874 
Journal of Agricultural Research 
Vol. xxm, No. II 
Kulthi bean (Dolichos biftorus L.), planted May 29, showed open blos¬ 
soms July 21 under a 13-hour daylight exposure. Flowering was sparse 
and temporary, followed by rapid growth. On September 1 flower buds 
were again evident. The controls first showed open blossoms August 2 
and also were again showing flower buds on September 1. It appears 
that a day length somewhat less than 13 hours is required for quick and 
profuse flowering in this species. 
Peruvian flour com (Zea mays L.), supplied by the Office of Cereal 
Investigations, Bureau of Plant Industry, was planted May 29 in boxes 
10 inches square and 3 feet long. Under a daylight period of 13 hours 
the plants were shedding pollen July 26 and under natural daylight 
conditions on August 24. The respective heights of the plants were 
71 and 92 inches. 
A very late-maturing variety of com from Mexico, known as Tuxpan, 
planted May 22 in boxes as above, was shedding pollen August 6 as a 
result of receiving a io-hour light exposure and the average height was 
50 inches. Under a 13-hour light exposure pollen was falling August 14 
and the average height was 53 to 54 inches. The controls were shedding 
pollen September 13 and the height was 86 inches. It is worthy of note 
that at the middle of September the io-hour day plants, as well as the 
controls, were decidedly greener in color than those exposed to a 13- 
hour day. 
Tests were made with several sorghums (Holcus halapensis U.) from 
tropical Africa and India, seed of which was furnished by the Office of 
Forage Crop Investigations, of the Bureau of Plant Industry. Seed 
was sown June 17. The pots containing the plants were transferred to 
the greenhouse October 11 to prevent injury from cold weather. The 
results of the tests are summarized in Table I. 
In the former paper (7) the behavior of buckwheat (Fagopyrum vulgare 
Hill) in the greenhouse in winter was briefly described. Under the 
natural day length the plants completed the life cycle within a few weeks, 
attaining a relatively uniform height of only 24 inches. Increase in the 
duration of the daily light period to about 18 hours with electric light 
gave marked irregularity in height attained and degree of flowering. 
Some individuals attained a height of 9 feet or more, and all acted as 
typical ever-bloomers, with indeterminate growth characteristics. 
Repetition of the experiment in summer (seed planted May 18) gave 
similar results except that the height attained by the plants under the 
longer natural day length was increased to between 4 and feet. Out¬ 
door tests also were made in the summer under regulated day lengths 
of 5, 10, and 13 hours, with controls, all plantings being made June 8. 
Flowering began in the controls on July 6; in all other cases on June 30. 
Under a daylight period of 5 hours the plants were very small and soon 
died, after having produced a few seeds. With 10 hours of light daily 
the plants lived longer and attained a height of 24 inches. Under the 
13-hour exposure the plants were slightly taller and more seeds were 
produced. The controls averaged 36 inches in height and fruited freely. 
Thus, it is easily seen why buckwheat makes best growth in high 
latitudes. 
