Journal of Agricultural Research voi. xxvii, No. 5 
234 
pendent position following their complete extrusion from the glumes 
were made on 25 flowers at different hours of the day favorable for 
blooming. The time required for the anthers to assume the pendent 
position varied in these 25 flowers from 1 minute 40 seconds to 5 minutes 
25 seconds, and averaged 3 minutes 36 seconds. The time required 
depends on (1) the position of the head at the time of the protrusion of 
the anthers, (2) the resistance offered by the glumes, (3) air movement, 
(4) temperature, and (5) rainfall and humidity. 
The time elapsing between the opening and closing of the glumes of a 
flower was found to vary from 11 to 66 minutes. Frequently difficulty 
was experienced in determining the exact time when the glumes were 
closed completely, for sometimes anthers or filaments became lodged 
obscurely between the glumes in such a way that complete closing was 
prevented. Table I shows the duration of blooming of 25 flowers, with 
their location on the spike. The average duration was found to be 
56.5 minutes. 
Table I .—Time of opening and closing and time elapsing between opening and closing 
of 25 flowers , with head number , position of spikelet on the head and position of the 
observed flowers on the spikelet 
Head 
number. 
Spikelet 
number. 
Flower 
number. 
Time of opening. 
Time of closing. 
Time 
between 
opening 
and 
closing. 
1922 
1922 
Minutes . 
2D . 
17 
1 
5.55 p. m., May 14... 
6.18 p. m., May 14... 
23 
3 c. 
IO 
1 
5.28 p. m., May 14... 
5.41 p. m., May 14... 
r 3 
3 C. 
16 
1 
5.29 p. m., May 14... 
5.40 p. m., May 14... 
II 
4 A. 
22 
1 
6.15 p. m., May 15... 
6.36 p. m., May 15... 
21 
4 A. 
22 
2 
4.50 p. m., May 14... 
5.20 p. m., May 14... 
30 
4 A. 
17 
2 
12.45 P- m » Ma y 15* • • 
1.10 p. m., May 15... 
25 
4 A. 
II 
2 
12.28 p. m., May 15... 
12.50 p. m., May 15... 
22 
4 A. 
12 
2 
10.26 a. m., May 15.... 
10.45 a - m -» May 15.... 
19 
4 A. 
20 
1 
4.43 p. m., May 14... 
5.10 p. m., May 14... 
27 
4 A. 
IO 
1 
5.33 p. m., May 14. . • 
6.15 p. m., May 14... 
42 
s c. 
IS 
1 
5.07 p. m., May 14... 
5.40 p. m., May 14.. . 
33 
s c. 
II 
2 
2.25 p. m., May 15... 
2.45 P- m., May 15... 
20 
s c. 
13 
1 
5.07 p. m., May 14... 
5.40 p. m., May 14... 
33 
s c. 
5 
1 
1.39 p. m., May 16... 
2.15 p. m., May 16... 
36 
S C. 
8 
2 
8.21 a. m., May 16.... 
8.50 a. m., May 16.... 
29 
S C. 
14 
I 
5.30 p. m., May 14... 
5.50 p. m., May 14... 
20 
6 C. 
13 
1 
5.30 p. m., May 14... 
5.55 p. m., May 14... 
25 
7 l>. 
7 
1 
7.49 a. m., May 16.... 
8.55 a. m., May 16.... 
66 
7 D. 
18 
2 
8.34 a. m., May 16.... 
9.15 a. m., May 16.... 
4 i 
8 B. 
17 
1 
10.27 a * m » May 15.... 
10.45 a - m -> May 15.... 
18 
8 B. 
13 
1 
9.30 a. m., May 15.... 
10.00 a. m., May 15.... 
30 
8 B. 
16 
I 
10.27 a. m., May 15.... 
10.48 a. m., May 15.... 
21 
8 B....... 
12 
1 
8.13 a. m., May 15.... 
8.29 a. m., May 15.... 
16 
8 B. 
10 
1 
10.27 a. m., May 15.... 
10.48 a. m., May 15.... 
21 
8 B. 
Average 
8 
1 
10.27 a. m., May 15.... 
10.48 a. m., May 15.... 
21 
26. 5 
Kirchner (5) and Koemicke and Werner (7) state that under favorable 
conditions wheat flowers remain open for about a quarter of an hour. 
According to Knuth ( 6 ) both Rimpau and Delpino found that each 
flower remains open only about 15 minutes. Friiwirth (2) states that 
the flower is closed usually in 12 to 20 minutes, sometimes 8 to 35 minutes, 
from the beginning of opening. Obermayer (9) records the duration of 
