Feb. 2,1924 
The Blooming 0} Wheat Flowers 
243 
was detected, and the anthers appeared to remain stationary, but pollen 
was discharged at as low a temperature as 52 0 F. 
The maximum temperature at which flowers were observed opening 
in a greenhouse was 8o° F. 
Table VIII .—Numbers of flowers blooming and kernels produced in different positions 
m the spikelets on six wheat heads 
Location in spikelet. 
Head No. 
xst flower. 
2d flower. 
3d flower. 
4th flower. 
Total. 
Number of— 
Number of — 
Number of— 
Number of— 
Number of— 
Flowers 
bloom¬ 
ing. 
Kernels 
ob¬ 
tained. 
Flowers 
bloom¬ 
ing. 
Kernels 
ob¬ 
tained. 
Flowers 
bloom¬ 
ing. 
Kernels 
ob¬ 
tained. 
Flowers 
bloom¬ 
ing. 
Kernels 
ob¬ 
tained. 
Flowers 
bloom¬ 
ing. 
Kernels 
ob¬ 
tained. 
2D. 
18 
17 
18 
18 
16 
14 
9 
5 
61 
54 
3 c. 
17 
16 
17 
17 
15 
12 
7 
3 
56 
48 
4 A. 
22 
22 
22 
21 
21 
15 
16 
2 
81 
60 
6 C. 
17 
16 
17 
17 
r 3 
12 
5 
2 
52 
47 
7 D. 
19 
19 
20 
19 
11 
IO 
6 
0 
56 
48 
8 B. 
23 
22 
23 
19 
18 
9 
13 
0 
77 
50 
Total. . . . 
116 
112 
117 
III 
94 
72 
56 
12 
383 
3°7 
Per cent. 
. 
96. 6 
. 
94.9 
. 
76.6 
21.4 
80. 2 
SUMMARY 
Seven wheat heads growing in the open were under practically con¬ 
tinuous observation throughout their blooming periods, and nearly all 
of the 406 flowers on these heads were observed to bloom. 
The time required for a wheat flower to open fully and the anthers to 
assume a pendent position varied considerably, but averaged 3 minutes 
36 seconds for 25 flowers, while the time from beginning of opening to 
complete closing averaged 26.5 minutes. 
Of all flowers under observation, 86.2 per cent bloomed during day¬ 
light, 6.9 per cent during twilight, and 6.9 per cent during the night. 
This study did not include the determination of the effect on blooming 
of the duration of the daily illumination period. 
In most of the heads blooming began in the lower half of the upper¬ 
most third of the head. The lowest flower in the spikelet usually bloomed 
first and the others followed in order from lowest to highest, usually 
on successive days, although two flowers in the same spikelet sometimes 
bloomed on the same day. 
Some of the upper flowers in certain spikelets bloomed before the 
lowest or lower flowers in other spikelets, depending on their position 
in the head. 
Blooming on different heads extended over periods from about 101 to 
about 123 hours, a maximum of 25 flowers on one head blooming in a day. 
Periods of intense and reduced blooming alternated throughout the 
day, the time of their occurrence depending to a considerable extent on 
temperature, rainfall, and sunshine. Blooming was observed at tem¬ 
peratures ranging from 56° to 78° F., inclusive. 
