EFFECTS OF SELECTION" ON ALKALOIDS IN BELLADONNA. 5 



A careful study of Table III reveals the fact that the individual 

 first-generation plants possess in large measure the same alkaloid- 



Fig. 1. — Diagram showing the alkaloidal content of the leaves of first-generation belladonna plants from 

 cross-pollinated parents at two stages of growth during the first season, 1912. The percentages indicated 

 represent the average of all the individuals from each parent plant. 



producing characteristic as the parent plant. Plant 6w, the richest 

 of the original 59 individual plants under observation for two years, 

 yielded from cross-pollination first-generation 

 plants which were distinctly rich in the first 

 season and again in the second season. Fur- 

 thermore, the plants of the first generation 

 from the cross-pollinated individuals selected 

 from the original list for low alkaloidal content 

 have shown a decidedly low percentage of 

 alkaloids during each of the two seasons of 

 growth. Figures 1 . to 4 show graphically the 

 average percentage of alkaloids in the leaves 

 of all the first-generation plants from each 

 parent at each of the pickings in 1912 and 

 1913. Besides showing at a glance what has 

 already been said regarding the plants which 

 are rich or poor in alkaloids, figure 1 also shows an interesting con- 

 dition with regard to the relative richness of the plants at the 



7iv 6nr 



Fig. 2. — Diagram showing the 

 average alkaloidal content of 

 all the individual belladonna 

 plants from each parent for 

 the season, first year, 1912. 



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Y\<.. 3.— Diagram showing the alkaloidal content of the leaves of first-generation belladonna plants from 

 cross-pollinated selected parents at four stages of growth during the first season. The percentages 

 indicated represent the average of all the individuals from each parent plant. 



various stsiges of growth. In the previous investigation 1 the plants 

 were richest in alkaloids at the first and fourth stages; that is, 



' Silvers, A. F. Op. cit. 



