ALFALFA SEED PRODUCTION, 



19 



RELATION OF THE NUMBER OF FLOWERS PER RACEME TO THE 

 NUMBER OF PODS FORMED. 



In Table III there is some slight evidence to indicate that racemes 

 with many flowers produce proportionately fewer pods than racemes 

 with few flowers. This matter was further investigated by McKee 

 at Chico, Cal., in 1909, and his results are shown in Table X. Accord- 

 ing to these results it would appear that few-flowered racemes produce 

 proportionately twice as many pods as many-flowered racemes. 

 While this factor is evidently one to be taken into consideration, it 

 could hardly modify materially the results shown in Table II, owing 

 to the very large number of flowers counted in these experiments. 



These data are the combined readings from 15 different plants. 

 Exactly analogous conclusions are shown, however, by tabulating the 

 results of each individual plant. 



Table X. — Effect of the number of alfalfa flowers per raceme on the percentage of pods set. 





Number 



of 

 racemes. 



Number 



of 

 flowers. 



Number 

 of pods. 



Number 

 of pods 



per 

 raceme. 



Number of seeds. 



Flowers 



Number of flowers per raceme. 



Total. 



Average 

 per pod. 



setting 

 pods. 



2to6 



153 



138 



50 



17 



707 



1,212 



669 



344 



317 

 464 

 205 

 68 



2.07 

 3.36 

 4.1 

 4.0 



553 



806 



401 



96 



1.7 

 1.7 

 1.9 

 1.4 



Per cent. 

 44.8 



7 to 11 



38.2 



12 to 16 



30.6 



17 to 26 



19.7 







AUTOMATIC TRIPPING. 



The term "automatic tripping" is used when an alfalfa flower 

 becomes tripped without the aid of insects or any other external body. 

 This phenomenon was first actually observed at Chinook, Mont., in 

 1909, but was suspected from observations of the previous season at 

 the same place. In 1909 two of the plants inclosed in netting pro- 

 duced pods on racemes from which insects had been excluded. To 

 obtain further facts in regard to the process, all wilted and all un- 

 opened flowers were removed from a number of the racemes under 

 the netting, leaving only opened, untripped flowers, which were 

 closely observed during the following days. In the course of a day 

 or two several of the flowers had become tripped. On one of these 

 two plants the keel petals were partially separating in some of the 

 flowers. While these flowers were being examined one flower was 

 seen in the process of tripping. The pistil and stamens snapped up 

 vigorously against the standard, scattering the pollen around. No 

 object had come in contact with any portion of the flower. 



The calyx of each tripped flower was marked with carbon ink as 

 soon as it was detected. Those which did not trip were watched until 

 the coroUa had wilted or the flower had fallen. The number of 



