16 
BULLETIN 844, U. S. DEPARTMENT OF AGRICULTURE. 
This experiment was duplicated at Ames in August, 1916, with the 
result that the three protected plants produced a total of 776 racemes, 
with an average of 0.19 pod each. 
The plants inclosed at Arlington produced 0.44 pod to the raceme 
more than the plants inclosed at Ames, and the average for the six 
plants at Arlington and at Ames is only 0.42 pod to the raceme. 
Results given below for nine plants inclosed in the glass-covered cage 
show that the pods 
produced per raceme 
by different plants 
varied from 0.1 to 
0.45, which is slightly 
less than the varia- 
tion in the two cages 
covered with cheese- 
cloth. 
In order to deter- 
mine whether the 
shading of the plants 
in the cheesecloth- 
covered cages had 
caused the produc- 
tion of seed to be re- 
duced, a cage 4 feet 
wide, 4 feet high, and 
10 feet long, having 
glass sides and top, 
but with ends covered with cheesecloth to permit ventilation, was 
placed over nine plants at Ames in August, 1916. The results 
obtained in this experiment are presented in Table IV. 
Table IV. — Production of sweet-clover seed hy plants protected from insect visitation 
during their entire flowering period at Ames, Iowa, in 1916. 
Fig. 6.— Cage covered with cheesecloth to protect plants from insect 
visitation. 
Racemes 
Plant. per 
plant. 
Pods pro- 
duced 
by all 
racemes. 
Average 
number 
of pods 
to the 
raceme. 
Plant. 
Picpmo^ Pod spro- 
™? duced 
X* I bvall 
P lant - J racemes. 
1 
Average 
number 
of pods 
to the 
raceme. 
No.l 
84 
130 
166 
199 
243 
131 
17 
58 
30 
88 
35 
36 
0.20 
.44 
.is; 
.44 
.14 
27 
No.7 ' 119 
13 
83 
142 
0.10 
No. 2 
No. 8 
182 
.45 
No.3 
No. 9 
340 
.41 
Total 
No. 5 
1,594 
502 
No. 6 
.31 
The results given in Table IV show that an average of 0.31 of a 
pod to the raceme was obtained from 1,594 racemes and that the 
variation in seed production of the different plants was from 0.1 to 
0.45 to the raceme. The average seed production for the nine plants 
