7 
18 : R. A. Emerson 
and about equally colored, the lower had its husks torn apart in the early 
forenoon so that the fresh inner husks were exposed at once to direct sun- 
light. In a few hours some red color began to show, and in a few days all 
the newly exposed husks were brilliantly colored, while the undisturbed 
upper ear remained only slightly colored. Similar results followed in 
repeated trials, and, in fact, failed only when the atmospheric conditions 
were such as to cause the newly exposed husks to wither during the first 
day. It is of interest to note also that similarly treated ears of dilute 
sun red plants, which rarely show any red color in the outer husks of young 
ears, failed to develop color when the husks were torn apart, even tho 
they remained fresh for some days. 
It is evident from all this, that, with respect to their relation to sunlight, 
there exists a series of color types varying more or less abruptly from 
dilute sun red, in which little or no sun red develops in even freshly exposed 
husks, thru weak sun red, in which color forms in only freshly exposed 
husks, and strong sun red, in which much color develops in all exposed 
parts of the husks but not in parts protected from light, to strong purple, 
in which, tho sunlight. may hasten color development, it is not essential 
to its formation. 
Tests of the influence on color development of light of different wave 
lengths have not been uniformly successful. Cramer photographie color 
screens were placed in partial contact with the uncolored inner husks of 
sun red plants, and the entrance of light otherwise than thru the screens 
was prevented by means of strips of black paper. These screens, by 
cutting out light of certain wave lengths, not only change the quality of 
light passing thru them but lessen the intensity of the light. While the 
results, therefore, can have little value, it may be of interest to physiolo- 
gists to note that considerable sun red formed under the orange and the 
bright red screens, and little or none under the green and the blue screens. 
MOISTURE IN RELATION TO COLOR 
It is well known that under field conditions maize does not grow well in 
wet soil. In such situations, not only are the plants small, with their 
‘ leaves pale green, but they often develop much red pigment. The writer 
has repeatedly observed that young plants, in flooded parts of fields where 
the soil had been covered with water for some days, were brilliantly red 
in all parts except the youngest leaves, while near-by plants on slightly 
