oo 
Experiment Station, and some of them showed a high degree of 
resistance, while others seemed to be somewhat susceptible to 
the Fulghum races of both loose and covered smuts. 
Studies on Cultures of the Oat Smuts 
Dr. L. Gordon Utter has continued his investigations on the 
cultural characteristics of the loose and covered smuts of oats 
grown in artificial media in flasks, and also his hybridization 
experiments between the two species. The extensive data ob- 
tained over a period of years have been prepared for publication 
and have been accepted by Columbia University as the basis of 
a thesis for the degree of Doctor of Philosophy. 
Single sporidial, single chlamydospore, and dilution cultures 
for eleven physiologic races of the loose smut and seven of the 
covered smut of oats have been studied. The size, color, and 
topography of the colonies were determined for 274 culture sets 
of the former and 307 of the latter. The individual cultures 
comprising the different triplicate sets were generally dissimilar. 
Approximately 60 per cent. of all the triplicate sets of both smuts 
showed dissimilarities. 
Successive culture generations failed to remain constant in 
characteristics, regardless of the method of isolation. The differ- 
ent single chlamydospore and dilution cultures of respective races 
were usually distinct from one another, while the single sporidial 
cultures could be roughly grouped into four classes. 
Similarities or dissimilarities between the races of both the 
loose and covered smuts were obtained by proper selection of 
cultures. It was concluded that the cultural characteristics did 
not offer a definite means for the identification of the races of 
loose or covered smuts studied. 
Hybridization between a race of loose smut and one of covered 
was accomplished. It was first demonstrated that cultures de- 
veloped from single sporidia of both smuts would not produce 
infection on susceptible varieties. When the proper mixture of 
two sporidial cultures was made, infection resulted, and the 
mixture of a certain culture of loose smut with one of the covered 
smut infected the variety Monarch, while Gothland remained 
resistant. The smut which developed had the symptomatic and 
