22 



BULLETIN 75, U. S. DEPARTMENT OF AGRICULTURE. 



After the flowers from which insects were to be excluded had been 

 inclosed in the netting tents, they were examined every day or every 

 second day until all of the flowers had become entirely wilted. When- 

 ever any flower was found tripped, the calyx was marked with a mix- 

 ture of carbon black and water in order that the pod wliich might 

 develop from the tripped flower could be distinguished from any pod 

 that might develop from a flower that had not been observed to be 

 tripped. The unmarked flowers were observed until they wilted, so 

 it is certain that none of them became tripped. 



Table XIII shows the number of flowers that became tripped and 

 also the number of pods and seeds that developed from tripped and 

 untripped flowers. 



Table XIII. — Pods and seeds from self-tripped alfalfa flowers at Pullman, Wash., 1910 





Number of flowers. 



Number 

 of pods 

 from 

 marked 

 flowers. 



Number 

 of mature 



seeds 



from 

 marked 



pods. 



Number 



of pods 



from 



flowers 



not 

 marked. 



Mature 



Plant. 



Total. 



Tripped 



and 

 marked. 



Not 

 tripped 

 and not 

 marked. 



seeds 



from 



pods not 



marked. 



No.8 



128 

 104 



69 

 100 



62 



91. 



79 



71 



81 



9 

 17 

 2 

 15 

 4 

 1 

 3 

 8 

 1 



119 

 87 

 57 

 85 

 58 

 90 

 76 

 63 

 80 



1 

 12 

 1 

 4 

 

 • 1 

 2 

 

 





 18 

 

 3 

 

 1 

 4 

 

 





 4 

 1 

 

 

 

 

 

 







No. 9 



4 



No. 10 







No. 11 







No. 12 







No. 13 







No. 18 







No. 19 







No. 20 











Total 



775 



60 



715 



21 



26 



5 



4 







Flowers tripped per cent . . 7. 74 



Tripped flowers producing pods do 35. 00 



Flowers not tripped producing pods do 69 



Average number of mature seeds per pod from tripped flowers 1. 23 



Average number of mature seeds per pod wMch developed from flowers 

 not observed to be tripped 80 



Table XIII shows that 7.7 per cent of the flowers observed on the 

 nine plants became tripped. In several of the flowers the keel was 

 observed gradually to open, and later the flowers were found to be 

 tripped. As the tents were made so that honey-gathering insects did 

 not have access to the flowers and as care was taken to prevent any 

 other object from coming in contact with the flowers, it seems clear 

 that the tripping which occurred was automatic. 



Five of the 775 flowers observed produced pods, when no evidence 

 that these flowers had been tripped could be found. It is possible 

 that three of these flowers may have become tripped without bemg 

 observed or that the carbon which was placed on the calyx may have 

 been removed. However, two flowers were found in which the pod 

 was developing and the tip of the young pod was protruding through 



