20 



BULLETIN 75, U. S. DEPAETMENT OF AGBICULTUBE. 



flowers that were tripped and the pods that developed from tripped 

 and untripped flowers are shown in Table XI. 



Table XI. — Pods and seeds from automatically tripped alfalfa flowers at Chinook, 



Mont., 1909. 





Raceme 

 No. 



Number of flowers. 



Flowers 

 tripped. 



Number of pods. 



Flowers 



bearing 



pods. 



Plant. 



Total. 



Tripped. 



Total. 



From 

 tripped 

 flowers. 



From un- 

 tripped 

 flowers. 



Ko.3.. 



34 

 35 

 36 

 37 

 38 

 39 



12 

 11 



7 

 11 



10 

 6 



9 

 3 



2 

 7 

 9 

 3 



Per cent. 

 75.00 

 27.27 

 28.57 

 63.63 

 90.00 

 50.00 



7 

 3 

 

 k5 

 "5 

 1 



7 

 3 





 6 

 5 



1 





 

 

 

 

 



Per cent. 

 58.33 



No. 3 



27 27 



Ko.3 







No. 3 



45.45 



No. 3 



50.00 



No. 3 



16.66 







Total 



57 



33 





21 



21 









Average 





67.88 



36 84 





30 

 31 

 32 

 33 



34 













No. 8 



14 



6 



20 



11 



13 



5 

 2 



14 

 2 



13 



35.71 

 33.33 

 70.00 

 18.18 

 100. 00 



3 





 8 

 

 5 



3 

 

 8 

 



6 





 

 

 

 



21.42 



No. 8 







No. 8 



40 00 



No. 8 







No. 8 



38.46 







Total 



64 



36 





16 



16 













56.25 



25.00 



















Flowers tripped on plants 3 and 8 per cent. . 57. 02 



Flowers producing seed -on plants 3 and 8 do 30. 57 



Tripped flowers produ<;ing seed o'n plants 3 and 8. . -'. do 53. 62 



Untripped flowers producing seeds on plants 3 and 8 do 



At Arhngton farm, Virginia, in 1909, an entire alfalfa plant was 

 inclosed in a screen of tarlatan about the time the first fiowei-s came 

 into bloom. Ten days or two weeks later the plant was observed 

 to be in full bloom. When the screen was removed it was noticed 

 that the flowers seemed larger than those on plants that had not been 

 screened. Seventeen racemes were tagged to show the number of 

 flowers on each, all unopened flowers being removed. The screen 

 had been removed only two or three minutes when a snappmg or 

 clicking sound was heard. On close observation it was found that 

 some of the flowers had become tripped. The sound of the column 

 striking the standard was quite distinct, but even with very close 

 watching no single flower was actually seen in the act of tripping. 

 No insects visited the flowers of this plant, and the only way in which 

 the flowers could be tripped would be automatic. The day was clear, 

 very warm, and with no breeze stirring. The screen was removed 

 about 11 o'clock in the morning and for not more than 15 minutes. 

 No actual count of the flowers tripped in the manner just described 

 was made. At first the flowers did not trip very fast, but as the plant 

 remained longer in the sunshine the trippings became more frequent. 

 At times three or four would be heard almost simultaneously. The 



