 







The results of this experiment compare favorably with those ob- 

 tained under field conditions at Ames in 1916. 



