10 BULLETIN 306, U. S. DEPARTMENT OF AGRICULTURE. 
From Tables IV and V it becomes apparent that during both the | 
first and second seasons these first-generation plants dispiay very 
markedly the characteristic of the parents as regards alkaloid pro- | 
duction. Thus, in 1913 the average percentage of alkaloids found — 
in the plants han the original parent 6w and the parent 7w, which | 
were selected for high alkaloid-producing tendencies, was 0.640 and | 
60 
.70 
.60 
50 
.FO Be 
30 fea 
PERCENTAGE OF ALAALOIOS 
Fic. 5.—Diagram showing the alkaloidal content of the leaves of first-generation belladonna plants from 7 
close-pollinated and cross-pollinated selected parents at two stages of growth during the first season, | 
1913. The percentages indicated es the average of all the individuals from each parent plant; | 
a, Plants from close-pollinated parents; 5, plants from cross-pollinated parents. | 
0.615 per cent, respectively. On ae other hand, the averages from a 
the plants 23 and 46, which were produced fae parents of the. | 
opposite tendencies, are 0.408 and 0.428 per cent, respectively. Agaim — 
the following year we find the average of plants 6w and 7w to be 
0.814 and 0.773 per cent, respectively. Lot 46 was not picked that 
year, but lot 23 ered 0.497 per cent. 
It will be seen from the tables that the effect of close pollination 
as compared with cross-pollination is not as great as would be expected. — 
In the case of 6w the plants from close pollina= 
tion are on the average 0.091 per cent richer | 
than those from cross-pollination in 1913, and 
0.042 per cent richer in 1914. The 7w plants’ 
show a difference of 0.001 per cent in favor of 
cross-pollination in 1913 and a difference of 
ane = 0.062 per cent in 1914. Figures 5 to 8 graphi- 
256) $6) 7W6) Wie) EW) OMe ) = ee F 
Fic. 6.—Diagram showingthe Cally illustrate these conditions. Sufficient 
averagealkaloidalcontentof information has not been obtained to indicate 
all the individual belladon- : : 5 
na plants from each parent With any degree of certainty the influence of 
for the first season, 1913: eross-pollination and close pollination on the 
eeeeme hs Bi ed tramsmissibility of the alkaloid-producing char- 
ee ee acteristic. As a possible explanation of the 
| large percentage of plants with high alkaloidal 
content among the first-generation plants secured from cross-polli- 
nated selected parents, Dr. W. Van Fleet, of the Office of Drug- 
Plant and Poisonous-Plant Investigations, has prepared the following 
statement: 
80 
.70 
.60 
PERCENTAGE OF ALHALOIOS 
The arrangement of anthers and stigma in the belladonna bloom and the respective 
periods of their maturity and receptivity are such as to fit the plant in a high degree 
