878 
Journal of Agricultural Research voi. xxiii. No. n 
TABLE II.— Effect of length of day on growth of winter and spring varieties of wheat , rye, 
oats , and barley. 
Date of first heading. 
Average height 
at time of 
heading. 
Average height, 
May 11. 
Average num¬ 
ber of basal 
branches. 
Under elec¬ 
tric light. 
Control. 
Under 
electric 
light. 
Con¬ 
trol. 
Under 
electric 
light. 
| Con- 
| trol. 
Under 
electric 
light. 
Con¬ 
trol. 
Wheat, Marquis 
(spring), C. 1 .3641 \ 
Jan. 24 
Apr. 8 
Inches. 
28 
Inches. 
51 
Inches. 
36 
I Inches. 
5 6 
8 
25 
Wheat, Purple Straw 
(winter). 
Mar. 17 
Mar. 23 
46 
41 
51 
52 
31 
13 
Rye (spring),C. 1 .169. 
Jan. 6 
Mar. 29 
16 
25 
24 
1 56 
6 
3 ° 
Rye, Abruzzi (win¬ 
ter), C. 1.40. 
Jan. 24 
Mar. 23 
27 
24 
62 
i 61 
25 
11 
Oats, Swedish Select, 
(spring), C. 1.1426.. 
Jan. 10 
Mar. 28 
15 
5 1 
3 6 
72 
28 
19 
Oats, Winter Turf, 
C. 1.274-20. 
Feb. 25 
Apr. 8 
49 
44 
. 61 
51 
33 
33 
Barley, Manchurian 
(spring), C. I. 
19A625. 
Feb. 1 
Mar. 15 
36 
46 
40 
46 
16 
26 
Barley, (Tennessee 
Winter), C. I. 257... 
Apr. 26 
Apr. 25 
3 6 
36 
1 The varietal numbers are those of the Office of Cereal Investigations, Bureau of Plant Industry. 
Young plants of arrowhead (Sagittaria latifolia Wild), taken from a 
marsh, were transplanted to 3-gallon metal buckets with perforated bot¬ 
tom and containing garden soil maintained at approximately optimum 
moisture content for such plants as soybeans. Similar lots of plants also 
were transplanted to 3-gallon earthen jars containing 6 inches of soil cov¬ 
ered to a depth of 4 to 5 inches with water. Under a 10-hour day, begin¬ 
ning May 3, two plants in a metal bucket flowered June 14 and 17, respec¬ 
tively, and three individuals in an earthen jar flowered June 28, July 5, 
and July 9, respectively. Two controls in each of two earthen jars, ex¬ 
posed to the full day length, flowered August 19, 22, 24, and 27, respec¬ 
tively. The plants in the metal bucket were restored to the full daylight 
period June 17, and one of these flowered the second time on August 22. 
In a second series, transplanted May 15, three plants in each of two earthen 
jars exposed to 10 hours of light daily, beginning May 15, began flowering 
June 11 and 14, respectively. Under io-hour day, beginning June 13, 
four plants in an earthen jar flowered June 27, 28, 29, and 30, respec¬ 
tively, while under a 12-hour day one of three plants flowered on June 3c 
and the other two on July 2. Under a io-hour day, beginning June 23, 
two plants in a metal bucket flowered July 5. The controls of the second 
series, transplanted May 15 to an earthen jar and to a metal bucket, had 
not flowered September 20. 
Very young plants of jewelweed (Impatiens biflora Walt) were trans¬ 
ferred from tiie swamp to 3-gallon metal buckets April 12, five plants 
being set in each bucket. Under a io-hour day flowering began June 7. 
The controls began flowering July 6. 
Morning-glory (Ipomoea hederacea Jacq.) was planted June 8 and 
had germinated June 11. Under a io-hour day flower buds appeared 
July 2 and the first open blossoms were in evidence July 10 (PI. 2, B). 
