FACTORS INFLUENCING FLOWER SIZE IN NICOTIANA 355 
F2 individuals were practically identical in spread and length of corolla 
on the first dates of measurement. They may, therefore, be compared 
with each other directly, so far as flower size is concerned. In the 
Table Xa 
Influence of Removal of Flowers on Spread of Corolla in ij F2 i^ios P2 
Plant No. 
Date 
Class Centers in 
Millimeters 
No. 
Mean 
15 
16 j 17 
18 
20 
22 
23 
?4 
25 
26 
Pl3.... 
August 22 
3 
4 
3 
2 
13 
23-23 
August 25 
3 
5 
I 
2 
12 
22.92 
September 9 . . . 
I 
I 
I 
I 
3 
3 
I 
I 
12 
21.75 
September 20 . . 
! 
I 
2 
2 
I 
3 
2 
I 
12 
23.08 
Pl4.... 
August 22 
I 
2 
3 
2 
2 
2 
12 
23.67 
August 25 
2 
2 
5 
3 
I 
13 
22.92 
September 9 . . 
1 
2 
I 
2 
5 
I 
I 
12 
20.42 
September 20 . . 
I 
I 
I ' 6 
3 
12 
17.61 
Table Xb 
Influence of Removal of Flowers o?i Length of Corolla in ij F2 i/103 -f 2 
Plant 
No. 
Date 
Class Ct 
nters in Millimeters 
No. 
Mean 
28 
29 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
Pl3... 
August 22 . . . 
I 
I 
2 
5 
I 
2 
I 
13 
38.08 
August 25 . . . 
I 
I 
3 
5 
I 
12 
36.67 
September 9 . 
I 
4 
4 
2 
I 
12 
36.67 
September 20 
3 
I 
4 
2 
2 
12 
36.67 
Pl4... 
August 22 . . . 
I 
I 
6 
2 
2 
12 
36.25 
August 25 . . . 
3 
3 
3 
3 
I 
13 
36.77 
September 9 . 
3 
I 
5 
3 
12 
37.42 
September 20 
I 
I 
2 
4 
2 
I 
I 
12 
31.08 
case of Plant 13, the old flowers and developing seed capsules were 
picked off, while Plant 14 was allowed to mature seed normally and 
only the 49 flowers measured were removed. The difiference between 
the size of the few flowers present on Plant 14 and the numerous flowers 
on Plant 13, as seen in figure 2, is striking. Table Xa shows that 
for spread of corolla in Plant 13 the decrease in size during the period 
of measurement was only 0.15 mm. as contrasted with a decrease of 
6.50 mm. for the flowers of Plant 14. Similarly for length of corolla. 
Plant 13 showed a decrease of 1.16 mm. while Plant 14 showed a 
decrease of 5.17 mm. 
