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barley by the covered smut. During the past year, his expert- 
ments have dealt with the influence of soil temperature, moisture, 
and reaction on the infection of Hannchen barley. He was able 
to obtain infection over a wide range of temperatures from 5° C. 
to 30° C. High infections occurred at temperatures from 10° 
to 25° C. Soil moisture and soil reaction had, however, a very 
marked influence on the extent of infection. In general the high- 
est percentages of infection at each temperature were obtained 
in a soil moisture of-50 per cent. as compared with one of 40 per 
cent., provided the soil was acid in reaction. It is interesting to 
note that, in many of his experiments, he obtained high percent- 
ages of infection—g5.8, 97.8, and 97.9 per cent. These results 
have been embodied in a manuscript which has been accepted for 
publication in the March, 1924, number of the American Journal 
of Botany. The results also form the basis of a thesis, which has 
been accepted by Columbia University in partial fulfilment of the 
requirements for the degree of Doctor of Philosophy. 
The papers embodying the results obtained on the influence of 
environmental factors on the infection of sorghums by loose and 
covered smut and on the infection of oats by covered smut have 
been accepted for publication in the American Journal of Botany. 
The studies on the influence of environmental factors on in- 
fection of oats and sorghwms by smuts have been carried out co- 
operatively by Dr. Reed and Mr. Faris. 
Genetics and Plant Breeding 
Variation and Heredity in Peas Investigations of the laws of 
heredity and variation in plants have been carried on, as in pre- 
vious years, by Dr. Orland E. White, curator of plant breeding. 
The investigations have been confined to peas, particularly to 
studies on the number of linkage groups and the inheritance of 
height. As a whole, height in garden peas is a very complex 
character or set of characters, with many gradating differences 
between the numerous varieties. Height varies from six inches to 
eight feet, according to the variety. The evidence so far accumu- 
lated demonstrates that at least three distinct kinds of genetic 
factors are primarily concerned in determining the type of height 
