AN EXCISED BRANCH OF THE SAHUARO 21 



The branch was watched closely with the approach of the grow- 

 ing season of 1915 in order to notice the slightest evidence of 

 renewed activity. Our vigilance was rewarded when early in 

 May numerous flower buds began to push out from the upper 

 portions of the cortical ridges. To our surprise the buds were 

 formed in greater numbers than in 1914 and their rate of growth 

 was much accelerated. This is probably accounted for by the 

 fact that May, 1915, was a rather warm and clear month at 

 Lincoln. These buds began opening on May 12 and for the fol- 

 lowing ten to twelve days there was scarcely a day when there 

 was not at least one flower open. As many as five flowers were 

 open on one day. Blooming came to a close on May 22 after the 

 production of thirty-two flowers and eight or ten aborted buds. 

 No fruits were set by any of these flowers and no flowers were 

 produced after this first burst of bloom from May 12 to 22. 



So intense was the interest in the flower production of the ex- 

 cised branch that it was rather late before anyone thought of the 

 desirability of taking the weight of the branch from time to time. 

 This was done for the first time on September 30 after the close 

 of the first flowering period. Further weighings have been made 

 at intervals since that time but these data are not yet ready 

 for publication. 



A second branch similar to the above was sent to us from the 

 Desert Laboratory in the autumn of 1914. This branch was 

 treated like the first one but it did not produce flowers or buds 

 in the spring of 1915. When our landscape gardener was plant- 

 ing the cactus bed upon the campus for the present summer we 

 decided to place this last specimen in the soil out of doors with 

 the rest of our cacti, all of which have invariably made very 

 satisfactory progress outside of the plant house during the sum- 

 mer. Heavy rains set in soon after the planting was done with 

 the result that the cut branch of the giant cactus began to rot 

 at the lower end. The progress of decay was so exceedingly 

 rapid after it was first discovered that we scarcely had time 

 to remove the branch from the out-of-door bed to the laboratory 

 and cut it into pieces in order to save some of the normal tissues 

 for histological study. The experiment proved conclusively 



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