EXPERIMENT STATION REPORT. 



285 



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On account of the much less favorable conditions of heat and 

 light after October 25, it could not be expected that the rates 

 prevailing before August 15 would be resumed, and the M. S., 

 dormant since August 30, indeed falls short of it. That both 

 the S. B. I and S. B. 2 should approach it or even surpass it, with 

 the drawback of feeding a set of young branches besides, and 

 that the dried up branches in pots 3 and B should renew their ac- 

 tivity, is indeed a striking demonstration of the fact that the 

 normal direction of the water current allows the plant a much 

 more rapid growth than the reversed current. 



The roots under observation in the box showed no increase In 

 circumference after October 25. They developed a rot on No- 

 vember 17 at the place where the raphia bands were tied, which 

 severed them from the stem. New roots were subsequently 

 formed. 



Another investigation, with the object of tracing the move- 

 ment of reserve starch in the circulation of a many-rooted sweet 

 potato plant was begun on June 11, 1910. A branch, about 18 

 feet long, of the original sweet potato plant of the previous ex- 

 periment, was rooted at intervals of approximately 18 inches in 

 10 inch pots, and given the best conditions in the greenhouse for 

 rapid growth. All larger branches springing from any part of 

 the vine were potted at intervals like the main stem, until Aug- 

 ust 5, when no more nodes were rooted. The plant then pre- 

 sented an appearance indicated by the diagram in Plate XXVII, 

 except that the long branches emerging from the final pots had 

 not then developed, and that there were many short branches 

 not marked in the diagram. Several of the older pots were then 

 examined, and no storage roots were found. 



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